Soil loss due to crop harvesting （SLCH） is a soil erosion process that signiifcantly contributes to soil degradation in crop-lands. However, little is known about soil nutrient losses caused by SLCH and its environm...Soil loss due to crop harvesting （SLCH） is a soil erosion process that signiifcantly contributes to soil degradation in crop-lands. However, little is known about soil nutrient losses caused by SLCH and its environmental impacts. In the North China Plain area, we measured the losses of soil organic carbon （SOC） and nitrogen as wel as phosphorus due to SLCH and assessed their relationship with soil particle size composition, agronomic practices and soil moisture content. Our results show that the losses by harvesting potato of SOC, total nitrogen （TN）, available nitrogen （AN）, available phosphorus （AP） and total phosphorus （TP） were 1.7, 1.8, 1.8, 15.9 and 14.1 times compared by harvesting sweet potato, respectively. The variation of SOC, N and P loss by SLCH are mainly explained by the variation of plant density （PD） （17–50%）, net mass of an individual tuber （Mcrop/p） （16–74%）, soil clay content （34–70%） and water content （19–46%）. Taking into account the current sewage treatment system and the ratio of the nutrients adhering to the tubers during transportation from the ifeld （NTRP/SP）, the loss of TN and TP by harvesting of potato and sweet potato in the North China Plain area amounts to 3% N and 20% P loads in the water bodies of this region. The fate of the exported N and P in the sewage treatment system ultimately controls the contribution of N and P to the polution of lakes and rivers. Our results suggest that a large amount of SLCH-induced soil nutrient export during transportation from the ifeld is a potential polutant source for agricultural water for vast planting areas of tuber crops in China, and should not be overlooked.展开更多
The critical nitrogen dilution curve (CNDC) can be used as a diagnostic tool to assess crop N nutrition during the growing season. Potato cultivars have different biomass production and accumulation of N and consequen...The critical nitrogen dilution curve (CNDC) can be used as a diagnostic tool to assess crop N nutrition during the growing season. Potato cultivars have different biomass production and accumulation of N and consequently different growth patterns. These differences among cultivars may result in different CNDC. The aims were a) to determine the CNDC for different potato cultivars;b) to compare these curves with reference curves;and c) to assess the possibility of using the CNDC to estimate the N nutritional status of the crop. The biomass production and N concentration of shoots and tubers of potato cultivars Innovator, Gem Russet, Umatilla Russet, Bannock Russet and Markies Russet were measured. The harvest index (HI) and N harvest index (NHI) were determined. The coefficient a of the CNDC was similar among cultivars, while the coefficients b for Innovator and Gem Russet (-0.42 and -0.36, respectively) were smaller than those for the other cultivars (average -0.25). HI and NHI were greater in Innovator, smaller in Markies Russet, and intermediated in the other three cultivars. The coefficients b of the CNDC were correlated with HI and NHI (HI, r = -0.62, p < 0.0001 and -0.53, p < 0.0001;NHI, r = -0.60, p < 0.0001 and -0.61, p < 0.0001 for 2004/5 and 2005/6, respectively). The relationship between relative tuber yield (RY) and N nutrition index (NNI) was fit by a quadratic-plateau function. At similar situations of N deficiency, Innovator had lower yield and greater response to N rate than the other potato cultivars. The differences in HI and NHI among cultivars may explain the differences in the coefficient b of the CNDC. The NNI identified the status of N adequately in potato cultivars.展开更多
基金the National Natural Science Foundation of China(31000944 and 41171231)the International Atomic Energy Agency,Vienna(18176 and 17908)+1 种基金the State Level Public Welfare Institute Basic Scientific Research Project of China(BSRF201407)the National Key Technologies R&D Program of China during the 12th Five-year Plan period(2013BAD11B03)for financial supports
文摘Soil loss due to crop harvesting （SLCH） is a soil erosion process that signiifcantly contributes to soil degradation in crop-lands. However, little is known about soil nutrient losses caused by SLCH and its environmental impacts. In the North China Plain area, we measured the losses of soil organic carbon （SOC） and nitrogen as wel as phosphorus due to SLCH and assessed their relationship with soil particle size composition, agronomic practices and soil moisture content. Our results show that the losses by harvesting potato of SOC, total nitrogen （TN）, available nitrogen （AN）, available phosphorus （AP） and total phosphorus （TP） were 1.7, 1.8, 1.8, 15.9 and 14.1 times compared by harvesting sweet potato, respectively. The variation of SOC, N and P loss by SLCH are mainly explained by the variation of plant density （PD） （17–50%）, net mass of an individual tuber （Mcrop/p） （16–74%）, soil clay content （34–70%） and water content （19–46%）. Taking into account the current sewage treatment system and the ratio of the nutrients adhering to the tubers during transportation from the ifeld （NTRP/SP）, the loss of TN and TP by harvesting of potato and sweet potato in the North China Plain area amounts to 3% N and 20% P loads in the water bodies of this region. The fate of the exported N and P in the sewage treatment system ultimately controls the contribution of N and P to the polution of lakes and rivers. Our results suggest that a large amount of SLCH-induced soil nutrient export during transportation from the ifeld is a potential polutant source for agricultural water for vast planting areas of tuber crops in China, and should not be overlooked.
文摘The critical nitrogen dilution curve (CNDC) can be used as a diagnostic tool to assess crop N nutrition during the growing season. Potato cultivars have different biomass production and accumulation of N and consequently different growth patterns. These differences among cultivars may result in different CNDC. The aims were a) to determine the CNDC for different potato cultivars;b) to compare these curves with reference curves;and c) to assess the possibility of using the CNDC to estimate the N nutritional status of the crop. The biomass production and N concentration of shoots and tubers of potato cultivars Innovator, Gem Russet, Umatilla Russet, Bannock Russet and Markies Russet were measured. The harvest index (HI) and N harvest index (NHI) were determined. The coefficient a of the CNDC was similar among cultivars, while the coefficients b for Innovator and Gem Russet (-0.42 and -0.36, respectively) were smaller than those for the other cultivars (average -0.25). HI and NHI were greater in Innovator, smaller in Markies Russet, and intermediated in the other three cultivars. The coefficients b of the CNDC were correlated with HI and NHI (HI, r = -0.62, p < 0.0001 and -0.53, p < 0.0001;NHI, r = -0.60, p < 0.0001 and -0.61, p < 0.0001 for 2004/5 and 2005/6, respectively). The relationship between relative tuber yield (RY) and N nutrition index (NNI) was fit by a quadratic-plateau function. At similar situations of N deficiency, Innovator had lower yield and greater response to N rate than the other potato cultivars. The differences in HI and NHI among cultivars may explain the differences in the coefficient b of the CNDC. The NNI identified the status of N adequately in potato cultivars.
