INTRODUCTION

1. EVALUATION OF IRRIGATION WATER PRODUCTIVITY FOR NERICA RICE AND SOYABEAN UNDER DIFFERENT IRRIGATION TECHNOLOGIES IN MWEA IRRIGATION SCHEMEDr. WanjoguR.K., Owilla B.P.O., Okinyi D.M.

2. INTRODUCTION • Kenya is expanding irrigation (vertically/horizontally) rapidly rising under water scarcity • Inefficient water management practices aggravate water scarcity and threatens irrigation sustainability • Sustainable irrigation expansion requires application of right quantity of water when the crop needs it • Limited research has been carried out to determine the appropriate quantity of water for irrigating non-flooded crops in Mwea

3. OBJECTIVE • To determine irrigation water productivity for rice and soyabean in Mwea irrigation scheme under different irrigation technologies • To evaluate water-use efficiency for rice and soyabean in Mwea irrigation scheme under different irrigation technologies

4. METHODOLOGY • Trial site MIAD (latitudes 37°13’E and 37°30’E, longitudes 0°32’S and 0°46’S and altitude of 1195 m a.s.l.) • RCBD with three treatments (drip, sprinkler, furrow) with three replications • Plot size: 7mx6m • Spacing: hill spacing 20cmx20cm for rice, plant to row 20cmx30cm for soyabean • Crops: NERICA 4 rice and soyabean

5. DATA COLLECTION • Rice growth data: plant height, total tillers • Soya growth data: plant height • Water applied to crop • Water used by crop • Rice yield data • Soya yield data

6. DATA ANALYSIS Analysis using SAS program (SAS institute,2002)

7. RESULTS –plant height NERICA rice Soya beans There was no significant difference in plant height in all irrigation technologies

8. RESULTS – total tillers Rice No significant difference in number of total tillers under different irrigation technologies

9. RESULTS -quantity of water applied • Significant difference in quantity of water applied among the three irrigation technologies in all crops • Furrow had highest volume of water applied followed by sprinkler, the lowest was recorded in drip

10. RESULTS-quantity of water used by crop No significant difference in the quantity of water used by crop under the three irrigation technologies

11. RESULTS - water use efficiency • There was significant difference in water use efficiency among the three irrigation technologies in all crops • Drip had highest efficiency followed by sprinkler then furrow

12. RESULTS - yields There was no significant difference in yield for both crops under the three irrigation technologies

13. RESULTS – crop water productivity No significant difference in crop water productivity in the two crops under furrow and sprinkler irrigation methods. On the other hand, drip revealed highest among the three irrigation technologies in both crops

14. DISCUSION • In the three technologies which were under investigation, there was no significant different on plant height, total tillers, crop water use, yield in both crops • There emerged significant differences in quantity of water applied, crop water use efficiency and productivity among the three irrigation technologies. Furrow had highest quantity of water applied followed by sprinkler then drip. WUE was highest and least in drip and furrow irrigation technologies respectively. Crop water productivity was highest in both crops which were under drip irrigation method, but no significant difference realized between crops which were either under sprinkler or furrow irrigation technology • Water applied: drip delivers water directly to the base of plant and saturates root zone only, sprinkler deliver water to open ground surface and plant canopy leading to greater but non-uniform soil saturation beyond root zone, furrow uniformly saturate entire field.

15. CONCLUSION AND RECOMMENDATIONS • It can be concluded that among the three irrigation technologies which were under test, drip was the most effective method in terms of water application, water use efficiency and crop water productivity, • However, comparative economic evaluation of the systems is necessary to inform the choice of irrigation technology to adopt