Optimal fertilizer use recommendations in maize production: analysis of experimental data.
Abstract
This study was conducted to enable the determination
of economically justifiable fertilizer recommendations for
maize farmers in Kisii and Busia Districts of lJIJestern
Kenya. The study also sought to indicate the discrepancies
between current. recommendations and the economically
optimal rates as calculated by the author. The study was
conducted within the framework of the Neoclassical Profit
Maximization assumption and employed the Production
Function Approach to input recommendation. Experimental
data from the Fertilizer Use Recommendation Project (FURP)
were used. Crop Response Functions were estimated and the
marginal products equated to the inverse price ratios.
Principally the study showed that there are wide
discrepancies between recommendations from the National
Agricultural Research Stations (NARS) and the economically
optimal rates which the author calculated. In Kisii the
optimal recommendation for Nitrogen (N) during the long
rains season was 119.3% higher than current NARS
recommendation. The corresponding figure for Phosphate (P)
was 127.6%. In the short rains season the required
increases are for N' and P 36.4% and 81% respectively.
Similar results were found in Busia. The study also found
that blanket recommendations can be misleading since
results from the two districts studied indicated that even
locations in the same district may require very different
recommendations. Season was found to be a very important
factor when optimal recommendations are being made. There
were wide differences between the recommendations for the
long rains season and those for the short rains for the
same locations. In the long rains optimal recommendations
were on average 107.9% higher than the current NARS N
recommendation and 118.8% higher for P. In the short rains
the optimal recommendations were only 54% higher than the
current NARS N recommendation. The study thus concluded
that current recommendations are not economically
justifiable and that Nitrogen and Phosphate
recommendations for various locations in Kenya need
reassessment. The study recommends that fertilizer trials
be conducted with closer involvement of economists so that
recommendations are made not only on the basis of
agronomic but on economic principles also.
Citation
Master of Science in Agricultural EconomicsPublisher
Department of Agricultural Economics