[Objectives]To investigate the effects of different planting densities and nitrogen application rates on the yield and quality of the tobacco cultivar Chuxue 80.[Methods]A field experiment was conducted in Hubei Provi...[Objectives]To investigate the effects of different planting densities and nitrogen application rates on the yield and quality of the tobacco cultivar Chuxue 80.[Methods]A field experiment was conducted in Hubei Province,evaluating various combinations of planting density and nitrogen rate for Chuxue 80.[Results]At the maturity stage,the TN1 treatment(5 kg N per 667 m^(2) with a density of 1900 plants per 667 m^(2))demonstrated the most favorable agronomic performance.The TN9 treatment(11 kg N per 667 m^(2) with a density of 1110 plants per 667 m^(2))achieved the highest wrapper tobacco yield and output value.Meanwhile,the TN5 treatment(8 kg N per 667 m^(2) with a density of 1515 plants per 667 m^(2))resulted in the best smoking quality.[Conclusions]The TN9 treatment,with a planting density of 1110 plants per 667 m^(2) and a nitrogen application rate of 11 kg per 667 m^(2),is recommended as the optimal cultivation practice for Chuxue 80 in Hubei Province.展开更多
Coordinating light and nitrogen(N)distribution within a canopy is essential for improving rice yield and resource use efficiency.However,limited research has examined light and N distribution in response to planting d...Coordinating light and nitrogen(N)distribution within a canopy is essential for improving rice yield and resource use efficiency.However,limited research has examined light and N distribution in response to planting density and N rate,and their relationships with grain yield,radiation use efficiency(RUE),and N use efficiency for grain production(NUEg)in rice.A two-year field experiment was conducted with two hybrid varieties under three N levels,0 kg ha^(-1)(N1),90 kg ha^(-1)(N2)and 180 kg ha^(-1)(N3),and two planting densities,22.2 hills m-2(D1)and 33.3 hills m^(-2)(D2).Results showed 3.4%higher yield and 4.4%higher NUEg under N2D2 compared with N3D1.The extinction coefficient for N(K_(N))and light(K_(L))and their ratio(K_(N)/K_(L))at heading stage were significantly influenced by N rate,planting density,and their interaction.K_(N)decreased with the increase of N input or planting density.Compared to N1,K_(N)decreased by 43.5 and 58.8%under N2 and N3,respectively,while K_(N)under D2 decreased by 16.0%compared to D1.Higher K_(L)and K_(N)/K_(L)values occurred under low N rates,with opposite trends under high N rates.Increased planting density led to decreased K_(L)and K_(N)/K_(L)values.N2D2 demonstrated higher K_(L)and K_(N),and thus comparable K_(N)/K_(L),compared to N3D1.Correlation analysis revealed K_(L)negatively correlated with RUE,while K_(N)and K_(N)/K_(L)positively correlated with NUEg.These findings indicate that increasing planting density under reduced N input could maintain rice yield while enhancing resource use efficiency through regulation of canopy light and N distribution.展开更多
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
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
[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
Planting genetically improved,fast-growing tree seedlings is gaining importance as a strategy to enhance forest productivity and reduce labor requirements during plantation establishment.In this study,we evaluated the...Planting genetically improved,fast-growing tree seedlings is gaining importance as a strategy to enhance forest productivity and reduce labor requirements during plantation establishment.In this study,we evaluated the early growth and survival of advanced-generation Cryptomeria japonica seedlings compared to conventional stock,under varying planting densities and cultivation methods.A field experiment was conducted over 5 years using containergrown and bare-root seedlings derived from first-and second-generation plus trees,alongside traditional seedlings.The results showed that advanced-generation seedlings exhibited higher growth in tree height,stem diameter,and crown development than traditional seedlings,particularly when planted as container stock.These seedlings also had higher survival rates,likely due to their rapid initial height growth,which reduced the risks of accidental damage during weeding operations.Wider planting intervals increased the risk of man-made injury and seedling mortality,while faster-growing seedlings were more likely to escape from competing vegetation.Our findings highlight the potential of improved seedling stock to enhance early plantation success and reduce management inputs in the critical establishment phase of forestry.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
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
In view of the existing composite planting cannot do independent control of fertilizer rate for each row,and fertilizer is easy to moisture solidification caking and rely on a single way to measure the speed of inaccu...In view of the existing composite planting cannot do independent control of fertilizer rate for each row,and fertilizer is easy to moisture solidification caking and rely on a single way to measure the speed of inaccurate problems,a split-drive variable fertilizer application system was designed for soybean and maize strip cropping composites.It includes roller crushing bi-directional spiral fertilizer discharger,split-drive variable fertilizer application system and‘GNSS+encoder’dual speed measurement system.By modeling agglomerated fertilizer particles,discrete element simulation was carried out to analyze the crushing effect.The speed measurement error variation folds of both GNSS and encoder under different speed conditions were obtained through field speed measurement tests.Finally,4.5 km/h was identified as the switching point between the two speed measurements.Through bench testing,a mathematical relationship model was developed for the soybean and maize belts in terms of‘Fertilizer Application Rate-Operating Travel Speed-Metering Mechanism Rotor Speed’,and the results are presented in the table below.Fertilizer discharge consistency was verified for fertilizer dischargers.Field trials were conducted,and the results show:The soybean belt had a maximum error of 4.81%at a fertilizer application rate of 150 kg/hm2 and an operating speed of 5 km/h;the maximum error in the corn belt was 4.67%at a fertilizer application rate of 600 kg/hm2 and operating speed of 4 km/h.Both have a maximum error of less than 5%,which meets the requirements for variable fertilizer application.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
基金Supported by Science and Technology Project of China Tobacco Zhejiang Industrial Co.,Ltd.(2023330000340093).
