Yield of Cassava Grown in Beginning of Early Rainy Season under Supplemental Subsurface–Dripped and Surface–Dripped Irrigations in Comparison to Natural Rainfed Condition

Abstract

Cassava production under well– and more precisely management of water and fertilizer would increase the yield up to its potential. Thus, the production methodology was developed to overcome these limitations and promote the crop productivity. The experiment was done to compare the crop physiological characteristics, root yield and starch content under 3 different regimens: subsurface dripped–, surface dripped–irrigations and control (rainfed condition) and cassava was planted at the beginning of early rainy seasons (April 2014). The Strip plot RCBD with 4 replications was adopted with 3 Vertical plots of 1) subsurface dripped–irrigation with fertigation (SDI), 2) surface dripped–irrigation with fertigation (DI) and 3) natural rainfed with top–dressed–fertilization (RF). Horizontal plots were 2 cassava varieties, KU50 and HB80. Data were collected for yield, root starch percentage, fresh and dry weight for all plant parts (leaves, stems, root) at 8, 10 and 12 months after planting (MAP), The results showed cassava responded to different irrigation and fertilization methods and 2 cassava varieties. Average yield of cassava was 6.3, 7.8 and 8.2 ton/rai at 8, 10 and 12 MAP, respectively. Cassava under subsurface dripped irrigation with fertigation had relative yield increase of 25, 20 and 57 % with the total supply of water (SDI+rainfall) of 742, 890 and 1,118 mm, dripped irrigation with fertigation increase of 23, 19 and 28 % with the total supply of water (DI + rainfall) of 755, 1,009 and 1,301 mm for cassava at 8, 10 and 12 MAP in comparison to natural rainfed condition that allowed the total rainfall of 509, 515 and 543 mm, respectively. Crop physiological characteristics and starch content under SDI and DI were higher than RF, especially the cassava into a state of drought. The expected output will be the distinction of water and fertilizer applications in 3 different methods to improve the cassava productivity to accommodate the expansion of industrial demand nowadays.