Assessment of Soil Erodibility and Productivity Potential for Winter Rice in a Transect of Jiyadhol River Basin Assam

Abstract

Soil erosion is a major environmental problem in developing countries like newlineIndia, where agriculture is the main economic activity of the people. The present newlineinvestigation aims to assess the soil erodibility and productivity potential for winter rice newlinein a transect of Jiyadhol river basin with respect to landform characteristics, newlinemorphometry, erosion hazard and potential for growing rice. The study area extends newlinefrom 27.335and#61616; N to 27.574and#61616; N latitudes and 94.294and#61616; E to 94.540and#61616; E longitudes, covering newlinean area of 47,389.13 ha. Based on topographical variation in satellite data, four distinct newlinelandform units were delineated which includes: piedmont plain (9,097.69 ha), upper newlinealluvial plain (9,594.9 ha) lower alluvial plain (13,706.57 ha) and flood plain (14,977.0 newlineha). The drainage map identified the transect as fifth order drainage basin with higher newlineno s of first order streams making it vulnerable to erosion hazard. There was significant newlinevariation of slope, physiographic structure and infiltration capacity across the basin. The newlinemean bifurcation ratio (3.56) indicated that the basin is underlined by uniform materials newlineand streams are branched systematically. Relatively lower value of and#8215;Rho coefficient newlineindicated meager capacity of hydrologic storage during the period of floods that could newlineleads to higher runoff. The relatively higher drainage density (0.91 km km-2) could be newlinethe results of impermeable subsoil material, sparse vegetation and high relief. The newlinedrainage intensity (0.43) indicated that the basin area was highly susceptible to flooding newlineand gully erosion. The elongation ratio, circulatory ratio, form factor ratio and shape newlinefactor indicated that the shape of the studied transect was nearly circular. Such basins newlineare highly erosion prone as compared to elongated basins. newlineA total of 170 no of geo-referenced surface (upto 30 cm) soil samples were newlinecollected for analyzing soil physico-chemical, hydro-physical and fertility related newlineparameters. There was a decreasing trend in total sand and very fine sand content in newlinesoils from..