[Objective] The aim was to select the optimal amount of controlled-release fertilizer and provide theoretical references for controlled-release fertilizers use in summer maize. [Method] Long-term controlled-release fe...[Objective] The aim was to select the optimal amount of controlled-release fertilizer and provide theoretical references for controlled-release fertilizers use in summer maize. [Method] Long-term controlled-release fertilizers were applied once at sowing summer maize to explore effects on maize growth, yield, economic profits and environment. [Result] Maize yield reduced a little in the treatment group with 60% CRF, and increased in varying degrees in the rest groups in the range of 1.1%-7.4%, and some showed significant differences. [Conclusion] Controlled-release fertilizers can be applied once at the amount of 80% common fertilizer＇s, with con- sideration of maize yield, nitrogen use rate and economic profits, which is beneficial for summer maize application and promotion in North China.展开更多
Field plot experiment was conducted to study the effects of two slow-re- lease fertilizers and balanced fertilization on dry matter accumulation, yield, fertilizer use efficiency, nitrogen, phosphorus and potassium up...Field plot experiment was conducted to study the effects of two slow-re- lease fertilizers and balanced fertilization on dry matter accumulation, yield, fertilizer use efficiency, nitrogen, phosphorus and potassium uptake of peppers at Jiangna Town, Yanshan County, Yunnan Province in 2011. The results showed that the dry matter accumulation in dried pepper plant, pepper yield, nitrogen, phosphorus, potassium uptake in peppers were significantly increased in all the fertilizer treat- ments, compared with those in control （no fertilizer）. Compared with conventional fertilization, balanced fertilization, slow-release compound fertilizer and slow-release urea fertilizer significantly increased dried pepper economic output by 20.94%, 17.5% and 14.54%, nitrogen uptake in dried peppers by 21.53%,18.46% and 13.19%, phosphorus uptake in dried peppers by 14.08%, 15.76% and 10.44%, potassium uptake in dried peppers by 22.66%, 15.73% and 16.28%; they also in- creased nitrogen and potassium use efficiency, but reduced potassium use efficiency due to the increased potassium addition. In treatments with balanced fertilization, slow-release compound fertilizer and slow-release urea fertilizer, the nitrogen utiliza- tion was 5.84%, 7.14% and 8.33% higher and the phosphorus utilization was 3.32%, 3.27% and 2.47% higher than those in treatment with conventional fertiliza- tion. In addition, the nitrogen application could be reduced by 20%-50% by bal- anced fertilization and the two slow-release fertilizers, thereby reducing environmen- tal pollution. Slow-release fertilizers could also reduce the frequency of fertilization and labor costs.展开更多
[Objective]The paper was to explore the effect of postponing application of N fertilizer on source-sink characteristics of super hybrid rice Ganxin688.[Method] With super hybrid rice Ganxin688 as test material,the sou...[Objective]The paper was to explore the effect of postponing application of N fertilizer on source-sink characteristics of super hybrid rice Ganxin688.[Method] With super hybrid rice Ganxin688 as test material,the source organ traits（leaf area index,leaf weight,chlorophyll content,photosynthetic rate of flag leaf,stem and sheath dry matter accumulation and output） and yield were measured,the effects of nitrogen application on source-sink relationship,yield and N fertilizer use efficiency were also studied.[Result] Appropriate postponing of N fertilizer was benefit for optimizing population quality,harmonizing source-sink relation,enhancing leaf function,prolonging leaf function period and increasing N fertilizer use efficiency.After heading,the leaves area index（LAI） and chlorophyll content increased with the increasing application amount of panicle fertilizer,and their reduction rate slowed down with the increased application amount of panicle fertilizer.Appropriate increased application of panicle fertilizer could prolong the function period of leaves in lower position,increase storage amount of stem and sheath matter,total sink capacity and sink capacity per unit leaf area during heading stage,improve panicle rate and seed setting rate,reduce the demand of grain sink on stem and sheath matter,and increase lodging resistance of plant,which could also increase dry matter productivity and rice productivity of N fertilizer,and increase absorption and application ratio and total accumulation amount of N fertilizer.For Ganxin 688,when N application amount was 175-205 kg/hm2,the proportion of panicle fertilizer in total nitrogen application should be better as 40%-45%.[Conclusion] The study provided basis for making reasonable and efficient N application strategy to establish a coordinated huge sink and strong source relationship for super rice.展开更多
[Objective] This study aimed to explore the effects of continuous application of controlled release nitrogen fertilizer under double rice cropping system. [Method] By modeling three types of paddy soils in Dong-Ting L...[Objective] This study aimed to explore the effects of continuous application of controlled release nitrogen fertilizer under double rice cropping system. [Method] By modeling three types of paddy soils in Dong-Ting Lake area, four treatments as no fertilizer （CK）, urea, controlled release nitrogen fertilizer （CRNF） and 70% controlled release nitrogen fertilizer （70% CRNF） were designed in the micro-plot trials from 2005 to 2008. [Result] The rice yield in treatment CRNF at N 150 kg/hm2 was increased by 10.3%, 8.0% and 2.4% compared with treatment of urea, in alluvial sandy loamy paddy soil （ALS）, purple calcareous clayey paddy soil （PCS）, and reddish yellow loamy paddy soil （RYS）, respectively; and the yield in treatment of 70% CRNF was increased by 6.1%, 2.6% and -0.8%, respectively. The ranking order of nitrogen uptake amount by plant in early rice and late rice was CRNF 70% CRNF urea CK in all three types of soil. Nitrogen utilization efficiency of CRNF in above three types of soil was 60.7%, 59.6% and 56.3%, increased by 23.8%, 19.4% and 16.3% compared with that in treatment of urea, respectively. Nitrogen utilization efficiency of CRNF in early rice was increased year by year, and was higher than that of 70% CRNF during the whole experiment stage, while that in late rice was increased first and then decreased from the 3rd year. [Conclusion] Continuous application CRNF could alleviate the decreasing of soil nitrogen fertility and organic carbon especially in ALS, increase rice yield and nitrogen utilization efficiency in double-rice cropping system.展开更多
