Effect of Tillage and Water Management on Aggregate Stability of a Gleyic Cambisols

Abstract

The objective of this study was to determine the effect of tillage and water management on the physical stability of irrigated lowland rice field, in Kwalkwalawa, Sokoto State. The experiment was carried out in a farmer`s field, near the Usmanu Danfodiyo University Teaching and Research Farm, Kwalkwalawa, Sokoto State. The coordinates of the area were taken using global positioning system (GPS) model Garmin etrex 20.0, which shows that the area is located on (N13°05.963”E005°12.650” and at 252 m asl). The soils of the study area were classified as Aeric Endoaquepts at subgroup level in the USDA Soil Taxonomy System which correlated with Gleyic Cambisols in the World Reference Base. The treatments consisted of factorial combination of two tillage systems (conventional tillage (CT) and reduced tillage (RT), three irrigation water managements (Alternate one, two and three days irrigation intervals, which were carried out from one week after transplanting to hard dough stage) and three rice varieties (FARO 44, 60 and 61) all laid in a split-plot design and replicated three times. After harvest, disturbed soil samples were collected with the aid of soil auger, prepared and passed through 5 mm sieve for aggregate stability determination. Result reveals that a consistent trend in aggregate size fraction was observed between the two tillage systems in both years, were a significant decrease in values of aggregate fractions of both the CT and RT in 2019 compared to in 2018. Aggregate size fraction of 5-2 mm had a significantly high value of RT compared to CT, 2-0.25 mm fractions were at par (0.41) while a greater value of aggregate fractions for CT in both 0.25-0.005 mm and ˂0.005 mm were observed compared to RT. Alternate days to irrigation and sampling depths increase with a corresponding in all the aggregate size classes in the two years of this study. A significant difference in mean weight diameter (MWD) and geometric mean diameter (GMD) between the two tillage, water management and depth was noticed in both years of the trial where RT and alternate one day had high value while MWD and GMD increase with increasing depth.