English

Abay Abebe

doi:10.5897/ajps2018.1717

Abstract

Litter mineralization is a crucial process in providing nutrients through decomposition to plants, which also depends in the biochemical composition of the litter and soil properties as well. Decomposition rate of Erythrina abyssinica and Erythrina brucei in Luvisol was investigated in relation to their nutrient release dynamics such as NH4+-N and NO3--N in relation to their initial concentrations of lignin, acid detergent fiber, cellulose and total polyphenol content and their ratios. The dynamic was followed in an incubation pot experiment, complete randomized design in replication. E. abyssinica has an average of 4.05, 9.7 and 2.04% TN, lignin and total polyphenol content respectively. E. brucei has also an average of 3.05, 12.63 and 1.05% content of TN, lignin and total polyphenol respectively. The samples of E. abyssinica and E. brucei were ground and incorporated with Luvisol in pots. To determine the amount of ammonium and nitrate released each treatment and control were sampled and analyzed on weekly basses. The lignin and total polyphenol was significantly positively correlated with the release of NH4+-N, while the NO3--N showed significant negative correlations with the release of ammonium. From the experiment, it was observed that the E. abyssinica with lower content of lignin and high in TN has released the nutrients faster whereas E. brucei with high lignin and low total polyphenol content released slowly.  In general, these leguminous trees released NH4+-N and NO3--N easily because of their high total nitrogen content and low lignin, ADF, cellulose and total polyphenol content. They attained their half-life within 2-3 weeks. Therefore, E. abyssinica and E. brucei bears fast mineralization as a result they can be used for fast-term correction of crop nutrient demand. However, more detailed researches are needed to synchronize and verify laboratory results with field measurements of their effect on crop production and synchronization of soil nutrient availability and crop demand in different agro ecology and soil types.   Key words: Incubation, lignin, luvisol, total polyphenol, nitrate, ammonium.

Highlights

Incorporation of agroforestry legumes trees to the soil have been identified as important management practice to increase soil fertility
Studies on Ethiopian soil and forest revealed that the very wide range of climate, topography, parent material and microorganisms’ and the local conditions of the specific areas have assisted in development of different soil types as well as over 6,600 higher plant species including indigenous leguminous and non-leguminous trees (Mesfin, 1998; MoA, 2000; Mohammed, 2003; Bekele, 2007)
E. abyssinica and E. brucei had diverse TN content and the data obtained in this study showed that no direct or inverse relationship was found between total nitrogen content and altitude.There was significant difference in TP content between EB and EA

Summary

Introduction

Incorporation of agroforestry legumes trees to the soil have been identified as important management practice to increase soil fertility. Plant litter mineralization is biological decomposition of litter by microorganisms and transfer of organic and mineral compounds to the soil (Loranger et al, 2002). Studies on Ethiopian soil and forest revealed that the very wide range of climate, topography, parent material and microorganisms’ and the local conditions of the specific areas have assisted in development of different soil types as well as over 6,600 higher plant species including indigenous leguminous and non-leguminous trees (Mesfin, 1998; MoA, 2000; Mohammed, 2003; Bekele, 2007). In the future agricultural system, application of organic farming systems is important in order to lessen impacts of climate change, decrease soil erosion (Reganold et al, 1987), improve biodiversity (Hole et al, 2005), and enhance soil fertility (Watson et al, 2002)

Methods

Results

Conclusion