Liu Ying, Tang Haiying, Smith Pete, Zhong Chuan, Huang Guoqin
College of Agriculture and Biotechnology, Hunan University of Humanities, Science and Technology, Dixing Road, Louxing District, Loudi, 417000, Hunan, China.
Research Center on Ecological Sciences, Jiangxi Agricultural University, No. 1101 Zhimin Avenue, Nanchang Economic and Technological Development Zone, Nanchang, 330045, Jiangxi, China.
Carbon Balance Manag. 2021 Mar 1;16(1):7. doi: 10.1186/s13021-021-00170-x.
Excessive application of chemical fertilizer has resulted in lower nitrogen uptake and utilization efficiency of crops, decreasing soil fertility, increasing greenhouse gas emissions, and worse environmental pollution. Organic material retention is regard as the key to solve these problems. The objective of this study is to conduct an assessment of carbon budget under Astragalus sinicus L. and rice straw retention combined with reduced mineral fertilizer based on the 2-year field experiment in a paddy field in the south of China. The experiment was randomized complete block design including four treatments with triplicates: control CK (winter follow, 120 kg ha N fertilizer for each rice season) and three treatments with Astragalus sinicus L. and rice straw retention named RA, RB, and RC (reduced N fertilizer by 15%, 27.5%, and 40% in each rice season).
Treatments RA, RB, and RC increased greenhouse gas emissions by 9.30-101.25%, among which CH accounted for more than 60%; Carbon input of crops from treatments RA, RB, and RC increased by 2.25-12.10% compared with control CK over the 2 years. Though treatments RA, RB, and RC enhanced CO emissions, treatment RB decreased carbon footprint and became carbon sink.
The results of this study reveal that treatment RB (Astragalus sinicus L. and rice straw retention with reduced N fertilizer by 27.5%) is better in reducing chemical fertilizer amount, increasing crop yield and carbon input, which is more conductive to sustainable development of agriculture.
化肥的过量施用导致作物氮素吸收和利用效率降低，土壤肥力下降，温室气体排放增加，环境污染加剧。有机物料还田被视为解决这些问题的关键。本研究的目的是基于中国南方稻田为期两年的田间试验，对紫云英和稻草还田并减少矿物肥料施用量的情况下进行碳预算评估。试验采用随机完全区组设计，包括四个处理，每个处理重复三次：对照CK（冬季休耕，每个水稻季施氮肥120 kg·ha）以及三个紫云英和稻草还田处理，分别命名为RA、RB和RC（每个水稻季氮肥减少15%、27.5%和40%）。
处理RA、RB和RC使温室气体排放量增加了9.30% - 101.25%，其中CH占比超过60%；与对照CK相比，处理RA、RB和RC在两年内作物的碳输入增加了2.25% - 12.10%。虽然处理RA、RB和RC增加了CO排放，但处理RB降低了碳足迹并成为碳汇。
本研究结果表明，处理RB（紫云英和稻草还田，氮肥减少27.5%）在减少化肥用量、提高作物产量和碳输入方面表现更好，更有利于农业的可持续发展。
