M.A. Thesis:

Effect of foliar application of solo potash and magnesium sulfate on yield, yield components and protein content of forage sorghum

Abstract: In order to evaluate the effect of foliar application of solo potash and magnesium sulfate on yield and quality of forage sorghum, a factorial experiment based on randomized complete block design with three replications was performed in Sabzevar. Experimental factors included foliar application of solo potash and magnesium sulfate, each in three levels of non-foliar application, foliar application at 6-8 leaf stage and two foliar applications at 6-8 leaf stage and emergence of inflorescences. The results showed that foliar application of solo potash had no significant effect on leaf number per plant, but considerably increased plant height, tiller number per plant, fresh forage yield, forage dry matter percentage, forage protein content and nitrogen uptake. There was no significant difference between treatments of solo potash folia application at 6-8 leaf stage and two foliar applications at 6-8 leaf stage and emergence of inflorescences in relation to plant height, tiller number per plant and fresh forage yield. The highest nitrogen uptake and forage dry matter percentage were observed in treatments of solo potash foliar application at 6-8 leaf stage and two foliar applications of solo potash at 6-8 leaf stage and emergence of inflorescences, respectively. Magnesium sulfate foliar application significantly increased plant height, leaf number per plant, fresh forage yield and nitrogen uptake, but considerably decreased forage dry matter percentage at two foliar applications treatment. Two stage foliar applications of magnesium sulfate in 6-8 leaf stage and emergence of inflorescence resulted in the highest nitrogen uptake by the plant. The highest fresh forage yield was obtained in two stage foliar applications of solo potash and magnesium sulfate in 6-8 leaf stage and emergence of inflorescence, which resulted in a significant increase compared to no foliar application conditions, as well as the two stage foliar applications of solo potash at 6-8 leaf stage and emergence of inflorescences. Foliar application of solo potash in 6-8 leaf stage produced the highest percentage of forage protein, which did not have significant difference with foliar application of solo potash and magnesium sulfate at 6-8 leaf stage, as well as two stage foliar applications of magnesium sulfate in 6-8 leaf stage and emergence of inflorescences. According to the results, one stage foliar application of solo potash and magnesium sulfate at beginning of vegetative growth (6-8 leaf stage) is recommended for production of maximum fresh forage yield of sorghum with high protein content.

Keywords: Key word: Nitrogen uptake, sorghum, magnesium, potassium, fresh forage.