Agronomic Strategies to Manage Soil Water Retention to Minimize Global Warming

Purpose: This paper focuses on the problems of soil water depletion and greenhouse gas emissions caused by improper soil management practices in arable lands. The results of previous studies were analyzed and the effects of deep ploughing on highly and less compacted soil were discussed. In addition, the effect of organic matter incorporation on soil water retention, and greenhouse gas emissions was evaluated.
Research Method: To assess the impact of deep ploughing on soil moisture, two soil series (Andigama and Madampe) were selected. Moisture content was measured in ploughed and un-ploughed soil over a year using a neutron moisture meter. Coconut cultivations interplanted with nitrogen-fixing trees for eight years were used to assess soil improvement of the unproductive Andigama series. Soil compaction and water retention were measured using a cone penetrometer and neutron scattering technique in dry and rainy seasons. Palm oil sludge was mixed with sandy loam soil in various ratios and incubated for three months. Greenhouse gas emission was then analyzed using gas chromatography.
Findings and Values: The results indicated that deep ploughing significantly (p < 0.05) improved soil water retention during both rainy and dry periods in compacted soils but had no significant (p > 0.05) effect in less compacted soils due to disruption of natural pore structure. Alternatively, agroforestry systems with nitrogen-fixing trees enhanced the soil water retention in degraded lands. Furthermore, an optimal ratio (15%) of palm oil sludge incorporation into the soil under optimal water conditions reduced the emissions of greenhouse gases such as CH₄ and N₂O. Overall, the findings demonstrate that incorporating organic matter and adopting appropriate land management practices minimizes the emission of greenhouse gases, which is essential to reducing global warming and mitigating climate change impacts.