Soil nitrate accumulation, leaching and crop nitrogen use as influenced by fertilization and irrigation in an intensive wheat–maize double cropping system in the North China Plain

Abstract

There is a growing concern about excessive nitrogen (N) and water use in agricultural systems in North China due to the reduced resource use efficiency and increased groundwater pollution. A two-year experiment with two soil moisture by four N treatments was conducted to investigate the effects of N application rates and soil moisture on soil N dynamics, crop yield, N uptake and use efficiency in an intensive wheat-maize double cropping system (wheat-maize rotation) in the North China Plain. Under the experimental conditions, crop yield of both wheat and maize did not increase significantly at N rates above 200 kg N ha maize crop has higher N use efficiency than wheat crop. Higher NO 3 -N leaching occurred in maize season than in wheat season due to more water leakage caused by the concentrated summer rainfall. The results of this study indicate that the optimum N rate may be much lower than that used in many areas in the North China Plain given the high level of N already in the soil, and there is great potential for reducing N inputs to increase N use efficiency and to mitigate N leaching into the groundwater. Avoiding excess water leakage through controlled irrigation and matching N application to crop N demand is the key to reduce NO 3 -N leaching and maintain crop yield. Such management requires knowledge of crop water and N demand and soil N dynamics as they change with variable climate temporally and spatially. Simulation modeling can capture those interactions and is considered as a powerful tool to assist in the future optimization of N and irrigation managements.

Leaching losses of nitrate nitrogen and dissolved organic nitrogen from a yearly two crops system, wheat-maize, under monsoon situations

“…This implied that rainfall and irrigation episodes during the first two winter wheat seasons had little effect on water seepage at the 2.0-m soil layer. Field observation and modeling in the NCP also suggested that no leakage occurred even under the recommended amount of irrigation (B75 mm) during the winter wheat season assuming 1-m as the rooting zone (Fan et al 2001;Gong and Li 1995;Yuan et al 1995).…”

Application of Nitrogen Fertilizers and its Effect on Timeliness of Fertilizers Decomposition Resulting in Lost of Nitrogen Through Nitrous Oxide Emissions from Soil

“…N leaching as it was emphasised by Šima et al (2014a) and Šima et al (2014b). Moreover, Fang et al (2006) conducted an experiment with two soil moisture by four N treatments. The study was conducted to investigate the effects of N application doses and soil moisture on soil N dynamics.…”

Water use efficiency and yield of cowpea and nutrient loss in lysimeter experiment under varying water table depth, irrigation schedules and irrigation method

“…The NO 3 -N in the drained solution for all treatment options was higher than NH 4 -N because of the higher solubility and lower affinity of NO 3 -ions for the adsorption sites in the soil. Significant higher (about 1.2 folds) N-(NO 3 -+NH 4 + ), P and K leaching occurred at deeper water table (90±1.5 cm depth) than shallow water table (30±1.5 cm depth) probably due to the higher starting available nutrients in the lower water table (Fang et al, 2006). On the other hand, 42.3, 50.0 and 56.4% losses of N-(NO 3 -+NH 4 + ), P and K, respectively, were recorded with 6 irrigations scheduled for IW: CPE of 0.3; these nutrient losses found maximum as compared to different water table depths and irrigation methods.…”