The Studies on Zn Content and Its Efficiency in Paddy Field of Ningde and Nanping Areas in Fujian Province

The average conent of availabe Zn in paddy fields of Ningde and Nanping Areas is 1.77 ppm.If the critical value of Zn deficiency for rice plant is 0.5ppm,about 30% area of paddy field in above two areas belongs to slightly Zn-deficient or potentialy Zn-deficient condition; about 10% belongs to seriously Zn-deficient condition.When the Zn content in paddy field is below 1.0ppm,the application of Zn fertilizer will receive a yield-increasing effect.In the case soil contains high Zn and available P,the Zn application will meet the requirement of high level of Zn.P nutritional balance and enhance the grain yield.The Zn application improve the protein and amino-acid contents in brown rice thus enhance the nutritional value of rice.It is suggested that Zn fertiliger will be applied in earlier stage of rice growth,and suitable amount is 15-30kg (ZnSo4,7H2O) /ha.The better Zn-applying methods are coating the roots of rice seedlings and foliage dressing.In severely Zn-deffecient soil,more high amount of Zn may be used as basal.