Nitrogen (N) losses from ammonium bicarbonate or urea applied to wheat and then followed immediately by irrigation were investigated. Ammonia volatilization was determined by a micrometeorological method (ammonia samp...Nitrogen (N) losses from ammonium bicarbonate or urea applied to wheat and then followed immediately by irrigation were investigated. Ammonia volatilization was determined by a micrometeorological method (ammonia sampler), total N loss was estimated by the 15N mass balance method, and denitrification loss was measured by the difference method (calculated from the difference between the total N loss and ammonia loss)and a direct method (measuring the emission of (N2+N2O)-15N ). Total ammonia losses from ammonium bicarbonate and urea in 33 days were 8.7% and 0.9% of the applied nitrogen, respectively. The corresponding total N losses were 21.6% and 29.5%. Apparent denitrification losses (by the difference method) were rather high, being 12.9% from ammonium bicarbonate and 28.6% from urea. However, no emission of (N2+N2O)-15N was detected using the direct method.展开更多
Ammonia volatilized from aboveground parts of winter wheat was collected with an enclosure growth chamber and measured from jointing to maturing stage. The results showed that ammonia released from unfertilized plants...Ammonia volatilized from aboveground parts of winter wheat was collected with an enclosure growth chamber and measured from jointing to maturing stage. The results showed that ammonia released from unfertilized plants grown in high and low fertility soils remained at low rates of 2.3 and 0. 9μg NH3 40 plant-1 h-1 respectively at late filling stage. However, fertilized plants rapidly increased the rates to 43. 4 and 52. 2μg NH3, 40 plant-1 h-1 in the high and low fertility soils, respectively, at the same period. The released a-mount was different in different parts of plants. At filling stage, lower senescing stems and leaves volatilized more ammonia than upper parts, i. e. , ears and flag leaves that grew normally, with an average of 1. 4 and 0.7μg NH3 20 plant-1 h-1 respectively, strongly suggesting that it was the senile organs that released large amounts of ammonia. At the grain filling stage, shortage of water supply (drought stress) reduced ammonia volatilization. The average rate of ammonia released under water stress was 0. 9μg NH3 40 plant-1 h-1, but 1.2μg NH3 40 plant-1 h-1 with moderate water supply. Application of N together with P fertilizer resulted in a higher ammonia volatilization than N fertilization alone at the maturing stage. The average rate released was 135.3 μg NH3 40 plant-1 h-1 when 0.4 g N and 0.13 g P had been added to per kg soil, while 33. 7μg when 0. 4 g N added alone. Ammonia volatilization from plants was closely related with plant biomass and N uptake;P fertilization increased plant biomass and N uptake and therefore increased its release.展开更多
【目的】基于定位试验平台,比较长期不同施肥处理下小麦-玉米轮作体系周年土壤氮素氨挥发损失的差异,为降低氨挥发损失、提高氮肥利用率提供理论依据。【方法】2019—2021年,依托山东农业大学黄淮海玉米技术创新中心定位试验平台,以冬...【目的】基于定位试验平台,比较长期不同施肥处理下小麦-玉米轮作体系周年土壤氮素氨挥发损失的差异,为降低氨挥发损失、提高氮肥利用率提供理论依据。【方法】2019—2021年,依托山东农业大学黄淮海玉米技术创新中心定位试验平台,以冬小麦品种石麦15和夏玉米品种郑单958为试验材料,以不施氮肥为对照(CK),采用有机肥(腐熟牛粪M)和无机氮肥(U)两种氮肥类型,设置两个施氮量分别为380 kg N·hm^(-2)(M1、U1、U2M2)和190 kg N·hm^(-2)(U2、M2),试验共计6个处理,其中氮肥在两季作物间的分配是小麦47.4%、玉米52.6%。采用通气法比较各处理土壤氨挥发速率、累积损失量、籽粒产量及氮肥利用效率的差异。【结果】两个种植周期内不同施肥处理均显著影响土壤氨挥发。各处理施肥后氨挥发损失速率变化趋势基本一致,小麦和玉米两季的土壤氨挥发均主要发生在施肥后0—7 d,之后处理间的差异逐渐变小。小麦玉米轮作体系周年氨挥发损失量可达8.6—79.4 kg N·hm^(-2),以U1处理最高,达到79.4 kg N·hm^(-2),其氨挥发损失量较U2、U2M2、M1、M2和CK分别增加18.5%、111.7%、162.3%、20.5%和825.7%,表明高施氮量增加土壤氨挥发损失量,无机氮肥较有机肥增加氨挥发损失量。U2M2、M1和M2处理的氨挥发损失率比U1处理降低80.9%、61.3%、24.8%,表明有机氮肥与无机氮肥配施或单施有机氮肥可显著降低氨挥发损失。周年籽粒产量以U2M2处理最高,达到24621.8 kg·hm^(-2),较U1、U2、M1、M2分别增产10.1%、24.7%、11.7%和32.7%。U2M2处理周年氮肥利用率达52.6%,较U1、U2、M1和M2处理分别提高11.3%、4.1%、13.4%和10.7%。U2M2处理降低了氨挥发损失、同步提高了产量和氮肥利用率,是冬小麦玉米周年轮作的理想施肥策略。【结论】施用有机肥可以显著降低小麦玉米轮作体系的周年氨挥发损失量,提高周年籽粒产量和氮肥利用效率。考虑到有机肥源及施用便捷性可将有机无机配施作为当前小麦玉米轮作生产体系降低氨挥发损失、提高氮肥利用效率的主要施肥方式。展开更多
文摘Nitrogen (N) losses from ammonium bicarbonate or urea applied to wheat and then followed immediately by irrigation were investigated. Ammonia volatilization was determined by a micrometeorological method (ammonia sampler), total N loss was estimated by the 15N mass balance method, and denitrification loss was measured by the difference method (calculated from the difference between the total N loss and ammonia loss)and a direct method (measuring the emission of (N2+N2O)-15N ). Total ammonia losses from ammonium bicarbonate and urea in 33 days were 8.7% and 0.9% of the applied nitrogen, respectively. The corresponding total N losses were 21.6% and 29.5%. Apparent denitrification losses (by the difference method) were rather high, being 12.9% from ammonium bicarbonate and 28.6% from urea. However, no emission of (N2+N2O)-15N was detected using the direct method.