The soybean, cotton, maize and sorghum were planted in pot under low nitrogen, high nitrogen treatments, the soil available nitrogen constitution and con- version and utilization of nitrogen fertilizer were determined...The soybean, cotton, maize and sorghum were planted in pot under low nitrogen, high nitrogen treatments, the soil available nitrogen constitution and con- version and utilization of nitrogen fertilizer were determined, so as to provide techni- cal guidance for reasonable use and improving use efficiency of nitrogen fertilizer for different types of crops. Compared with the control with nitrogen but unplanted crop, growing soybean, cotton, maize, sorghum significantly decreased the soil available N contents by 53. 48%, 51.54%, 33.10%, 55.03%,and influenced the constitution of soil available N. Thereinto, growing soybean, cotton, maize and sorghum significantly decreased soil inorganic N contents by 85.41%, 83.09%, 70.89% and 83.35%,but increased soil hydrolysable organic N contents by 1.41, 1.53, 2.11 and 1.28 times, respectively; growing soybean, cotton, maize and sorghum significantly decreased the rate of soil inorganic N to available N by 68.61%, 65.09%, 56.47% and 63.00%, but increased the rate of soil hydrolysable organic N to available N by 4.18, 4.21, 3.66 and 4.08 times, respectively. Compared with the control, growing soybean, cotton, maize and sorghum significantly increased the transform rate of ammonium nitrogen fertilizer by 93.66%, 38.19%, 32.58% and 38.31% respectively, and growing soybean treatment had the highest increasing range; the nitrification rates of ammo- nium nitrogen fertilizer of growing soybean, cotton, maize and sorghum treatments were negative values, and growing soybean treatment had the highest decreasing amplitude. The ammonium nitrogen fertilizer use efficiency of growing soybean, cot- ton, maize and sorghum treatments were 52.01%, 28.31%, 24.16% and 28.40% re- spectively and growing soybean treatment had the highest value. In conclusion, growing crops suppressed the soil nitrification and accelerated the development of soil hydrolysable organic nitrogen by the utilization of soil available nitrogen and the alteration of soil environment, and hence impacted the constitution of soil available nitrogen and the transform and use of ammonium nitrogen applied in soil. Legumi- nous crops had stronger ability of suppressing nitrification, making use of ammonium compared with non-Leguminous crops.展开更多
To increase fertilizer use efficiency （FUE） and to minimize its negative impact on environment have been the focal points in the world for a long time. It is very important to increase FUE in China for its relativel...To increase fertilizer use efficiency （FUE） and to minimize its negative impact on environment have been the focal points in the world for a long time. It is very important to increase FUE in China for its relatively low FUE and serious losses of nutrients. Recent advances of the technologies to increase FUE are reviewed in this article. These include site-specific and real-time nitrogen management, non-destructive quick test of the nitrogen status of plants, new types of slow release and controlled release fertilizers, site-specific nutrient management, and use of urease inhibitor and nitrification inhibitor to decrease nitrogen losses. Future outlook in technologies related to FUE improvement is also discussed.展开更多
This paper studied the fertilizer rate(FR), fertilizer use efficiency(FUE) and fertilizer overuse rate(FOR) of rice, corn and wheat in China from 1998 to 2018 and briefly analysed the reasons why farmers were willing ...This paper studied the fertilizer rate(FR), fertilizer use efficiency(FUE) and fertilizer overuse rate(FOR) of rice, corn and wheat in China from 1998 to 2018 and briefly analysed the reasons why farmers were willing to apply more fertilizers.(1) The FR of grain in China reached 373.7 kg/ha in 2018, an increase of 26.8% compared to that in 1998. In 2018, the FR for corn was the highest, at 411.2 kg/ha, compared to the values of 338.3 kg/ha for rice and 371.7 kg/ha for wheat.(2) In recent years, the FUE of grain in China has obviously improved, with values of 32.9% in 1998, 36.7% in 2008, and 39.3% in 2018. In 2018, the FUE for rice was the highest(41.2%), followed by that for corn(39.9%), and the FUE for wheat was the lowest(36.0%).(3) By 2018, fertilizer was overused in all zones of rice, corn and wheat. In 2018, the average FOR for wheat reached 69.0%, which was 35.9% higher than that for corn and 42.8% higher than that for rice.(4) The lower price of chemical fertilizers was the main reason leading to overapplication.(5) Establishing market mechanisms and adjusting regional planting structures can be effective in reducing the application of chemical fertilizers.展开更多
Low fertilizer use efficiency is commonly found in China’s agriculture sector. It is critical to understand the drivers of fertilizer use in order to increase fertilizer use efficiency(FUE). The purpose of this paper...Low fertilizer use efficiency is commonly found in China’s agriculture sector. It is critical to understand the drivers of fertilizer use in order to increase fertilizer use efficiency(FUE). The purpose of this paper is to investigate the relationship between farm size and FUE based on farm-level data in China. The results suggest a positive farm size–FUE relationship. The estimated elasticities of farm size for rice, maize, wheat–maize, and rice–maize are similar, and the average elasticity of farm size is around 0.2. Statistically, a 1% increase in farm size is associated with a 0.2%increase in FUE. The positive effect of farm size on FUE is not due to the increase in yield, but the reduction in fertilizer use while keeping yield largely unchanged. The findings suggest that promoting the expansion of farm size may increase FUE, and thus reduce environmental pollution caused by fertilizer overuse.展开更多
This study examines the role of farmers’risk attitudes toward fertilizer use in cotton production in China.Contradicting previous studies,this paper theoretically shows that the relationship between farmers’risk ave...This study examines the role of farmers’risk attitudes toward fertilizer use in cotton production in China.Contradicting previous studies,this paper theoretically shows that the relationship between farmers’risk aversion and fertilizer use is not always monotonic.Field survey data were collected to test this relationship using the Cobb–Douglas production function.Results suggest that when the elasticity of fertilizer use and the probability of achieving the desired effects from fertilizer use are high,risk-averse farmers apply more fertilizer than risk-taking farmers.Conversely,when the elasticity of fertilizer use and the probability of achieving the desired effects are low,risk-taking farmers apply more fertilizer than risk-neutral or risk-averse farmers.展开更多
The effects of application of N fertilizer on wheat on the grain yield and N use efficiency （FNUE） of rice in the wheat-rice rotation system, as well as on the soil fertility were studies. N-fertilizer application o...The effects of application of N fertilizer on wheat on the grain yield and N use efficiency （FNUE） of rice in the wheat-rice rotation system, as well as on the soil fertility were studies. N-fertilizer application on wheat significantly increased total N, arnrnoniurn-N and nitrate-N contents in paddy field, resulting in high indigenous N supply of soil （INS）. Compared with low INS, the effect of N rate on the grain yield of rice was reduced significantly, and FNUE was decreased under high INS. These results indicated that high INS was one of the main reasons for the low FNUE in rice.展开更多
[Objectives]This study was conducted to explore the rational formula for rice fertilization in Jianghan Plain.[Methods]An experiment on the combined application of nitrogen,phosphorus and potassium fertilizers was car...[Objectives]This study was conducted to explore the rational formula for rice fertilization in Jianghan Plain.[Methods]An experiment on the combined application of nitrogen,phosphorus and potassium fertilizers was carried out in Jianghan Plain,an important rice producing area in Hubei,with a total of five treatments to study the effects of nitrogen,phosphorus and potassium fertilizers on the fertilizer use efficiency and yield of rice.[Results]Fertilization had a significant effect on improving rice yield,and nitrogen fertilizer had the greatest effect on rice yield,followed by potassium fertilizer and phosphorous fertilizer.[Conclusions]This study provides a scientific basis for the application of rice fertilizers and the reduction and efficiency improvement of chemical fertilizers in Jianghan Plain.展开更多
