Impact of Mineral Fertilizer, with ‘in-situ’ Mulches, on the Properties and Productivity of Soil on a Cultivated Slope in Akwa Ibom State, Nigeria
Usuah, P. E.1, A. N. Ukut2 & U. S. Akpan1
Department of Soil Science and Land Resources Management, University of Uyo,Uyo,
Akwa Ibom State College of Science & Technology, Nnung Ukim, Nigeria
Corresponding author: peterusuah@gmail.com
ABSTRACT
Effect of the application of mineral fertilizer with “in-situ” mulches on selected physico-chemical properties of the soil and the grain yield of maize on a cultivated slope were investigated. The study was conducted on a 9.5% sloping farmland during the 2015 and 2016 early planting seasons, using the traditional no-till system with seeds planted through the mulch. There were four (4) treatments viz: decomposing ‘in-situ’ mixed mulches at 10 Mgha-1 (designated M); fertilizer (N.P.K. 20.10.10) at 0.4 Mgha-1 (F); mulch at 10 Mgha-1 plus NPK fertilizer at 0.4 Mgha-1 (MF); no mulch, no fertilizer (NMF) – the control. Experimental design was the randomized complete block design (RCBD) in six (6) replications. Soil moisture levels in mulched plots increased over the control by a range of 30 to 45 percent. Mulched plots had lower soil temperatures, ranging from 5 to 16 percent over the control. Mulching increased soil organic C levels by a range of 7 to 40 percent over the control. Post study values of total N in plots under MF were 111 and 106 percent over the control in 2015 and 2016 respectively. Treatment MF increased P levels by 14 and 16 mgkg-1 in 2015 and 2017 respectively. Exchangeable K in mulched plots was raised by 27 to 225.6 percent over the control. Treatment MF gave highest maize grain yields of 2.66 and 2.89 Mgha-1 for 2015 and 2016 respectively. These were significantly (p ≥ .01) higher than values for M, F and the control (MNF).
Key words: slopes, “in-situ” mulches, grain yields, Niger Delta.