基金This work was part of the projects of 40201028,30070429,49890330 and 30230230 supported by the National Natural Science Foundation of China(NFSC)the project of G1999011707 supported by National Key Basic Research Special Funds(NKBRSF).The authors would like to take the opportunity to thank the NFSC and the NKBRSF for their kindness of supporting these projects.
文摘Ammonia volatilized from aboveground parts of winter wheat was collected with an enclosure growth chamber and measured from jointing to maturing stage. The results showed that ammonia released from unfertilized plants grown in high and low fertility soils remained at low rates of 2.3 and 0. 9μg NH3 40 plant-1 h-1 respectively at late filling stage. However, fertilized plants rapidly increased the rates to 43. 4 and 52. 2μg NH3, 40 plant-1 h-1 in the high and low fertility soils, respectively, at the same period. The released a-mount was different in different parts of plants. At filling stage, lower senescing stems and leaves volatilized more ammonia than upper parts, i. e. , ears and flag leaves that grew normally, with an average of 1. 4 and 0.7μg NH3 20 plant-1 h-1 respectively, strongly suggesting that it was the senile organs that released large amounts of ammonia. At the grain filling stage, shortage of water supply (drought stress) reduced ammonia volatilization. The average rate of ammonia released under water stress was 0. 9μg NH3 40 plant-1 h-1, but 1.2μg NH3 40 plant-1 h-1 with moderate water supply. Application of N together with P fertilizer resulted in a higher ammonia volatilization than N fertilization alone at the maturing stage. The average rate released was 135.3 μg NH3 40 plant-1 h-1 when 0.4 g N and 0.13 g P had been added to per kg soil, while 33. 7μg when 0. 4 g N added alone. Ammonia volatilization from plants was closely related with plant biomass and N uptake;P fertilization increased plant biomass and N uptake and therefore increased its release.
文摘【目的】基于定位试验平台,比较长期不同施肥处理下小麦-玉米轮作体系周年土壤氮素氨挥发损失的差异,为降低氨挥发损失、提高氮肥利用率提供理论依据。【方法】2019—2021年,依托山东农业大学黄淮海玉米技术创新中心定位试验平台,以冬小麦品种石麦15和夏玉米品种郑单958为试验材料,以不施氮肥为对照(CK),采用有机肥(腐熟牛粪M)和无机氮肥(U)两种氮肥类型,设置两个施氮量分别为380 kg N·hm^(-2)(M1、U1、U2M2)和190 kg N·hm^(-2)(U2、M2),试验共计6个处理,其中氮肥在两季作物间的分配是小麦47.4%、玉米52.6%。采用通气法比较各处理土壤氨挥发速率、累积损失量、籽粒产量及氮肥利用效率的差异。【结果】两个种植周期内不同施肥处理均显著影响土壤氨挥发。各处理施肥后氨挥发损失速率变化趋势基本一致,小麦和玉米两季的土壤氨挥发均主要发生在施肥后0—7 d,之后处理间的差异逐渐变小。小麦玉米轮作体系周年氨挥发损失量可达8.6—79.4 kg N·hm^(-2),以U1处理最高,达到79.4 kg N·hm^(-2),其氨挥发损失量较U2、U2M2、M1、M2和CK分别增加18.5%、111.7%、162.3%、20.5%和825.7%,表明高施氮量增加土壤氨挥发损失量,无机氮肥较有机肥增加氨挥发损失量。U2M2、M1和M2处理的氨挥发损失率比U1处理降低80.9%、61.3%、24.8%,表明有机氮肥与无机氮肥配施或单施有机氮肥可显著降低氨挥发损失。周年籽粒产量以U2M2处理最高,达到24621.8 kg·hm^(-2),较U1、U2、M1、M2分别增产10.1%、24.7%、11.7%和32.7%。U2M2处理周年氮肥利用率达52.6%,较U1、U2、M1和M2处理分别提高11.3%、4.1%、13.4%和10.7%。U2M2处理降低了氨挥发损失、同步提高了产量和氮肥利用率,是冬小麦玉米周年轮作的理想施肥策略。【结论】施用有机肥可以显著降低小麦玉米轮作体系的周年氨挥发损失量,提高周年籽粒产量和氮肥利用效率。考虑到有机肥源及施用便捷性可将有机无机配施作为当前小麦玉米轮作生产体系降低氨挥发损失、提高氮肥利用效率的主要施肥方式。
