Effect of fertilizer and manure application on growth and area adaptability of three common aloe species in a semi-arid Eastern Kenya

Abstract

Semi-arid lands have limited sustainable cash crops that can survive the dry climatic conditions and provide a stable source of income to the people in the region. Aloes, which grow wildly in this region controls a large world market valued at U$ 20 billion and are a source of natural products that are used in cosmetic and pharmaceutical industries worldwide. In order to commercialize this crop in the dry lands of eastern Kenya, studies were conducted to investigate adaptability, response to fertilizer and/or manure application and growth of three commonly occurring aloe varieties in the semi–arid lands. The 3 aloes were tested for response to 9 fertilizer and/or manure treatments (Nil fertilizer or manure, 20 kg P2O5/ha, 10 kg P2O5/ha, 4 t FYM /ha, 2 t FYM/ha, 20 kg P2O5 + 2 t FYM/ha, 10 kg P2O5 + 2 t FYM/ha, 20 kg P2O5 +4 t FYM/ha, 10 kg P2O5 +4 t FYM/ha) and their environmental adaptability in a randomized complete block design in a split plot arrangement at Kambi ya Mawe in Makueni district from 2007-2009. The results revealed that, aloe secundifolia Engler and aloe vera barbadensis Miller had a significantly (P ≤ 0.05) better survival proportion of 96% and 92% after first and 93% and 79.5% at end of second year of growth respectively. Leaf area index (LAI) which is a measure of aloe growth, was significantly (P ≤ 0.05) higher in aloe secundifolia Engler and aloe turkanensis Christian than aloe vera barbadensis Miller. After the 2 years of study, the 3 aloes species did not respond significantly (P ≤ 0.05) to fertilizer and/or manure application. Participating farmers were empowered on aloe agronomy and processing. It was recommended that, A. secundifolia Engler was most adaptable for growing in the semi-arid lands followed by A. vera barbadensis and can be grown up to 2 years without fertilizer or manure application in very low fertile soils. However, more data is required to show how long the aloes can be grown without soil fertility improvements.