Maize （Zea mays L.） is an important food crop in Niger, but low and irregular rainfall combined with sandy soils having low fertility level limit productivity. A two-year study was conducted at Institut National de ...Maize （Zea mays L.） is an important food crop in Niger, but low and irregular rainfall combined with sandy soils having low fertility level limit productivity. A two-year study was conducted at Institut National de Recherche Agronomique du Niger （INRAN） stations in Tarna/Maradi and Bengou/Gaya in 2014 and 2015 in order to evaluate maize agronomic and economic fertilizer use efficiency. The experimental design was a randomised complete block design （RCBD） with three replications. Results indicate higher effect of fertilizer in 2015 compared to 2014. At low N rates 20 kg N/ha and 40 kg N/ha, application of 20 kg P/ha increased maize grain yield across locations and years. The highest agronomic efficiency of N （AEN） was recorded with 60 kg N/ha in 2015 at Bengou and Tarna with 9.65 kg and 14.05 kg grain yield per kg of applied N, respectively. At Tarna, the low N rates of 20 kg N/ha and 40 kg N/ha recorded important AEN of more than 12 kg yield increases per kg of applied N. The highest rainfall use efficiency （RUE） of 6.13 kg/year/mm was obtained with application of 80 kg/ha N, 0 kg/ha P and 40 kg/ha N, 20 kg/ha P in 2015 at Tarna. Without P, the highest value cost ratio （VCR） value of 4.31 was recorded at Tarna in 2015 with 60 kg/ha N, and the lowest value of 0.08 at Bengou in 2014 with 20 kg/ha N. Based on VCR and RUE derived from this study, the optimal fertilizer recommendation for maize in the semi-arid conditions of Niger could be 40 kg/ha N, 20 kg/ha P and 0 kg/ha K.展开更多
Fertilizers use can be optimized through soil testing and leaf analysis. This paper deals with using soil analysis as a base for fertilizer use in maize. A field experiment was carried out in two summer seasons of 201...Fertilizers use can be optimized through soil testing and leaf analysis. This paper deals with using soil analysis as a base for fertilizer use in maize. A field experiment was carried out in two summer seasons of 2013 and 2014 with maize (triple hybrid) in Oraby Village, Mariut sector, Alexandria, Egypt. Soil testing shows that soil was clay loam, with high Na and CaCO<sub>3</sub> contents with high pH, low organic matter, medium P and K and low micronutrient contents (Fe, Zn, Mn and Cu), seven treatments were designed. The most promising treatment was when P and K were increased and micronutrients were added based on soil testing. This treatment resulted in the highest yield with better grain contents of protein and nutrients which indicated that soil-test based on fertilizer use was superior. Soil analysis at the end of the experiment showed higher P and K contents. This approach could be adopted for regions with similar soil conditions in other parts of the world.展开更多
[Objective] The aim was to explore effects of application postponing of N fertilizer and the mechanism of yield increase in order to provide references for N fertilizer application in a rational way. [Method] In a sup...[Objective] The aim was to explore effects of application postponing of N fertilizer and the mechanism of yield increase in order to provide references for N fertilizer application in a rational way. [Method] In a super-high yielded region of summer maize, field experiment was conducted to research effects of N fertilizer postponing on key enzymes of N metabolism, yield of maize and N fertilizer use. [Result] After application of N fertilizer was postponed, NR, SPS and GS activities of ear-leaf of summer maize increased by 11.99%-34.87%, 8.25%-10.64% and 10.00%- 16.81% on the 28^th d of silking; content of soluble sugar in leaves enhanced signifi- cantly and accumulated nitrogen increased by 5.00%-9.74% in mature stage. The postponing fertilization of ＂30% of fertilizer in seedling stage＋30% of fertilizer in flare- opening stage＋40% of fertilizer in silking stage meets N demands of summer maize in late growth period. Compared with conventional fertilization, the maize yield, agro- nomic efficiency and use of N fertilizer all improved by 5.05%, 1.75 kg/kg and 6.87%, respectively, after application postponed. [Conclusion] Application postponing of N fertilizer maintains activity of NR, GS and SPS higher and coordinates metabolism of C and N in late growth period, to further improve yield of maize.展开更多
China is now the world’s largest producer and user of industrial fertilizers and manures. Consequently China plays a substantial role in global N cycle dynamics and in man’s disruption of the nitrogen cycle though t...China is now the world’s largest producer and user of industrial fertilizers and manures. Consequently China plays a substantial role in global N cycle dynamics and in man’s disruption of the nitrogen cycle though there are still significant uncertainties about the size and importance of emission and leaching rates. A major cause of China’s global role is the overuse of nitrogen fertilizers, which is most serious with intensive vegetable production where application rates can be up to 50% greater than crop needs, but is also a problem with wheat, rice and maize. China’s overuse of nitrogen fertiliser over the past 10-20 years has resulted in non-point source (NPS) pollution from crop production becoming a major cause of water pollution, and the situation is projected to get worse. In contrast, water pollution from point sources such as intensive livestock production and urban or industrial development is being brought more under control. The consequences for air pollution are equally serious. Emissions of nitrous oxide from fertilizers and manures may be so large that China could be responsible for 25-30% of global emissions of this damaging greenhouse gas and of the global warming resulting from it. The main national and local issues relate particularly to low fertilizer use efficiency and the losses of ammonia and NOx that lead to acid precipitation, and leaching and run-off losses that result in high nitrate levels in groundwater and eutrophication of rivers and lakes. The reasons why farmers overuse nitrogen fertilizer are complex and not fully understood. They involve agro-climate differences between provinces and counties, farming systems and farm income structures. Although there is a wide range of institutional and technological improvements that can greatly reduce this overuse rapid progress in reducing NPS is unlikely.展开更多
As part of their efforts to control water pollution,local governments in China introduced the river chief system,whereby a named individual undertakes responsibility for protecting a specified waterway.As one of the m...As part of their efforts to control water pollution,local governments in China introduced the river chief system,whereby a named individual undertakes responsibility for protecting a specified waterway.As one of the most prominent sources of water pollution,agricultural non-point-source(NPS)pollution is becoming increasingly serious.Determining whether the river chief system,an institutional reform in China's decentralized environmental regulation regime,is effective in alleviating NPS pollution is important for the realization of green development.The effect of the river chief system on reducing agricultural NPS pollution is explored in this study using panel data from 308 Chinese counties during the period from 2004 to 2015.The results reveal that the negative impact of manure output from animal breeding operations on surface water quality is reduced with the implementation of the river chief system.However,the river chief system is ineffective in dealing with the water pollution caused by fertilizer use.Furthermore,in the current system,cooperation among river chiefs only occurs within a province.Local governments should increase their efforts in reducing fertilizer source loads and preventing fertilizer loads from entering surface waters.In addition,the central government should improve cooperation among the river chiefs in upstream and downstream provinces.展开更多
