EFFECT OF FERTILIZER APPLICATION ON THE YIELD AND PROTEIN CONTENT OF SOYBEAN HARVESTED AT VARIOUS STAGES OF MATURITY

Abstract

Fertilizer application significantly increased the yield of soybean when harvested not earlier than 35 days after flowering. The crude protein content of soybean was not influenced by fertilizer application regardless of its stage of maturity. With or without fertilizer application, significant differences existed only between crude protein content of the sample harvested at 15 days after flowering and those harvested at the other three stages of maturity. However when fertilizer was applied, significant difference was also observed between the protein content of samples harvested at 25 and 45 days after flowering. Furthermore, fertilizer application significantly influenced the total protein yield of soybean. Without fertilization, there was no significant increase in the total protein yield when plants were harvested at 25 days after flowering instead of 15 days after. When the plants were fertilized, a significant increase in total protein yield for every 10-day increment in maturity was observed. Higher yield, crude protein content and total protein yield were obtained when the plants were harvestec 45 days after flowering than when harvested at 15, 25 and 35 days after flowering. Yield and protein content of the beans increased linearly as time of harvest was delayed frorr 15 to 45 days after flowering.