Maize Production: Enhancing Soil Fertility for Greater Productivity

The staple food crops in Kenya include maize, beans, rice, potatoes and sorghum. The yields of food crops per acre are on the decline due to adverse effects of climate change, low adoption of quality farm inputs and continuous farming without adequate soil nutrients replenishment. This calls for better soil management practices through soil investigations that provide farmers with soil amendment and management solutions that not only increases crop productivity but also conserve the environment.

Optimal Conditions for Maize Growth
Maize can be grown on a wide range of soils but performs best on well-drained, well aerated and deep soils containing adequate organic matter content and well supplied with available nutrients. High yields of maize results in heavy drain on soil nutrients and therefore requires regular replenishment with soil nutrients to replace nutrients taken up after every harvest. To sustain yields at a certain level, nutrients out of soil must always be almost equal to nutrients applied within a growing period taking into consideration nutrient losses through harvested materials, leaching, volatilization, and erosion. For optimum production, factors such as soil moisture, temperature, pests and diseases, weed control, and soil chemical and physical conditions must be taken into consideration.

Maize crop grows generally well in soils with a pH range of 5.0 to 8.0 with an optimum pH range for growth at 5.5 to 7.0. The pH outside this range usually makes certain elements more or less available, so toxicity or deficiency develops and growth rates of the crops is reduced. It is very important to maintain the pH as close to the optimum range as possible because below a soil pH of 5.0, alluminium and manganese toxicities may occur and deficiencies of P, Mg and Ca become common. At pH above 8.0, deficiencies of Fe, Mn, Zn and P tend to occur. For example if pH is lower than 6.0, P starts forming insoluble compounds with iron (Fe) and aluminum (Al) and if pH is higher than 7.5, P starts forming insoluble compounds with calcium (Ca) making it unavailable to the plants.

Soil suitability evaluation is a useful tool to guide farmers, farmer groups, extension providers, dealers in fertilizers and other stakeholders on the types and levels of fertilizer application for different areas in the country. Farmers and other stakeholders are encouraged to acquire the soil test information and use the fertilizer recommendations to improve their crop productivity and guide agro dealers in procurement of fertilizer for various regions in the country. Further, the long term goal is to encourage farmers to test their soils before applying organic and inorganic fertilizers.

The National Agricultural Accelerated Input Access program (NAAIAP) is a pro poor program in the State Department of Agriculture that offers support to resource poor farmers through fertilizer subsidy and an Agricultural Credit Guarantee Scheme. The primary objective of NAAIAP is to improve the availability of farm inputs to vulnerable households by offering startup inputs grants in the form of seeds and fertilizers for one acre of maize. The targeted subsidy is intended to uplift beneficiaries out of the vicious cycle of poverty and enable them to participate in commercial agriculture through their own resource mobilization initiatives and the credit guarantee scheme.

To maximize on inputs use, soil sampling and analysis was incorporated in the program to provide information on the nutrient status of soils to enable farmers apply the right types and quantities of fertilizers to minimize problems of land degradation through build up of soil acidity as a result of blanket fertilizer recommendations.

A strong agricultural sector provides a sound foundation for a prosperous country. From this recognition, the goal of the government is expressed in Kenya Vision 2030; that is ‘a viable and vibrant agricultural sector that is commercially oriented’ and can compete at international level with more advanced world economies

The sector, however, faces a number of challenges which include reduced productivity, high cost of farm inputs, inefficient utilization of inputs, poor adoption of mechanization, impacts of climate change and lack of access to agricultural credit.

The country’s fertilizer market is fully liberalized with the bulk of fertilizers imported and distributed by the private sector. However, since 2008, the government through the fertilizer subsidy program has procured 494,000 metric tonnes of fertilizer in support of the agricultural sector.

A Kenya Government report provides recommendations on the most appropriate fertilizer formulation or blend for maize. However, the farm specific results may be interpreted for other crops. A data base for soils in the sampled sub counties has been compiled and this report can be uploaded on the ministry’s website www.kilimo.go.ke. The report is an invaluable resource for use by farmers, agricultural extension providers and stakeholders as a tool for appropriate fertilizer use.