International Journal of Agriculture, Environment and Bioresearch Vol. 07, No. 04; 2022 ISSN: 2456-8643 www.ijaeb.org Page 141 EFFECTS OF SOME TREES ON SOIL MINERALS IN HADEJIA-NGURU WETLAND ZONE IN THE SEMI-ARID REGION OF NIGERIA Bello, H. B. 1 , Usman, D. D. 2 Adeosun, M. O. 3 Coker, A. O. 4 Koko, J. O. 5 and Ajayi, O.A. 6 1 Ogun Rural Access and Agricultural Marketing Project (Ogun RAAMP), Ogun State, Nigeria. 2 Agricultural Mechanization and Sustainable Environment Programme, Centre of Excellence in Agricultural Development and Sustainable Environment (CEADESE), Federal University of Agriculture, Abeokuta. 3 Ogun Rural Access and Agricultural Marketing Project (Ogun RAAMP), Ogun State, Nigeria. 4 Ogun State Waste Management Authority (OGWAMA), Abeokuta, Ogun state. 5 Ogun State Ministry of Agriculture, Okemosan, Abeokuta, Ogun State. 6 Ogun State Primary Health Care Development Board, Okemosan, Abeokuta, Ogun State. https://doi.org/10.35410/IJAEB.2022.5752 ABSTRACT 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. Keywords: Wetland, Climate change, Organic carbon, Soil mineral, Potassium. 1. INTRODUCTION Small scale farming system which is also referred to as smallholder farming system is an old and popular type of farming system in the semi-arid region of the northern part of Nigeria [1]. Hadejia-Nguru Wetland Zone (HNWz) where this study was carried out is not an exception to the practice of small scale farming by large number of farmers. The size of a small scale farm in the northern part of Nigeria is estimated by [2] as a farm with an average size of 0.3ha of land. Soils in the semi-arid region of Nigeria are characterized by low soil fertility and high susceptibility to degradation through erosion and nutrient loss [3]. This issue of decline in soil quality is therefore a major concern to food security issue in the entire region and very important to be worked on. HNWz is a very valuable resource to man and the environment providing avenues for farming, irrigation, fishing, grazing and recreation. The zone supplies agricultural