Impacts of conservation agriculture on soil structure and hydraulic properties of Malawian agricultural systems
Impacts of conservation agriculture on soil structure and hydraulic properties of Malawian agricultural systems
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DOI：
10.1016/j.still.2020.104639
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发表时间：
2020-07-01
影响因子：
6.5
通讯作者：
Thierfelder, Christian
中科院分区：
文献类型：
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作者：
Eze, Samuel;Dougill, Andrew J.;Thierfelder, Christian
撒哈拉以南非洲地区 (SSA) 面临气候变化和粮食不安全的挑战，需要采取行动创建有复原力的农业系统。保护性农业（CA）在整个撒哈拉以南非洲地区得到广泛推广，但其对关键土壤物理性质和功能（例如控制水储存和输送的土壤结构和水力性质）的影响尚不清楚。本研究的目的是评估长期（10-12 年）玉米基 CA 对土壤导水率、保水性和孔径分布的影响。将传统玉米单作农业系统 (CP) 的根区（0-30 厘米深）土壤总孔隙度、孔径分布、饱和导水率 (K-sat) 和植物有效水容量 (PAWC) 与相邻的单作玉米或玉米与豇豆 (Vigna unguiculata L.)、木豆 (Cajanus cajan L.) 或绒豆 (Mucuna pruriens) 间作/轮作的 CA 试验进行比较L.）在马拉维中部和南部的试验地点。结果表明，基于玉米的 CA 系统会导致土壤水力特性发生显着变化，从而改善土壤结构。结果表明，总孔隙率增加了 5-15%，K-sat 增加了 0.06 - 0.22 厘米/分钟，储水细孔增加了 3-7%，PAWC 增加了 3-6%。玉米单作 CA 对水力特性的影响与玉米-豆类组合相似。 CA 系统的 K sat 值在最佳水平 (0.03-0.3 cm/min) 内，而 PAWC 低于最佳水平 (< 20 %)。 CA 系统中的土壤有机质 (OM) 没有显着积累。研究结果提出建议，农业推广人员应在 CA 指导中更加积极主动地推行农作物残留物管理，以提高土壤 OM 水平、增加产量并增强撒哈拉以南非洲农业系统的气候适应能力。
Sub-Saharan Africa (SSA) faces climate change and food insecurity challenges, which require action to create resilient farming systems. Conservation agriculture (CA) is widely promoted across SSA but the impacts on key soil physical properties and functions such as soil structure and hydraulic properties that govern water storage and transmission are not well understood. The aim of this study was to assess the impacts of long term (10-12 years) maize-based CA on soil hydraulic conductivity, water retention and pore size distribution. Root zone (0-30 cm depth) soil total porosity, pore size distribution, saturated hydraulic conductivity (K-sat) and plant available water capacity (PAWC) of conventional maize monocrop farming systems (CP) are compared with those of adjacent CA trials with either sole maize or maize intercrop/rotation with cowpea (Vigna unguiculata L.), pigeon pea (Cajanus cajan L.) or velvet bean (Mucuna pruriens L.) in trial locations across central and southern Malawi. Results show that maize-based CA systems result in significant changes to soil hydraulic properties that correlate with improved soil structure. Results demonstrate increases of 5-15 % in total porosity, 0.06 - 0.22 cm/min in K-sat, 3-7 % in fine pores for water storage and 3-6 % in PAWC. Maize monocrop CA had similar effect on the hydraulic properties as the maize-legume associations. The values of K sat for CA systems were within optimum levels (0.03-0.3 cm/min) whereas PAWC was below optimum (< 20 %). There was no significant build-up in soil organic matter (OM) in the CA systems. The results lead to a recommendation that crop residue management should be more pro-actively pursued in CA guidance from agricultural extension staff to increase soil OM levels, increase yields and enhance climate resilience of sub-Saharan African farming systems.