Exploring the impact of tillage methods on crop residue decomposition and nutrient release: A litter bag study

Recycling of crop residues has gained attention over the past few decades due to its influence in sustaining the soil fertility and crop production. In this context, it is of crucial to study the effect of crop residue type, placement and tillage on decomposition and nutrient release in tropical agriculture.

We conducted a litter bag decomposition experiment to evaluate the rate of mass loss, carbon (C), nitrogen (N) and phosphorus (P) mineralization from crops residues. We used residues of cotton, maize and cowpea.

Result indicated that cowpea and cotton residues decomposed more rapidly than maize residues, with mass loss of 50-65% occurring within 40 days of placement. Plough depth placement resulted in faster decomposition than deep placement, with 78% of initial mass and nutrient contents lost at the end of 120 days. Over 50% of nutrient mineralization occurred in the first 30 days of decomposition from cowpea residues. At the end of the 120^th day, 0.28%, 0.19% and 0.30% of total nitrogen content remained out of 2.15%, 0.86% and 1.22% of the initial total nitrogen in cowpea, maize and cotton residues, respectively. More than 48% of residue breakdown and nutrient mineralization occurred in the first 40 days of decomposition, suggesting that farmers can boost crop growth by choosing crop residues with a low and medium C:N ratio and placing residues at a plough depth (0-15 cm) using reduced tillage practices.