WATER RETENTION AND YIELD OF RICE CROP UNDER DIFFERENT LAND PREPARATION TECHNIQUES IN MAUGO SMALLHOLDER IRRIGATION SCHEME, HOMA BAY COUNTY, KENYA

Abstract

The area under rice cultivation in Kenya has been increasing but production and productivity are still low compared to demand due to inappropriate, poor and untimely land preparation and field water management. For this reason, therefore, a research experiment was conducted in a farmer's field in Maugo Irrigation Scheme, Homa Bay County, Kenya during July 2019- January 2020 crop season. The main purpose of the study was to determine the effect of land preparation techniques on water retention and yield of rice (Oriza sativa L.,) crop in the scheme. Treatments were arranged in Randomized Complete Block Design (RCBD) with four replicates. Four tillage treatments were used. The first one was conventional ox- ploughing practised by farmers where they first flood the field with water before ploughing. The other three treatments were ox- plough, hand- hoe and tractor plough and all were not flooded before ploughing. Data on the depth of ploughing and harrowing during ploughing, furrow slice sizes during ploughing and harrowing, water retention, number of tillers, yield and rooting were collected, recorded and analysed. The findings of the study indicated that tractor ploughing had the highest mean depth of ploughing of 42.00 ± 0.81 cm followed by conventional ox- ploughing with 17.75 ± 0.75 cm, ox ploughing15.75 ± 0.62 cm and hand hoe ploughing had the lowest mean depth 15.50 ± 0.28 cm. Tractor ploughing had the largest mean furrow slice size of 62.00 ± 0.91cm followed by conventional ox-ploughing 32.25 ± 0.85 cm, ox- ploughing 30.25 ± 0.85 cm while hand- hoe ploughing had the smallest mean furrow slice of 16.5 ± 0.50 cm. The highest mean of retained water was recorded in week 4 in the paddy rice fields that were prepared using conventional ox ploughing (10.5 cm), ox ploughing (10 cm), hand hoe ploughing (11.5 cm) and tractor ploughing (11.5 cm) while the lowest was recorded in week 15 for conventional plots. There were significant differences in mean depths among the treatments during both ploughing and harrowing. Tractor ploughing means depths were significantly different from the other three treatments. The weekly mean water depths retained in the plots were more than 6 cm for the entire growing season of rice. The results also showed that conventional ox-ploughing consumed the highest amount of water to the tune of 1240 mm. The highest water use efficiency of 0.49 kg/m3 and highest milled yield of 5.7 tons/ha were observed in the hand hoe ploughing treatment. Use of the hand hoe ploughing technique was found increased rice yields by 20 per cent, as compared to the conventional ox-ploughing. Therefore, the use of water for ploughing is not necessary for the study area. Future research will be needed to see how farmers are adopting the study recommendations before scaling up to full mechanization, as partial mechanization was not profitable during this research.