Nitrification inhibitors are widely used in agriculture to mitigate nitrous oxide(N_(2)O)emission and increase crop yield.However,no concrete information on their mitigation of N_(2)O emission is available under soil ...Nitrification inhibitors are widely used in agriculture to mitigate nitrous oxide(N_(2)O)emission and increase crop yield.However,no concrete information on their mitigation of N_(2)O emission is available under soil and environmental conditions as in Pakistan.A field experiment was established using a silt clay loam soil from Peshawar,Pakistan,to study the effect of urea applied in combination with a nitrification inhibitor,nitrapyrin(2-chloro-6-tri-chloromethyl pyridine),and/or a plant growth regulator,gibberellic acid(GA_3),on N_(2)O emission and the nitrogen(N)uptake efficiency of maize.The experimental design was a randomized complete block with five treatments in four replicates:control with no N(CK),urea(200 kg N ha^(-1))alone,urea in combination with nitrapyrin(700 g ha^(-1)),urea in combination with GA_3(60 g ha^(-1)),and urea in combination with nitrapyrin and GA_3.The N_(2)O emission,yield,N response efficiency,and total N uptake were measured during the experimental period.The treatment with urea and nitrapyrin reduced total N_(2)O emission by 39%–43%and decreased yield-scaled N_(2)O emission by 47%–52%,relative to the treatment with urea alone.The maize plant biomass,grain yield,and total N uptake increased significantly by 23%,17%,and 15%,respectively,in the treatment with urea and nitrapyrin,relative to the treatment with urea alone,which was possibly due to N saving,lower N loss,and increased N uptake in the form of ammonium;they were further enhanced in the treatment with urea,nitrapyrin,and GA_3 by 27%,36%,and 25%,respectively,probably because of the stimulating effect of GA_3 on plant growth and development and the reduction in biotic and abiotic stresses.These results suggest that applying urea in combination with nitrapyrin and GA_3 has the potential to mitigate N_(2)O emission,improve N response efficiency,and increase maize yield.展开更多
This study has focused on the processes of soil degradation and chemical element concentration in tea-growing regions of Rwanda,Africa.Soil degradation accelerated by erosion is caused not only by topography but also ...This study has focused on the processes of soil degradation and chemical element concentration in tea-growing regions of Rwanda,Africa.Soil degradation accelerated by erosion is caused not only by topography but also by human activities.This soil degradation involves both the physical loss and reduction in the amount of topsoil associated with nutrient decline.Soil samples were collected from eleven tropical zones in Rwanda and from variable depth within each collecting site.Of these,Samples from three locations in each zone were analyzed in the laboratory,with the result that the pH of all soil samples is shown to be less than 5（pH〈5） with a general average of 4.4.The elements such as iron（Fe）, copper（Cu）,manganese（Mn）,and zinc（Zn） are present in high concentration levels.In contrast calcium （Ca） and sodium（Na） are present at low-level concentrations and carbon（C） was found in minimal concentrations.In addition,elements derived from fertilizers,such as nitrogen（N）,phosphorous（P）,and potassium（K） which is also from minerals such as feldspar,are also present in low-level concentrations. The results indicate that the soil in certain Rwandan tea plantations is acidic and that this level of pH may help explain,in addition to natural factors,the deficiency of some elements such as Ca,Mg,P and N.The use of chemical fertilizers,land use system and the location of fields relative to household plots are also considered to help explain why tea plantation soils are typically degraded.展开更多
Oilseed flax is one of the most important oil crops in China.With the improvement of people's living standards and the deepening knowledge of the nutritional value of oilseed flax,the demand and economic value of ...Oilseed flax is one of the most important oil crops in China.With the improvement of people's living standards and the deepening knowledge of the nutritional value of oilseed flax,the demand and economic value of oilseed flax are increasing,and the cultivated area in China is expanding.However,the grain yield of oilseed flax is lower than other oil crops.It varies significantly from year to year,combined with a lower degree of mechanization,which has greatly limited the healthy development of the flax industry.Some of the effects of agronomic measures on productivity and water use efficiency of oilseed flax are reviewed in this paper.The major agronomic strategies for the productivity of oilseed flax were presented based on fertilization,plant density,irrigation,cropping pattern and weed control.Future research should investigate the effect of silicon and potassium fertilizers on the mechanism of lodging resistance of oilseed flax,the effects of diversified cropping systems(strip intercropping and crop rotation)on high and stable productivity and efficient utilization of resources.展开更多
Soil carbon（C） and nitrogen（N） play a crucial role in determining the soil and environmental quality. In this study, we investigated the effects of 26 years（from 1984 to 2010） of farmland management on soil orga...Soil carbon（C） and nitrogen（N） play a crucial role in determining the soil and environmental quality. In this study, we investigated the effects of 26 years（from 1984 to 2010） of farmland management on soil organic carbon（SOC） and soil N in abandoned, wheat（Triticum aestivum L.） non-fertilized, wheat fertilized（mineral fertilizer and organic manure） and alfalfa（Medicago Sativa L.） non-fertilized treatments in a semi-arid region of the Loess Plateau, China. Our results showed that SOC and soil total N contents in the 0–20 cm soil layer increased by 4.29（24.4%） and 1.39 Mg/hm2（100%）, respectively, after the conversion of farmland to alfalfa land. Compared to the wheat non-fertilized treatment, SOC and soil total N contents in the 0–20 cm soil layer increased by 4.64（26.4%） and 1.18 Mg/hm2（85.5%）, respectively, in the wheat fertilized treatment. In addition, we found that the extents of changes in SOC, soil total N and mineral N depended on soil depth were greater in the upper soil layer（0–30 cm） than in the deeper soil layer（30–100 cm） in the alfalfa land or fertilizer-applied wheat land. Fertilizer applied to winter wheat could increase the accumulation rates of SOC and soil total N. SOC concentration had a significant positive correlation with soil total N concentration. Therefore, this study suggested that farmland management, e.g. the conversion of farmland to alfalfa forage land and fertilizer application, could promote the sequestrations of C and N in soils in semi-arid regions.展开更多
基金Supported by S&T Development Plan Program of Shandong Province(2014GNC113001)State Key Laboratory for Biology of Crops(2014KF11)S&T Development Plan Program of Tai'an City~~
文摘[Objective] The aim was to select the optimal amount of controlled-release fertilizer and provide theoretical references for controlled-release fertilizers use in summer maize. [Method] Long-term controlled-release fertilizers were applied once at sowing summer maize to explore effects on maize growth, yield, economic profits and environment. [Result] Maize yield reduced a little in the treatment group with 60% CRF, and increased in varying degrees in the rest groups in the range of 1.1%-7.4%, and some showed significant differences. [Conclusion] Controlled-release fertilizers can be applied once at the amount of 80% common fertilizer＇s, with con- sideration of maize yield, nitrogen use rate and economic profits, which is beneficial for summer maize application and promotion in North China.
