Alleviation of Plough Pan Problem for Growing Cassava

Abstract

Effect of deep ripping and soil amendments on plough pan alleviation in a Typic Paleusult whereplough pan was found between depths of 20-70 cm from soil surface. This pan restricted plant growth due to itsmoderately high bulk density and slow saturated hydraulic conductivity. Split-plot in randomized complete blockdesign with four replications was employed. Main plot consisted of deep ripping using ripper (P1) and no ripping(P2) before conventional land preparation (3 disc followed by 7 disc plough and contour ridging). Each main plotwas composed of four factors as follow; no soil amendment (T1), amended with 200 kg/rai of gypsum (T2) andlimestone dust (T3), and 1,000 kg/rai of chicken manure application (T4). Deep ripping gave significantly the higherfresh tuber yield than did the other without ripping (2.92 compared to 2.58 tonne/rai). Types of soil amendmentsshowed no effect on the fresh tuber yield but above ground biomass. Chicken manuring significantly gave the highestabove ground biomass of 2.82 tonne/rai and tended to give the highest fresh tuber yield (3.1 tonne/rai) compared tonon-soil amendment treatment, and applications of gypsum and limestone dust whether with or without deep ripping.However, deep ripping combined with the addition of chicken manure tended to give the lowest starch contentpercentage of 21.7.