Effect of micro irrigation on corm yield and water productivity of elephant foot yam (Amorphophallus paeoniifolius (Dennst.)Nicolson ) in India
Sunitha,* S., George,J., Haripriya,S. and Suja, G.
Central Tuber Crops Research Institute, (ICAR) Sreekariyam, Trivandrum-695017, Kerala, India
*Email:Registrant ID# 3276
Elephant foot yam (Amorphophallus paeoniifolius (Dennst.) Nicolson)is gaining popularity in tropical countries not only as a food security crop, but also as a cash crop due to its production potential and popularity as a starchy vegetable having high nutritive and medicinal values. It has been recognized as a highly remunerative and accepted vegetable in India due to the development of varieties having low acridity and excellent cooking quality. Presently its cultivation is getting extended to non traditional areas, which necessitates assured irrigation. Field experiments were conducted at Central Tuber Crops Research Institute (ICAR), Kerala, India during 2013-2014 and 2014-2015 to find out the influence of micro irrigation and the most critical stage of irrigation in elephant foot yam for attaining maximum corm yield, water use efficiency and water productivity. The experiment was laid out in split plot design with two methods of irrigation as main plots (M1: drip and M2: bed method) and two levels of irrigation at different phases of growth as sub plots (I1: Irrigation at 75% of pan evaporation (PE) during 1-12 weeks after planting (WAP), I2: Irrigation at 75% PE during 13-24 WAP, I3: Irrigation at 75% PE during 1-24 WAP, I4: Irrigation at 100% PE during 1-12 WAP, I5: Irrigation at 100% PE during 13-24 WAP, I6: Irrigation at 100% PE during 1-24 WAP, I7: Irrigation at 75% PE during 1-12 WAP and 100 % during 13-24 WAP and I8: Irrigation at 100% PE during 1-12 WAP and 75 % during 13-24 WAP. A rainfed crop with no irrigation was kept as control. The best combination was arrived based on the growth indices, yield attributes and corm yield. The leading variety in India, 'Gajendra' was used for the study by planting 500g each of the seed corms. During both years, drip irrigation resulted in significantly higher corm yield than bed method. Among the sub plot treatments, irrigation given at 100% PE during 1-24 weeks resulted in maximum corm yield on par with irrigation at 100% PE during 13-24 WAP, 75% during 1-12 weeks and 100% irrigation during 13-24 weeks and vice versa. When the interaction effects were compared, M1I5 recorded maximum corm yield followed by bed irrigation given during the entire period of 24 weeks (M2I6). Pooled analysis of the data also showed the superiority of the treatment M1I5 (44.2 tha-1), however, this was on par with bed irrigation given during the entire period of 1-24 weeks at 75% and 100% level alone or in combination. On an average, the rainfed crop produced only 24.5 tha-1. Water use efficiency and water productivity were also worked out for different treatments. M1I5 resulted in 42% increase in water use efficiency compared to M2I6 to attain the same level of productivity. M1I5 also recorded the maximum water productivity (5.5 kg m-3). Water requirement was found to be critical during 13-24 weeks, ie, tuber development phase of elephant foot yam compared to initial sprouting phase. Based on the pooled data, water requirement of elephant foot yam was worked out to be 4.3-4.5 mm per day for attaining highest yield.