基金Supported by Special Fund from Ministry of Agriculture for Scientific Research(200903025-05)~~
文摘Field plot experiment was conducted to study the effects of two slow-re- lease fertilizers and balanced fertilization on dry matter accumulation, yield, fertilizer use efficiency, nitrogen, phosphorus and potassium uptake of peppers at Jiangna Town, Yanshan County, Yunnan Province in 2011. The results showed that the dry matter accumulation in dried pepper plant, pepper yield, nitrogen, phosphorus, potassium uptake in peppers were significantly increased in all the fertilizer treat- ments, compared with those in control （no fertilizer）. Compared with conventional fertilization, balanced fertilization, slow-release compound fertilizer and slow-release urea fertilizer significantly increased dried pepper economic output by 20.94%, 17.5% and 14.54%, nitrogen uptake in dried peppers by 21.53%,18.46% and 13.19%, phosphorus uptake in dried peppers by 14.08%, 15.76% and 10.44%, potassium uptake in dried peppers by 22.66%, 15.73% and 16.28%; they also in- creased nitrogen and potassium use efficiency, but reduced potassium use efficiency due to the increased potassium addition. In treatments with balanced fertilization, slow-release compound fertilizer and slow-release urea fertilizer, the nitrogen utiliza- tion was 5.84%, 7.14% and 8.33% higher and the phosphorus utilization was 3.32%, 3.27% and 2.47% higher than those in treatment with conventional fertiliza- tion. In addition, the nitrogen application could be reduced by 20%-50% by bal- anced fertilization and the two slow-release fertilizers, thereby reducing environmen- tal pollution. Slow-release fertilizers could also reduce the frequency of fertilization and labor costs.
基金Supported by National"Eleventh Five-Year"Technology Support Program(2006BAD02A04)Special Project of Ministry of Agriculture for Super Rice"Development and Technology Integration of Cultivation Techniques for Super Rice"~~
文摘[Objective]The paper was to explore the effect of postponing application of N fertilizer on source-sink characteristics of super hybrid rice Ganxin688.[Method] With super hybrid rice Ganxin688 as test material,the source organ traits（leaf area index,leaf weight,chlorophyll content,photosynthetic rate of flag leaf,stem and sheath dry matter accumulation and output） and yield were measured,the effects of nitrogen application on source-sink relationship,yield and N fertilizer use efficiency were also studied.[Result] Appropriate postponing of N fertilizer was benefit for optimizing population quality,harmonizing source-sink relation,enhancing leaf function,prolonging leaf function period and increasing N fertilizer use efficiency.After heading,the leaves area index（LAI） and chlorophyll content increased with the increasing application amount of panicle fertilizer,and their reduction rate slowed down with the increased application amount of panicle fertilizer.Appropriate increased application of panicle fertilizer could prolong the function period of leaves in lower position,increase storage amount of stem and sheath matter,total sink capacity and sink capacity per unit leaf area during heading stage,improve panicle rate and seed setting rate,reduce the demand of grain sink on stem and sheath matter,and increase lodging resistance of plant,which could also increase dry matter productivity and rice productivity of N fertilizer,and increase absorption and application ratio and total accumulation amount of N fertilizer.For Ganxin 688,when N application amount was 175-205 kg/hm2,the proportion of panicle fertilizer in total nitrogen application should be better as 40%-45%.[Conclusion] The study provided basis for making reasonable and efficient N application strategy to establish a coordinated huge sink and strong source relationship for super rice.
基金Supported by the National Key Technology Research and Development Program of China during the11th Five-Year Plan Period(2008BADA4B08)Science and Technology Innovation Project of Hunan Academy of Agricultural Sciences(2010hnnkycx56)~~
文摘[Objective] This study aimed to explore the effects of continuous application of controlled release nitrogen fertilizer under double rice cropping system. [Method] By modeling three types of paddy soils in Dong-Ting Lake area, four treatments as no fertilizer （CK）, urea, controlled release nitrogen fertilizer （CRNF） and 70% controlled release nitrogen fertilizer （70% CRNF） were designed in the micro-plot trials from 2005 to 2008. [Result] The rice yield in treatment CRNF at N 150 kg/hm2 was increased by 10.3%, 8.0% and 2.4% compared with treatment of urea, in alluvial sandy loamy paddy soil （ALS）, purple calcareous clayey paddy soil （PCS）, and reddish yellow loamy paddy soil （RYS）, respectively; and the yield in treatment of 70% CRNF was increased by 6.1%, 2.6% and -0.8%, respectively. The ranking order of nitrogen uptake amount by plant in early rice and late rice was CRNF 70% CRNF urea CK in all three types of soil. Nitrogen utilization efficiency of CRNF in above three types of soil was 60.7%, 59.6% and 56.3%, increased by 23.8%, 19.4% and 16.3% compared with that in treatment of urea, respectively. Nitrogen utilization efficiency of CRNF in early rice was increased year by year, and was higher than that of 70% CRNF during the whole experiment stage, while that in late rice was increased first and then decreased from the 3rd year. [Conclusion] Continuous application CRNF could alleviate the decreasing of soil nitrogen fertility and organic carbon especially in ALS, increase rice yield and nitrogen utilization efficiency in double-rice cropping system.
