Tests on the effect of potassium and calcium soil fertilization on lemon fruit size—made when the fruit was in the silver stage of maturity—showed that the potassium-calcium ratio in the nutrient was effective in bringing about a marked response in the potassium and calcium content in the peel and pulp. Comparative results obtained with lemon flowers also indicated that the period of flowering and fruit setting can be of considerable importance in setting the pattern of mineral nutrition to be followed in the fruit until maturation occurs.

The above progress report is based on Research Project No. 1086.