Abstract:
Deteriorating soil fertility, low unreliable rainfall and soil moisture stress has resulted to
low crop yields among farmers of sub-Saharan Africa (SSA), necessitating a search
for more sustainable production practices. Zai technology has the ability to promote
soil moisture retention and enhances soil fertility. A four-seasons field experiment was
conducted to assess the impact of Zai technology combined with cattle manure and
inorganic fertilizer on selected soil properties and sorghum yields in Kabati, Kitui County.
The experiment was set up in a Randomized Complete Block Design (RCBD) with
eight treatments replicated thrice with sorghum Gadam as the test crop. Soil sampling
was done at the beginning of the first season and at the end of the fourth season
at a dept of 0–15 cm across each plot for laboratory analyses. From the results, the
increase in electrical conductivity was significant at p < 0.05 in all the treatments after
four cropping seasons. Total organic carbon significantly increased in Zai with cattle
manure (p = 0.045), conventional with no input (p = 0.038) and conventional with
cattle manure (p = 0.045). Available phosphorous significantly (p < 0.05) increased in
treatments under Zai technology while total nitrogen significantly (p < 0.05) reduced
after the four cropping seasons. There was a significant (p < 0.05) interactive effect of the
tested factors on soil pH, electrical conductivity, total nitrogen, and available phosphorous
at the end of the experiment. Moreover, there was significant (p < 0.05) interactive
effects on grain yields (SR18 and SR19 seasons) and stover yields (SR18, LR19, and
SR19 seasons), with higher yields being recorded in treatments under Zai technology.
This study demonstrates the importance of Zai technology in increasing crop yield by
trapping water and enhancing its retention and infiltration into the soil for uptake by plants.
This study concluded that positive impacts on important soil properties and crop yield
could be realized when Zai technology is utilized alongside either sole inorganics or a
combination of organic and inorganic amendments and this could be used as a strategy
to improve crop production in eastern Kenya and other similar areas.
