Tropical and Subtropical Agroecosystems (Oct 2024)
THE EFFECTS OF INTEGRATED SOIL FERTILITY MANAGEMENT AND CROPPING SYSTEMS ON SOIL WATER CONTENT ON SORGHUM AND COWPEA PRODUCTION IN CENTRAL HIGHLANDS OF KENYA
Abstract
Background: Soil fertility degradation remains the major biophysical cause of declining per capita crop production on smallholder farmers in Central Kenya highlands. The study was carried out for 3 consecutive seasons in Embu County classified as semi-arid lands in Kenya. Objectives: To determine the effect of Soil Water Harvesting (SWH), cropping systems and Integrated Soil Fertility Management technologies on sorghum and cowpea production in Mbeere South Sub-County, Kenya. Methodology: The treatments were arranged in a factorial structure with 3 levels of SWH, 2 cropping systems and 6 soil fertility management options laid out in a partially balanced incomplete block design. The SWC was measured after 2 weeks after planting interval stages in the whole season. Data were analyzed by ANOVA and significant means separated using Least Significant Difference (LSD) at 95% Confidence Interval. Results: There was a two way interactions effect between SWH*Fertility management options on sorghum grain yields was significant (p=0.0027, p=0.0008 and p=0.0057) during long rains (LR) of 2011 and 2012, and short rains (SR) of 2011, respectively. Additionally, SWH methods significantly affected sorghum grain yields in a similar trend (p=0.002, p=0.0005 and p=0.0003) in their respective seasons. In SR 2011 and LR 2012, soil fertility options also produced significant effects (p=0.0047 and p=0.0024) on cowpea grain yields, respectively. The results further indicated that there were significant higher SWC measurements at initial stages of 2 WAP, 4 WAP and 6 WAP intervals as compared to the late stages of the season. However, sole cropping systems had significantly more SWC measurement than those in intercropping systems in both seasons. Implications: Manure added treatments positively affected SWC conservation and this could be as a result of increased soil organic carbon which improved soil fertility. The available SWC played a great role in drought effect mitigation by availing moisture to sorghum and cowpea productivity especially when prolonged dry spells coincide with crop’s sensitive phenological growing stages. Conclusions: Water harvesting methods cropping systems and soil fertility management options had positive influence on soil moisture conservation and crop yields production in Central Kenya Highland.
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