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 grow...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>i.e.</i> Katumani 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: Z<sub>0</sub>, 30 cm: Z<sub>30</sub>, 45 cm: Z<sub>45</sub> and 60 cm: Z<sub>60</sub>) as subplot factor, replicated four times. Cowpea (M66 variety) was used as the test crop. Inorganic N and extractable P were significantly (P < 0.05) higher, at 1.37 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> for N<sub>in</sub> and 80.4 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> for P<sub>ex</sub> in Zai pits compared to flat plots which were at 0.91 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> for N<sub>in</sub> and 47.1 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> for P<sub>ex</sub>. The values of N<sub>in</sub> and P<sub>ex</sub> also varied depending on depths, with Z<sub>45</sub> having highest N<sub>in</sub> at 1.17 against the least, at 0.89 in the Z<sub>0</sub>, while Pex was highest in Z<sub>30</sub> at 102.3 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> while Z<sub>0</sub> having the least P<sub>ex</sub> of 89.7 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup>. Generally, crops in “Zai” pitted plots were larger in diameter at 0.46 cm than crops in flat plots at 0.42 cm. Better performance was observed in yield, with Z<sub>30</sub> yielding 30.5% against 18.2% Flat plots in Machakos while 27.9% in Z<sub>30</sub> against 22.5% 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 N<sub>in</sub>, P<sub>ex</sub> and is a guarantee of great crop performance in terms of high final yields.展开更多
文摘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>i.e.</i> Katumani 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: Z<sub>0</sub>, 30 cm: Z<sub>30</sub>, 45 cm: Z<sub>45</sub> and 60 cm: Z<sub>60</sub>) as subplot factor, replicated four times. Cowpea (M66 variety) was used as the test crop. Inorganic N and extractable P were significantly (P < 0.05) higher, at 1.37 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> for N<sub>in</sub> and 80.4 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> for P<sub>ex</sub> in Zai pits compared to flat plots which were at 0.91 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> for N<sub>in</sub> and 47.1 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> for P<sub>ex</sub>. The values of N<sub>in</sub> and P<sub>ex</sub> also varied depending on depths, with Z<sub>45</sub> having highest N<sub>in</sub> at 1.17 against the least, at 0.89 in the Z<sub>0</sub>, while Pex was highest in Z<sub>30</sub> at 102.3 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup> while Z<sub>0</sub> having the least P<sub>ex</sub> of 89.7 mg<span style="white-space:nowrap;"><span style="white-space:nowrap;">⋅</span></span>kg<sup><span style="white-space:nowrap;"><span style="white-space:nowrap;">−</span></span>1</sup>. Generally, crops in “Zai” pitted plots were larger in diameter at 0.46 cm than crops in flat plots at 0.42 cm. Better performance was observed in yield, with Z<sub>30</sub> yielding 30.5% against 18.2% Flat plots in Machakos while 27.9% in Z<sub>30</sub> against 22.5% 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 N<sub>in</sub>, P<sub>ex</sub> and is a guarantee of great crop performance in terms of high final yields.