基金Supported by National Natural Science Foundation of China(41371259)Hubei Natural Science Foundation(2014CFB545)~~
文摘The soybean, cotton, maize and sorghum were planted in pot under low nitrogen, high nitrogen treatments, the soil available nitrogen constitution and con- version and utilization of nitrogen fertilizer were determined, so as to provide techni- cal guidance for reasonable use and improving use efficiency of nitrogen fertilizer for different types of crops. Compared with the control with nitrogen but unplanted crop, growing soybean, cotton, maize, sorghum significantly decreased the soil available N contents by 53. 48%, 51.54%, 33.10%, 55.03%,and influenced the constitution of soil available N. Thereinto, growing soybean, cotton, maize and sorghum significantly decreased soil inorganic N contents by 85.41%, 83.09%, 70.89% and 83.35%,but increased soil hydrolysable organic N contents by 1.41, 1.53, 2.11 and 1.28 times, respectively; growing soybean, cotton, maize and sorghum significantly decreased the rate of soil inorganic N to available N by 68.61%, 65.09%, 56.47% and 63.00%, but increased the rate of soil hydrolysable organic N to available N by 4.18, 4.21, 3.66 and 4.08 times, respectively. Compared with the control, growing soybean, cotton, maize and sorghum significantly increased the transform rate of ammonium nitrogen fertilizer by 93.66%, 38.19%, 32.58% and 38.31% respectively, and growing soybean treatment had the highest increasing range; the nitrification rates of ammo- nium nitrogen fertilizer of growing soybean, cotton, maize and sorghum treatments were negative values, and growing soybean treatment had the highest decreasing amplitude. The ammonium nitrogen fertilizer use efficiency of growing soybean, cot- ton, maize and sorghum treatments were 52.01%, 28.31%, 24.16% and 28.40% re- spectively and growing soybean treatment had the highest value. In conclusion, growing crops suppressed the soil nitrification and accelerated the development of soil hydrolysable organic nitrogen by the utilization of soil available nitrogen and the alteration of soil environment, and hence impacted the constitution of soil available nitrogen and the transform and use of ammonium nitrogen applied in soil. Legumi- nous crops had stronger ability of suppressing nitrification, making use of ammonium compared with non-Leguminous crops.
文摘To increase fertilizer use efficiency （FUE） and to minimize its negative impact on environment have been the focal points in the world for a long time. It is very important to increase FUE in China for its relatively low FUE and serious losses of nutrients. Recent advances of the technologies to increase FUE are reviewed in this article. These include site-specific and real-time nitrogen management, non-destructive quick test of the nitrogen status of plants, new types of slow release and controlled release fertilizers, site-specific nutrient management, and use of urease inhibitor and nitrification inhibitor to decrease nitrogen losses. Future outlook in technologies related to FUE improvement is also discussed.
基金The Second Tibetan Plateau Scientific Expedition and Research Program,No.2019QZKK0603Strategic Priority Research Program of Chinese Academy of Sciences,No.XDA20040000,No.XDA20090000。
文摘This paper studied the fertilizer rate(FR), fertilizer use efficiency(FUE) and fertilizer overuse rate(FOR) of rice, corn and wheat in China from 1998 to 2018 and briefly analysed the reasons why farmers were willing to apply more fertilizers.(1) The FR of grain in China reached 373.7 kg/ha in 2018, an increase of 26.8% compared to that in 1998. In 2018, the FR for corn was the highest, at 411.2 kg/ha, compared to the values of 338.3 kg/ha for rice and 371.7 kg/ha for wheat.(2) In recent years, the FUE of grain in China has obviously improved, with values of 32.9% in 1998, 36.7% in 2008, and 39.3% in 2018. In 2018, the FUE for rice was the highest(41.2%), followed by that for corn(39.9%), and the FUE for wheat was the lowest(36.0%).(3) By 2018, fertilizer was overused in all zones of rice, corn and wheat. In 2018, the average FOR for wheat reached 69.0%, which was 35.9% higher than that for corn and 42.8% higher than that for rice.(4) The lower price of chemical fertilizers was the main reason leading to overapplication.(5) Establishing market mechanisms and adjusting regional planting structures can be effective in reducing the application of chemical fertilizers.
基金supported by the National Social Science Fund of China(16AJY013)。
文摘Low fertilizer use efficiency is commonly found in China’s agriculture sector. It is critical to understand the drivers of fertilizer use in order to increase fertilizer use efficiency(FUE). The purpose of this paper is to investigate the relationship between farm size and FUE based on farm-level data in China. The results suggest a positive farm size–FUE relationship. The estimated elasticities of farm size for rice, maize, wheat–maize, and rice–maize are similar, and the average elasticity of farm size is around 0.2. Statistically, a 1% increase in farm size is associated with a 0.2%increase in FUE. The positive effect of farm size on FUE is not due to the increase in yield, but the reduction in fertilizer use while keeping yield largely unchanged. The findings suggest that promoting the expansion of farm size may increase FUE, and thus reduce environmental pollution caused by fertilizer overuse.
基金financial support from the National Natural Sciences Foundation of China(71773150,71273290,and 71934003)。
文摘This study examines the role of farmers’risk attitudes toward fertilizer use in cotton production in China.Contradicting previous studies,this paper theoretically shows that the relationship between farmers’risk aversion and fertilizer use is not always monotonic.Field survey data were collected to test this relationship using the Cobb–Douglas production function.Results suggest that when the elasticity of fertilizer use and the probability of achieving the desired effects from fertilizer use are high,risk-averse farmers apply more fertilizer than risk-taking farmers.Conversely,when the elasticity of fertilizer use and the probability of achieving the desired effects are low,risk-taking farmers apply more fertilizer than risk-neutral or risk-averse farmers.
基金the Nation al Natural Science Foundation of China(30390080)948 Project of Ministry of Agriculture of China(2003-Z53) the International Rice Research Institute.
文摘The effects of application of N fertilizer on wheat on the grain yield and N use efficiency （FNUE） of rice in the wheat-rice rotation system, as well as on the soil fertility were studies. N-fertilizer application on wheat significantly increased total N, arnrnoniurn-N and nitrate-N contents in paddy field, resulting in high indigenous N supply of soil （INS）. Compared with low INS, the effect of N rate on the grain yield of rice was reduced significantly, and FNUE was decreased under high INS. These results indicated that high INS was one of the main reasons for the low FNUE in rice.
文摘[Objectives]This study was conducted to explore the rational formula for rice fertilization in Jianghan Plain.[Methods]An experiment on the combined application of nitrogen,phosphorus and potassium fertilizers was carried out in Jianghan Plain,an important rice producing area in Hubei,with a total of five treatments to study the effects of nitrogen,phosphorus and potassium fertilizers on the fertilizer use efficiency and yield of rice.[Results]Fertilization had a significant effect on improving rice yield,and nitrogen fertilizer had the greatest effect on rice yield,followed by potassium fertilizer and phosphorous fertilizer.[Conclusions]This study provides a scientific basis for the application of rice fertilizers and the reduction and efficiency improvement of chemical fertilizers in Jianghan Plain.
