Dense cropping increases crop yield but intensifies resource competition,which reduces single plant yield and limits potential yield growth.Optimizing canopy spacing could enhance resource utilization,support crop mor...Dense cropping increases crop yield but intensifies resource competition,which reduces single plant yield and limits potential yield growth.Optimizing canopy spacing could enhance resource utilization,support crop morphological development and increase yield.Here,a three-year study was performed to verify the feasibility of adjusting row spacing to further enhance yield in densely planted soybeans.Of three row-spacing configurations(40-40,20-40,and 20-60 cm)and two planting densities(normal 180,000 plants ha 1 and high 270,000 plants ha 1).The differences in canopy structure,plant morphological development,photosynthetic capacity and their impact on yield were analyzed.Row spacing configurations have a significant effect on canopy transmittance(CT).The 20-60 cm row spacing configuration increased CT and creates a favorable canopy light environment,in which plant height is reduced,while branching is promoted.This approach reduces plant competition,optimizes the developments of leaf area per plant,specific leaf area,leaf area development rate,leaf area duration and photosynthetic physiological indices(F_(v)/F_(m),ETR,P_(n)).The significant increase of 11.9%-34.2%in canopy apparent photosynthesis(CAP)is attributed to the significant optimization of plant growth and photosynthetic physiology through CT,an important contributing factor to yield increases.The yield in the 20-60 cm treatment is 4.0%higher than in equidistant planting under normal planting density,but 5.9%under high density,primarily driven by CAP and pod number.These findings suggest that suitable row spacing configurations optimize the light environment for plants,promote source-sink transformation in soybeans,and further improve yield.In practice,a 20-60 cm row spacing configuration could be employed for high-density soybean planting to achieve a more substantial yield gain.展开更多
[Objective] This paper aimed to clarify the rice planting methods and its supporting technology to be developed in rice producing areas in China. [Method] Evolvement of rice planting methods in rice producing areas in...[Objective] This paper aimed to clarify the rice planting methods and its supporting technology to be developed in rice producing areas in China. [Method] Evolvement of rice planting methods in rice producing areas in China and in representative rice-growth countries abroad, its characteristics, adaptability and key issues were analyzed. [Result] The analysis of development of rice planting method in China and abroad indicated that rice planting method was adapted to rice-based cropping system and ecological environment, and its transition accompanied with social and economic development. With agricultural labor transfer from agriculture to other industries since 1990’s, rice seedling throwing was gradually applied and in recent decades, while direct seeding and machine transplanting were practiced. Now, hand transplanting is still the main rice planting method, adopted in 50% of national rice planting area; seedling throwing, direct seeding and machine transplanting are conducted in 25% , 12% and 13% of the national rice planting area. [Conclusion] Machine transplanting should be a leading rice planting method. Though area covered with machine direct seeding is still small up to now, it can be practiced in some rice growing area due to labor saving and low cost. Leading planting methods and its supporting key technologies are proposed in various rice producing areas in the future.展开更多
Three big field projects, independent irrigation and drainage facilities, and a blocking net, which are auxiliary projects of a green planting and breeding pattern composed of rice and red swamp crawfish （Procambarus...Three big field projects, independent irrigation and drainage facilities, and a blocking net, which are auxiliary projects of a green planting and breeding pattern composed of rice and red swamp crawfish （Procambarus clarkii）, spatial and temporal coupling technology of ＂planting rice in one season and breeding red swamp crawfish in three seasons＂, green fertilization technology, green prevention and control technology, control technology of water level, and throwing technology of bait in Lixiahe region of Jiangsu Province were introduced successively, which can provide technical support for the development of ecological planting and breeding patterns and realization of green production in paddy fields.展开更多
From rice paddies to poultry farms,an ambitious generation of Tanzanian youth is cultivating dreams of agricultural entrepreneurship A tender breeze sweeps across Zanzibar’s golden paddies at sunrise,carrying with it...From rice paddies to poultry farms,an ambitious generation of Tanzanian youth is cultivating dreams of agricultural entrepreneurship A tender breeze sweeps across Zanzibar’s golden paddies at sunrise,carrying with it the calm rhythm of a new day.展开更多
The rapeseed,as the second oilseed crop in China,is an important source of edible oil.Reasonable planting density can improve rapeseed production efficiency,and indirectly increase farmers'the production enthusias...The rapeseed,as the second oilseed crop in China,is an important source of edible oil.Reasonable planting density can improve rapeseed production efficiency,and indirectly increase farmers'the production enthusiasm of planting rapeseed.To gain a more comprehensive understanding of the study on effect of rapeseed yield to planting density,this article reviews the effect on planting density to yield in rapeseed,including the influences of the interaction between cultivation factors(variety,sowing period,and fertilization),the impact of plant density to lodging resistance and growth and development(biological characteristics,agronomic characteristics,yield traits,and quality tracts),and planting density and the relationship between light and planting density,are reviewed.The lodging resistance of oilseed rape and population yield of different rape varieties can be improved by choosing the appropriate sowing date and fertilizer application,and give full play to the rational utilization of resources and the maximization of benefits.The oilseed rape can make rational use of light and nutrients,which is conducive to dry matter accumulation and yield improvement,with proper planting density.This review will provide a theoretical basis and practical support for rapeseed planting,management,and mechanized production.展开更多
The exogenous plant growth regulator,diethyl aminoethyl hexanoate(DA-6),in combination with suitable varieties and planting densities,is important to increase yield in the maize-soybean strip intercropping system.To i...The exogenous plant growth regulator,diethyl aminoethyl hexanoate(DA-6),in combination with suitable varieties and planting densities,is important to increase yield in the maize-soybean strip intercropping system.To identify the role of DA-6 in mitigating high-density stress and increasing yield,we conducted a two-year field experiment examining changes in branching architecture and other yield traits of soybeans in maize-soybean strip intercropping systems.In the planting system,two soybean cultivars(ND:Nandou 25 and QH:Qihuang 34)were grown under three planting densities(D1:102,000 plants ha^(-1),D2:130,000 plants ha^(-1),D3:158,000 plants ha^(-1))with DA-6 treatments(DA0:water control;DA60:60 mg L^(-1);DA100:100 mg L^(-1)).Applying DA-6 at 60 mg L^(-1)at the fourth trifoliolate leaf stage increased soybean yield,with QH yield rising by 22.4% and 29.5% at D3 density,and ND yield by 29.5% and 30.0% at D2 density in 2022 and 2023,respectively,compared with D1 under DA0.DA-6improved photosynthesis in both varieties under D2 density,with DA60 increasing ND canopy photosynthetic rate by 15.1%-16.4% and QG by 9.1%-20.6% over two years.In ND,DA-6 enhanced branching,raising the leaf area index by 37%,branch number from 3.6 to 4.7 per plant,and total pod number by 19.7%.In QH,yield grains were mainly due to a 17% increase in the number of stem pods and a 6.5% improvement in hundred-grain weight.In the maize-soybean strip intercropping system,QH achieved a high yield by forming a high-density(D2 to D3)main stem pod,and ND by combining moderate density(D1 to D2)with DA-6-induced branching.展开更多
