Field lysimeter method was employed to investigate the downward movement and leaching of N applied to summer corn (Zea may L.) on dryland soil in Beiling. A N-fertilizer (120 kg N hm-2) and a control treatment were ar...Field lysimeter method was employed to investigate the downward movement and leaching of N applied to summer corn (Zea may L.) on dryland soil in Beiling. A N-fertilizer (120 kg N hm-2) and a control treatment were arranged for the study. Soil solution was collected at depths of 20, 40, 60, 120 and 170 cm,while leachate was collected at the bottom (200 cm) of the lysimeter. The results showed that the downward movement of NO3-N in soil profile was greatly affected by rainfall pattern. The peak of leached NO3-N from both treatments coincided with the peak of the rainfall. In addition, leached NO3-N from both treatments and rainfall were significantly correlated (P<0.05). The amount of leached NO3-N was not great in the N-fertilizer treatment. The results also suggested that N fertilization could cause NO3-N contamination of groundwater during the rainy season.展开更多
A field experiment about effects of nitrogen application rates and different NO3-N to NH4-N ratios on agronomic, chemical and biological characteristics as well as yield and quality of flue-cured tobacco grown in a bl...A field experiment about effects of nitrogen application rates and different NO3-N to NH4-N ratios on agronomic, chemical and biological characteristics as well as yield and quality of flue-cured tobacco grown in a black soil was conducted from 2004 to 2005 in Heilongjiang Province. The results showed that the nitrogen application rates at 45 kg·hm^-2 with the ratio of 75% NO3-N to 25% NH4-N resulted in the highest potassium and reducing sugar contents in the flue-cured tobacco leaving with the highest quality grade and value. It is recommended that this ni- trogen application rate and NO3-N to NH4-N ratio should be widely applied on flue-cured tobacco grown in the black soil in Heilongjiang Province.展开更多
The upland agricultural soils in North China are distributed north of a line between the Kunlun Mountains, the Qinling Mountains and the Huaihe River. They occur in arid, semi-arid and semi-humid regions and crop prod...The upland agricultural soils in North China are distributed north of a line between the Kunlun Mountains, the Qinling Mountains and the Huaihe River. They occur in arid, semi-arid and semi-humid regions and crop production often depends on rain-fed or irrigation to supplement rainfall. This paper summarizes the characteristics of gross nitrogen（N） transformation, the fate of N fertilizer and soil N as well as the N loss pathway, and makes suggestions for proper N management in the region. The soils of the region are characterized by strong N mineralization and nitrification, and weak immobilization and denitrification ability, which lead to the production and accumulation of nitrate in the soil profile. Large amounts of accumulated nitrate have been observed in the vadose-zone in soils due to excess N fertilization in the past three decades, and this nitrate is subject to occasional leaching which leads to groundwater nitrate contamination. Under farmer＇s conventional high N fertilization practice in the winter wheat-summer maize rotation system（N application rate was approximately 600 kg ha–1 yr–1）, crop N uptake, soil residual N, NH_3 volatilization, NO_3~– leaching, and denitrification loss accounted for around 27, 30, 23, 18 and 2% of the applied fertilizer N, respectively. NH_3 volatilization and NO_3~– leaching were the most important N loss pathways while soil residual N was an important fate of N fertilizer for replenishing soil N depletion from crop production. The upland agricultural soils in North China are a large source of N_2O and total emissions in this region make up a large proportion（approximately 54%） of Chinese cropland N_2O emissions. The “non-coupled strong ammonia oxidation” process is an important mechanism of N_2O production. Slowing down ammonia oxidation after ammonium-N fertilizer or urea application and avoiding transient high soil NH4＋ concentrations are key measures for reducing N_2O emissions in this region. Further N management should aim to minimize N losses from crop and livestock production, and increase the recycling of manure and straw back to cropland. We also recommend adoption of the 4 R（Right soure, Right rate, Right time, Right place） fertilization techniques to realize proper N fertilizer management, and improving application methods or modifying fertilizer types to reduce NH_3 volatilization, improving water management to reduce NO_3~– leaching, and controlling the strong ammonia oxidation process to abate N_2O emission. Future research should focus on the study of the trade-off effects among different N loss pathways under different N application methods or fertilizer products.展开更多
