Effects of Long-Term Winter Planted Green Manure on Distribution and Storage of Organic Carbon and Nitrogen in Water-Stable Aggregates of Reddish Paddy Soil Under a Double-Rice Cropping System

• Published in: Journal of Integrative Agriculture Vol. 13; no. 8; pp. 1772 - 1781
• Main Authors: YANG, Zeng-ping, ZHENG, Sheng-xian, NIE, Jun, LIAO, Yu-lin, XIE, Jian
• Format: Journal Article
• Language: English
• Published: Science Press 01.08.2014; Soil and Fertilizer Institute of Hunan Province, Hunan Academy of Agricultural Sciences, Changsha 410125, P.R.China; Elsevier
• Subjects: green manure; green manure organic carbon reddish paddy soil total nitrogen water-stable aggregates; organic carbon; reddish paddy soil; total nitrogen; water-stable aggregates; 冬季; 土壤有机质; 存储; 有机碳; 水稳性团聚体; 种植系统; 红壤性水稻土; 绿肥; water-stable aggregates; reddish paddy soil; green manure; total nitrogen; organic carbon
• ISSN: 2095-3119; 2352-3425
• DOI: 10.1016/s2095-3119(13)60565-1

In agricultural systems, maintenance of soil organic matter has long been recognized as a strategy to reduce soil degradation. Manure amendments and green manures are management practices that can increase some nutrient contents and improve soil aggregation. We investigated the effects of 28 yr of winter planted green manure on soil aggregate-size distribution and aggregateassociated carbon（C） and nitrogen（N）. The study was a randomized completed block design with three replicates. The treatments included rice-rice-fallow, rice-rice-rape, rice-rice-Chinese milk vetch and rice-rice-ryegrass. The experiment was established in 1982 on a silty light clayey paddy soil derived from Quaternary red clay（classified as Fe-Accumuli-Stagnic Anthrosols） with continuous early and late rice. In 2009, soil samples were collected（0-15 cm depth） from the field treatment plots and separated into water-stable aggregates of different sizes（i.e., 〉5, 2-5, 1-2, 0.5-1, 0.25-0.5 and 〈0.25 mm） by wet sieving. The long-term winter planted green manure significantly increased total C and N, and the formation of the 2-5-mm water-stable aggregate fraction. Compared with rice-rice-rape, rice-rice-Chinese milk vetch and rice-rice-ryegrass, the rice-rice-fallow significantly reduced 2-5-mm water-stable aggregates, with a significant redistribution of aggregates into micro-aggregates. Long-term winter planted green manure obviously improved C/N ratio and macro-aggregate-associated C and N. The highest contribution to soil fertility was from macro-aggregates of 2-5 mm in most cases.