Open Journal of Soil Science

Volume 11, Issue 1 (January 2021)

ISSN Print: 2162-5360   ISSN Online: 2162-5379

Google-based Impact Factor: 1.23  Citations  h5-index & Ranking

Zai Pit Effects on Selected Soil Properties and Cowpea (Vigna unguiculata) Growth and Grain Yield in Two Selected Dryland Regions of Kenya

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DOI: 10.4236/ojss.2021.111003    261 Downloads   1,065 Views  


Erratic rainfall and temperature regimes, strongly affect agricultural productivity. To address the reduction in production, this study assessed the effect of Zai pit depths on selected soil properties and cowpea growth and grain yield. Zai pit technology was tested in two locations falling under Agroecological Zone IV (relatively dry areas) i.e. Machakos in Machakos County and Naivasha in Nakuru County, Kenya, aiming to determine the combined effect of four Zai pit depths and two levels of manure (plots with manure and plots without manure) on selected soil properties, growth and yield of cowpea. Experiment was laid out in split plot arrangement, with manure levels as the main plot factor and Zai pit depths (Flat: Z0, 30 cm: Z30, 45 cm: Z45 and 60 cm: Z60) as subplot factor, replicated four times. Cowpea (M66 variety) was used as the test crop. Inorganic nitrogen (Nin) and extractable phosphorus (Pex) were significantly (P < 0.05) higher, at 1.37 mg·kg1 for Nin and 80.4 mg·kg1 for Pex in Zai pits compared to flat plots which were at 0.91 mg·kg1 for Nin and 47.1 mg·kg1 for Pex. The values of Nin and Pex also varied depending on depths, with Z45 having highest Nin at 1.17 against the least, at 0.89 in the Z0, while Pex was highest in Z30 at 102.3 mg·kg1 while Z0 having the least Pex of 89.7 mg·kg1. Generally, crops in Zai pitted plots were larger in diameter (0.46 cm) and height (34.20 cm) than crops in flat plots at (0.42 cm) and (18.11 cm) diameter and height respectively. Better performance was observed in yield, with Z45 yielding 853.33 kg·Ha1 against 685.0 kg·Ha1 in Flat plots in Machakos while 931.66 kg·Ha1 in Z45 against 563.33 kg·Ha1 from Flat plots in Naivasha. This study demonstrated great potential of Zai pit technology on crop production, as reflected on improved growth and yield of cowpeas. Combining Zai pits with manure increases soil Nin, Pex and is a guarantee of great crop performance in terms of high final yields.

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Oduor, S. , Mungai, N. and Owido, S. (2021) Zai Pit Effects on Selected Soil Properties and Cowpea (Vigna unguiculata) Growth and Grain Yield in Two Selected Dryland Regions of Kenya. Open Journal of Soil Science, 11, 39-57. doi: 10.4236/ojss.2021.111003.

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