Plant phenotypic plasticity is a common feature that is crucial for explaining interspecific competition, dynamics and biological evolution of plant communities. In this study, we tested the effects of soil CaCO_3(cal...Plant phenotypic plasticity is a common feature that is crucial for explaining interspecific competition, dynamics and biological evolution of plant communities. In this study, we tested the effects of soil CaCO_3(calcium carbonate) on the phenotypic plasticity of a psammophyte, Artemisia ordosica, an important plant species on sandy lands in arid and semi-arid areas of China, by performing pot experiments under different CaCO_3 contents with a two-factor randomized block design and two orthogonal designs. We analyzed the growth responses(including plant height, root length, shoot-leaf biomass and root biomass) of A. ordosica seedlings to different soil CaCO_3 contents. The results revealed that, with a greater soil CaCO_3 content, A. ordosica seedlings gradually grew more slowly, with their relative growth rates of plant height, root length, shoot-leaf biomass and root biomass all decreasing significantly. Root N/P ratios showed significant negative correlations with the relative growth rates of plant height, shoot-leaf biomass and root length of A. ordosica seedlings; however, the relative growth rate of root length increased significantly with the root P concentration increased, showing a positive correlation. These results demonstrate that soil CaCO_3 reduces the local P availability in soil, which produces a non-adaptive phenotypic plasticity to A. ordosica seedlings. This study should prove useful for planning and promoting the restoration of damaged/degraded vegetation in arid and semi-arid areas of China.展开更多
Soil calcium carbonate(CaCO_3) has a strong solid phosphorus effect, and high content of CaCO_3 can significantly reduce the effectiveness of soil phosphorus. To reveal the limiting effect of soil CaCO_3 on the growth...Soil calcium carbonate(CaCO_3) has a strong solid phosphorus effect, and high content of CaCO_3 can significantly reduce the effectiveness of soil phosphorus. To reveal the limiting effect of soil CaCO_3 on the growth of plants on sand land and its mechanism of plant physiology, we performed pot experiments with a two-factor randomized block design and a three-factor orthogonal design for different soil CaCO_3 content treatments using Artemisia ordosica seedlings. In the experiments, we surveyed plant height, aboveground biomass, root length and root weight and analyzed N, P concentrations and RNA content of the seedlings, and discussed the relationships between relative growth rate(RGR) of the seedlings and N:P ratio as well as RNA. Results show that, the RGRs of plant height and above-ground biomass of the seedlings decreased significantly with the increase of soil CaCO_3 content, and those for root length and root weight decreased. The RGRs of plant height and above-ground biomass of the seedlings were significantly negatively correlated with leaf N:P ratios, but significantly positively correlated with leaf RNA content and leaf P concentrations. It can be seen that soil CaCO_3 is a stress factor for the growth of A. ordosica seedlings, and the growth response of the seedlings under the influence of soil CaCO_3 is in line with the Growth Rate Hypothesis.展开更多
