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The increase in population and industrial growth has led to increased production of industrial and domestic waste which contain heavy metals in various forms. Therefore, affect the diversity and activities of soil microbes and subsequently affect environmental sustainability. This research aimed at assessing the distribution of heavy metals, soil enzymes, and evaluate the functional relationship if any. The study area was divided into two locations as contaminated and control; thus, each location one square kilometre was demarcated and divided into 25 small square (grid). A Sample was collected in each grid from 0-15 cm depth using point composite sampling technique. The properties investigated are heavy metals, enzymes, pH, and soil temperature. The results of the analyses were subjected to statistical analyses to undertake one-way analysis of variance, and a t-test of means at value of <0.05, also correlation, and regression at a P<0.05 significant level. The results revealed that there is a gradual accumulation of all heavy metals and the concentration is higher in the contaminated than control locations. The soil is potentially polluted with Cd is clean from Cr, Fe, Mn, Zn, Pb, and Cu. High values of heavy metals were discovered in the dry season than the wet season due to rainfall which enhanced the dissolution, leaching, and runoff of heavy metals which is capable of removing the metals from the subsurface. High pH and temperature in the contaminated location influenced the toxicity and microbial activity respectively, this results in high enzymatic activity in the contaminated location. Favourable environmental conditions in the wet season led to the higher activity of the enzymes than the dry season. The finding also revealed that phosphatase and urease were negatively correlated with Cd and Ni. Inversely, dehydrogenase was negatively correlated with Ni and Zn. It was concluded that the determination of the heavy metals and enzymes reflects the microbial activities in soils and is considered as soil quality indicators.

Summary: Field experiment was conducted in the biotite-granite area (Alfisol) of the Jos Plateau, Nigeria, consisting of five cropping seasons to determine the effects of the tree rows (under alley cropping) and green manure of Albizia lebbeck Benth. (rattle tree) on the yield / productivity of Solanum tuberosum L. (Irish potato). The experiment was a randomized complete block design comprising five treatments and three replicates. An early maturing potato variety (Bertita) was employed, its pre-sprouted tubers were planted in the alleys (spaces between the tree rows) of A. lebbeck two weeks after green manure was applied (5 and 10 t ha -1 ), pre and post experimental soil sample analyses and cultivation operations were carried out. Results indicated that the rattle tree had profound effect on the potato growth parameters (plant height, leaf count, collar girth (at P < 0.01)) and yield indices (tuber count (P < 0.05) and tuber weight (P < 0.01)) due to nutrients from the green manure and nitrogen fixation activities of the rattle tree. A. lebbeck green manure application at 10 t ha