Effect of polyhalite as potassium source on growth, yield and quality of sugarcane ratoons under different irrigation regimes

Abstract

Given that the 82% of sugarcane cultivation in Maharashtra, India occurs in low-rainfall areas with limited surface irrigation access, it is crucial to utilize available water judiciously. Despite potassium-rich soils, its availability to meet sugarcane demands is low, and reliance on imported muriate of potash (MOP) is economically burdensome and potentially harmful to sugar recovery. A field experiment was conducted to evaluate the effects of polyhalite as a potassium source and different drip irrigation regimes on the growth and yield of suru sugarcane ratoons in the inceptisols of MPKV, Rahuri, Maharashtra. The study examined the impact of three drip irrigation levels (100%, 80%, and 60% Etc.) on sugarcane, alongside the potassium sources MOP and Polyhalite combinations. Polyhalite, a multi-nutrient, slow-release mineral containing potassium, calcium, magnesium, and sulfur, was tested as an alternative potassium source. Results showed that irrigation at 100% Etc. regime significantly enhanced nutrient uptake, yield attributes, and sugarcane quality, with comparable results at 80% Etc., suggesting a potential 20% water saving with alternate day drip irrigation at 80% Etc. Potassium application through polyhalite alone or combined with MOP (75:25) significantly improved nutrient uptake, yield attributes, and sugarcane quality.