文摘[Objectives]To investigate the effects of different planting densities and nitrogen application rates on the yield and quality of the tobacco cultivar Chuxue 80.[Methods]A field experiment was conducted in Hubei Province,evaluating various combinations of planting density and nitrogen rate for Chuxue 80.[Results]At the maturity stage,the TN1 treatment(5 kg N per 667 m^(2) with a density of 1900 plants per 667 m^(2))demonstrated the most favorable agronomic performance.The TN9 treatment(11 kg N per 667 m^(2) with a density of 1110 plants per 667 m^(2))achieved the highest wrapper tobacco yield and output value.Meanwhile,the TN5 treatment(8 kg N per 667 m^(2) with a density of 1515 plants per 667 m^(2))resulted in the best smoking quality.[Conclusions]The TN9 treatment,with a planting density of 1110 plants per 667 m^(2) and a nitrogen application rate of 11 kg per 667 m^(2),is recommended as the optimal cultivation practice for Chuxue 80 in Hubei Province.
基金supported by the Hubei Provincial Science and Technology Project,China(2025CSA039)the National Natural Science Foundation of China(32001467)。
文摘Coordinating light and nitrogen(N)distribution within a canopy is essential for improving rice yield and resource use efficiency.However,limited research has examined light and N distribution in response to planting density and N rate,and their relationships with grain yield,radiation use efficiency(RUE),and N use efficiency for grain production(NUEg)in rice.A two-year field experiment was conducted with two hybrid varieties under three N levels,0 kg ha^(-1)(N1),90 kg ha^(-1)(N2)and 180 kg ha^(-1)(N3),and two planting densities,22.2 hills m-2(D1)and 33.3 hills m^(-2)(D2).Results showed 3.4%higher yield and 4.4%higher NUEg under N2D2 compared with N3D1.The extinction coefficient for N(K_(N))and light(K_(L))and their ratio(K_(N)/K_(L))at heading stage were significantly influenced by N rate,planting density,and their interaction.K_(N)decreased with the increase of N input or planting density.Compared to N1,K_(N)decreased by 43.5 and 58.8%under N2 and N3,respectively,while K_(N)under D2 decreased by 16.0%compared to D1.Higher K_(L)and K_(N)/K_(L)values occurred under low N rates,with opposite trends under high N rates.Increased planting density led to decreased K_(L)and K_(N)/K_(L)values.N2D2 demonstrated higher K_(L)and K_(N),and thus comparable K_(N)/K_(L),compared to N3D1.Correlation analysis revealed K_(L)negatively correlated with RUE,while K_(N)and K_(N)/K_(L)positively correlated with NUEg.These findings indicate that increasing planting density under reduced N input could maintain rice yield while enhancing resource use efficiency through regulation of canopy light and N distribution.
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 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.
基金supported by FFPRI FTBC Operational Expense Grants。
文摘Planting genetically improved,fast-growing tree seedlings is gaining importance as a strategy to enhance forest productivity and reduce labor requirements during plantation establishment.In this study,we evaluated the early growth and survival of advanced-generation Cryptomeria japonica seedlings compared to conventional stock,under varying planting densities and cultivation methods.A field experiment was conducted over 5 years using containergrown and bare-root seedlings derived from first-and second-generation plus trees,alongside traditional seedlings.The results showed that advanced-generation seedlings exhibited higher growth in tree height,stem diameter,and crown development than traditional seedlings,particularly when planted as container stock.These seedlings also had higher survival rates,likely due to their rapid initial height growth,which reduced the risks of accidental damage during weeding operations.Wider planting intervals increased the risk of man-made injury and seedling mortality,while faster-growing seedlings were more likely to escape from competing vegetation.Our findings highlight the potential of improved seedling stock to enhance early plantation success and reduce management inputs in the critical establishment phase of forestry.
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China Agriculture Research System of MOF and MARA(CARS-04)National Key Research and Development Program of China(Grant No.2022YFD2300904)the Key Scientific and Technological Project of Henan Province Department of China(Grant No.252102111171).
文摘In view of the existing composite planting cannot do independent control of fertilizer rate for each row,and fertilizer is easy to moisture solidification caking and rely on a single way to measure the speed of inaccurate problems,a split-drive variable fertilizer application system was designed for soybean and maize strip cropping composites.It includes roller crushing bi-directional spiral fertilizer discharger,split-drive variable fertilizer application system and‘GNSS+encoder’dual speed measurement system.By modeling agglomerated fertilizer particles,discrete element simulation was carried out to analyze the crushing effect.The speed measurement error variation folds of both GNSS and encoder under different speed conditions were obtained through field speed measurement tests.Finally,4.5 km/h was identified as the switching point between the two speed measurements.Through bench testing,a mathematical relationship model was developed for the soybean and maize belts in terms of‘Fertilizer Application Rate-Operating Travel Speed-Metering Mechanism Rotor Speed’,and the results are presented in the table below.Fertilizer discharge consistency was verified for fertilizer dischargers.Field trials were conducted,and the results show:The soybean belt had a maximum error of 4.81%at a fertilizer application rate of 150 kg/hm2 and an operating speed of 5 km/h;the maximum error in the corn belt was 4.67%at a fertilizer application rate of 600 kg/hm2 and operating speed of 4 km/h.Both have a maximum error of less than 5%,which meets the requirements for variable fertilizer application.
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.
