Effect of Iron Application on Rice Plants in Improving Grain Nutritional Quality in Northeastern of Thailand

Iron (Fe) deficiency in humans caused by inadequate dietary intake is a global nutritional problem. The field experiments in this paper were conducted in the same paddy field over two consecutive years during the dry seasons of 2017 and 2018. The aims of the experiments were to evaluate the effects of iron application methods (soil or foliar alone and a combination of soil + foliar) on the Fe content in brown rice grain and to compare the grain yields of three rice cultivars, namely Chinat1 (poor Fe grain concentration), Riceberry and Tubtim Chumpae (rich Fe grain concentration). The results show that all iron application methods significantly increase the iron content of brown rice grains in comparison with non-iron application in two cropping years. The iron application to the soil combined with foliar gave the highest iron content in the brown rice grain. However, the responses to the iron application methods were different among rice cultivars. The highest grain iron contents of Chainat1 and Riceberry were shown in the combination of soil and foliar application, whereas Tubtim Chumpae had the highest grain iron content in the foliar application alone. The differences in grain yield were affected by the rice cultivar, but not by iron application methods. The Chainat1 produced the highest grain yield. In addition, Chainat1 had the strongest correlation between brown rice grain iron content and grain yield for both cropping years.