Effect of Calcium Source and Application Method on Potato Yield and Cation Composition

Abstract

AbstractCalcium applications to low Ca, sandy soils can improve potato (Solanum tuberosum L.) grade and USlA size grade, and these improvements are significantly correlated with increased periderm Ca concentrations. This study evaluated the effectiveness of several Ca sources (pelleted CaSO4, granulated CaSO4, sieved CaSO4, dolomitic lime, triple superphosphate, or CaCl2), methods of application (broadcast, sidedress, and preplant strip), and rates (84–336 kg Ca ha−1) on increasing tuber Ca on two irrigated loamy sands (Typic Udipsamments) in Wisconsin from 1983 to 1985. The addition of Ca increased the percent of grade USlA tubers, the yield of prime size (<170–370 g) USlA tubers, and periderm Ca concentrations. It also reduced the percent of USlB or cull tubers, the yield of small (170 g) USlA tubers, and the concentration of periderm Mg. Improvements of grade USlA tubers ranged from 3 to l0%, and yield of USlA prime tubers was increased from 2 to 10 Mg ha−1. Dolomitic lime, triple superphosphate, and CaCl2 did not consistently improve tuber yield or grade, whereas CaSO4 in any of the forms applied was an effective Ca source. In 1985, a vertical cross‐section of the potato hill was sampled to determine the distribution of exchangeable Ca in the hill for each application method. The accumulation and uptake of Ca in the plant tops and in tuber periderm and medullar tissue for an untreated control and each application method were determined at several times during the season. The preplant strip method concentrated more material in the central portion of the potato hill where the tubers formed, and increased Ca uptake in both periderm and medullar tissue compared to the sidedress and broadcast treatments. Calcium concentration and uptake in the plant tops was not affected by any method of Ca application. Total Ca uptake averaged 8.5 and 32.9 kg Ca ha−1 in the tuber and plant tops, respectively.