Biochar effects on legume growth and biological nitrogen fixation have been studied extensively, mostly in acidic soils with laboratory produced biochar. In the present study, a pot experiment in a full factorial expe...Biochar effects on legume growth and biological nitrogen fixation have been studied extensively, mostly in acidic soils with laboratory produced biochar. In the present study, a pot experiment in a full factorial experimental design was performed to examine soybean yield and nodulation of three genotypes grown with or without biochar and NPK fertilizers in an alkaline soil. We observed synergistic effects of biochar and NPK fertilizer applications on biomass and seed yields for all three soybean genotypes. Total biomass production and seed yield increased on average by 67% and 54%, respectively, with biochar and by 201% and 182% with NPK fertilizer application compared to the control. When applications of biochar and NPK fertilizer were combined, the increases were 391% and367%, respectively. However, the biomass production in the control was very low(692 kg ha-1) due to a high soil p H(8.80). The nodulation increased with biochar and NPK fertilizer applications, and was largest with the combined application. A correlation was found between leaf chlorophyll content(single photon avalanche diode value) and nodule number. We suggested that the synergistic increase in yield was due to a decrease in soil p H caused by biochar and NPK fertilizer applications thereby increasing P availability in this alkaline soil.展开更多
The influences of frequency on nitrogen fixation of dielectric barrier discharge in air were studied by electrical diagnostics, gas detection and infrared detection methods. The system power, nitrogen oxide concentrat...The influences of frequency on nitrogen fixation of dielectric barrier discharge in air were studied by electrical diagnostics, gas detection and infrared detection methods. The system power, nitrogen oxide concentration, voltage-current waveform, dielectric surface temperature distribution and filamentous discharge pictures were measured, and then the energy yield was calculated; paper studied their changing tendencies in the presence of frequency. Results show that frequency has strong influences on nitrogen fixation. When the parameters of reaction chamber and amplitude of applied voltage is fixed, with the increasing of frequency, the system power increases; in 5-10 kHz, nitrogen oxide gas concentration up to 1113.7 mg m-3, and 7 kHz is the optimal nitrogen fixation frequency whose energy yield is 20.5 mR （m3 W）-1.展开更多
Intercropping is a very effective cultivation method in the agricultural production with a long history. The use of intercropping to build a niche complementary crop community can not only enhance the stability of far...Intercropping is a very effective cultivation method in the agricultural production with a long history. The use of intercropping to build a niche complementary crop community can not only enhance the stability of farmland ecosystem and the resistance of crop community to environmental stress but also reduce the damage of diseases, insect pests, environmental pollution and improve the efficiency of resource use to finally achieve high and stable yield of crop community. By collecting the intercropping researches at home and abroad, this thesis describes the impact of intercropping on crop nitrogen fixation and nitrogen transfer, accumulation and distribution of soil nitrate nitrogen, soil microorganism, crop diseases and insect pests, ventilation and light transmission, quality, yield and nutrient absorption, draws a conclusion on intercropping advantages and points out the sections requiring further study in the future.展开更多
To explore the variations in symbiotic N2 fixation and water use efficiency in cowpea, this study evaluated 25 USDA cowpea genotypes subjected to drought under field conditions at two locations (Kpachi and Woribogu) i...To explore the variations in symbiotic N2 fixation and water use efficiency in cowpea, this study evaluated 25 USDA cowpea genotypes subjected to drought under field conditions at two locations (Kpachi and Woribogu) in the Northern region of Ghana. The 15N and 13C natural abundance techniques were respectively used to assess N2 fixation and water use efficiency. The test genotypes elicited high symbiotic dependence in association with indigenous rhizobia, deriving between 55% and 98% of their N requirements from symbiosis. Consequently, the amounts of N-fixed by the genotypes showed remarkable variations, with values ranging from 37 kg·N-fixed·ha-1 to 337 kg·N-fixed·ha-1. Most genotypes elicited contrasting symbiotic performance between locations, a finding that highlights the effect of complex host/soil microbiome compatibility on the efficiency of the cowpea-rhizobia symbiosis. The test genotypes showed marked variations in water use efficiency, with most of the genotypes recording higher δ13C values when planted at Kpachi. Despite the high symbiotic dependence, the grain yield of the test cowpeas was low due to the imposed drought, and ranged from 56 kg/ha to 556 kg/ha at Kpachi, and 143 kg/ha to 748 kg/ha at Woribogu. The fact that some genotypes could grow and produce grain yields of 627 - 748 kg/ha under drought imposition is an important trait that could be tapped for further improvement of cowpea. These findings highlight the importance of the cowpea-rhizobia symbiosis and enhanced water relations in the crop’s wider adaptation to adverse edaphoclimatic conditions.展开更多
