Author:

Keywords:

Science & Technology, Life Sciences & Biomedicine, Ecology, Forestry, Environmental Sciences & Ecology, sustainability, maize stover, banana homegardens, nutrient flows, agroforestry, nutrient balance, cattle manure, agroecosystems, LAND-USE, SOIL PRODUCTIVITY, MT. KILIMANJARO, DYNAMICS, SYSTEMS, YIELD, 3007 Forestry sciences

Abstract:

Maize (Zea mays) stover produced in the drier lowland areas on the volcanic foot slopes of Mount Kilimanjaro serves as an important additional fodder for smallholder zero-grazed dairy cattle farming system in the humid highland areas of the region. The obtained cattle manure is used to replenish nutrients and manage soil fertility in banana-based agroforestry homegardens of the highlands, which contributes significantly to sustaining crop production, thus food security and the livelihoods of the community. The study aims to provide a preliminary evaluation of the amounts of stover removed from smallholder maize fields in the lowlands, and the subsequent nutrient flows to the banana-based agroforestry homegardens of the highlands. An agronomic survey was conducted in 45 smallholder maize fields randomly selected from 11 villages in Hai and Siha districts in the Kilimanjaro region. During the survey, information on the type and amounts of fertilizer used was collected and measurements were taken on plant spacing at harvest and on stover biomass yield. Most maize fields received inadequate nutrient inputs, which were limited to mineral nitrogen alone if any. Of the surveyed fields, 38 % received adequate amounts of this nutrient, 16 % below the recommended rate of 50 kg N ha-1 and 46 % did not receive fertilizer at all. Plant density was only 50 % of the recommended population density. While this was only a preliminary study on nutrient flows between maize and banana-based agroecosystems, our findings demonstrated a negative potassium balance in the homegardens. We conclude that (i) soil fertility management techniques, preferably integrated soil fertility management, suitable for small-scale maize production in the lowlands should be formulated while optimizing plant density to increase production, (ii) cattle manure should be supplemented with mineral fertilizers to increase nutrient replenishment in banana-based agroforestry homegardens, (iii) maize-based agroforestry farming system adapted to smallholder farmers conditions to deal with windstorm and soil erosion problems in the lowlands is urgently needed, and (iv) a wider and more detailed study on nutrient flows between maize and banana-based agroecosystems should be conducted to document their respective nutrient stocks and the sustainability of such practice.