Yang Guoying, Ji Hongting, Liu Hongjiang, Feng Yanfang, Zhang Yuefang, Chen Liugen, Guo Zhi
Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China.
Key Laboratory for Crop and Animal Integrated Farming, Ministry of Agriculture, Nanjing, Jiangsu, China.
PeerJ. 2021 Mar 16;9:e11077. doi: 10.7717/peerj.11077. eCollection 2021.
Excessive nitrogen (N) application rate with low N use efficiency (NUE) caused a considerable amount of N losses, especially ammonia volatilization (AV). Proper N fertilizer reduction (RN) could significantly reduce AV. However, continuous RN led to a nutrient deficiency in the soil and therefore negatively impacted the NUE and rice yield. Paddy , a good green manure, is considered as a promising measure to decrease AV and improve NUE and grain yield of rice. However, there is limited information on the integrated effects of RN and cover on the AV, NUE, and rice yield, especially in the highly fertilized rice-growing systems.
The experiment was conducted including eight treatments: the control (without N fertilizer and cover), cover without N fertilizer (A), farmer's N application rate (FN), FN + cover (FNA), 15% RN from FN (RN), RN + cover (RNA). 30% RN from FN (RN), RN + cover (RNA). The integrated effects of N fertilizer reduction and cover on AV, NUE, and rice grain was evaluated.
RNA and RNA substantially reduced total AV by 50.3 and 66.9% compared with FN, respectively, primarily due to the lower surface water ammonia concentrations and pH. RN improved the efficiency of cover on reducing AV, with 4.1-9.9% higher than for FN. Compared with the FN, RNA and RNA enhanced apparent N recovery efficiency (ANRE) by 46.5 and 39.1%, which might be responsible for the lower NH emission and the increased total N uptake / total chemical N applied. Furthermore, RNA and RNA reduced yield-scaled volatilization by 52.3 and 64.3% than for FN, respectively. Thus, combining 15-30% RN with cover may be a way to reduce AV and improve ANRE without decreasing rice grain yield.
氮肥施用量过高且氮素利用效率（NUE）低导致大量氮素损失，尤其是氨挥发（AV）。适当减少氮肥用量（RN）可显著降低氨挥发。然而，持续减少氮肥用量会导致土壤养分缺乏，从而对氮素利用效率和水稻产量产生负面影响。稻田绿肥是一种很有前景的措施，可减少氨挥发，提高水稻的氮素利用效率和籽粒产量。然而，关于减少氮肥用量和覆盖物对氨挥发、氮素利用效率和水稻产量的综合影响的信息有限，尤其是在高施肥量的水稻种植系统中。
进行了包括八个处理的试验：对照（不施氮肥和无覆盖物）、不施氮肥的覆盖物（A）、农民习惯施氮量（FN）、FN + 覆盖物（FNA）、在FN基础上减少15%氮肥用量（RN）、RN + 覆盖物（RNA）、在FN基础上减少30%氮肥用量（RN）、RN + 覆盖物（RNA）。评估了减少氮肥用量和覆盖物对氨挥发、氮素利用效率和水稻籽粒的综合影响。
与FN相比，RNA和RNA分别使总氨挥发量大幅降低了50.3%和66.9%，主要原因是地表水氨浓度和pH值较低。减少氮肥用量提高了覆盖物减少氨挥发的效率，比FN高4.1 - 9.9%。与FN相比，RNA和RNA使表观氮素回收效率（ANRE）提高了46.5%和39.1%，这可能是氨排放量较低和总氮吸收量/总化学氮肥施用量增加的原因。此外，RNA和RNA的产量尺度挥发量分别比FN降低了52.3%和64.3%。因此，将15 - 30%的氮肥用量减少与覆盖物相结合可能是一种在不降低水稻籽粒产量的情况下减少氨挥发和提高表观氮素回收效率的方法。