To understand the dynamics of added nitrogen (N) in alpine meadow and the role of alpine plants and soil microorganisms in the retention of deposited N, the fate of 15 N labeled nitrate and ammonium salts was...To understand the dynamics of added nitrogen (N) in alpine meadow and the role of alpine plants and soil microorganisms in the retention of deposited N, the fate of 15 N labeled nitrate and ammonium salts was determined in an alpine meadow for two months. Two weeks after 15 N application, total recovery of 15 N from NO - 3_ 15 N was 73.5% while it was 78% from NH + 4_ 15 N. More 15 N was recovered in plants than in soil organic matter or in microbial biomass, irrespective of forms of N added. After one month, 70.6% of added NO - 3_ 15 N and 57.4% of NH + 4_ 15 N were recovered in soils and plants. 15 N recovered in soil organic matter decreased greatly while that recovered in plants varied little, irrespective of the form N. Compared with the results of two weeks after 15 N application, more NO - 3_ 15 N than NH + 4_ 15 N was recovered in microbial biomass. Total recovery was 58.4% (six weeks) and 67% (eight weeks) from NO - 3_ 15 N, and 43.1% and 49% from NH + 4_ 15 N, respectively. Both plants and soil microorganism recovered more NO - 3_ 15 N than NH + 4_ 15 N. But plants recovered more 15 N than soil microorganisms. During the whole experiment plants retained more NO - 3_N and 15 N than soil microorganisms while 15 N recovered in inorganic N pool did not exceed 1% due to lower amount of inorganic N. This indicates that plants play more important roles in the retention of deposited N although microbial biomass can be an important sink for deposited N in early days after N application.展开更多
As a result of intensive greenhouse vegetable production in northern China, the potential risk of nitrogen （N） fertilizer over-applied is increasingly apparent and is threatening ecosystem and the sustainability of ...As a result of intensive greenhouse vegetable production in northern China, the potential risk of nitrogen （N） fertilizer over-applied is increasingly apparent and is threatening ecosystem and the sustainability of food production. An experiment was carried out in Shouguang, Shangdong Province, China to evaluate agronomic benefit and soil quality under different N applications, including the conventional chemical N rate （1000 kg N ha^（-1） season^（-1）, N1）, 70% of N1 （N2）, 70% of N1 ＋ maize straw （N3）, 50% of N1 ＋ maize straw ＋ drip irrigation （N4）, and 0% of N1 （NO）, during two successive growing seasons of autumn-winter （AW） and winter-spring （WS）. The maximum yields for N4 were 1.1 and 1.0 times greater than those for N1 in the AW and WS seasons, respectively. N agronomic efficiency （AEN） and apparent N recovery efficiency （REN） were greatest with the N4. A significant relationship was found between soil NO3-N content and electrical conductivity （EC） （R^2 = 0.61 in the AW season and R^2= 0.29 in the WS season）. Reducing N fertilizer decreased soil NO3-N accumulation （20.9%-37.8% reduction in the AW season and 11.7%-20.1% reduction in the WS season） relative to the accumulation observed for N1 within the 0-100 cm soil layer. Soil urease and invertase activities were not significantly different among N treatments. The N4 treatment would be practical for reducing excess N input and maintaining the sustainability of greenhouse-based intensive vegetable systems in Shouguang.展开更多
文摘Field lysimeter method was employed to investigate the downward movement and leaching of N applied to summer corn (Zea may L.) on dryland soil in Beiling. A N-fertilizer (120 kg N hm-2) and a control treatment were arranged for the study. Soil solution was collected at depths of 20, 40, 60, 120 and 170 cm,while leachate was collected at the bottom (200 cm) of the lysimeter. The results showed that the downward movement of NO3-N in soil profile was greatly affected by rainfall pattern. The peak of leached NO3-N from both treatments coincided with the peak of the rainfall. In addition, leached NO3-N from both treatments and rainfall were significantly correlated (P<0.05). The amount of leached NO3-N was not great in the N-fertilizer treatment. The results also suggested that N fertilization could cause NO3-N contamination of groundwater during the rainy season.
文摘A field experiment about effects of nitrogen application rates and different NO3-N to NH4-N ratios on agronomic, chemical and biological characteristics as well as yield and quality of flue-cured tobacco grown in a black soil was conducted from 2004 to 2005 in Heilongjiang Province. The results showed that the nitrogen application rates at 45 kg·hm^-2 with the ratio of 75% NO3-N to 25% NH4-N resulted in the highest potassium and reducing sugar contents in the flue-cured tobacco leaving with the highest quality grade and value. It is recommended that this ni- trogen application rate and NO3-N to NH4-N ratio should be widely applied on flue-cured tobacco grown in the black soil in Heilongjiang Province.