"Look at this!This one grows well and big.And its shape,so round and plump.How.adorable,"exclaimed Pema Chosphel as he carefully unearthed a palm-sized gastrodia from the damp soil.Overjoyed,he called his fa..."Look at this!This one grows well and big.And its shape,so round and plump.How.adorable,"exclaimed Pema Chosphel as he carefully unearthed a palm-sized gastrodia from the damp soil.Overjoyed,he called his father to share his excitement.展开更多
This study investigated the effects of planting duration(1,5,10 and 15 years)on soil properties,bacterial community diversity,and function in the rhizosphere of Zanthoxylum bungeanum.We employed Illumina highthroughpu...This study investigated the effects of planting duration(1,5,10 and 15 years)on soil properties,bacterial community diversity,and function in the rhizosphere of Zanthoxylum bungeanum.We employed Illumina highthroughput sequencing and PICRUSt2 functional prediction to analyze the structure and functional potential of rhizosphere soil bacterial communities.The Mantel test and redundancy analysis were used to identify physicochemical factors influencing bacterial community structure and function.The results indicated significant differences in rhizosphere soil physicochemical properties across planting years:the content of organic matter,alkaline hydrolyzable nitrogen in the soil,as well as the activity of invertase,urease,and alkaline phosphatase initially increased and then decreased,while available potassium,Olsen-phosphorus content,and peroxidase activity continued to increase.However,bacterial alpha diversity(Chao1 and Shannon indices)and the number of amplicon sequence variants increased continuously with planting duration.Principal coordinate analysis and Adonis tests revealed that the planting year significantly influenced the bacterial community structure(p<0.05).The phyla Proteobacteria,Actinobacteria,Acidobacteriota and Chloroflexi collectively constituted 56.7%to 71.2%of the relative abundance,representing the dominant taxa.PICRUSt2 predictions indicated key functional categories(cellular processes,metabolism,genetic information processing,and environmental information processing)each exceeding 10%relative abundance.BugBase analysis revealed a progressive increase in aerobic and oxidative stress-tolerant bacteria and a decrease in anaerobic and potentially pathogenic bacteria.Differential indicator species analysis identified Firmicutes,Planctomycetes,Methylomirabilota and Actinobacteriota as key discriminators for the 1-,5-,10-and 15-year stages,respectively.Organic matter,alkaline phosphatase,soil pH,and available phosphorus were the primary physicochemical drivers of bacterial communities.Notably,soil organic matter significantly influenced both the community structure(p<0.05)and predictedmetabolic functions(p<0.05).In conclusion,prolonged planting duration significantly enhanced rhizosphere microbial diversity and functional gene abundance in Z.bungeanumwhile driving the structural succession of bacterial communities dominated by Proteobacteria,Actinobacteria,Acidobacteriota,and Chloroflexi.This ecological shift,characterized by increased aerobic/oxidative-stress taxa and decreased anaerobic/pathogenic bacteria,was primarily regulated by soil organic matter,a key driver shaping both community structure and metabolic functions,ultimately improving soil microecological health.展开更多
The soybean and corn strip compound planting technology is a crucial measure for improving land use efficiency and ensuring food security.This paper deeply analyzed the principles,advantages,and key technical aspects ...The soybean and corn strip compound planting technology is a crucial measure for improving land use efficiency and ensuring food security.This paper deeply analyzed the principles,advantages,and key technical aspects of this technology,including variety selection,planting pattern,sowing management,and field management.It also illustrated its application effectiveness through practical cases and proposed corresponding solutions to existing challenges in its promotion.This study provides theoretical support and practical reference for the widespread adoption and efficient application of this technology.展开更多
In order to enhance the guidance for Yuluxiang pear cultivation in hilly and mountainous regions, this study provides a comprehensive introduction to various aspects, including the establishment of high-standard orcha...In order to enhance the guidance for Yuluxiang pear cultivation in hilly and mountainous regions, this study provides a comprehensive introduction to various aspects, including the establishment of high-standard orchards and the reinforcement of integrated management techniques, in order to offer a valuable reference for fruit farmers engaged in scientific planting practices.展开更多
In the new phase of sustainable development,agriculture is seeking sustainable management of the water-land-energy-economy-environment-food nexus.At present,there are few studies on optimizing crop planting structure ...In the new phase of sustainable development,agriculture is seeking sustainable management of the water-land-energy-economy-environment-food nexus.At present,there are few studies on optimizing crop planting structure and analyzing its spatial layout with consideration of natural and socio-economic factors.Herein,we proposed a framework for addressing this issue.In this framework,the NSGA-II algorithm was used to construct the multi-objective optimization model of crop planting structures with consideration of water and energy consumption,greenhouse gas(GHG)emissions,economic benefits,as well as food,land,and water security constraints,while the model for planting spatial layout optimization was established with consideration of crop suitability using the MaxEnt model and the improved Hungarian algorithm.This framework was further applied in the Black Soil Region of Northeast China(BSRNC)for analyzing optimized crop planting structures and spatial layouts of three main crops(rice,maize,and soybean)under various scenarios.This study showed that the sown area of rice in the BSRNC decreased by up to 40.73%and 35.30%in the environmental priority scenario and economic-environmental balance scenario,respectively,whereas that of soybean increased by up to 112.44%and 63.31%,respectively.In the economic priority scenario,the sown area of rice increased by up to 93.98%.Expanding the sown area of soybean was effective in reducing GHG emissions.On the contrary,rice production led to greater environmental costs though it provided higher economic returns.Among the three crops,maize exhibited an advantage in balancing environmental and economic benefits.Hegang-Jixi area in the northeast of the BSRNC was identified as the key area with the most intense crop planting transfer among different scenarios.Overall,this framework provides a new methodology for optimizing crop planting structures and spatial layouts with con-sideration of the nexus of various factors.Moreover,the case study demonstrates the applicability and expansion potential of the framework in the fields of sustainable agricultural development and food security assurance.展开更多
