Difficulties in efficient utilization of seasonal precipitation cause limitations in yields and even total crop failure on rainfed farms in semi-arid East Africa. The objective of the present study was to find out if covering the soil with plant residue mulch at a semi-arid site could retain water in the soil between precipitation events and build dry spell resilience by reducing soil water evaporation and increasing infiltration to deeper soil. Covering soil with plant residue mulch was studied at a smallholder farm in semi-arid Kenya by continuously measuring volumetric soil moisture content with soil sensors at multiple depths in bare soil and in maize (Zea mays L.) plant residue mulched soil. A physically based one-dimensional soil moisture model was calibrated and used to estimate the effect of plant residue mulch on soil moisture over a two-year period (multiple growing seasons). The modelled multiyear time series provides an estimate of the effect residue mulches of different thicknesses have on soil moisture over time. The simple soil moisture model was able to estimate soil moisture in the effective root zone of maize. By comparing measured data from mulched and uncovered soil and by model prediction, it was demonstrated that maize residue mulch conserved soil moisture over time in the effective root zone of maize compared to bare soil. During the two-year period mulching increased the total amount of days when measured relative soil moisture (s) exceeded water stress limit of maize (s*) by 24%–46%. Moisture accumulated in the mulched profile, especially in the deeper layers of the effective root zone. Calculations indicated that further increasing mulch thickness (δ_m) from 1 to 3 cm would have increased the total days when s > s* 59%. Furthermore, increasing δ_m from 3 to 5 cm would have resulted in 25% increase in total days when s > s*. According to our calculations mulching (δ_m > 1 cm) could have maintained s > s* throughout a 19 days dry spell that occurred during the measurement period. The demonstrated moisture conserving effect of mulch increases with δ_m, but availability of plant residue may set limits on mulch application rates. The results suggest that maize residue mulching is as an accessible and feasible method for conserving soil moisture in the effective root zone in dryland smallholder systems in East Africa.

有效利用季节性降水的困难导致东非半干旱雨养农场的产量受到限制，甚至导致作物歉收。本研究的目的是找出在半干旱地区植物残膜覆盖土壤是否可以在降水事件之间保留水分，并通过减少土壤水分蒸发和增加对深层土壤的渗透来建立干旱的适应能力。在半干旱的肯尼亚的一个小农户农场上研究了用植物残基覆盖物覆盖土壤的方法，该方法是利用土壤传感器在裸土和玉米的多个深度连续测量土壤的体积水分含量（玉米）。）植物残基覆盖土壤。对基于物理的一维土壤水分模型进行了校准，并用于估计两年（多个生长季节）中植物残料覆盖对土壤水分的影响。建模的多年时间序列提供了不同厚度的残留物覆盖物随时间对土壤水分的影响的估算值。简单的土壤水分模型能够估算玉米有效根区的土壤水分。通过比较覆盖和未覆盖土壤的实测数据并通过模型预测，证明与有效土壤相比，玉米残留覆盖层在玉米有效根区中随时间保持了土壤水分。在两年期间，当测量相对土壤湿度（秒）时，覆盖增加了总天数）超出玉米的水分胁迫极限（s *）24％–46％。水分累积在覆盖的剖面中，尤其是在有效根区的较深层中。计算表明，进一步增加覆盖厚度（δ_米从1至3厘米）总天数时会增加小号> S * 59％。此外，增加δ_米从3〜5厘米，这样就造成增加25％总天数时小号> S *。根据我们的计算覆膜（δ_米> 1cm）的能保持S> S *在整个测量期间发生的19天干旱期间。所表现出的湿气保护的与覆盖的增加效果δ_米植物残基的，但是可用性可能设置上覆盖施用率限制。结果表明，在东非旱地小农户系统中，玉米渣覆盖是在有效根区保护土壤水分的一种可行且可行的方法。