Assessment of Soil Quality under two Irrigation Systems in the Sokoto-Rima Basin, Nigeria

Abstract

Most irrigation projects in Nigeria are presently in a state of disrepair. One principal factor responsible for this is a decline of soil quality (SQ). Two soil quality indices were developed (one, rice based (RSQI) the other, vegetable based (VSQI)) using four soil attributes associated with irrigated agriculture namely; nutrient relations, water relations, soil physical stability/support and salt constraints. The indices were used to evaluate soil quality in the Zauro Polder Pilot Irrigation Scheme (ZPPIS), comparing this scheme to an adjacent area outside this scheme (FS) where non-formal irrigation is practised. With respect to RSQI, the soils of both systems rated good in soil quality with mean total SQ ratings of 0.554 (ZPPIS) and 0.459 (FS). Of the four soil attributes the only significant difference in SQ was with respect to the water relations attribute. On the contrary, when considering the VSQI, the soils of the FS out-performed the soils of the ZPPIS in regards to all soil attributes and the total SQ. With a mean SQ rating of 0.634, the soils of the FS had good SQ while the soils of ZPPIS rated poor in SQ with a mean SQ rating of 0.360.