Effect of Pre - Wetted Technique on Soil Temperature, Moisture Content, Organic Carbon and Greenhouse Gas Emissions in Niger State, Nigeria

Abstract

Poor agricultural practices, depletion of croplands productivity and carbon pools have continued to exacerbate indirect greenhouse gas (GHGs) emissions subsequently aggravating malnutrition and food security issues in Nigeria. For this purpose, an experiment was conducted at Edozhigi, in Niger State on integrated formulations of rice straw and urea at different rates respectively: 2, 3 and 4 t/ha and 25, 50 and 75 kg/ha with one check plot (C) (without straw and urea). Pre-wetted technique of the integrated formulations was adopted under Randomized Complete Block Design with (04) replications of ten (10) plots. The effect of treatments on the following variables; Soil Temperature (ST, oC), Moisture Content (SMC, %), GHGs emissions (kg/ha), Soil Organic Carbon Density (SOCD, t/ha), Soil Organic Carbon Density Gain per Month (SOCDG/month, kg/ha) and SOCD versus ST and SMC under each treatment were determined in order to identify the best treatments. Data collected were analysed using GenStat 16.2 and CCAFS-MOT 1.0 for SOC balance. Matlab 11.0 and Excel 2013 were also used for data plotting and regression graphs. Significance and Duncan’s Multiple Range Test were performed at 95% confidence level. Results indicated significant difference of treatments on each parameters evaluated. ST reduction; SMC, SOCD and SOCDG increase is a function of the quantity of straw and urea incorporated (Fpr.<0.001). Moreover, the study revealed strong decrease of SOCD with ST (r= -0.801) and increase with SMC (r= 0.851), and three best treatments (T2, T4 and T5) were identified. Their responses (TR, %) to each variable were; Soil Temperature (ST, oC) reduction was up to 20 %, Soil Moisture Content (SMC, %) increased about 41%. Similarly, Soil Organic Carbon Density (SOCD, t/ha) and Soil Organic Carbon Density Gain per Month (SOCDG/month, kg/ha) have increased respectively to 40.3% and 43 %. Potential carbon sequestration was about 44.4 % for the improved practices identified with 0 % methane emission and scanty nitrous oxide emission up to 31.3 %. These results gave strong evidence concerning the use of pre-wetted technique as panacea to both mitigate climate change and enhance croplands productivity and resilience to these changes in Edozhigi.