Uptake and Availability of Potassium and Nitrogen in Wheat as Influenced by their Split Application under Temperate Conditions of Kashmir: Experimental Investigation

Abstract

An experiment was carried out at the University Research Farm, SKUAST-K, Shalimar, Srinagar (J&K) to assess the effect of split application of potassium and nitrogen on their uptake and availability in wheat. The experiment was designed as a split plot with 15 treatment combinations, viz.,3 levels of potassium (K) @ 30 kg ha-1 [K1: 100% K as basal dose –[recommended fertilizer dose (RFD)]; K2: split 50:50; K3: split 25:75] and 5 of nitrogen (N) @ 120 kg ha-1 [N₁: 50:25:25 (RFD); N2: 25:75, N3: 25:50:25, N4:50:50 and N5: 0:75:25]. Using K in equal splits (basal + active tillering) increased grain yield by 10.6 and 11.6 percent, straw yield by 11.6 and 13.4 percent, K uptake by 17.2 and 18.8 percent, and N uptake by 16.4 and 17.2 percent, respectively, over RFP in 2013-14 and 2014-15. The available K decreased steadily with the recommended application but remained constant when applied in split doses. The N management plays a key role in improving crop growth, environmental safety and economics of crop production.  The available N in soil remained constant with RFP; however, it decreased when K was applied in splits. During both years, N application in 25:50:25 ratios (basal + active tillering + booting) increased grain yield, straw yield, and total K and N uptake. Furthermore, K and N content in soil decreased when N was applied in three splits as opposed to two splits, where it remained constant after harvest of the second year crop. This suggests that an increase in N dose may be required to maintain soil N status.