• ISSN 1008-505X
  • CN 11-3996/S
HE Hu, WU Jian-fu, ZENG Yan-hua, HU Kai, HUANG Shan, ZENG Yong-jun, PAN Xiao-hua, SHI Qing-hua. Effects of nitrogen management on yield and nitrogen utilization of double cropping late rice under total rice straw incorporation[J]. Journal of Plant Nutrition and Fertilizers, 2014, 20(4): 811-820. DOI: 10.11674/zwyf.2014.0403
Citation: HE Hu, WU Jian-fu, ZENG Yan-hua, HU Kai, HUANG Shan, ZENG Yong-jun, PAN Xiao-hua, SHI Qing-hua. Effects of nitrogen management on yield and nitrogen utilization of double cropping late rice under total rice straw incorporation[J]. Journal of Plant Nutrition and Fertilizers, 2014, 20(4): 811-820. DOI: 10.11674/zwyf.2014.0403

Effects of nitrogen management on yield and nitrogen utilization of double cropping late rice under total rice straw incorporation

  • 【Objectives】Rice straw incorporation and appropriate nitrogen (N) management can not only improve soil fertility and crop yield, but also reduce environmental pollution. With the rapid development of mechanized harvest, the area of in situ total incorporation of rice straw is expanded rapidly. Thus, it is important to determine reasonable N fertilization regimes under the total incorporation of rice straw. The objective of this study is to investigate the proper management for late rice under total incorporation of chopped early rice straw by a combine harvester. 【Methods】Using a late rice variety (Ganxin 688) as materials the experiment included four N rates (0, 120, 180 and 240 kg/ha) with a ratio of 5∶2∶3 for basal, tillering, and panicle initiation, respectively. At the same time, under the N rate of 180 kg/ha, a control treatment without straw return and different N application ratios (5∶0∶5, 5∶1∶4, 5∶2∶3, 5∶3∶2, 5∶4∶1, 5∶5∶0 for basal, tillering, and panicle initiation, respectively) under total incorporation of rice straw were arranged. Rice yield, yield components, N absorption and utilization in different treatments were investigated. 【Results】The yield increased with increasing N application rates, and was highest at the N rate of 180 kg/ha under total incorporation of rice straw. The number of effective panicles increased with increasing application rates, while the percentage of filled grains showed the opposite trend. In comparison with no straw retention, the higher yield under straw retention mainly attributed to the higher number of effective panicles, percentage of filled grains and 1000\|grain weights, with an increase of 8.83% in yield. Under the same N rate, the yield, number of grains per panicle, and 1000\|grain weight were the highest at the N ratio of 5∶2∶3. The number of effective panicles decreased with increasing N proportions at the tillering stage, while the percentage of filled grains showed no significant differences among treatments. Under straw incorporation, the N accumulation, N recovery efficiency (NRE), N uptake rate (NUR) and N requirement for producing 100-kg grain increased with increasing N application rates. However, N harvest index (NHI) and nitrogen physiological efficiency (NPE) decreased with increasing N application rates. Under the same N rate, the nitrogen agronomic efficiency (NAE) and NPE under total incorporation of rice straw were significantly higher than those under no straw incorporation. The correlation between yield and N accumulation was quadratic. NRE and NUR were significantly positively correlated with yield. Under the same nitrogen rate with total incorporation of rice straw, total N accumulation (TNA), N accumulation ratio in middle stage, NRE, NHI, and NUR were decreased with decreasing N proportions at panicle initiation, whereas N accumulation and ratio in early stage were increased. Both NAE and NPE were increased at first, but then decreased with decreasing N proportions at panicle initiation with the highest at the ratio of 5∶2∶3. The N application rate at panicle initiation was significantly positively correlated with TNA, N accumulation in middle stage, NRE, NHI and NUR, while NAE and NPE were positively correlated with yield. 【Conclusion】The highest yield achieved when the N application rate is 180 kg/ha. The N accumulation, NRE, NUR and N requirement for producing 100-kg grain increased with increasing N application rates from 0 to 240 kg/ha. Under the same N application rate, the highest yield, the highest NAE and NPE can be achieved with the N application ratio of 5∶2∶3 for basal, tillering, and panicle initiation, respectively.
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