PERFORMANCE EVALUATION OF ALTERNATE AND CONVENTIONAL FURROW IRRIGATION METHODS UNDER DIFFERENT WATER APPLICATION LEVELS FOR CABBAGE (Brassica Oleraceacapita. L.) PRODUCTION IN KOMBOLCHA DISTRICT, EASTERN HARARGE ZONE OF OROMIA REGION

Abstract

Often scarcity of water is the most severe constraint for development of agriculture in arid and semi-arid areas. Under this condition, it is essential to use this limited availed resource effectively and efficiently. Based on the actual crop need, the irrigation water management has to be improved, so that the water supply to the crop can be meet to achieve high yield by less water. The purpose of this study was to evaluate whether alternate and fixed furrow irrigation enable to save irrigation water and labor. Performance evaluation has been under taken among AFI, FFI and CFI (Alternative, Fixed and Convectional) furrow irrigation method, under full, three forth and half application levels (ALs) at Kombolcha ATEVT Collage, farm site for cabbage production for one season. Field experiment was designed as a two factor factorial experiment in RCBD, replicated three times. The two factors were 3 IMs (AFI, FFI and CFI) and 3 ALs (100%, 75%, 50% ETc). Fresh head weight per plant (FHW) and total head yield (THY) were highly significantly (P<0.01) affected by both IMs and ALs. Maximum mean as 2.37 kg per plant and 78.22 t ha-1 of FHW and THY respectively observed under CFI, while maximum FHW of 2.45 kg per plant and 81.03 t ha-1 THY was recorded by 100% ETc, water ALs respectively. Marketable and unmarketable head yield (MHY and UMHY) was significantly (P<0.05) affected by IMs. Similarly ALs had highly significant (P<0.01) on MHY, but on UMHY significant (P<0.05) influence. CWUE, IWUE and EWP were highly significantly (P<0.01) affected by both IMs and ALs. The highest and the lowest mean crop and irrigation water use efficiency (CWUE and IWUE), and economic water productivity (EWP) were recorded by AFI and CFI irrigation. Whereas, under ALs the highest and the lowest mean CWUE, IWUE and EWP were recorded by 50% and 100% ETc Application depth. This indicates CWUE, IWUE and EWP significantly increased with irrigation depth decreased or deficit level increase Thus, CWUE and IWUE related to, the amount of water supplied has inverse relation with yield obtained. Maximum water saved resulted from AFI and FFI, with 50%, 75% and 100% ETc application depth was equally computed as 58.33%, 37.50% and 16.67% which could irrigate additional area of 0.20, 0.60 and 1.40 ha for each treatment respectively. Contrarily yield reduction was higher in FFI followed by AFI and CFI with the same ALs. NR (net return) produced per hectare was higher in CFI followed by AFI and FFI. In case of BCR, AFI with 75% and 50% ETc was higher than FFI followed and the smallest by CFI of 50% and 75% ETc deficit level. Hence yield reduction and NR incurred by alternate (AFI and FFI) were compensated from additional irrigable area by diverting the water and labour saved. Generally from over all investigation of CWUE, IWUE, EWP, NR and BCR alternative furrow irrigation (AFI) was better than FFI and CFI for the water scarce area.