Influence of tillage practices,cropping systems and organic inputs on soil moisture content, nutrients status and crop yield in matuu,yatta sub county, Kenya.
Crop production in arid and semi-arid lands (ASALs) is constrained by insufficient and unreliable rainfall, and low soil fertility. Against this backdrop a survey and field experimentwas conducted in Matuu, Yatta sub-county. Survey was meant to determined farmers’ perception on climate change, crop production trends and moisture conservation techniques whereas the on farm field experimentsevaluated the influence of tillage practices, cropping systems and organic inputs on soil moisture content, soil nutrient (NPK and organic carbon) and crop yield.The experimental was laid out in Randomized Complete Block Design with a split-split plot arrangement replicated thrice. The main plots were tillage practices (TP); Oxen plough (OP), tied ridges (TR) and furrows and ridges (FR). Split-plots were cropping systems (CS); mono cropping (MC), intercropping (IC) and crop rotation (CR) while split-split plots were organic inputs; Farm Yard manure (FYM), Minjingu Rock Phosphate (MRP), combined MRP and FYM (MRP+FYM) and their control. The test crops were sorghum and sweet potatoes with Dolichos (Dolichos lablab) and chickpea (CicerarietinumL.) grown either as intercrops or in rotation. The experiment was carried out for two seasons between October 2012 to February 2013 and March to August 2013.Soil samples were taken from the test plots randomly at crops maturity, at a depth of 0–15, for determination of; soil moisture content on per cent dry weight basis, Nitrogen, Phosphorous, Potassium and organic Carbon. Crop yield was also determined by weighing grain and tuber. Most (92%) farmers have perceived climate change in the study area and the aspects include increasing temperature, erratic rainfall. Most (83.3%) farmers reported, unreliable rainfall, pests and diseases, drought, low soil fertility, lack of inputs and low soil moisture as constraints to agricultural production. The crop production trend showed that most farmers hadabandoned crops such as cassava, sorghum and sweet potatoes (also known as traditional crops) in favour of introduced crops such as beans, maize and wheat. About 15%, of the farmers stated manure application, basin and terraces respectively as methods of coping with low soil moisture. Significant (p≤0.05) increased in soil moisture content was recorded in TR under IC of dolichos with application of FYM (7.53% and 7.88%) for sorghum and sweet potato plots respectively. Least moisture levels were recorded in MRP applied plots across all TP and CS. Moisture content in the second season followed same pattern across TP and CS as for first season but not significantly (P≤0.05) different between seasons. There was a significant (P≤0.05) increased potassium (1.91 Cmol+Kg), phosphorous (51.45 ppm), Total vi nitrogen (0.19%) and organic carbon (2.19%), in TR underintercrop sorghum/chickpeawith application of MRP+FYM.There was a significant (P≤0.05) increase on the yield of sorghum and sweet potatoes with a significant (P≤0.05) increase yield in plots with MRP+ FYM and FYM across all the tillage practices and cropping systems. Mono cropped sweet potato (16.27t/ha) and sorghum (1.38 t/ha) yields were highest under tied ridges with application of MRP+FYM. The changing climate as perceived by the farmers vis-à-vis the emerging crop production trends calls for better methods of soil moisture conservation and production of adapted crops. The field experiment conformed from concern raised during the survey i.e. decreased soil fertility, crop yield and soil moisture these were as a result of climate change and crop production trends these led the researchers to carry out field experiment on tillage practices, cropping systems and oranic inputs identified by the farmers. Intercrop and crop rotation of sorghum and sweet potatoes with dolichos under tied ridges with application of MRP+FYM is a viable technology for increased soil moisture, nutrients, and crop yield. Key words: Arid and semi arid areas; climate change; cropping systems; organic inputs; tillage practices; Traditional crops.