基金supported by the National Natural Science Foundation of China (41471190)the National Key Research and Development Program of China (2016YFD0800102)+2 种基金the Special Fund for the Agricultural Public Welfare Profession of China (201503106)the Newton Fund, United Kingdom (BB/N013484/1)the GEF on the ‘Towards INMS’
文摘The upland agricultural soils in North China are distributed north of a line between the Kunlun Mountains, the Qinling Mountains and the Huaihe River. They occur in arid, semi-arid and semi-humid regions and crop production often depends on rain-fed or irrigation to supplement rainfall. This paper summarizes the characteristics of gross nitrogen（N） transformation, the fate of N fertilizer and soil N as well as the N loss pathway, and makes suggestions for proper N management in the region. The soils of the region are characterized by strong N mineralization and nitrification, and weak immobilization and denitrification ability, which lead to the production and accumulation of nitrate in the soil profile. Large amounts of accumulated nitrate have been observed in the vadose-zone in soils due to excess N fertilization in the past three decades, and this nitrate is subject to occasional leaching which leads to groundwater nitrate contamination. Under farmer＇s conventional high N fertilization practice in the winter wheat-summer maize rotation system（N application rate was approximately 600 kg ha–1 yr–1）, crop N uptake, soil residual N, NH_3 volatilization, NO_3~– leaching, and denitrification loss accounted for around 27, 30, 23, 18 and 2% of the applied fertilizer N, respectively. NH_3 volatilization and NO_3~– leaching were the most important N loss pathways while soil residual N was an important fate of N fertilizer for replenishing soil N depletion from crop production. The upland agricultural soils in North China are a large source of N_2O and total emissions in this region make up a large proportion（approximately 54%） of Chinese cropland N_2O emissions. The “non-coupled strong ammonia oxidation” process is an important mechanism of N_2O production. Slowing down ammonia oxidation after ammonium-N fertilizer or urea application and avoiding transient high soil NH4＋ concentrations are key measures for reducing N_2O emissions in this region. Further N management should aim to minimize N losses from crop and livestock production, and increase the recycling of manure and straw back to cropland. We also recommend adoption of the 4 R（Right soure, Right rate, Right time, Right place） fertilization techniques to realize proper N fertilizer management, and improving application methods or modifying fertilizer types to reduce NH_3 volatilization, improving water management to reduce NO_3~– leaching, and controlling the strong ammonia oxidation process to abate N_2O emission. Future research should focus on the study of the trade-off effects among different N loss pathways under different N application methods or fertilizer products.
基金supported by the National Key Research and Development Program of China (2016YFC0500706)
文摘Plant phenotypic plasticity is a common feature that is crucial for explaining interspecific competition, dynamics and biological evolution of plant communities. In this study, we tested the effects of soil CaCO_3(calcium carbonate) on the phenotypic plasticity of a psammophyte, Artemisia ordosica, an important plant species on sandy lands in arid and semi-arid areas of China, by performing pot experiments under different CaCO_3 contents with a two-factor randomized block design and two orthogonal designs. We analyzed the growth responses(including plant height, root length, shoot-leaf biomass and root biomass) of A. ordosica seedlings to different soil CaCO_3 contents. The results revealed that, with a greater soil CaCO_3 content, A. ordosica seedlings gradually grew more slowly, with their relative growth rates of plant height, root length, shoot-leaf biomass and root biomass all decreasing significantly. Root N/P ratios showed significant negative correlations with the relative growth rates of plant height, shoot-leaf biomass and root length of A. ordosica seedlings; however, the relative growth rate of root length increased significantly with the root P concentration increased, showing a positive correlation. These results demonstrate that soil CaCO_3 reduces the local P availability in soil, which produces a non-adaptive phenotypic plasticity to A. ordosica seedlings. This study should prove useful for planning and promoting the restoration of damaged/degraded vegetation in arid and semi-arid areas of China.
