Effects of a catch crop and reduced nitrogen fertilization on nitrogen leaching in greenhouse vegetable production systems
J.M.n; Weiming Shi; Guangxi Xing; Hailin Zhang; Zhaoliang Zhu
Nutrient Cycling in Agroecosystems 91(1): 31-39
Greenhouse vegetable cultivation has greatly increased productivity but has also led to a rapid accumulation of nitrate in soils and probably in plants. Significant losses of nitrate nitrogen (NO3-N) could occur after heavy N fertilization under open-field conditions combined with high precipitation in the summer. It is urgently needed to improve N management under the wide spread greenhouse vegetable production system. The objective of this study was to evaluate the effects of a summer catch crop and reduced N application rates on N leaching and vegetable crop yields. During a 2-year period, sweet corn as an N catch crop was planted between vegetable crops in the summer season under 5 N fertilizer treatments (, 348, 522, 696, and 87 kg ha?1) in greenhouse vegetable production systems in Tai Lake region, southern China. A water collection system was installed at a depth of .5 m in the soil to collect leachates during the vegetable growing season. The sweet corn as a catch crop reduced the total N concentration from 94 to 59 mg l?1 in leached water and reduced the average soil nitrate N from 36 to 195 mg kg?1 in the top .1-m soil during the fallow period of local farmers N application rate (87 kg ha?1). Reducing the amount of N fertilizer and using catch crop during summer fallow season reduced total N leaching loss by 5 and 73%, respectively, without any negative effect on vegetable yields.