Investigating the Tillage, Desmodium intortum, Fertilizer Rates for Carbon Stock, Soil Quality and Grain Yield in Northern Guinea Savanna of Nigeria

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. Globally, the effects of land use change on soil carbon stocks
(SOC) are of concern in the context of international policy agendas on greenhouse gas emissions
mitigation and sustainable crop production, because there is a dare need to produce sufficient food for
the world’s growing population 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; “Investigating the 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.