Efficacy of fertilizing method for different potash sources in cotton (Gossypium hirsutum L.) nutrition under arid climatic conditions

Precise choice of potassium (K) source and application method does matter for its cost-effectiveness. This study was aimed to evaluate the best source and method of K fertilizer application to improve cotton productivity and profitability under an arid climate. Three different K sources (KNO(3), K(2)SO(4) and KCl) were applied at 100 kg ha(-1) by four methods, i.e. a) basal application, b) side dressing, c) fertigation and d) foliar application of 2% K(2)SO(4). The highest productivity and profitability were recorded with K(2)SO(4) applied as foliar application. Total boll weight per plant was similar in foliar applied K(2)SO(4) and basal application of KNO(3). Better boll opening in foliar applied K(2)SO(4), perhaps, played decisive role for increased seed-cotton yield. For basal application and side dressing, KNO(3) produced the highest seed-cotton yield, but the benefit cost ratio was better for foliar applied K(2)SO(4). In crux, foliar application of K(2)SO(4) might be opted to improve the seed cotton yield, fiber quality and net returns under the arid climate. However, soil K application through K(2)SO(4) and/or KNO(3) is essential to balance the K removal from soil.