"I am a Rice farmer in Mwea, please advise on the best fertilizer program for growing rice in the Mwea region."
Successful production of Paddy Rice such as is the case in Mwea calls for careful management of two important factors; Irrigation water and the Fertilization program.
Irrigation water management is critical in ensuring that the Nutrients applied in the fertilizers have a better chance of being taken up by the crop and not lost either by leaching, Volatilization, Denitrification or even immobilization.
Balanced Nutrition in Rice like all other crops is critical in achieving Optimal yields. The application time as well as type and form of the nutrients, are essential factors determining the Agronomic efficiency of the fertilizer applied. Nitrogen as a nutrient is particularly prone to many types of losses, and as such requires careful management to achieve desired good yields.
Unlike many other crops, a rice crop will benefit from an Ammonium source of Nitrogen at the early growth stages, but becomes more efficient on uptake of Nitrate Nitrogen at the later stages of panicle initiation. This is so because in the early stages of low Nitrogen demand, the Ammonium is taken up and some nitrified in time for plant uptake.
However, in the peak demand periods – at Panicle initiation- application of Ammonium N fertilizer is inefficient as there are heavy losses from Volatilization more than denitrification and leaching. For this reason, a Nitrate source of N is more efficient as the plant quickly takes up the Nitrogen.
As already mentioned, all these fertilization practices must be done under a sound irrigation management system as well as other Agronomic activities to optimize the nutrient uptake for the best quality yields.
By: Vitalis Wafula
East Africa Regional Agronomist - YARA