Late sowing is a critical factor that hinders achieving high-yield,good-quality wheat under rice-wheat rotation.Understanding the physiological basis and regulatory pathways that lead to high yield and sound quality l...Late sowing is a critical factor that hinders achieving high-yield,good-quality wheat under rice-wheat rotation.Understanding the physiological basis and regulatory pathways that lead to high yield and sound quality late-sown wheat is crucial for developing effective cultivation strategies.A 2-year field experiment was conducted to investigate the effects of sowing date,nitrogen(N)application rate,and planting density on wheat yield,grain quality,population characteristics,and the underlying physiological factors.The results revealed significant interactions among the sowing date,planting density,and N application in regulating both yield and quality.Late sowing reduced grain yield primarily by reducing the number of spikes and kernels.However,the latter was improved by increasing N application and the planting density,thus mitigating the yield losses caused by late sowing.Moreover,the grain protein content(GPC)and wet gluten content(WGC)increased with delayed sowing dates and higher N rates but decreased with increased planting densities.For wheat yields over 9,000 or 7,500 kg ha^(-1),the latest sowing date should not be later than Nov.4 or 15,respectively.In addition,specific criteria should be met,including a maximum of 1.5 and 1.0 million stems and tillers ha^(-1),a maximum leaf area index of 6.7 and 5.5,and a dry matter accumulation(DMA)at anthesis of 14,000 and 12,000 kg ha^(-1),respectively.For high-yield,good-quality late-sown wheat,the optimal combination is a 25%increase in the N rate(300 kg N ha^(-1))and a planting density of 2.25 million(N300D225)or 3.75 million(N300D375)plants ha^(-1)for 10-or 20-day delays in sowing,respectively.These combinations result in a higher leaf net photosynthetic rate,higher activities of leaf nitrate reductase,glutamine synthetase,grain glutamic pyruvic transaminase,and a lower sugar-N ratio during post-anthesis.展开更多
Highlights Hybrid-Maize Model’s performance under dense planting conditions were investigated across China.Hybrid-Maize Model performed well in the simulation of maize grain yield and aboveground biomass under dense ...Highlights Hybrid-Maize Model’s performance under dense planting conditions were investigated across China.Hybrid-Maize Model performed well in the simulation of maize grain yield and aboveground biomass under dense planting conditions.Future model modifications and corrections should focus on the leaf area index dynamics and harvest index.展开更多
[Objective] The aim was to resolve the issue of sparsely planting （37 500-40 500 plants/hm2） of sweet potato in hilly areas. [Method] The starch-oriented Jishu No.21 and raw-eating oriented Jishu No.22 were studied ...[Objective] The aim was to resolve the issue of sparsely planting （37 500-40 500 plants/hm2） of sweet potato in hilly areas. [Method] The starch-oriented Jishu No.21 and raw-eating oriented Jishu No.22 were studied to explore effects of planting density on yield and sink and source characteristics of sweet potato. [IRe- suit] Leaf area index of Jishu No.21 and Jishu No.22 were increasing upon planting density. Leaf area index of the same planting density showed a single-peak curve. Specifically, leaf area index grew fast during the 40th-80th d after planting, and reached the peak on the 80th d after planting, followed by decreasing. What＇s more, ventilation and sunshine transmission both declined upon planting density, as well as the number of leaf, the number of branch, the length of vine, dry and fresh weights of stem and leaf. When planting density exceeded 75 000 plants/hm2, the yield of sweet potato dropped dramatically. Besides, the optimal planting density tended to be volatile upon cultivars. For example, the range of 45 000-60 000 plants/hm2 is the optimal planting density of Jishu No.21 and the range of 60 000-75 000 plants/hm2 is the optimal planting density of Jishu No.22. [Conclusion] It can be concluded that rational planting densities would well coordinate sweet potato growth of ground parts and underground parts to get a high yield by providing a rational group structure. Considering the optimal planting density differs upon cultivars, it is necessary to take genotype, environment, soil fertility and planting density into consideration in determining planting density.展开更多
[Objective] This study aimed to explore agronomical measures to reduce the mechanical harvesting loss of rapeseed. [Method] Two rapeseed cultivars, Ningza 19 and Ningza 21, with certain pod-cracking resistance, were e...[Objective] This study aimed to explore agronomical measures to reduce the mechanical harvesting loss of rapeseed. [Method] Two rapeseed cultivars, Ningza 19 and Ningza 21, with certain pod-cracking resistance, were employed in field experiments. The two-factor split plot design and randomized complete block design were adopted. The rapeseed seeds were directly sowed with four different seeding rates （1.50, 2.25, 3.00 and 3.75 kg/hm2）. A total of four treatments were designed （112 500, 225 000, 337 500 and 450 000 plants/hm2）. After ripe, the rapeseed was harvested with harvester. Then the yield and harvesting loss rate were determined. [Result] When the planting density ranged from 112 500 to 450 000 plants/hm2, the mechanical harvesting loss rate was decreased with the increase of planting density （Ningza 19, 7.54%-4.01%; Ningza 21, 7.19%-3.81%）. The total loss rates were all below 5% for the high plant densities, 337 500 and 450 000 plants/hm2. High planting density had certain regulating effects on plant type of rapeseed, including reducing plant height, reducing biomass per plant, reducing branch pod numbers per plant, weakening crossing and tangling among stems and improving ripening uniformity of pods. All the changes above were all conducive to reducing mechanical harvesting loss. In addition, the test results showed after the pods grew to maturity, especially when pods were yellow and the moisture content in grains was reduced to 11%, the mechanical harvesting loss only accounted for about 1% of the total field loss. In addition, the shattering loss, caused by mild col- lision, represented more than 90%, and the cleaning loss, occurred during the threshing and cleaning process, represented 4%-8% of the total field loss. The un- harvesting loss accounted for approximately 1% of the total loss. The shattering loss is closely related to cultivar characteristics, planting density, production level and other agronomic factors. The cleaning loss is determined by properties of harvesting machines. The unharvesting loss depends on mechanical properties ad skills of workers or farmers who drive harvesting machines. [Conclusion] In order to reduce mechanical harvesting loss, the rapeseed production should be improved from the perspectives of agricultural machinery and agronomic measures.展开更多
[Objective] The experiment was conducted to explore the suitable planting density and nitrogen amount for summer maize in Sichuan Basin with the objective to provide technical reservation and scientific basis for high...[Objective] The experiment was conducted to explore the suitable planting density and nitrogen amount for summer maize in Sichuan Basin with the objective to provide technical reservation and scientific basis for high-yielding cultivation technique.[Method] A widely planted maize cultivar ＇Chengdan 30＇ was used as experimental material to study the effects of planting density and nitrogen amount on the stalk agronomic traits,stalk lodging-resistance mechanical characters,stalk breaking percentage and yield of maize.Experiment was arranged in a two-factor split plot design with three replicates.The planting density was the main factor with three density gradients（4.5×10^4,6.0×10^4 and 7.5×10^4 plants/hm^2） and the nitrogen amount was the second factor with two different levels of nitrogen content（300 and 375 kg/hm^2）.[Result] The stalk lodging-resistance and yield were affected by planting density significantly.The increase of planting density would result in an increase of internode length and decrease of internode diameter,dry matter weight of per unit stalk length,rind penetration strength and breaking resistance of 3rd and 4th basal internodes.When planting density increased from 6.0×10^4 plants/hm2 to 7.5×10^4 plants/hm^2,the stalk breaking percentage in the whole growing season increased by 17.17%,and the yield reduced by 17.58%.The interaction between planting density and nitrogen amount affected the stalk breaking percentage in the whole growing season and yield significantly.The treatment with planting density of 6.0×104 plants/hm^2 and nitrogen amount of 375 kg/hm^2 of pure N was an optimal combination,which may not only control the stalk breaking percentage of whole growing stage effectively,but also could obtain an optimum grain yield.[Conclusion] In Sichuan Basin,the appropriate planting density and nitrogen amount for summer maize were 6.0×10^4 plants/hm^2 and 375 kg/hm^2.展开更多
