TITLE:
Tillage, Desmodium intortum, Fertilizer Rates for Carbon Stock, Soil Quality and Grain Yield in Northern Guinea Savanna of Nigeria
AUTHORS:
Odunze Azubuike Chidowe, Asholo David Blessing, Ogunwole Joshua Olalekan, Oyinlola Eunice Yetunde, Chinke Nkechi Mary
KEYWORDS:
Carbon Stock, Tillage, Soil Quality, Grain Yield, Climate Change Mitigation
JOURNAL NAME:
American Journal of Climate Change,
Vol.8 No.2,
June
28,
2019
ABSTRACT: Northern Guinea Savanna of Nigeria soils are continuously and intensively cultivated, resulting in soil quality degradation, carbon stock depletion, accelerated soil erosion and soil nutrient depletion. Effects of land use change on soil carbon stocks (SOC) are of concern regarding greenhouse gas emissions mitigation and sustainable crop production, because there is a need for food sufficiency while conserving the environment. Also, managing soils under intensive use and restoring degraded soils are top priorities for a sustained agronomic production while conserving soil and water resources. Hence, this study; “Tillage, Desmodium intortum, fertilizer rates for carbon stock, soil quality and grain yield in Northern Guinea Savanna” is aimed at devising possible mitigating measures for soil quality degradation, carbon stock depletion and impoverished crop yields using Zea mays as test crop. The study was a Randomized Complete Block Design (RCBD) in split-split plot arrangement with four replicates. The four main tillage and Desmodium intortum combination treatments were: 1) Maize − without Desmodium + Conventional tillage (MC), 2) Maize + Desmodium live-mulch incorporated and relayed + Conservation tillage (MDIC), 3) Maize + Desmodium in no-tillage system (MDNT), 4) Maize + Desmodium in strip tillage (MDST). The main treatment plots were each divided to accommodate four (4) rates of N (60, 80, 100 and 120 kg·ha−1) as sub plots, while the N rate plots were further divided to accommodate three (3) rates of P (6.6, 13.2, and 26.4 kg·ha−1) as sub-subplots. Findings support that Desmodium intercrops with Maize treatments (MDIC, MDNT, and MDST) resulted in increased organic carbon contents in 2013, with MDNT resulting in significantly higher organic carbon content (7.37 g·kg−1 in 2012 and 8.37 g·kg−1 in 2013) than the other treatments. Also, zero tillage practice (MDNT) sequestered significantly higher carbon stock (18.06 t C ha−1), followed by minimum tillage (MDIC) that sequestered 15.99 t C ha−1 than the other treatments. Highest grain yield of 2.61 tha−1 under MDIC and MDNT was followed by MDST and least under MC. Total score of soil quality assessment gave least score values of 13 under MDIC and MDNT; thus best soil quality (SQ1) was ascribed to the minimum tillage with D. intortum intercrop and relayed (MDIC) and Zero tillage with D. intortum (MDNT) treatments. Maize Strip cropped with D. intortum treatment (MDST) was ranked SQ2.