Studies on crop productivity and soil fertility under long-term cropping have long been a subject of immense importance. An experiment entitled "Long-range effect of continuous cropping and manuring" was initiated in 1977-78 under the All India Coordinated Research Project on Cropping Systems at Faizabad. Rice (Oryza sativa L. Spp. indica) is responsible for feeding more than one-third world's population. It plays a major role as a staple food, supporting more than three billion people and comprising 50-80 % of their daily calorie intake. It is globally grown in 156.8 million hectares area with a production of 456 million tonnes. India ranks first in acreage with 44 million hectare area under rice and second in production with 104.3 million tonnes with productivity of 2.37 tonnes per hectare
