107168 Calcium Uptake in Irrigated and Non-Irrigated Runner Peanut.
Poster Number 408
Tuesday, October 24, 2017
Tampa Convention Center, East Exhibit Hall
Calcium (Ca2+) is important in peanut (Arachis hypogaea L.) production as it improves quality and yield. The two main sources of Ca2+ fertilization in peanut are flue gas desulfurized (FGD) gypsum (CaSO4) and dolomitic lime (CaCO3). This study was conducted to determine whether gypsum, lime, or a combination of both increase Ca2+ uptake, yield, and grade (% Total Sound Mature Kernels [TSMK]) with or without irrigation. Peanut was grown in 2016 on a Tifton loamy sand in Tifton, GA. Irrigated and non-irrigated blocks (main-plot effect) with four treatments of Ca2+ sources in each block (sub-plot effect) were applied in a split plot design with eight replications. The treatments in each irrigated and non-irrigated block included: 1. gypsum (330 kg Ca2+ ha-1) plus lime (897 kg Ca2+ ha-1) at planting, 2. gypsum (330 kg Ca2+ ha-1) at first bloom (approximately 35 days after planting), 3. lime (897 kg Ca2+ ha-1) at the time of planting, and 4. a non-treated check that received no supplemental Ca2+. Typical soil test Ca2+ was initially in the range of 569- 1151 kg Ca2+ ha-1 in the pegging zone (top 8 cm of soil) at planting. Non-irrigated treatments (0.85% K+) had higher K+ concentration in the pod than irrigated treatments (0.65% K+). Gypsum plus lime (0.089% Ca2+), gypsum (0.08% Ca2+), and lime (0.081% Ca2+) treatments had greater concentration of Ca2+ in the pods than the treatment that received no Ca2+ (0.07% Ca2+). Based on the 2016 study, irrigation was significant for yield (p<0.0001). Irrigated peanut (6761 kg ha-1) yielded more than non-irrigated peanut (5051 kg ha-1) averaged over Ca2+ treatments. There was no significance between Ca2+ treatments (p>0.10) and no interaction between irrigation and Ca2+ treatment effects (p>0.10) for yield. Peanut grade based on percent total sound mature kernel (TSMK) was significantly greater in gypsum plus lime treatments (76.4%) and gypsum (76.2%) treatments than lime (75.1%) or non-treated peanut (74.6%). Irrigation plays a role in moving Ca2+ into the peanut plant, specifically the pods. With the use of irrigation and Ca2+ sources in the form of dolomitic lime and FGD gypsum, pod Ca2+ levels, yield and TSMK will increase when soil Ca2+ levels originate above 560 kg Ca2+ ha-1.