Supplemental Calcium Application on Yield, Grade, and Seed Quality of Runner Peanut
The need for supplemental Ca continues to be the most likely nutritional problem of peanut (Arachis hypogaea L.) production on acid, sandy, and low ration exchange capacity (CEC) soils. The need for supplemental Ca from gypsum for improved yield, quality, and seed germination of four runner-type cultivars was evaluated on 14 sites with a range in available soil Ca of 48 to 242 mg kg−1 during 1987 to 1989. Yields of all four cultivars were increased by addition of gypsum at the five sites with the lowest Mehlich-I extractable Ca (< 158 mg kg−1), although the magnitude of response varied among cultivars. Increases in sound mature kerual occurred for GK 7 and Southern Runner at soil Ca levels higher than that required for maximum yield. Calcium composition of nuts also was affected more by supplemental gypsum than was either yield or SMK. Germination percentage and seedling survival were both highly correlated with seed-Ca concentration. Minimum seed Ca needed for maximum gemination ranged between 368 and 414 mg kg−1 for the four cultivars. Comparable Ca values for seedling survival ranged between 361 and 445 mg kg −1. The correlations between soil Ca and either germination or seedling vigor were less than those between seed Ca and gemination or seedling vigor. All correlations involving Ca and gemination suggest that soils used to produce seed, probably need a higher level of available Ca than those used for general production.
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