Global Journal of Agricultural Research Vol.8, No.4, pp.10-16, October 2020 Published by ECRTD-UK Print ISSN: ISSN 2053-5805(Print), Online ISSN: ISSN 2053-5813(Online) 10 PRODUCTIVITY ASSESSMENT OF TWO DIFFERENT MANAGEMENT SYSTEMS IN SUB-DIVIDED FOUR DIFFERENT GRADIENTS Nweke, I. A., 1 Nnabude P. C., 2 Ekwealor, K. U. 2 Anochie C. 1 , Ijearu, S. I. 3 1 Department of Soil and Land Resource Management, Nnamdi Azikiwe University, Awka, Anambra, Nigeria 2 Department of Soil Science Chukwuemeka Odumegwu Ojukwu University 3 Department of Agricultural Technology, Akanu Ibiam Federal Polytechnic, Uwana Afikpo, Ebonyi State, Nigeria ABSTRACT: Watersheds are naturally productive but most ecologically vulnerable section of the landscape. Productivity assessment of two contrasting watershed were studied in Amawbia south east, Nigeria using amaranthus as test crop under field and pot experiments. The experiments were arranged in randomized complete block design (RCBD) and complete randomized design (CRD) respectively in managed and unmanaged system of the watershed with NPK at the rate of 150kg/ha. Findings from the study showed significant differences (P < 0.05) among the slopes, managements, slope and management as well as natural environment and NPK in all the parameters assessed. Higher values were recorded in managed system in all the parameters and values obtained from NPK were observed to be higher than the values obtained from natural environment. Natural environment of the four slopes studied in managed plot significantly recorded increased growth and yield of amaranthus than the unmanaged plots. Thus, the findings of the study are evidence that sustainable management of soil and water resources is based on the judicious and scientific management of all landscape units within a watershed. As land degradation beyond the point of no return, pollution and eutropication of water and environment are all traceable to poor and mismanagement of landscape units within a watershed. KEYWORDS: Amaranthus, ecosystem, fertilizer, management systems, natural environment, slope INTRODUCTION Amaranthus is an erect plant that has branching and occasional pubescent stem is a popular vegetable crop in Nigeria and south east in particular. It is a commonly grown leafy vegetable of the low land tropics in Africa and Asia. Amaranthus is of many species of which their cultivation have increased tremendously all over Nigeria and probably other parts of tropical Africa basically for its leafy material relevance in soup and stew making, salad, porridge etc. It is a source of dietary protein and like other leafy vegetables contains more Ca than meat. It’s rich sources of vitamins B and C enhances its nutritional values (Ali 1999). Medically, the leaves can be used as alternative drug therapy for the hypertension and cardiovascular disease patients (Martiorosyan and Mirostinichen, 2007). The crop is a shallow rooted crop, sensitive to soil nutrients and water hence management practices affect the development and productivity of the crop. Amaranthus for instance, requires a fertile soil well supplied with organic matter for good productivity (Okoli and Nweke, 2015). Nitrogen has equally, proven to be the limiting soil nutrient in most situations (Weber, 1989) which has led to a study on the effect of nitrogen fertilizer on amaranthus in Nigeria (Ibrahim and Lawal, 2001). The crop is very tolerant to varying soil and weather conditions. Therefore, soils that should be used for effective production of the crop should be managed by conservation, though sustainable crop production in the face of ever increasing human population in Africa and Nigeria in particular with their expanding nutritional demands has made the environmental and social development a very big challenging issue.