Soil properties after change to conservation agriculture from ridge tillage in sandy clay loams of mid-altitude Central Malawi

• Published in: Soil use and management Vol. 30; no. 4; pp. 569 - 578
• Main Authors: Mloza-Banda, M. L., Cornelis, W. M., Mloza-Banda, H. R., Makwiza, C. N., Verbist, K.
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Publishing Ltd 01.12.2014; Wiley-Blackwell; Wiley Subscription Services, Inc
• Subjects: Aggregates; Agriculture; Agronomy. Soil science and plant productions; Biological and medical sciences; Carbon; Conservation; crop residues; Cropping systems. Cultivation. Soil tillage; dry spells; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Moisture content; Ridges; small-scale farmers; Soil (material); Soil erosion, conservation, land management and development; Soil science; Soil tillage; Texture; Tillage; Tillage. Tending. Growth control; water retention; Malawi; Southern Africa; Sub-Saharan Africa; Africa; Water; Cultural practice; Soil tillage; Tropical zone; Small scale; Property of soil; Retention; Soil management; Sustainable agriculture; Aggregates; Ridge tillage; Sandy clay loam soil; Conservation tillage; Crop residues; dry spells; water retention; Dry spell; Soil science; small-scale farmers; Small farms; Aggregate; Farming; Altitude
• ISSN: 0266-0032; 1475-2743
• DOI: 10.1111/sum.12139

A comparative study was carried out of annual ridge tillage (RT) and short‐term effects of conservation agriculture (CA) on soil properties in fields of small‐scale farmers. Soil samples were collected at depths of 0–10 and 10–20 cm from a total of 12 fields which had been under CA for two and four seasons, respectively, and from adjacent RT fields for direct comparisons. CA fields were converted from fields previously under continuous RT. Soil organic carbon, total nitrogen and available phosphorus were greater in CA fields while extractable potassium, pH and salt content were moderated under CA. Conversion of long‐term RT to CA did not significantly influence bulk density and aggregate stability (geometric mean diameter) although structural stability was greater under CA practices. Total porosity, macroporosity and matrix porosity, and volumetric water content at saturation, field capacity and permanent wilting point did not substantively respond to tillage effects. Relative water capacity and air–water storage parameter, θfc/PORt, were significantly greater after 4 yr of CA. Soils under CA showed greater values for field‐saturated hydraulic conductivity compared with RT fields. With the highest loadings in a principal component analysis, this work suggests that variables related to volumetric water content and aeration of the soil matrix, organic carbon, available phosphorus and soil texture were the most useful indices for future field comparison of RT and CA practices.