Horizontal distribution of phosphorus in soils of irrigation ditches
The cultivation of vegetable crops during the dry season is an age-long practice by peasant farmers in northern Nigeria. The water for the irrigation of the plots is supplied by shallow streams, or ponds and wells dug along the banks of the streams. Phosphorus is an important plant nutrient. The effect of flowing irrigation water on the horizontal distribution of phosphorus in soils of irrigation ditches of five vegetable plots located along the banks of the stream in Bosso village, Niger state, Nigeria, was investigated. Higher P levels and lower organic matter content were found close to the upper end of the ditches where the irrigation water was applied. Mean P values of individual ditch soils which produced a definite but unexpected pattern of distribution of the element are also presented. Data on pH and phosphorus values of the stream water provided the level of the contribution from this source. Non-significant correlations were found between soil P and stream water P on one hand, and between soil pH and stream water pH on the other, indicating that the irrigation water may indeed, have had little or no influence on the properties of the ditches’ soils.