[Objective] The aim was to make full use of light-heat resources to expand the potato planting area on the base of ensuring the production of main grain crops and the limited arable land. [Methods] Through catch crops...[Objective] The aim was to make full use of light-heat resources to expand the potato planting area on the base of ensuring the production of main grain crops and the limited arable land. [Methods] Through catch crops, multiple cropping and intercropping, new multiple planting patterns of potato with efficiency are constructed, for the purpose of increasing yield and benefit of potato. [Result] In irrigated plain and hill area, three new planting patterns such as autumn potato/rope-rice,winter potato-rice-autumn potato, and autumn（winter） potato-rice were constructed.In dry land of plain and hill area, three new planting patterns such as spring（winter）potato/maize/sweet potato, spring（winter） potato/maize-autumn potato, and wheat ＋ winter potato/maize/sweet potato were constructed. In plateau mountainous area, spring potato/maize was constructed. [Conclusion] With use of new planting patterns, the cropping index of new patterns was 200%-300%, while the accumulated temperature utilization was 68.9%-93.4%, light energy utilization was 0.98%-1.59% and straw utilization was 50%-100%. To compared with traditional planting patterns, the yield increased by 2.6%-93%, and benefit increased by 15.8%-284.3%. Furthermore,multiple planting patterns of potato have become main planting patterns in increasing yield and income in Sichuan.展开更多
The effects ol different genotypes and planting densities on main agronomic traits, storage root traits and yield were studied with 6 high-quality sweetpotato varieties as study objects by 2-factor completely random d...The effects ol different genotypes and planting densities on main agronomic traits, storage root traits and yield were studied with 6 high-quality sweetpotato varieties as study objects by 2-factor completely random design. The results showed that there were significant differences in stem diameter, length of the longest vine and top/root （T/R） between different genotypes, T/R differed significantly under dif- ferent planting densities, and number of basal branches decreased with planting density increasing. Genotype and genotype x density showed significant or very sig- nificant effects on fresh root yield per plant, dry matter content and fresh root yield per hectare, fresh root yield per plant gradually decreased with planting density in- creasing, while fresh root yield per hectare increased with planting density increas- ing. Numbers of storage roots in different sizes of the 6 sweetpotato cultivars all exhibited an order of number of large-sized storage roots〈number of medium-sized storage roots〈small-sized storage root; and there were very significant differences in ratio of large-sized storage roots between different genotypes. The number of large- sized storage roots, ratio of large-sized storage roots and number of commercial storage roots deceased with planting density increasing, while there were no signifi- cant differences in number of medium-sized storage roots, number of small-sized storage roots, ratio of medium-sized storage roots and ratio of small-sized storage roots between different densities. Correlation analysis showed that there was signifi- cant positive correlation between number of basal branches and fresh root yield per plant; dry matter content in storage roots was in significant positive correlation with stem diameter, and in significant negative correlation with length of the longest vine; fresh root yield per hectare was in significant positive correlation with fresh root yield per plant, and in very significant negative correlation with dry matter content; and ratio of large-sized storage roots was in very significant positive correlation with number of large-sized storage root and fresh root yield per plant, and in very sig- nificant negative correlation with ratio of medium-sized storage roots and ratio of small-sized storage roots. This experiment showed that under the planting density of 7.5×104 plants/hm2, the 6 sweetpotato cultivars all reached the highest numbers of commercial storage roots and fresh root yields per hectare.展开更多
[ Objective] This study was to understend the optimized combination of planting density, duration of disclosing plastic film and nitrogen fertilization under no-tillage cultivation. [ Method] Quadratic polynomial regr...[ Objective] This study was to understend the optimized combination of planting density, duration of disclosing plastic film and nitrogen fertilization under no-tillage cultivation. [ Method] Quadratic polynomial regression and saturated D-optimal design were employed to investigate the effects of planting density, duration of disclosing plastic film and nitrogen fertilization on the dynamics growth of rapeseed under no-tillage cultivation.[ Result] Within the experimental range, the growth dynamics of no-tillage cultivated rapeseed assumed a rise-fall tend. For the effects to the growth dynamics of no-tillage cultivated rapeseed, nitrogen application amount was higher than planting density and duration of disclosing plastic film. The interaction effect between planting density and duration of disclosing plastic film was higher than that between nitrogen application amount and planting density, and between nitrogen application amount and duration of disclosing plastic film. [ Conclusion] The optimized combination of these factors for dynamic growth of rapeseed under no-tillage cultivation was determined to be： planting density of per hectare 154 925 individuals, duration of disclosing plastic film of 110 d, nitrogen application amount of 315 kg/hm^2.展开更多
Elite maize hybrid Guidan0810 was selected as material, and the effects of fertilizing level and planting densities on yield and nitrogen utilization were dis- cussed in the study. In field experiments as per double-c...Elite maize hybrid Guidan0810 was selected as material, and the effects of fertilizing level and planting densities on yield and nitrogen utilization were dis- cussed in the study. In field experiments as per double-cropping system, 4 main plots （fertilization levels） and 6 subplots （planting densities） were set in a split plot design. The results suggested that yield had close relationship with fertilization levels and planting densities. Different fertilization levels and planting densities significantly affected yield. With the increase of nitrogen fertilization, nitrogen use efficiency, nitrogen agronomic efficiency and nitrogen physiological efficiency declined. Under the same fertilization level, nitrogen use efficiency, nitrogen agronomic efficiency and nitrogen physiological efficiency grew a little with the increase of planting density, so nitrogen efficiency could be improved by regulating planting density. The results also showed that A2 （including N 225.0 kg/hm2, P205 75.0 kg/hm^2, K20 187.5 kg/hm^2） matching to B3 （52 500 plants/hm^2） or B4（60 000 plants/hm^2） was a better design, which could obtain a higher yield in the range of 7 913.2-8 207.8 kg/hm2, respectively.展开更多
基金supported by the Biological Breeding-National Science and Technology Major Project(2023ZD0403305)National Natural Science Foundation of China(32101845)+1 种基金the National Key Research and Development Program of China(2023YFE0105000)the China Agriculture Research System(CARS-04).