基金supported by the National Key Research and Development Program of China (2016YFC0500706)
文摘Soil calcium carbonate(CaCO_3) has a strong solid phosphorus effect, and high content of CaCO_3 can significantly reduce the effectiveness of soil phosphorus. To reveal the limiting effect of soil CaCO_3 on the growth of plants on sand land and its mechanism of plant physiology, we performed pot experiments with a two-factor randomized block design and a three-factor orthogonal design for different soil CaCO_3 content treatments using Artemisia ordosica seedlings. In the experiments, we surveyed plant height, aboveground biomass, root length and root weight and analyzed N, P concentrations and RNA content of the seedlings, and discussed the relationships between relative growth rate(RGR) of the seedlings and N:P ratio as well as RNA. Results show that, the RGRs of plant height and above-ground biomass of the seedlings decreased significantly with the increase of soil CaCO_3 content, and those for root length and root weight decreased. The RGRs of plant height and above-ground biomass of the seedlings were significantly negatively correlated with leaf N:P ratios, but significantly positively correlated with leaf RNA content and leaf P concentrations. It can be seen that soil CaCO_3 is a stress factor for the growth of A. ordosica seedlings, and the growth response of the seedlings under the influence of soil CaCO_3 is in line with the Growth Rate Hypothesis.
文摘To understand the dynamics of added nitrogen (N) in alpine meadow and the role of alpine plants and soil microorganisms in the retention of deposited N, the fate of 15 N labeled nitrate and ammonium salts was determined in an alpine meadow for two months. Two weeks after 15 N application, total recovery of 15 N from NO - 3_ 15 N was 73.5% while it was 78% from NH + 4_ 15 N. More 15 N was recovered in plants than in soil organic matter or in microbial biomass, irrespective of forms of N added. After one month, 70.6% of added NO - 3_ 15 N and 57.4% of NH + 4_ 15 N were recovered in soils and plants. 15 N recovered in soil organic matter decreased greatly while that recovered in plants varied little, irrespective of the form N. Compared with the results of two weeks after 15 N application, more NO - 3_ 15 N than NH + 4_ 15 N was recovered in microbial biomass. Total recovery was 58.4% (six weeks) and 67% (eight weeks) from NO - 3_ 15 N, and 43.1% and 49% from NH + 4_ 15 N, respectively. Both plants and soil microorganism recovered more NO - 3_ 15 N than NH + 4_ 15 N. But plants recovered more 15 N than soil microorganisms. During the whole experiment plants retained more NO - 3_N and 15 N than soil microorganisms while 15 N recovered in inorganic N pool did not exceed 1% due to lower amount of inorganic N. This indicates that plants play more important roles in the retention of deposited N although microbial biomass can be an important sink for deposited N in early days after N application.
基金the National Natural Science Foundation of China (No.21107139)the Ministry of Agriculture Public Benefit Research Foundation of China (No.201103007)+1 种基金the Special Fund of Research Institute Technology Development of China (No.2012EG134235)the National Basic Research Program (973 program) of China (No.2007CB109308)
文摘As a result of intensive greenhouse vegetable production in northern China, the potential risk of nitrogen （N） fertilizer over-applied is increasingly apparent and is threatening ecosystem and the sustainability of food production. An experiment was carried out in Shouguang, Shangdong Province, China to evaluate agronomic benefit and soil quality under different N applications, including the conventional chemical N rate （1000 kg N ha^（-1） season^（-1）, N1）, 70% of N1 （N2）, 70% of N1 ＋ maize straw （N3）, 50% of N1 ＋ maize straw ＋ drip irrigation （N4）, and 0% of N1 （NO）, during two successive growing seasons of autumn-winter （AW） and winter-spring （WS）. The maximum yields for N4 were 1.1 and 1.0 times greater than those for N1 in the AW and WS seasons, respectively. N agronomic efficiency （AEN） and apparent N recovery efficiency （REN） were greatest with the N4. A significant relationship was found between soil NO3-N content and electrical conductivity （EC） （R^2 = 0.61 in the AW season and R^2= 0.29 in the WS season）. Reducing N fertilizer decreased soil NO3-N accumulation （20.9%-37.8% reduction in the AW season and 11.7%-20.1% reduction in the WS season） relative to the accumulation observed for N1 within the 0-100 cm soil layer. Soil urease and invertase activities were not significantly different among N treatments. The N4 treatment would be practical for reducing excess N input and maintaining the sustainability of greenhouse-based intensive vegetable systems in Shouguang.
