Foliar fertilization with phosphorus and potassium in red clover seed production on an acidic soil

A field trial with four red clover cultivars ('K-39', 'K-17', 'Una' and 'Viola') was conducted on a leached vertisol acid in reaction (pHH2O 4.8) to assess the effect of foliar treatment with phosphorus and potassium on seed yield and seed yield components. A single foliar application of phosphorus and potassium (P52K34) was made at the intensive growth stage during the second growth in the second year of cultivation. Seed yield and seed yield components were analyzed from the second growth in the second year of the experiment. Foliar treatment with phosphorus and potassium had a significant positive effect on seed yield and yield components in some red clover cultivars in some years. The most positive effect was recorded in 'K-17' and 'Viola'. The different effects of foliar-applied mineral fertilizers on the tested cultivars were the result of their phenotypic differences. Foliar treatment gave the best performance in 2011, when the climatic conditions were the most favorable for red clover growth and development. In general, the seed yield of red clover cultivars increased by 105 kg ha-1 under foliar fertilization. The positive effect of the foliar treatment with phosphorus and potassium was attributed to the need for these elements in many plant processes. The results showed that the foliar application of mineral fertilizers in red clover seed production on acid soils can be an acceptable practice under conditions favoring high yields.