Relationship among different forms of soil potassium and availability as influenced by the contrasting management practices in Apple (Malus domestica Borkh.) orchards of Kumaon region

Abstract

The distribution of K forms (water soluble, exchangeable, non-exchangeable, mineral and total K) in two apple (cv. Royal Delicious) orchards differing in fertilizer management practices located in the Kumaon region of Uttarakhand was investigated. The apple orchard at Mukteshwar is managed by the conventional fertilizer management practice, and the other at Dutkanedhar is managed organically. At Mukteshwar, the distribution of water soluble, exchangeable, non-exchangeable, mineral and total K was 0.23, 0.86, 5.46, 78.2, and 86.7 cmol kg-1, respectively. Further, soil analysis revealed that both the soils contain very high levels of available K (>350 mg kg-1). Leaf K content in orchard of Dutkanedhar was deficient (0.81%) with the appearance of K deficiency symptoms as necrotic leaf edges; whereas, the same at Mukteshwar was recorded as sufficient (1.93%). The positive and significant correlations were observed between available and water soluble (r= 0.78), available and exchangeable (r= 0.45), exchangeable and non-exchangeable (r= 0.33), non-exchangeable and mineral (r=0.77) and mineral and total K (r= 0.95) in the orchard of Mukteshwar. It was concluded that K requirement in apple could not be satisfied entirely through addition of organic manures only, and thus, K fertilization is indispensable.