文摘Dense cropping increases crop yield but intensifies resource competition,which reduces single plant yield and limits potential yield growth.Optimizing canopy spacing could enhance resource utilization,support crop morphological development and increase yield.Here,a three-year study was performed to verify the feasibility of adjusting row spacing to further enhance yield in densely planted soybeans.Of three row-spacing configurations(40-40,20-40,and 20-60 cm)and two planting densities(normal 180,000 plants ha 1 and high 270,000 plants ha 1).The differences in canopy structure,plant morphological development,photosynthetic capacity and their impact on yield were analyzed.Row spacing configurations have a significant effect on canopy transmittance(CT).The 20-60 cm row spacing configuration increased CT and creates a favorable canopy light environment,in which plant height is reduced,while branching is promoted.This approach reduces plant competition,optimizes the developments of leaf area per plant,specific leaf area,leaf area development rate,leaf area duration and photosynthetic physiological indices(F_(v)/F_(m),ETR,P_(n)).The significant increase of 11.9%-34.2%in canopy apparent photosynthesis(CAP)is attributed to the significant optimization of plant growth and photosynthetic physiology through CT,an important contributing factor to yield increases.The yield in the 20-60 cm treatment is 4.0%higher than in equidistant planting under normal planting density,but 5.9%under high density,primarily driven by CAP and pod number.These findings suggest that suitable row spacing configurations optimize the light environment for plants,promote source-sink transformation in soybeans,and further improve yield.In practice,a 20-60 cm row spacing configuration could be employed for high-density soybean planting to achieve a more substantial yield gain.
基金Supported by the Special Funds for Agro-scientific Research in the Public Interest (201003016 201203029)Special Fund for the Industrial Technology System Construction of Modern Agriculture (CARS-01-04A)~~
文摘[Objective] This paper aimed to clarify the rice planting methods and its supporting technology to be developed in rice producing areas in China. [Method] Evolvement of rice planting methods in rice producing areas in China and in representative rice-growth countries abroad, its characteristics, adaptability and key issues were analyzed. [Result] The analysis of development of rice planting method in China and abroad indicated that rice planting method was adapted to rice-based cropping system and ecological environment, and its transition accompanied with social and economic development. With agricultural labor transfer from agriculture to other industries since 1990’s, rice seedling throwing was gradually applied and in recent decades, while direct seeding and machine transplanting were practiced. Now, hand transplanting is still the main rice planting method, adopted in 50% of national rice planting area; seedling throwing, direct seeding and machine transplanting are conducted in 25% , 12% and 13% of the national rice planting area. [Conclusion] Machine transplanting should be a leading rice planting method. Though area covered with machine direct seeding is still small up to now, it can be practiced in some rice growing area due to labor saving and low cost. Leading planting methods and its supporting key technologies are proposed in various rice producing areas in the future.
基金Supported by Gaoyou Demonstration and Extension Base of Modern Agricultural(Rice and Wheat)Industrial Technology System in Jiangsu(SXGC[2017]168)Funds for Independent Innovation of Jiangsu Province(CX17(2007),KF(17)1022)+1 种基金Key Research and Development Plan Project(BE2017332)Agricultural Standardization Pilot Project of Jiangsu Province([2017]46)~~
文摘Three big field projects, independent irrigation and drainage facilities, and a blocking net, which are auxiliary projects of a green planting and breeding pattern composed of rice and red swamp crawfish （Procambarus clarkii）, spatial and temporal coupling technology of ＂planting rice in one season and breeding red swamp crawfish in three seasons＂, green fertilization technology, green prevention and control technology, control technology of water level, and throwing technology of bait in Lixiahe region of Jiangsu Province were introduced successively, which can provide technical support for the development of ecological planting and breeding patterns and realization of green production in paddy fields.
文摘From rice paddies to poultry farms,an ambitious generation of Tanzanian youth is cultivating dreams of agricultural entrepreneurship A tender breeze sweeps across Zanzibar’s golden paddies at sunrise,carrying with it the calm rhythm of a new day.
基金Supported by Analysis on Oil Synthesis Process of NAPA Rapeseed by cDNA-AFLP and Proteomics(2018J01713).
文摘The rapeseed,as the second oilseed crop in China,is an important source of edible oil.Reasonable planting density can improve rapeseed production efficiency,and indirectly increase farmers'the production enthusiasm of planting rapeseed.To gain a more comprehensive understanding of the study on effect of rapeseed yield to planting density,this article reviews the effect on planting density to yield in rapeseed,including the influences of the interaction between cultivation factors(variety,sowing period,and fertilization),the impact of plant density to lodging resistance and growth and development(biological characteristics,agronomic characteristics,yield traits,and quality tracts),and planting density and the relationship between light and planting density,are reviewed.The lodging resistance of oilseed rape and population yield of different rape varieties can be improved by choosing the appropriate sowing date and fertilizer application,and give full play to the rational utilization of resources and the maximization of benefits.The oilseed rape can make rational use of light and nutrients,which is conducive to dry matter accumulation and yield improvement,with proper planting density.This review will provide a theoretical basis and practical support for rapeseed planting,management,and mechanized production.
基金supported by the earmarked fund for the China Agriculture Research System(CARS-04-PS21)National Key Research and Development Program of China(2024YFD2300401)a recipient of a joint Ph.D.scholarship supported by the China Scholarship Council(CSC)(202306910067)。
文摘The exogenous plant growth regulator,diethyl aminoethyl hexanoate(DA-6),in combination with suitable varieties and planting densities,is important to increase yield in the maize-soybean strip intercropping system.To identify the role of DA-6 in mitigating high-density stress and increasing yield,we conducted a two-year field experiment examining changes in branching architecture and other yield traits of soybeans in maize-soybean strip intercropping systems.In the planting system,two soybean cultivars(ND:Nandou 25 and QH:Qihuang 34)were grown under three planting densities(D1:102,000 plants ha^(-1),D2:130,000 plants ha^(-1),D3:158,000 plants ha^(-1))with DA-6 treatments(DA0:water control;DA60:60 mg L^(-1);DA100:100 mg L^(-1)).Applying DA-6 at 60 mg L^(-1)at the fourth trifoliolate leaf stage increased soybean yield,with QH yield rising by 22.4% and 29.5% at D3 density,and ND yield by 29.5% and 30.0% at D2 density in 2022 and 2023,respectively,compared with D1 under DA0.DA-6improved photosynthesis in both varieties under D2 density,with DA60 increasing ND canopy photosynthetic rate by 15.1%-16.4% and QG by 9.1%-20.6% over two years.In ND,DA-6 enhanced branching,raising the leaf area index by 37%,branch number from 3.6 to 4.7 per plant,and total pod number by 19.7%.In QH,yield grains were mainly due to a 17% increase in the number of stem pods and a 6.5% improvement in hundred-grain weight.In the maize-soybean strip intercropping system,QH achieved a high yield by forming a high-density(D2 to D3)main stem pod,and ND by combining moderate density(D1 to D2)with DA-6-induced branching.
