Manure recycling from urban livestock farms for closing the urban–rural nutrient loops

Rapid urbanization in developing countries is attracting urban livestock farming, which is associated with feed nutrient imports and manure nutrient accumulations. Here, we report on manure nutrients (N, P and K) production on urban livestock farms in Addis Ababa and Jimma in Ethiopia, and estimate manure recovery on these farms and its recycling in urban, peri-urban and rural crop farms. Estimates were based on data from farm surveys, statistics, literature and model calculations. Urban livestock farms had on average 13 tropical livestock units and positive N, P and K balances. Urban crop farms had negative N and K balances, and did not use manure from urban livestock farms. We estimated that 0.5–2.6 Gg N, 0.2–0.8 Gg P and 0.9–3.7 Gg K can be collected in manure from the 5,200 urban livestock farms in Addis Ababa year−1, and can be recycled in crop land. Two manure allocation strategies were explored: balanced P fertilization and balanced N fertilization. The former allowed greater precision in matching nutrient supply to demand, and was associated with greater manure transport and distribution, up to rural areas. Manure recycling has several benefits: synthetic fertilizer savings (75–300 million Ethiopian Birr year−1 for Addis Ababa), soil fertility replenishment, and reductions in water pollution. However, there are various cultural, educational and institutional barriers for manure recycling. We argue that more quantitative data and scenario analyses are needed for deliberative decision making and for exploring more sustainable development pathways of urban livestock farms, re-connected to crop farms via manure recycling.

Perception of Farmers’ on Soil Fertility Problems and Replenishment Technologies in the North Rift Region of Kenya

This paper investigates the farmers’ perception on soil fertility replenishment technologies in the North Rift Region of Kenya. A survey was conducted in Trans Nzoia and Uasin Gishu counties of the North Rift Region of Kenya. A total of 108 respondents were interviewed. A two stage random sampling technique was employed in the study. In the first stage, farmer groups growing maize as the main crop were selected. The second stage involved the selection of farmers who were practicing cereal banking for ease of marketing of their produce. A survey and field demonstration plots were adopted. On-farm demonstration were carried out and used to ascertain the farmers’ perception towards the technologies. A structured questionnaire was administered to them to elicit information on their perception on soil fertility replenishment technologies (SFRT). Descriptive statistics and the multiple regression analysis was done using a Statistical Package for Social Sciences (SPSS). The results revealed that farmers perceived that technologies could be used to address the declining soil fertility. The inputs were affordable available, the Ministry of Agriculture, Livestock and Fisheries (MOALF) was effective in disseminating the technologies and that the technologies could work on any farm at mean score of 3.5, 4.1, 4.0, 3.4 and 4.6 out of 5.0 respectively. Farmers in Trans Nzoia county identified lack of capital (70.4%) compared to Uasin Gishu (39.9%) as the greatest challenge in the adoption of SFRT technologies. Credit schemes that offer loans with low interest rates should be established to enable farmers have access to credit.

Farming with rocks and minerals: challenges and opportunities

In many parts of the world food security is at risk. One of the biophysical root causes of falling per-capita food production is the declining quality and quantity of soils. To reverse this trend and increase soil fertility soil and plant nutrients have to be replenished. This review provides a literature survey of experiences of using multi-nutrient rock fertilizers for soil fertility enhancement from temperate and tropical environments. Advantages and limitations of the application of rock fertilizers are discussed. Examples are provided from two successful nutrient replenishment projects in Africa where locally available rock fertilizers are used on highly leached acid soils. The potential of combining organic materials alongside rock fertilizers in soil fertility replenishment strategies is stressed.