Carbon sequestration and selected hydraulic characteristics under conservation agriculture and traditional tillage practices in Malawi
Carbon sequestration and selected hydraulic characteristics under conservation agriculture and traditional tillage practices in Malawi
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DOI：
10.1071/sr20007
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发表时间：
2020-10
期刊：
影响因子：
1.6
通讯作者：
Pacsu L. Simwaka;E. Tesfamariam;A. Ngwira;P. Chirwa
中科院分区：
文献类型：
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作者：
Pacsu L. Simwaka;E. Tesfamariam;A. Ngwira;P. Chirwa
保护性农业（CA）在撒哈拉以南非洲的小农中得到越来越多的推广，以期改善粮食安全，同时维持农业生态系统的自然资源基础。本研究的目的是调查马拉维两个对比农业生态区的 CA 和传统耕作对土壤有机碳 (SOC) 和选定水力特性的影响。六名农民在每个地点进行了农场试验，每个农民都接受了以下处理：连续鳅玉米的CA（CA-SM）、玉米-豆类间作的CA（CA-ML）和连续鳅玉米的传统耕作（CT-SM）。土壤样本于 2015 年 10 月从位于 Chipeni、Chinguluwe、Lemu 和 Zidyana 的农民田地中随机采集，这些地区的 CA 已实施了 10 年（2005-2015 年），六个深度间隔为：0-10、10-20、20-40、40-60、60-80 和 80-100 厘米。使用未扰动的岩心样品测定堆积密度、土壤水特性和孔径分布。在所有地点，CA 都提高了总 SOC、碳储量和颗粒有机碳的稳定比例。在 Chipeni、Lemu 和 Zidyana，CA 下的玉米-豆类间作比 CT-SM 的总 SOC 分别高出 35%、33% 和 73%。在 Chinguluwe 和 Lemu，CA-ML 的颗粒有机碳 (POMP) 含量分别比 CT-SM 稳定 0.54 和 0.50 g kg-1；而在奇佩尼，CA-SM 的 POMP 比 CT-SM 高 0.73 g kg-1。与 CT-SM 相比，CA 还通过增加中孔和微孔的比例来改善土壤孔隙度、孔径分布和保水能力。因此，将管理实践从 CT-SM 改为 CA 有可能改善马拉维农业生态区的土壤有机质和土壤水力特性，这对于可持续农业非常重要。应鼓励农民尽量减少耕作，将残留物保留在土壤表面作为覆盖物，并实行轮作。
Conservation agriculture (CA) is increasingly promoted among smallholder farmers of sub-Saharan Africa in a quest to improve food security while sustaining the natural resource base of the agro-ecosystems where agriculture is based. The aim of this study was to investigate the effects of CA and traditional tillage on soil organic carbon (SOC) and selected hydraulic properties in two contrasting agro-ecological zones of Malawi. Six farmers hosted on-farm trials in each location, with each farmer having the following treatments: CA with continuous sole maize (CA-SM), CA with maize–legume intercrops (CA-ML), and traditional tillage with continuous sole maize (CT-SM). Soil samples were randomly collected in October 2015, from farmers’ fields located in Chipeni, Chinguluwe, Lemu, and Zidyana where CA had been implemented for 10 years (2005–2015) at six depth intervals: 0–10, 10–20, 20–40, 40–60, 60–80, and 80–100 cm. Bulk density, soil water characteristics, and pore size distribution were determined using undisturbed core samples. At all sites, CA improved total SOC, carbon stocks, and the stable fraction of particulate organic carbon. Maize–legume intercropping under CA had 35%, 33%, and 73% more total SOC than CT-SM in Chipeni, Lemu, and Zidyana respectively. In Chinguluwe and Lemu, CA-ML had 0.54 and 0.50 g kg–1 respectively more stable fraction of particulate organic carbon (POMP) than CT-SM; whereas in Chipeni, CA-SM had 0.73 g kg–1 higher POMP compared with CT-SM. CA also improved soil porosity, pore size distribution, and water retention capacity by increasing the proportion of mesopores and micropores compared with CT-SM. Thus, changing management practices from CT-SM to CA has the potential to improve the soil organic matter and soil hydraulic properties across agro-ecological zones in Malawi, which is important for sustainable agriculture. Farmers should be encouraged to minimise tillage, retain residues as mulch on the soil surface, and practice crop rotation.