Soils and Nutrients Losses and Gains during Rainy Season in the Fadama of Semi-Arid Sokoto, Nigeria

Abstract

A study was conducted to quantify the amount of soil and plant nutrients losses and gains during rainy season in the fadama land in the Sokoto semi-arid ecosystem, Nigeria. Field measurements revealed that about 33.3 tonne ha-1 of soil was moved from the adjacent uplands by run-off and wind and subsequently deposited in the fadama, while 22 ton ha-1 was removed from the fadama land during the period of the study (May-September). Over the same period, plant nutrients losses (in kg ha-1) with the eroded soil amounted to 30.8 organic matter, 0.3 K, 9.0 Na and 0.07 available P. Nutrient gains (in kg ha-1) amounted to 2.2 Total N and 4.4 Mg. Soil deposition was found to be greater than soil removal because of the gusty winds that accompany early and late rains.
The major problem of erosion in the fadama lands is the deposition of sandy materials moved from the upland which are by far less fertile. The continuous deposition of these materials could render the fertile fadama infertile. Soil removal is not a very serious threat to the fadama as soil deposition because the land is often flat and covered with vegetation in almost all part of the year with little cover in the dry season and early part of the rainy season.

Key words: Nutrient losses, Erosion, Fadama, Semi-arid Sokoto and Rainy season