An exploratory pre-planting and post-harvest assessment of short-term soil-chemical changes within a shrub–cereal–legume intercropping experiment in western Kenya
DOI:
https://doi.org/10.51867/ajernet.7.4.36Keywords:
Camphor Basil, Composite Soil Sampling, Exploratory Assessment, Intercropping, Nutrient Dynamics, Soil Organic Carbon, Western Kenya.Abstract
Poor soil fertility, characterized by soil acidity, low organic carbon and nutrient imbalances, constrains smallholder crop production in western Kenya. This exploratory study characterized soil-chemical changes between pre-planting and post-harvest sampling within a field experiment comprising sole crops and two- and three-component shrub–cereal–legume intercrops under rainfed, minimum-tillage and low-external-input management. The experiment comprised 12 treatments arranged in three blocks. However, soil subsamples collected in a zig-zag pattern across the treatment plots were composited within each block, resulting in an effective sample size of three paired block-level observations and precluding assessment of treatment-specific soil effects. After one cropping season, mean soil pH changed from 4.63 to 5.20 and soil organic carbon from 1.09% to 1.78%. Available phosphorus changed from 11.37 to 17.07 mg kg⁻¹ and exchangeable potassium from 95.75 to 132.99 mg kg⁻¹, whereas total nitrogen, exchangeable calcium and EDTA-extractable zinc decreased numerically. None of the paired differences was statistically significant at p < 0.05, and all 95% confidence intervals included zero, reflecting substantial uncertainty associated with the small sample. Because no independently sampled temporal reference was included, the findings represent experiment-wide temporal associations rather than treatment-specific effects. Nevertheless, the contrasting estimates demonstrate why regenerative performance should be evaluated across multiple soil indicators rather than inferred from a single property. They provide preliminary evidence of short-term soil dynamics and generate hypotheses concerning soil acidity, carbon cycling, nutrient redistribution and adaptive nutrient stewardship. Treatment-specific sampling, appropriate temporal controls, greater replication, multi-season monitoring, plant-tissue analysis, nutrient budgets and integrated field-based soil-health assessments are required to test the observed patterns and evaluate the regenerative potential of shrub–cereal–legume intercropping.
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Copyright (c) 2026 Reuben K. Bulungu Chumba, Prof Muyekho Francis Namsaka, Vitalis Ogemah, Dr. Gebrehawaryat Yosef Kidane, Dr. Jacob Omollo, Betty Alosa Mulianga
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