Infiltration and runoff losses under fallowing and conservation agriculture practices on contrasting soils, Zimbabwe

Abstract

Fallowing and conservation agriculture are sustainable farming practices that can be used for soil and water conservation. The objectives of the study were to evaluate the effects of different conservation agriculture practices on rainfall infiltration and soil and water losses across 4 sites, using simulated rainfall. The study was carried out at Domboshawa and the Institute of Agricultural Engineering and Chikwaka smallholder farming areas, 4 sites with different soil types. Conservation agriculture practices evaluated were mulch reaping (MR) and clean reaping (CR) at Domboshawa with 5% clay and the Institute of Agricultural Engineering (IAE) with 50% clay. The study also evaluated runoff losses from fallow plots subjected to no tillage (NT) and conventional tillage (CT) at ICRAF Domboshawa site (20% clay) and fallows subjected to CT in Chikwaka smallholder farming areas (4% clay). Infiltration rates were greater under conservation agriculture practices (>35 mm•h ). On fallows infiltration rates ranged from 24-35 mm•h -1 when compared to <15 mm•h -1 in maize under CT. Runoff losses were highest under CT at both Domboshawa and IAE sites, and were 21.5 and 15% respectively, while there was no runoff under MR and CR. At the ICRAF Domboshawa site, runoff ranged between 0-31% in fallows and was 57% in maize under CT. At Chikwaka runoff in CT maize was 58%, while in fallow plots runoff ranged 37-44%. Soil losses ranged from 0.2-0.3 t•ha -1 per rainfall event in maize, while in fallows, soil loss ranged from 0-0.1 t•ha -1. The results showed that CT resulted in reduced infiltration rates, increased soil and water loss when compared to fallowing and conservation agriculture across different range of soils. Conservation agriculture practices and fallowing are potential sustainable cropping practices that reduce soil and water loss and increase water use efficiency.

No-tillage controls on runoff: A meta-analysis

“…Runoff was summed, if it was measured multiple times in a growing season or by multiple rainfall runs, or was determined separately in wheeled and non-wheeled areas. One study in which runoff was zero in some treatments was excluded (Nyamadzawo et al, 2012), as zero values are not suitable for the present meta-analysis that used the response ratio as the effect size (Hedges et al, 1999). In order to examine the temporal trend in the effectiveness of NT, studies that reported only average runoff across multiple years were excluded.…”

Farmers’ Perceptions and Factors Influencing the Adoption of No-Till Conservation Agriculture by Small-Scale Farmers in Zashuke, KwaZulu-Natal Province

“…Although the role of no-till as a climate-smart solution is being questioned [1][2][3], the technology still remains one of the solutions to address some of the challenges affecting small-scale farming in Africa [1]. Amongst the major challenges faced by small-scale farmers are soil erosion and the efficiency in which the limited water is used [4][5][6]. The situation is further worsened by climate change effects such as persistent droughts, which are currently being experienced in the sub-Saharan region [5].…”

“…Amongst the major challenges faced by small-scale farmers are soil erosion and the efficiency in which the limited water is used [4][5][6]. The situation is further worsened by climate change effects such as persistent droughts, which are currently being experienced in the sub-Saharan region [5]. Agriculture remains one of the most important components of most African economies [7] and its success is based on the foundation of good soils and efficient utilization of the available water resources, among other factors.…”

The State of Soil Degradation in Sub-Saharan Africa: Baselines, Trajectories, and Solutions

“…Extensive research has been conducted into the broader frameworks of integrated soil fertility management [130][131][132][133][134][135][136][137], conservation agriculture [138][139][140][141][142][143], erosion control [144][145][146][147][148], and improved grazing management [149][150][151]. There is also a wealth of information on the benefits of specific practices such as short legume rotations (improved fallows) [152][153][154][155][156][157][158], agroforestry systems [159][160][161][162][163][164][165], and no-till systems [166][167][168][169][170]. Most of these studies, however, are short-term and geographically limited.…”