Effect of Cultivar, Irrigation, and Soil Calcium On Runner Peanut Response to Gypsum.

Effect of cultivar, irrigation, and soil calcium on runner peanut response to gypsum

ABSTRACT

Calcium (Ca) is often limiting to peanut yield, grade, and germination in the southeastern US.  The response of small-seeded (Georgia-06G) and large-seeded (Georgia Green) runner peanuts to gypsum applications was evaluated in 14 tests in southern Alabama and Georgia.  Experiments were established in a randomized complete block design with four replications of gypsum treatments (0, 560, 1120, and 1680 kg ha^-1) in soils with a range of soil Ca (178 – 498 mg kg^-1) in both irrigated and non-irrigated tests.  Increases in yield, grade, seed Ca, and germination were observed when data were combined for all tests; however, there was a strong effect of irrigation practice.  The response to applied Ca was significant only in the non-irrigated peanuts where yield increases ranged from 500 – 1000 kg ha^-1 and grade increased by 3.4 – 5% sound mature kernels (SMK).  Critical value pegging zone soil Ca values of 150 and 250 mg kg^-1 were evaluated and found to be appropriate for irrigated and non-irrigated peanuts, respectively.  The larger seeded Georgia-06G had lower seed Ca concentrations and therefore slightly lower germination than the smaller seeded Georgia Green cultivar.  Greater than 95% germination of Georgia-06G and Georgia Green was observed when seed calcium concentrations were > 600 mg kg^-1.  Analysis of calcium concentrations in nearly mature seeds pre-harvest may provide an indication of seed germination quality as seed calcium concentration increased at approximately the same rate as seed size.