文摘"Look at this!This one grows well and big.And its shape,so round and plump.How.adorable,"exclaimed Pema Chosphel as he carefully unearthed a palm-sized gastrodia from the damp soil.Overjoyed,he called his father to share his excitement.
基金supported by Forestry and Grassland Science and Technology Innovation Project(LCKJCX2022001)from Forestry and Grassland Bureau of Gansu Province’s.
文摘This study investigated the effects of planting duration(1,5,10 and 15 years)on soil properties,bacterial community diversity,and function in the rhizosphere of Zanthoxylum bungeanum.We employed Illumina highthroughput sequencing and PICRUSt2 functional prediction to analyze the structure and functional potential of rhizosphere soil bacterial communities.The Mantel test and redundancy analysis were used to identify physicochemical factors influencing bacterial community structure and function.The results indicated significant differences in rhizosphere soil physicochemical properties across planting years:the content of organic matter,alkaline hydrolyzable nitrogen in the soil,as well as the activity of invertase,urease,and alkaline phosphatase initially increased and then decreased,while available potassium,Olsen-phosphorus content,and peroxidase activity continued to increase.However,bacterial alpha diversity(Chao1 and Shannon indices)and the number of amplicon sequence variants increased continuously with planting duration.Principal coordinate analysis and Adonis tests revealed that the planting year significantly influenced the bacterial community structure(p<0.05).The phyla Proteobacteria,Actinobacteria,Acidobacteriota and Chloroflexi collectively constituted 56.7%to 71.2%of the relative abundance,representing the dominant taxa.PICRUSt2 predictions indicated key functional categories(cellular processes,metabolism,genetic information processing,and environmental information processing)each exceeding 10%relative abundance.BugBase analysis revealed a progressive increase in aerobic and oxidative stress-tolerant bacteria and a decrease in anaerobic and potentially pathogenic bacteria.Differential indicator species analysis identified Firmicutes,Planctomycetes,Methylomirabilota and Actinobacteriota as key discriminators for the 1-,5-,10-and 15-year stages,respectively.Organic matter,alkaline phosphatase,soil pH,and available phosphorus were the primary physicochemical drivers of bacterial communities.Notably,soil organic matter significantly influenced both the community structure(p<0.05)and predictedmetabolic functions(p<0.05).In conclusion,prolonged planting duration significantly enhanced rhizosphere microbial diversity and functional gene abundance in Z.bungeanumwhile driving the structural succession of bacterial communities dominated by Proteobacteria,Actinobacteria,Acidobacteriota,and Chloroflexi.This ecological shift,characterized by increased aerobic/oxidative-stress taxa and decreased anaerobic/pathogenic bacteria,was primarily regulated by soil organic matter,a key driver shaping both community structure and metabolic functions,ultimately improving soil microecological health.
基金Supported by Special Project for the Construction of the National Modern Agricultural Industry Technology System(CARS-04-CES16).
文摘The soybean and corn strip compound planting technology is a crucial measure for improving land use efficiency and ensuring food security.This paper deeply analyzed the principles,advantages,and key technical aspects of this technology,including variety selection,planting pattern,sowing management,and field management.It also illustrated its application effectiveness through practical cases and proposed corresponding solutions to existing challenges in its promotion.This study provides theoretical support and practical reference for the widespread adoption and efficient application of this technology.
文摘In order to enhance the guidance for Yuluxiang pear cultivation in hilly and mountainous regions, this study provides a comprehensive introduction to various aspects, including the establishment of high-standard orchards and the reinforcement of integrated management techniques, in order to offer a valuable reference for fruit farmers engaged in scientific planting practices.
基金funded by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(Grant No.72221002)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA28060200)National Natural Science Foundation of Youth Project(Grant No.72303087).
文摘In the new phase of sustainable development,agriculture is seeking sustainable management of the water-land-energy-economy-environment-food nexus.At present,there are few studies on optimizing crop planting structure and analyzing its spatial layout with consideration of natural and socio-economic factors.Herein,we proposed a framework for addressing this issue.In this framework,the NSGA-II algorithm was used to construct the multi-objective optimization model of crop planting structures with consideration of water and energy consumption,greenhouse gas(GHG)emissions,economic benefits,as well as food,land,and water security constraints,while the model for planting spatial layout optimization was established with consideration of crop suitability using the MaxEnt model and the improved Hungarian algorithm.This framework was further applied in the Black Soil Region of Northeast China(BSRNC)for analyzing optimized crop planting structures and spatial layouts of three main crops(rice,maize,and soybean)under various scenarios.This study showed that the sown area of rice in the BSRNC decreased by up to 40.73%and 35.30%in the environmental priority scenario and economic-environmental balance scenario,respectively,whereas that of soybean increased by up to 112.44%and 63.31%,respectively.In the economic priority scenario,the sown area of rice increased by up to 93.98%.Expanding the sown area of soybean was effective in reducing GHG emissions.On the contrary,rice production led to greater environmental costs though it provided higher economic returns.Among the three crops,maize exhibited an advantage in balancing environmental and economic benefits.Hegang-Jixi area in the northeast of the BSRNC was identified as the key area with the most intense crop planting transfer among different scenarios.Overall,this framework provides a new methodology for optimizing crop planting structures and spatial layouts with con-sideration of the nexus of various factors.Moreover,the case study demonstrates the applicability and expansion potential of the framework in the fields of sustainable agricultural development and food security assurance.
