Impact of Temperature and Humidity on Sugar Recovery in Uttar Pradesh

Sugarcane is one of the main cash crops in India, and around 42 lakh farmers directly or indirectly depend on this crop which occupies 23 lakh hectare areas in Uttar Pradesh. Temperature and humidity plays an important role in sucrose synthesis and accumulation in C4 plant such as sugarcane. In C4 plants, formation of phosphoenolpyruvate carboxykinase is sensitive to low temperatures. During low temperature and high humidity, there is an increase in juice acidity, probably due to the formation of organic acids, which are formed by the conversion of stored sucrose in the stalk. This conversion is reversed when the atmospheric temperature becomes favourable for sucrose accumulation. In subtropical India, sugarcane crop experiences varied weather conditions during its growth and development. The crushing season of sugar mills of Uttar Pradesh (UP), India, starts from November and continues till the April/May. However, due to immaturity of plant crop, sugar industries avoid starting their crushing season in November, but due to pressure of cane quantity as well as sowing time of wheat crop during this time by the farmers, sugar mills are forced to start their crushing season in November. The area of early varieties in UP was about 35% during crushing season 2015–2016, and sugar recovery was 10.62%; however, area of early-maturing high sugared varieties in UP increased up to 53% during crushing season 2016–2017, but sugar recovery was at par, i.e., 10.61%. Seeing the recovery data of different crushing seasons, a study was conducted at UPCSR Shahjahanpur to evaluate the impact of climatic conditions on sugar recovery percentage. Totally, 15 sugar mills were selected for this study from east, central and west zones of UP and their recoveries were observed and correlated with temperature and humidity. The study revealed that in spite of 18% increase in the area of high yielding, high sugared varieties in the state, which could have increased the sugar recovery, the low-temperature and high-humidity conditions during the start of the crushing season 2016–2017, affected the sugar accumulation in sugarcane, resulting into the average recovery which was at par as the previous year.