文摘Maize （Zea mays L.） is an important food crop in Niger, but low and irregular rainfall combined with sandy soils having low fertility level limit productivity. A two-year study was conducted at Institut National de Recherche Agronomique du Niger （INRAN） stations in Tarna/Maradi and Bengou/Gaya in 2014 and 2015 in order to evaluate maize agronomic and economic fertilizer use efficiency. The experimental design was a randomised complete block design （RCBD） with three replications. Results indicate higher effect of fertilizer in 2015 compared to 2014. At low N rates 20 kg N/ha and 40 kg N/ha, application of 20 kg P/ha increased maize grain yield across locations and years. The highest agronomic efficiency of N （AEN） was recorded with 60 kg N/ha in 2015 at Bengou and Tarna with 9.65 kg and 14.05 kg grain yield per kg of applied N, respectively. At Tarna, the low N rates of 20 kg N/ha and 40 kg N/ha recorded important AEN of more than 12 kg yield increases per kg of applied N. The highest rainfall use efficiency （RUE） of 6.13 kg/year/mm was obtained with application of 80 kg/ha N, 0 kg/ha P and 40 kg/ha N, 20 kg/ha P in 2015 at Tarna. Without P, the highest value cost ratio （VCR） value of 4.31 was recorded at Tarna in 2015 with 60 kg/ha N, and the lowest value of 0.08 at Bengou in 2014 with 20 kg/ha N. Based on VCR and RUE derived from this study, the optimal fertilizer recommendation for maize in the semi-arid conditions of Niger could be 40 kg/ha N, 20 kg/ha P and 0 kg/ha K.
文摘Fertilizers use can be optimized through soil testing and leaf analysis. This paper deals with using soil analysis as a base for fertilizer use in maize. A field experiment was carried out in two summer seasons of 2013 and 2014 with maize (triple hybrid) in Oraby Village, Mariut sector, Alexandria, Egypt. Soil testing shows that soil was clay loam, with high Na and CaCO<sub>3</sub> contents with high pH, low organic matter, medium P and K and low micronutrient contents (Fe, Zn, Mn and Cu), seven treatments were designed. The most promising treatment was when P and K were increased and micronutrients were added based on soil testing. This treatment resulted in the highest yield with better grain contents of protein and nutrients which indicated that soil-test based on fertilizer use was superior. Soil analysis at the end of the experiment showed higher P and K contents. This approach could be adopted for regions with similar soil conditions in other parts of the world.
基金Crop Harvest Technology and Engineering in the Twelfth Five-year Plan (2011BAD16B15-2)Special Foundation of National Modern Maize Industrial Technology System(nycytx-02-17)Cooperation Project of China-International Plant Nutrition Research Institute (NMBF-HenanAU-2009)~~
文摘[Objective] The aim was to explore effects of application postponing of N fertilizer and the mechanism of yield increase in order to provide references for N fertilizer application in a rational way. [Method] In a super-high yielded region of summer maize, field experiment was conducted to research effects of N fertilizer postponing on key enzymes of N metabolism, yield of maize and N fertilizer use. [Result] After application of N fertilizer was postponed, NR, SPS and GS activities of ear-leaf of summer maize increased by 11.99%-34.87%, 8.25%-10.64% and 10.00%- 16.81% on the 28^th d of silking; content of soluble sugar in leaves enhanced signifi- cantly and accumulated nitrogen increased by 5.00%-9.74% in mature stage. The postponing fertilization of ＂30% of fertilizer in seedling stage＋30% of fertilizer in flare- opening stage＋40% of fertilizer in silking stage meets N demands of summer maize in late growth period. Compared with conventional fertilization, the maize yield, agro- nomic efficiency and use of N fertilizer all improved by 5.05%, 1.75 kg/kg and 6.87%, respectively, after application postponed. [Conclusion] Application postponing of N fertilizer maintains activity of NR, GS and SPS higher and coordinates metabolism of C and N in late growth period, to further improve yield of maize.
基金Project supported by the Canadian International Development Agency, Canada and the Chinese Academy of Sciences,China (No. KZCX2-413).
文摘China is now the world’s largest producer and user of industrial fertilizers and manures. Consequently China plays a substantial role in global N cycle dynamics and in man’s disruption of the nitrogen cycle though there are still significant uncertainties about the size and importance of emission and leaching rates. A major cause of China’s global role is the overuse of nitrogen fertilizers, which is most serious with intensive vegetable production where application rates can be up to 50% greater than crop needs, but is also a problem with wheat, rice and maize. China’s overuse of nitrogen fertiliser over the past 10-20 years has resulted in non-point source (NPS) pollution from crop production becoming a major cause of water pollution, and the situation is projected to get worse. In contrast, water pollution from point sources such as intensive livestock production and urban or industrial development is being brought more under control. The consequences for air pollution are equally serious. Emissions of nitrous oxide from fertilizers and manures may be so large that China could be responsible for 25-30% of global emissions of this damaging greenhouse gas and of the global warming resulting from it. The main national and local issues relate particularly to low fertilizer use efficiency and the losses of ammonia and NOx that lead to acid precipitation, and leaching and run-off losses that result in high nitrate levels in groundwater and eutrophication of rivers and lakes. The reasons why farmers overuse nitrogen fertilizer are complex and not fully understood. They involve agro-climate differences between provinces and counties, farming systems and farm income structures. Although there is a wide range of institutional and technological improvements that can greatly reduce this overuse rapid progress in reducing NPS is unlikely.
基金the financial support from the National Natural Sciences Foundation of China(71742002 and 71934003)the Priority Academic Program Development of Jiangsu Higher Education Institutions,China(PAPD)the China Center for Food Security Studies in Nanjing Agricultural University,China。
文摘As part of their efforts to control water pollution,local governments in China introduced the river chief system,whereby a named individual undertakes responsibility for protecting a specified waterway.As one of the most prominent sources of water pollution,agricultural non-point-source(NPS)pollution is becoming increasingly serious.Determining whether the river chief system,an institutional reform in China's decentralized environmental regulation regime,is effective in alleviating NPS pollution is important for the realization of green development.The effect of the river chief system on reducing agricultural NPS pollution is explored in this study using panel data from 308 Chinese counties during the period from 2004 to 2015.The results reveal that the negative impact of manure output from animal breeding operations on surface water quality is reduced with the implementation of the river chief system.However,the river chief system is ineffective in dealing with the water pollution caused by fertilizer use.Furthermore,in the current system,cooperation among river chiefs only occurs within a province.Local governments should increase their efforts in reducing fertilizer source loads and preventing fertilizer loads from entering surface waters.In addition,the central government should improve cooperation among the river chiefs in upstream and downstream provinces.
