Scaling Up Minjingu Phosphate Utilization For Balanced Fertilization Of Crops In Tanzania
Ensuring food security at household level and at national scale is the fundamental role of Agriculture in Tanzania. Agricultural food production in Tanzania is dominated by small scale farming system, characterized by small farm size, low input use, and employing about 70% of population, who reside in rural areas. Since independence and after the collapse of state owned farms, small scale farming has been the dependable source of food for majority of the population in Tanzania. Therefore achieving food security in the current agriculture sector requires that effort be placed in small scale farming. Sustainable food security can only be achieved if our soils are healthy, that is, with adequate and balanced nutrients for crop growth, soil organic matter, beneficial soil organisms and absence of physical barriers.
Sokoine University of Agriculture (SUA) in collaboration with the Alliance for Green Revolution in Africa (AGRA) reached out small scale farmers to bring about sustainable food production through appropriate use of fertilizers. Specifically, scaling up and out the use of locally available phosphorus fertilizer – Minjingu Phosphate in agricultural food production to increase productivity of crops, soil and water. The upscaling of Minjingu phosphate use is the result of success of research on Minjingo Rock Phosphate (MPR) for use in agriculture” initiated at the Department of Soil Science, SUA in collaboration with and University of Guelph, Ontario, Canada, followed by extensive research in various research institutions in East Africa, which all proved that Minjingu Phosphate rock is of acceptable high quality for direct application in agricultural production. We are proud and honored to share the fruits of long term research on Minjingu Phosphate with the farming community of Tanzania and beyond.
Background & The rationale of the project
Phosphorus is the second most important macronutrients in crop production in terms of quantity required and rate of depletion in soils after Nitrogen. Phosphorus depletion in Tanzanian soils has been increasing and spreading in many areas. The major cause of P depletion to the extent of limiting crop production is nutrient mining through continuing cultivation and harvesting of crops without replenishment of P removal by crops. The P deficiencies in many agricultural soils leads to reduced response of N fertilizers applied to crop, and hence contributing to low nutrient use efficiencies (Liebig Principle).
The problem of P deficiency necessitate the use of P fertilizers. However, the use of P fertilizers will obviously lead to increased cost of agricultural production to farmers. In addition, conventional P sources are usually expensive due to industrial processes to obtain easily soluble P fertilizers for plant availability. In view of this, a cheap and locally available rock phosphate was investigated for over 10 years to determine its suitability for agricultural use (References). The 10-years research at SUA revealed that Minjingu rock phosphate (MPR) can be used directly as P source in agriculture and perform best in soils with low pH (acid soils with pH < 6.0), low Ca soil and low P soils.
Following the success of initial research, the government of Tanzania in partnership with private sector endorsed and establish a plant to mine and process Minjingu phosphate rock to make it available for use as fertilizer at reasonable price. Due to its newness in the market, many farmers were not aware of Minjingu fertilizers. Also areas where Minjingu phosphate fertilizers will be suitable were not clearly known due to limited access of soil testing services among farmers in different areas. Thus there was a need to upscale use of Minjingu phosphate fertilizers so as to enable farmers in Tanzania take advantage of locally available resources in the country and cut off government fertilizer importation costs.
Minjingu phosphate supplies only one most frequently deficient macronutrient which is phosphorus. However, N is the first most limiting nutrients in most agricultural soils. Therefore, Minjingu phosphate fertilizers should be used in combination with N fertilizers. Thus, there was a need to emphasize on appropriate use of fertilizers in food crop production if food security goals are to be achieved.
The current fertility status studies reveals trends of deficiencies of micronutrients, especially Zinc and Copper in addition to N and P. To address the micronutrient deficiencies, the Minjingu mining company developed another brand of fertilizers by blending Minjingu phosphate rock with N, S, Zn, Cu, and B, and came up with a new fertilizer named Minjingu Mazao. However, the agronomic performance and relative effectiveness of Minjingu mazao was scant, especially in food crops.