Abstract

Organic amendments have been known to improve soil physical and chemical properties in sub-Saharan Africa. However, research information on how organic amendments affect aggregate stability and the degree of their effects in comparison to others is inadequate in Zambia. The study was carried out to assess the effect of organic amendments on soil dry aggregate stability and organic matter on soils from Chipata, Zambia. The specific objectives were to: Assess the effect of organic amendments on soil dry aggregate stability and assess if there is a relationship between soil organic matter and soil aggregate stability on a loamy ferric luvisol soil. Soil aggregates were collected from the top 10 cm of 10 m × 10 m plots in each treatment replicated five times. These aggregates were sieved through a 9.5 mm, and the retained aggregates on an 8 mm sieve were collected and used for aggregate stability analysis. Analysis of variance (ANOVA) of results showed significant differences among the means of five treatments: Sunn hemp, Tephrosia vogelii alley cropping, pigeon pea alley cropping, animal manure, and conventional treatments on a loamy ferric luvisol. Amending soils with Sunn hemp showed a significantly higher mean weight diameter (MWDd) of 2.393 compared to amending soils with T. vogelii alley cropping MWDd 1.767 (P value <0.001). Hence, for a loamy ferric luvisol soil, Sunn hemp and animal manure may be used to improve the condition especially for aeration and aggregate stability.

Key words:  Tephrosia vogeli, Sunn hemp, animal manure, conventional, loamy ferric luvisol.