Effects of Root Layer Regulation on Nitrogen Utilization and Soil NO3--N Residue of Wheat-Maize System
[Objective] Low resource utilization efficiency of water and fertilizer and high soil nitrogen accumulation were common problems of the winter wheat-summer maize system in the North China Plain. This study was conducted to investigate the effects of different root layer regulation measures on nitrogen utilization and soil NO3--N residue of crops.[Method] The field experiment was conducted in the high-yield farmlands in North China Plain. Traditional water-nitric nitrogen, water-nitric nitrogen regulation, regulation+Agh (soil conditioner), regulation+CRU (controlled-release urea), regulation+GGR (plant growth regulator) were designed as five treatments. Soil, plant and root samples were collected and measured, and the nitrogen utilization effects of different root layer regulation measures were analyzed.[Result]The results indicated that under the premise of controlling water and nitrogen, the wheat-maize yield and nitrogen uptake in Agh and GGR treatments were higher than traditional water and nitrogen treatments. At jointing stage of wheat, roots at 80-100 cm soil layers in GGR treatment distributed much, which shows that GGR could promote the development of roots at lower layer. At bell stage of maize, at 20-50 cm layer, root length density of Agh treatment in Gaocheng and GGR treatment in Daming was significantly higher than those of traditional water and nitrogen treatment. In the first rotation season, in 0-200 cm layer, the soil residual nitrate-N in GGR treatment in Gaocheng and Shenzhou was significantly lower than that of traditional water and nitrogen treatment, especially at 60-100 cm layer soil residue nitrate nitrogen was the lowest. In the second rotation season, the soil residual nitrate-N in Agh treatment in Gaocheng and GGR treatment in Daiming were significantly lower than traditional water and nitrogen treatment. The amount of apparent deficiency of nitrogen of Agh in the first rotation season and GGR (Gaocheng) in the second rotation season was large, which indicate that root regulation could promote crop to absorb soil accumulated nitrogen. Root layer regulation measures were of benefits to economy and ecology, Water Use Efficiency (WUE) and Partial Factor ProductivityNitrogen (PFPN) increased by 2.47 kg·m-3 and 18.08 kg·kg-1 compared with traditional water and nitrogen treatment, and the average income was 258.43 yuan/667 m2.[Conclusion] In high yield land in the North China Plain, different root-layer regulation measures of single cropping and annual production of wheat and maize respectively increased by 8.58%, 5.99% and 7.13% in average compared with the traditional water and nitrogen treatment. After two seasons the residue of soil nitrate nitrogen in 0-100 cm layer soil were reduced by 70.73 kg·hm-2 and 59.44 kg·hm-2 in average compared with the conventional water and nitrogen treatment, obviously reduced the residue of soil nitrate nitrogen, slowed the leaching loss of nitrogen to deep soil, and promoted root development during critical growing period of wheat-maize. All in all, Agh and GGR were effective measures to improve crops yield, use the soil accumulated nitrogen, achieve cost synergies and improve water and fertilizer use efficiency.
国家科技期刊平台
NSTL
万方数据
维普
