Effects of Calcium and Micronutrient Deficiencies on the Formation of Unfilled Pods in Peanut Grown in Yasothorn Province

Abstract

A study on the effects of calcium (Ca) and mironutrient deficiencies on the formation of unfilled pods in peanut was conducted in Yasothorn province, northeastern part of Thailand, during 1995 to 1996. The experiment was carried out on sandy loam soil (10-21 ppm exchangeable Ca), and arandomized complite block design with 4 replications was used. Peanut seeds cv. Tainan 9 were sown in the experimental plots of 4 treatements as ; without ca an dmicronutrients, with only Ca, with only micronutrents, and with both Ca and micronutrient applications. The results suggested that the formation of unfilled pods in peanut was due to the deficiency of Ca. The applications of CaCO3, as a Ca source, at the rate of 400 kg/rai could significazntly reduce the unfilled pod percentage from 55.6-89.6 to 3.1-16.8. In addition, Ca application significantly increased the soil pH from 4.06-4.61 to 5.75-5.90. This consequently resulted in the significant increases in number of pods per plant and dry pod yield. The investigation also found that micronutrient application had no effect on the percentage of unfilled pods but increased seed size and shelling percantage.