An investigation of the factors affecting paddy yields from two districts

Factors affecting paddy yield in the Anuradhapura and Ratnapura districts are investigated. Regression analyses are performed using data from 1962 - 1978, and particular attention is given to the growth stages of the Paddy plant and its water requirements at each stage. The results indicate that if the total extents cultivated has been increasing then this has a large influence on yield per acre. This was seen at Ratnapura for both seasons and in the Maha season at Anuradhapura. The study also shows that the non-climatic factors influenced by technological research, (called technological factors in this paper), such as transplanting, type of variety, fertilizers and irrigation have played a major role in paddy production, particularly at Anuradhapura. Variations in climatic variables have not influenced variation in yield, as greatly as changes in technological factors. Also the results indicate that the climatic variables which are important depend on the type of technology employed. For example at Anuradhapura, the Yala season has increasingly relied on major irrigation schemes and temperature was shown to be important, but in the Maha season some farmers still rely, to a certain extent, on rainfall, and consequently rainfall was indicated as an important climatic factor. The study has highlighted many areas of further work and the direction further research should take to enable a comprehensive knowledge of the effects of factors and their interactions to be developed.