基金supported by the National Natural Science Foundation of China(32272215)the Key R&D Program of Jiangsu Province,China(BE2021361-1)the Collaborative Innovation Center for Modern Crop Production by Province and Ministry(CIC-MCP),Nanjing Agricultural University,China。
文摘Late sowing is a critical factor that hinders achieving high-yield,good-quality wheat under rice-wheat rotation.Understanding the physiological basis and regulatory pathways that lead to high yield and sound quality late-sown wheat is crucial for developing effective cultivation strategies.A 2-year field experiment was conducted to investigate the effects of sowing date,nitrogen(N)application rate,and planting density on wheat yield,grain quality,population characteristics,and the underlying physiological factors.The results revealed significant interactions among the sowing date,planting density,and N application in regulating both yield and quality.Late sowing reduced grain yield primarily by reducing the number of spikes and kernels.However,the latter was improved by increasing N application and the planting density,thus mitigating the yield losses caused by late sowing.Moreover,the grain protein content(GPC)and wet gluten content(WGC)increased with delayed sowing dates and higher N rates but decreased with increased planting densities.For wheat yields over 9,000 or 7,500 kg ha^(-1),the latest sowing date should not be later than Nov.4 or 15,respectively.In addition,specific criteria should be met,including a maximum of 1.5 and 1.0 million stems and tillers ha^(-1),a maximum leaf area index of 6.7 and 5.5,and a dry matter accumulation(DMA)at anthesis of 14,000 and 12,000 kg ha^(-1),respectively.For high-yield,good-quality late-sown wheat,the optimal combination is a 25%increase in the N rate(300 kg N ha^(-1))and a planting density of 2.25 million(N300D225)or 3.75 million(N300D375)plants ha^(-1)for 10-or 20-day delays in sowing,respectively.These combinations result in a higher leaf net photosynthetic rate,higher activities of leaf nitrate reductase,glutamine synthetase,grain glutamic pyruvic transaminase,and a lower sugar-N ratio during post-anthesis.
基金supported by the National Key Research and Development Program of China(2023YFD1900603)the National Natural Science Foundation of China(32172118)the China Agriculture Research System of MOF and MARA(CARS-02)。
文摘Highlights Hybrid-Maize Model’s performance under dense planting conditions were investigated across China.Hybrid-Maize Model performed well in the simulation of maize grain yield and aboveground biomass under dense planting conditions.Future model modifications and corrections should focus on the leaf area index dynamics and harvest index.
基金Supported by Special Fund for China Agriculture Research SystemKey Application Technology and Innovation Subject of Shandong Province in 2013~~
文摘[Objective] The aim was to resolve the issue of sparsely planting （37 500-40 500 plants/hm2） of sweet potato in hilly areas. [Method] The starch-oriented Jishu No.21 and raw-eating oriented Jishu No.22 were studied to explore effects of planting density on yield and sink and source characteristics of sweet potato. [IRe- suit] Leaf area index of Jishu No.21 and Jishu No.22 were increasing upon planting density. Leaf area index of the same planting density showed a single-peak curve. Specifically, leaf area index grew fast during the 40th-80th d after planting, and reached the peak on the 80th d after planting, followed by decreasing. What＇s more, ventilation and sunshine transmission both declined upon planting density, as well as the number of leaf, the number of branch, the length of vine, dry and fresh weights of stem and leaf. When planting density exceeded 75 000 plants/hm2, the yield of sweet potato dropped dramatically. Besides, the optimal planting density tended to be volatile upon cultivars. For example, the range of 45 000-60 000 plants/hm2 is the optimal planting density of Jishu No.21 and the range of 60 000-75 000 plants/hm2 is the optimal planting density of Jishu No.22. [Conclusion] It can be concluded that rational planting densities would well coordinate sweet potato growth of ground parts and underground parts to get a high yield by providing a rational group structure. Considering the optimal planting density differs upon cultivars, it is necessary to take genotype, environment, soil fertility and planting density into consideration in determining planting density.
基金Supported by National High Technology Research and Development Program of China(863 Program)(2011AA10A10403)National Key Technology Research and Development Program(2010BAD01B06)+1 种基金Jiangsu Province Science and Technology Support Program(BE2012327)Jiangsu Agricultural Science and Technology Innovation Fund(CX(14)2003)~~
文摘[Objective] This study aimed to explore agronomical measures to reduce the mechanical harvesting loss of rapeseed. [Method] Two rapeseed cultivars, Ningza 19 and Ningza 21, with certain pod-cracking resistance, were employed in field experiments. The two-factor split plot design and randomized complete block design were adopted. The rapeseed seeds were directly sowed with four different seeding rates （1.50, 2.25, 3.00 and 3.75 kg/hm2）. A total of four treatments were designed （112 500, 225 000, 337 500 and 450 000 plants/hm2）. After ripe, the rapeseed was harvested with harvester. Then the yield and harvesting loss rate were determined. [Result] When the planting density ranged from 112 500 to 450 000 plants/hm2, the mechanical harvesting loss rate was decreased with the increase of planting density （Ningza 19, 7.54%-4.01%; Ningza 21, 7.19%-3.81%）. The total loss rates were all below 5% for the high plant densities, 337 500 and 450 000 plants/hm2. High planting density had certain regulating effects on plant type of rapeseed, including reducing plant height, reducing biomass per plant, reducing branch pod numbers per plant, weakening crossing and tangling among stems and improving ripening uniformity of pods. All the changes above were all conducive to reducing mechanical harvesting loss. In addition, the test results showed after the pods grew to maturity, especially when pods were yellow and the moisture content in grains was reduced to 11%, the mechanical harvesting loss only accounted for about 1% of the total field loss. In addition, the shattering loss, caused by mild col- lision, represented more than 90%, and the cleaning loss, occurred during the threshing and cleaning process, represented 4%-8% of the total field loss. The un- harvesting loss accounted for approximately 1% of the total loss. The shattering loss is closely related to cultivar characteristics, planting density, production level and other agronomic factors. The cleaning loss is determined by properties of harvesting machines. The unharvesting loss depends on mechanical properties ad skills of workers or farmers who drive harvesting machines. [Conclusion] In order to reduce mechanical harvesting loss, the rapeseed production should be improved from the perspectives of agricultural machinery and agronomic measures.
基金Supported by the Special Fund for Agricultural and Rural Research in the Public Interest of Sichuan Province(12ZC1930)~~
文摘[Objective] The experiment was conducted to explore the suitable planting density and nitrogen amount for summer maize in Sichuan Basin with the objective to provide technical reservation and scientific basis for high-yielding cultivation technique.[Method] A widely planted maize cultivar ＇Chengdan 30＇ was used as experimental material to study the effects of planting density and nitrogen amount on the stalk agronomic traits,stalk lodging-resistance mechanical characters,stalk breaking percentage and yield of maize.Experiment was arranged in a two-factor split plot design with three replicates.The planting density was the main factor with three density gradients（4.5×10^4,6.0×10^4 and 7.5×10^4 plants/hm^2） and the nitrogen amount was the second factor with two different levels of nitrogen content（300 and 375 kg/hm^2）.[Result] The stalk lodging-resistance and yield were affected by planting density significantly.The increase of planting density would result in an increase of internode length and decrease of internode diameter,dry matter weight of per unit stalk length,rind penetration strength and breaking resistance of 3rd and 4th basal internodes.When planting density increased from 6.0×10^4 plants/hm2 to 7.5×10^4 plants/hm^2,the stalk breaking percentage in the whole growing season increased by 17.17%,and the yield reduced by 17.58%.The interaction between planting density and nitrogen amount affected the stalk breaking percentage in the whole growing season and yield significantly.The treatment with planting density of 6.0×104 plants/hm^2 and nitrogen amount of 375 kg/hm^2 of pure N was an optimal combination,which may not only control the stalk breaking percentage of whole growing stage effectively,but also could obtain an optimum grain yield.[Conclusion] In Sichuan Basin,the appropriate planting density and nitrogen amount for summer maize were 6.0×10^4 plants/hm^2 and 375 kg/hm^2.