There is little understanding as to whether the addition of biochar requires less fertilizer to obtain the potential yield.Furthermore,the additional yield ascribed to the non-nutrient effects of biochar is ambiguousl...There is little understanding as to whether the addition of biochar requires less fertilizer to obtain the potential yield.Furthermore,the additional yield ascribed to the non-nutrient effects of biochar is ambiguously quantified.Therefore,this study is aimed to elucidate the influence of biochar application rate and production temperature on(i)marginal agronomic efficiency(AELN),(ii)potential yield(Yopt),(iii)the amount of mineral fertilizer required to obtain the potential yield(Fopt);and(iv)nutrient use efficiency.AELN,Yopt and Fopt were calculated after fitting the yield response at different levels of mineral fertilizer with a second-degree polynomial.Application of biochar reduced marginal agronomic efficiency,implying that the plant utilized the applied nutrient more efficiently without biochar at a low dose of mineral fertilizer.Biochar increased potential yield but required more mineral fertilizer to obtain the optimum yield.The non-nutrient associated effect of biochar reached to 39% and is mainly attributed to its liming effect.The effect of biochar on AELN,Yopt,Fopt,fertilizer use efficiency and soil pH were more pronounced at the higher application rate.Addition of biochar,however,increased soil Mehlich-P and carbon content,irrespective of production temperature and application rate.This study demonstrated that the short-term effect of biochar application on fertilizer utilization should be examined with caution in low-input cropping systems because the biochar effects were dependent on fertilizer level,biochar application rate,production temperature and their interactions.Further manipulative experiments are recommended to identify the mechanisms that explain the non-nutrient effect of biochar on yield.展开更多
通过田间试验,利用15N自然丰度法,研究了太湖地区水稻土冬季绿肥的固氮量,以及绿肥还田后配施氮肥对水稻产量、稻田土壤供氮能力及土壤氮素淋失特征的影响。试验结果表明,紫云英和蚕豆当季分别能固定氮约32.8和68.8 kg km-2进入稻田生...通过田间试验,利用15N自然丰度法,研究了太湖地区水稻土冬季绿肥的固氮量,以及绿肥还田后配施氮肥对水稻产量、稻田土壤供氮能力及土壤氮素淋失特征的影响。试验结果表明,紫云英和蚕豆当季分别能固定氮约32.8和68.8 kg km-2进入稻田生态系统以培肥土壤和供下季水稻利用。蚕豆秸秆还田后基本能满足水稻生长所需的氮,紫云英和蚕豆还田施氮120 kg km-2时,既可保证水稻较高产量,又节约当季化学氮肥45%～55%。紫云英和蚕豆还田不施氮肥处理,整个生长期耕层土壤溶液NH+4-N、NO-3-N和TN浓度均低于配施氮肥的处理;蚕豆还田处理土壤溶液TN浓度高于紫云英还田处理。随氮肥用量增加,NH+4-N、NO-3-N和TN浓度有增加趋势,不同施氮量间差异不显著。绿肥-水稻轮作,紫云英和蚕豆还田土壤氮素淋溶显著降低。配施氮肥增加了土壤氮的淋失量,尤其施氮300 kg km-2处理,土壤淋溶液NH+4-N、TN浓度显著高于施氮0～240 kg km-2的处理。展开更多
基金Patuakhali Science and Technology University (PSTU),Bangladesh for funding of project
文摘Biochar effects on legume growth and biological nitrogen fixation have been studied extensively, mostly in acidic soils with laboratory produced biochar. In the present study, a pot experiment in a full factorial experimental design was performed to examine soybean yield and nodulation of three genotypes grown with or without biochar and NPK fertilizers in an alkaline soil. We observed synergistic effects of biochar and NPK fertilizer applications on biomass and seed yields for all three soybean genotypes. Total biomass production and seed yield increased on average by 67% and 54%, respectively, with biochar and by 201% and 182% with NPK fertilizer application compared to the control. When applications of biochar and NPK fertilizer were combined, the increases were 391% and367%, respectively. However, the biomass production in the control was very low(692 kg ha-1) due to a high soil p H(8.80). The nodulation increased with biochar and NPK fertilizer applications, and was largest with the combined application. A correlation was found between leaf chlorophyll content(single photon avalanche diode value) and nodule number. We suggested that the synergistic increase in yield was due to a decrease in soil p H caused by biochar and NPK fertilizer applications thereby increasing P availability in this alkaline soil.
文摘The influences of frequency on nitrogen fixation of dielectric barrier discharge in air were studied by electrical diagnostics, gas detection and infrared detection methods. The system power, nitrogen oxide concentration, voltage-current waveform, dielectric surface temperature distribution and filamentous discharge pictures were measured, and then the energy yield was calculated; paper studied their changing tendencies in the presence of frequency. Results show that frequency has strong influences on nitrogen fixation. When the parameters of reaction chamber and amplitude of applied voltage is fixed, with the increasing of frequency, the system power increases; in 5-10 kHz, nitrogen oxide gas concentration up to 1113.7 mg m-3, and 7 kHz is the optimal nitrogen fixation frequency whose energy yield is 20.5 mR （m3 W）-1.
