Zai pit combined with integrated nutrient management for improving soil aggregate stability, moisture content and microbial biomass in drylands of Eastern Kenya

Abstract

This study sought to assess the impact of selected soil conservation and water harvesting technologies as promising options for alleviating soil moisture crisis, enhancing soil fertility and reducing soil erosion in the drylands of Eastern Kenya. An experiment was set up to investigate the responses of soil aggregate stability, moisture contents and soil microbial biomass carbon and nitrogen (SMBC and SMBN) to Zai technology combined with selected integrated nutrient amendment. Zai pit technology involves the use of holes or basins with varying diameters for farming activities in drylands. The experiment was done in a completely randomized block design. Soils (0 to 15cm) from eight treatments (replicated thrice): Zai with no input (ZNO), Zai with sole manure (ZM60), Zai with full rate chemical fertilizer (ZF60), Zai with manure and mineral fertilizer (ZM30F30), conventional with sole manure (CM60), conventional with full rate mineral fertilizer (CF60), conventional with manure and mineral fertilizer (CM30F30) and control (CNO), were subjected to laboratory analyses using various methods as suggested by previous studies. ZM60 recorded 25% significantly high (p<0.05) stable aggregation compared to CM60. 32 days after sowing in the LR2019 season, ZM30F30 recorded 34% significantly high soil moisture content than CM30F30. ZM60 recorded the highest values for SMBC and SMBN which were 17.1% and 36.5% significantly higher that value recorded CM60. The results of this study demonstrate the importance of using Zai technology combined with organic and inorganic amendments as an agricultural intervention that can improve soil aggregate stability, soil moisture content and soil microbial biomass, thus contributing in the overall improvement of soil health and fertility.