基金Supported by Special Fund of Sichuan Financial Genetic Engineering(2011QNJJ-019)Science and Technology Support Program of Sichuan Province(2011NZ0068)"12th Five-Year Plan" Breeding Project of Crops and Livestock of Sichuan Province(2011NZ0098-15)~~
文摘[Objective] The aim was to make full use of light-heat resources to expand the potato planting area on the base of ensuring the production of main grain crops and the limited arable land. [Methods] Through catch crops, multiple cropping and intercropping, new multiple planting patterns of potato with efficiency are constructed, for the purpose of increasing yield and benefit of potato. [Result] In irrigated plain and hill area, three new planting patterns such as autumn potato/rope-rice,winter potato-rice-autumn potato, and autumn（winter） potato-rice were constructed.In dry land of plain and hill area, three new planting patterns such as spring（winter）potato/maize/sweet potato, spring（winter） potato/maize-autumn potato, and wheat ＋ winter potato/maize/sweet potato were constructed. In plateau mountainous area, spring potato/maize was constructed. [Conclusion] With use of new planting patterns, the cropping index of new patterns was 200%-300%, while the accumulated temperature utilization was 68.9%-93.4%, light energy utilization was 0.98%-1.59% and straw utilization was 50%-100%. To compared with traditional planting patterns, the yield increased by 2.6%-93%, and benefit increased by 15.8%-284.3%. Furthermore,multiple planting patterns of potato have become main planting patterns in increasing yield and income in Sichuan.
基金Supported by Earmarked Fund for China Agriculture Research System(CARS-11,sweetpotato)Jiangsu Science and Technology Support Program(BE2014315)+1 种基金Jiangsu Agricultural Science and Technology Independent Innovation Fund(CX(13)2032)Jiangsu Key Research and Development Program(modern agriculture)(BE2015313)~~
文摘The effects ol different genotypes and planting densities on main agronomic traits, storage root traits and yield were studied with 6 high-quality sweetpotato varieties as study objects by 2-factor completely random design. The results showed that there were significant differences in stem diameter, length of the longest vine and top/root （T/R） between different genotypes, T/R differed significantly under dif- ferent planting densities, and number of basal branches decreased with planting density increasing. Genotype and genotype x density showed significant or very sig- nificant effects on fresh root yield per plant, dry matter content and fresh root yield per hectare, fresh root yield per plant gradually decreased with planting density in- creasing, while fresh root yield per hectare increased with planting density increas- ing. Numbers of storage roots in different sizes of the 6 sweetpotato cultivars all exhibited an order of number of large-sized storage roots〈number of medium-sized storage roots〈small-sized storage root; and there were very significant differences in ratio of large-sized storage roots between different genotypes. The number of large- sized storage roots, ratio of large-sized storage roots and number of commercial storage roots deceased with planting density increasing, while there were no signifi- cant differences in number of medium-sized storage roots, number of small-sized storage roots, ratio of medium-sized storage roots and ratio of small-sized storage roots between different densities. Correlation analysis showed that there was signifi- cant positive correlation between number of basal branches and fresh root yield per plant; dry matter content in storage roots was in significant positive correlation with stem diameter, and in significant negative correlation with length of the longest vine; fresh root yield per hectare was in significant positive correlation with fresh root yield per plant, and in very significant negative correlation with dry matter content; and ratio of large-sized storage roots was in very significant positive correlation with number of large-sized storage root and fresh root yield per plant, and in very sig- nificant negative correlation with ratio of medium-sized storage roots and ratio of small-sized storage roots. This experiment showed that under the planting density of 7.5×104 plants/hm2, the 6 sweetpotato cultivars all reached the highest numbers of commercial storage roots and fresh root yields per hectare.
基金Supported by Key Agricultural R&D Program in Guizhou Province dur-ing the Eleventh Five-year Plan[NZ(2005)3001]~~
文摘[ Objective] This study was to understend the optimized combination of planting density, duration of disclosing plastic film and nitrogen fertilization under no-tillage cultivation. [ Method] Quadratic polynomial regression and saturated D-optimal design were employed to investigate the effects of planting density, duration of disclosing plastic film and nitrogen fertilization on the dynamics growth of rapeseed under no-tillage cultivation.[ Result] Within the experimental range, the growth dynamics of no-tillage cultivated rapeseed assumed a rise-fall tend. For the effects to the growth dynamics of no-tillage cultivated rapeseed, nitrogen application amount was higher than planting density and duration of disclosing plastic film. The interaction effect between planting density and duration of disclosing plastic film was higher than that between nitrogen application amount and planting density, and between nitrogen application amount and duration of disclosing plastic film. [ Conclusion] The optimized combination of these factors for dynamic growth of rapeseed under no-tillage cultivation was determined to be： planting density of per hectare 154 925 individuals, duration of disclosing plastic film of 110 d, nitrogen application amount of 315 kg/hm^2.
文摘Elite maize hybrid Guidan0810 was selected as material, and the effects of fertilizing level and planting densities on yield and nitrogen utilization were dis- cussed in the study. In field experiments as per double-cropping system, 4 main plots （fertilization levels） and 6 subplots （planting densities） were set in a split plot design. The results suggested that yield had close relationship with fertilization levels and planting densities. Different fertilization levels and planting densities significantly affected yield. With the increase of nitrogen fertilization, nitrogen use efficiency, nitrogen agronomic efficiency and nitrogen physiological efficiency declined. Under the same fertilization level, nitrogen use efficiency, nitrogen agronomic efficiency and nitrogen physiological efficiency grew a little with the increase of planting density, so nitrogen efficiency could be improved by regulating planting density. The results also showed that A2 （including N 225.0 kg/hm2, P205 75.0 kg/hm^2, K20 187.5 kg/hm^2） matching to B3 （52 500 plants/hm^2） or B4（60 000 plants/hm^2） was a better design, which could obtain a higher yield in the range of 7 913.2-8 207.8 kg/hm2, respectively.
