Release of Ammonium-N (NH4+) and Nitrate-N (NO3-) by Different Leguminous Cover Crops (LCCs) Planted in Peat Soils

Abstract

Peat soils is renowned for the low mineral-N concentration which is crucial for crop’s growth. One of the effective and conserving method to improve the soil mineral-N concentration is by planting leguminous cover crop (LCC) which is common in oil palm plantation area. However, different LCCs was found to release different concentration of mineral-N into the soils. Hence, this study aims to determine the concentration of soil mineral-N in form of soil ammonium-N (NH4+) and soil nitrate-N (NO3-) by different types of LCCs namely Mucuna bracteata, Calopogonium mucunoides, Pueraria javanica and Centrosema pubescens as well as to evaluate the effects on physico-chemical properties of peat soils. Results showed most of the LCCs can survive in acidic peat condition whilst improving the concentration of mineral-N in the soils. Mucuna bracteata was found to release a significant amount of mineral-N into the soils and shows a vigorous growth compared to others during the study period. However, it should be noted that different LCCs required distinct time to fix N since the maturity for different LCCs is different. Hence, prolonged studies on release of mineral N into the soil by LCCs are recommended.