EFFECTS OF SOME TREES ON SOIL MINERALS IN HADEJIA-NGURU WETLAND ZONE IN THE SEMI-ARID REGION OF NIGERIA

This research work was carried out in Hadejia-Nguru wetland zone (HNWz) in the semi-arid region of the northern part of Nigeria. This region has become a major concern to researchers due to frequently reported soil nutrient decline worsened by climate change and declining environmental quality. This research work investigates the effects of some trees on availability of minerals like potassium (K), nitrogen (N), phosphorous (P) and organic carbon (O.C) on small scale farmlands in the study area. The results obtained from this work, showed that some indigenous savanna trees are deliberately left on farms in a manner that is likened to Agroforestry. Predominant trees found on farms in the study area include; Anogeissus leiocarpus (26%), Faidherbia albida (21%), parkia biglobasa (18%) and Vitellaria paradoxa (9%). Soil analysis carried out on soil samples collected at 4m, 8m, 12m from the trees found on the farms showed statistically significant differences in available soil minerals at p<0.05. The nitrogen, potassium, phosphorus and organic carbon availability ranged between 0.16 to 0.26%, 0.1024 to 0.2467 cmol./kg, 58.34 to 65.05 ppm and 1.89 to 2.42 cmol./kg respectively in the study area. Interviews conducted amongst four hundred and fifty (450) small scale farmers agreed that crops that are closer to trees found on the farms yield better than crops that are farther away. This implies that crops closer to tree stands on farms have access to more minerals than those farther apart and this supports better yield for farmers.