基金funded by the International Atomic Energy Agency through a Coordinated Research Project(CRP D1.50.16)“Minimizing Farming Impacts on Climate Change by Enhancing Carbon and Nitrogen Capture and Storage in Agro-Ecosystems”(18595)of Soil and Water Management and Crop Nutrition Section,Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture,Department of Nuclear Sciences and Applications。
文摘Nitrification inhibitors are widely used in agriculture to mitigate nitrous oxide(N_(2)O)emission and increase crop yield.However,no concrete information on their mitigation of N_(2)O emission is available under soil and environmental conditions as in Pakistan.A field experiment was established using a silt clay loam soil from Peshawar,Pakistan,to study the effect of urea applied in combination with a nitrification inhibitor,nitrapyrin(2-chloro-6-tri-chloromethyl pyridine),and/or a plant growth regulator,gibberellic acid(GA_3),on N_(2)O emission and the nitrogen(N)uptake efficiency of maize.The experimental design was a randomized complete block with five treatments in four replicates:control with no N(CK),urea(200 kg N ha^(-1))alone,urea in combination with nitrapyrin(700 g ha^(-1)),urea in combination with GA_3(60 g ha^(-1)),and urea in combination with nitrapyrin and GA_3.The N_(2)O emission,yield,N response efficiency,and total N uptake were measured during the experimental period.The treatment with urea and nitrapyrin reduced total N_(2)O emission by 39%–43%and decreased yield-scaled N_(2)O emission by 47%–52%,relative to the treatment with urea alone.The maize plant biomass,grain yield,and total N uptake increased significantly by 23%,17%,and 15%,respectively,in the treatment with urea and nitrapyrin,relative to the treatment with urea alone,which was possibly due to N saving,lower N loss,and increased N uptake in the form of ammonium;they were further enhanced in the treatment with urea,nitrapyrin,and GA_3 by 27%,36%,and 25%,respectively,probably because of the stimulating effect of GA_3 on plant growth and development and the reduction in biotic and abiotic stresses.These results suggest that applying urea in combination with nitrapyrin and GA_3 has the potential to mitigate N_(2)O emission,improve N response efficiency,and increase maize yield.
基金supported by the State Key Development Program for Basic Research of China(973 program,Grant No.2010CB951002)the Knowledge Innovation Project of Chinese Academy of Science(KZCX2-YW-334)
文摘This study has focused on the processes of soil degradation and chemical element concentration in tea-growing regions of Rwanda,Africa.Soil degradation accelerated by erosion is caused not only by topography but also by human activities.This soil degradation involves both the physical loss and reduction in the amount of topsoil associated with nutrient decline.Soil samples were collected from eleven tropical zones in Rwanda and from variable depth within each collecting site.Of these,Samples from three locations in each zone were analyzed in the laboratory,with the result that the pH of all soil samples is shown to be less than 5（pH〈5） with a general average of 4.4.The elements such as iron（Fe）, copper（Cu）,manganese（Mn）,and zinc（Zn） are present in high concentration levels.In contrast calcium （Ca） and sodium（Na） are present at low-level concentrations and carbon（C） was found in minimal concentrations.In addition,elements derived from fertilizers,such as nitrogen（N）,phosphorous（P）,and potassium（K） which is also from minerals such as feldspar,are also present in low-level concentrations. The results indicate that the soil in certain Rwandan tea plantations is acidic and that this level of pH may help explain,in addition to natural factors,the deficiency of some elements such as Ca,Mg,P and N.The use of chemical fertilizers,land use system and the location of fields relative to household plots are also considered to help explain why tea plantation soils are typically degraded.
基金funded by the Research Program Sponsored by Gansu Provincial Key Laboratory of Arid Land Crop Science,Gansu Agricultural University(GSCS-2020-Z6)the China Agriculture Research System of MOF and MARA(CARS-14-1-16)+2 种基金the National Natural Science Foundation of China(31760363 and 32060437)the Fuxi Outstanding Talent Cultivation Plan of Gansu Agriculture University(Gaufx-02J05)the Education Science and Technology Innovation Project of Gansu Province(2021CXZX-366)。
文摘Oilseed flax is one of the most important oil crops in China.With the improvement of people's living standards and the deepening knowledge of the nutritional value of oilseed flax,the demand and economic value of oilseed flax are increasing,and the cultivated area in China is expanding.However,the grain yield of oilseed flax is lower than other oil crops.It varies significantly from year to year,combined with a lower degree of mechanization,which has greatly limited the healthy development of the flax industry.Some of the effects of agronomic measures on productivity and water use efficiency of oilseed flax are reviewed in this paper.The major agronomic strategies for the productivity of oilseed flax were presented based on fertilization,plant density,irrigation,cropping pattern and weed control.Future research should investigate the effect of silicon and potassium fertilizers on the mechanism of lodging resistance of oilseed flax,the effects of diversified cropping systems(strip intercropping and crop rotation)on high and stable productivity and efficient utilization of resources.
基金funded by the Fok Ying-Tong Education Foundation for Young Teachers in the Higher Education Institutions of China (131025)the Natural Science Foundation of Shaanxi Province (2014KJXX-52)
文摘Soil carbon（C） and nitrogen（N） play a crucial role in determining the soil and environmental quality. In this study, we investigated the effects of 26 years（from 1984 to 2010） of farmland management on soil organic carbon（SOC） and soil N in abandoned, wheat（Triticum aestivum L.） non-fertilized, wheat fertilized（mineral fertilizer and organic manure） and alfalfa（Medicago Sativa L.） non-fertilized treatments in a semi-arid region of the Loess Plateau, China. Our results showed that SOC and soil total N contents in the 0–20 cm soil layer increased by 4.29（24.4%） and 1.39 Mg/hm2（100%）, respectively, after the conversion of farmland to alfalfa land. Compared to the wheat non-fertilized treatment, SOC and soil total N contents in the 0–20 cm soil layer increased by 4.64（26.4%） and 1.18 Mg/hm2（85.5%）, respectively, in the wheat fertilized treatment. In addition, we found that the extents of changes in SOC, soil total N and mineral N depended on soil depth were greater in the upper soil layer（0–30 cm） than in the deeper soil layer（30–100 cm） in the alfalfa land or fertilizer-applied wheat land. Fertilizer applied to winter wheat could increase the accumulation rates of SOC and soil total N. SOC concentration had a significant positive correlation with soil total N concentration. Therefore, this study suggested that farmland management, e.g. the conversion of farmland to alfalfa forage land and fertilizer application, could promote the sequestrations of C and N in soils in semi-arid regions.
