Impact of irrigation frequency and farm yard manure on a salt-affected soil and wheat production in Dongola

A field experiment was conducted in January 2001 and December 2002, at Dongola University Farm to investigate the effects of irrigation frequency and farm yard manure on salt leaching and on wheat (Triticum aestivum L.) growth on a saline-sodic sandy loam soil classified as fine loam, mixed, hyperthermic, Sodic Haplocalcids. Each experiment consisted of three irrigation frequencies: 7, 14, and 21 days, and three levels of farm yard manure (F.Y.M): 0, 4.8 and 9.7 ton/fed. The quantity of water applied was proportional to the irrigation frequency and estimated from knowledge of reference evapotranspiration as predicted by Jensen and Haise equation, a crop factor and an irrigation efficiency value. Each treatment was replicated thrice in a split-plot design. Irrigation treatments accommodated main plots (7 x 18m) and organic amendment sub-plots (7 x 6m). Results showed that all irrigation treatments caused salt leaching, which decreased with increase of soil depth. Furthermore, irrigating every 7 or 14 days caused more leaching than irrigation every 21 days. Application of F.Y.M. increased the effectiveness of salt leaching, however, 9.7 ton/fed was disadvantageous in salt leaching, because it required more water. The effect of irrigation frequency on yield components was greater than the effect of organic amendment. Irrigation every 7 or 14 days increased leaf area index (L.A.I.). Addition of F.Y.M. increased plant height at 7 and 14 days, other yield components including head length, number of heads/square m, number of grains/head and 1000 grain weight increased significantly in the following order: 7 14 21, days in the first season. The effects of treatments on biomass had the same trend in the first season, but the trend was different in the second season. However, the effects on grain yield had the same trend in both seasons. Decrease in irrigation frequency and addition of organic amendments increased crop water use efficiency (W.U.E.) in both seasons