Research Article
Phosphorus Adsorption Characteristics of Soils in the Four Selected Agroecological Zones of Southern Highlands of Tanzania
Issue:
Volume 14, Issue 5, October 2026
Pages:
229-240
Received:
17 August 2026
Accepted:
28 August 2026
Published:
18 September 2026
Abstract: The Southern Highland Zone constitutes Tanzania’s principal agricultural belt, accounting for approximately fifty percent of the nation’s food supply. Most of the soil of the region’s agroecozones is strongly acidic, causing poor crop yields and inefficient fertilizer utilization. Phosphorus (P) sorption characteristics were investigated across acidic soils to assess their implications for P availability and soil fertility management. Surface soil samples (0-30) cm sampling depth obtained from the unlimed and limed plots of study sites were analyzed for P-sorption dynamics. The P-sorption data were fitted to the Freundlich isotherms to estimate sorption capacities and heterogeneity of adsorption sites. The results on Freundlich P-adsorption capacity (KF) in mg/Kg of soil recorded 1433.0±131.0 and 1396.6±141.7, 971.0±222.4 and 883.3±269.5, 1644.2±26.3 and 1595.7±43.0, 1055.4±62.3 and 1001.9±105.5; standard phosphorus requirement (SPR) in mg/Kg of soil 223.0±5.8 and 205.1±13.2, 122.8±17.7 and 104.7±18.4, 235.4±5.0 and 221.6±3.0, 113.3±19.0 and 97.9±13 for unlimed and limed experimental plots at Mbimba, Kifyulilo, Igeri and Uyole respectively. These results revealed strong P adsorption trends. Liming substantially reduced P-sorption capacities and heterogeneity of adsorption sites in the soil, increased equilibrium P concentration, indicating improved P availability through charge neutralization and reduced activity of iron (Fe) and aluminum (Al) sesquioxides. The SPR computed values indicated that the external addition of phosphorus according to national recommendations provide suboptimal fertilization of phosphorus in the Southern Highlands of Tanzania. These findings highlight that managing soil acidity through liming is essential to minimize P-adsorption and enhance fertilizer use efficiency in low-P tropical soils.
Abstract: The Southern Highland Zone constitutes Tanzania’s principal agricultural belt, accounting for approximately fifty percent of the nation’s food supply. Most of the soil of the region’s agroecozones is strongly acidic, causing poor crop yields and inefficient fertilizer utilization. Phosphorus (P) sorption characteristics were investigated across aci...
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Research Article
Assessment of Resource Use Efficiency and Its Determinants in Maize Production Among Smallholder Farmers in Uasin Gishu and Transzoia Counties, Kenya
Nickson Kiprotich Kimais*
Issue:
Volume 14, Issue 5, October 2026
Pages:
241-247
Received:
6 August 2025
Accepted:
21 August 2025
Published:
15 October 2026
DOI:
10.11648/j.ajaf.20261405.12
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Abstract: Maize remains a cornerstone crop for food security and livelihoods in Kenya, particularly in the high-producing counties of Uasin Gishu and Transzoia. Although these regions have the potential to yield 900,000 and 1,000,000 metric tons respectively, actual production lags considerably at approximately 400,000 and 600,000 metric tons. This productivity gap underscores inefficiencies in how resources are utilized by smallholder farmers. This study evaluated resource use efficiency and explored key determinants impacting maize production among a sample of 274 farmers drawn from a population of 16,300 using stratified random sampling guided by Cochran’s formula. Primary data were collected through a structured, self-administered questionnaire designed on a 5-point Likert scale, and the analysis was grounded in production theory and efficiency analysis using a stochastic frontier model estimated by maximum likelihood. Utilizing descriptive statistics alongside Stochastic Frontier Analysis, the findings revealed an average technical efficiency of 82%, with scores ranging between 75% and 91%. Major contributors to inefficiency included limited education, smaller farm sizes, and inadequate access to extension services. The input-output analysis further showed that seed was the most efficiently utilized resource, with an input-output ratio of 66.67, whereas fertilizer and labor recorded lower ratios of 13.33 and 6.67, respectively. Farmers with more than two acres of land, college-level education or above, and access to credit reported higher resource efficiency ratings. The research highlights that optimizing resource use could increase maize yields by up to 25%, advocating for policies that improve farmer training, expand extension outreach, and enhance access to modern inputs to drive sustainable productivity gains.
Abstract: Maize remains a cornerstone crop for food security and livelihoods in Kenya, particularly in the high-producing counties of Uasin Gishu and Transzoia. Although these regions have the potential to yield 900,000 and 1,000,000 metric tons respectively, actual production lags considerably at approximately 400,000 and 600,000 metric tons. This productiv...
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