Initial Litter Chemical Indices as Selection Criteria of Organic Nutrient Resources for Enhancement of Soil Fertility for Smallholder Farmers in Southern Ethiopia

Nutrient release from applied organic nutrient source (ONS) depends on temperature, soil moisture, soil properties, their chemical composition and microbial activity. In order to apply ONS to fulfill the nutrient requirements of plants, knowledge of quality and quantity of chemical constituents of the ONS has paramount importance. Erythrina abyssinica (EA), Erythrina brucei (EB) and Ensete ventricosum (EV), the first two being nitrogen-fixing indigenous multipurpose agroforestry trees in Ethiopia, were randomly collected from Southern Ethiopia. The average total nitrogen (TN) contents of EA, EB and EV were 4.05%, 3.35% and 2.56%, respectively. Similarly, the mean total soluble polyphenolics contents were 0.052%, 0.023% and 0.19%, and the mean lignin contents were 9.7%, 12.6% and 6.5%, respectively. In general, these ONS had medium to high TN content. Thus, the ONS can be selected based on their quality, quantity and ratio of their chemical constituents as alternative or supportive organic sources. A "decision tree" is best fitted for selection of these ONS.