基金Supported by National Natural Science Foundation (U1033004)
文摘Intercropping is a very effective cultivation method in the agricultural production with a long history. The use of intercropping to build a niche complementary crop community can not only enhance the stability of farmland ecosystem and the resistance of crop community to environmental stress but also reduce the damage of diseases, insect pests, environmental pollution and improve the efficiency of resource use to finally achieve high and stable yield of crop community. By collecting the intercropping researches at home and abroad, this thesis describes the impact of intercropping on crop nitrogen fixation and nitrogen transfer, accumulation and distribution of soil nitrate nitrogen, soil microorganism, crop diseases and insect pests, ventilation and light transmission, quality, yield and nutrient absorption, draws a conclusion on intercropping advantages and points out the sections requiring further study in the future.
文摘To explore the variations in symbiotic N2 fixation and water use efficiency in cowpea, this study evaluated 25 USDA cowpea genotypes subjected to drought under field conditions at two locations (Kpachi and Woribogu) in the Northern region of Ghana. The 15N and 13C natural abundance techniques were respectively used to assess N2 fixation and water use efficiency. The test genotypes elicited high symbiotic dependence in association with indigenous rhizobia, deriving between 55% and 98% of their N requirements from symbiosis. Consequently, the amounts of N-fixed by the genotypes showed remarkable variations, with values ranging from 37 kg·N-fixed·ha-1 to 337 kg·N-fixed·ha-1. Most genotypes elicited contrasting symbiotic performance between locations, a finding that highlights the effect of complex host/soil microbiome compatibility on the efficiency of the cowpea-rhizobia symbiosis. The test genotypes showed marked variations in water use efficiency, with most of the genotypes recording higher δ13C values when planted at Kpachi. Despite the high symbiotic dependence, the grain yield of the test cowpeas was low due to the imposed drought, and ranged from 56 kg/ha to 556 kg/ha at Kpachi, and 143 kg/ha to 748 kg/ha at Woribogu. The fact that some genotypes could grow and produce grain yields of 627 - 748 kg/ha under drought imposition is an important trait that could be tapped for further improvement of cowpea. These findings highlight the importance of the cowpea-rhizobia symbiosis and enhanced water relations in the crop’s wider adaptation to adverse edaphoclimatic conditions.
基金We gratefully acknowledge the United Nations Environment program for its funding of the“Biochar for sustainable soil”project(GEF-5824-GFL-5060-2770-4F17)for which this research work was one of the working packages.We acknowledge Mr.Abraham for his help during data collection.We greatly appreciate Mr.Bayu Dume,Mr.Zeleke Wondimu and Mr.Abiyot Hunde for their considerable help during laboratory work.
文摘There is little understanding as to whether the addition of biochar requires less fertilizer to obtain the potential yield.Furthermore,the additional yield ascribed to the non-nutrient effects of biochar is ambiguously quantified.Therefore,this study is aimed to elucidate the influence of biochar application rate and production temperature on(i)marginal agronomic efficiency(AELN),(ii)potential yield(Yopt),(iii)the amount of mineral fertilizer required to obtain the potential yield(Fopt);and(iv)nutrient use efficiency.AELN,Yopt and Fopt were calculated after fitting the yield response at different levels of mineral fertilizer with a second-degree polynomial.Application of biochar reduced marginal agronomic efficiency,implying that the plant utilized the applied nutrient more efficiently without biochar at a low dose of mineral fertilizer.Biochar increased potential yield but required more mineral fertilizer to obtain the optimum yield.The non-nutrient associated effect of biochar reached to 39% and is mainly attributed to its liming effect.The effect of biochar on AELN,Yopt,Fopt,fertilizer use efficiency and soil pH were more pronounced at the higher application rate.Addition of biochar,however,increased soil Mehlich-P and carbon content,irrespective of production temperature and application rate.This study demonstrated that the short-term effect of biochar application on fertilizer utilization should be examined with caution in low-input cropping systems because the biochar effects were dependent on fertilizer level,biochar application rate,production temperature and their interactions.Further manipulative experiments are recommended to identify the mechanisms that explain the non-nutrient effect of biochar on yield.
文摘通过田间试验,利用15N自然丰度法,研究了太湖地区水稻土冬季绿肥的固氮量,以及绿肥还田后配施氮肥对水稻产量、稻田土壤供氮能力及土壤氮素淋失特征的影响。试验结果表明,紫云英和蚕豆当季分别能固定氮约32.8和68.8 kg km-2进入稻田生态系统以培肥土壤和供下季水稻利用。蚕豆秸秆还田后基本能满足水稻生长所需的氮,紫云英和蚕豆还田施氮120 kg km-2时,既可保证水稻较高产量,又节约当季化学氮肥45%～55%。紫云英和蚕豆还田不施氮肥处理,整个生长期耕层土壤溶液NH+4-N、NO-3-N和TN浓度均低于配施氮肥的处理;蚕豆还田处理土壤溶液TN浓度高于紫云英还田处理。随氮肥用量增加,NH+4-N、NO-3-N和TN浓度有增加趋势,不同施氮量间差异不显著。绿肥-水稻轮作,紫云英和蚕豆还田土壤氮素淋溶显著降低。配施氮肥增加了土壤氮的淋失量,尤其施氮300 kg km-2处理,土壤淋溶液NH+4-N、TN浓度显著高于施氮0～240 kg km-2的处理。
