Evaluating Different Management Strategies to Increase Calcium Availability of Tomatoes In Salt-Affected Soils.

Calcium availability is a major problem for vegetable crops grown in saline-sodic environments.  Reduced soil availability can lead to deficiency and result in yield losses and reduced crop quality.  This problem is particularly important in tomatoes where calcium deficiency often leads to blossom end rot during periods of reduced plant transpiration.  Therefore, the objective of our study was to evaluate different management strategies to increase calcium (Ca) availability in soils exhibiting saline and/or sodic properties. Calcium fertilization and irrigation water acidification were used in an effort to increase Ca availability and decrease soil pH, thereby improving Ca uptake by plants.  Four treatments were tested in a commercial processing tomato field, including two calcium-based fertilizers (calcium ammonium nitrate and calcium thiosulfate), water acidification, and a conventionally used nitrogen fertilizer (urea ammonium nitrate).  All treatments were applied through a sub-surface drip system and replicated four times in a randomized complete block design.  Comparison among treatments was determined on crop yield, incidence of blossom-end rot, soil Ca and sodium (Na) levels, plant Ca status, and nutrient use efficiency for Ca.  Results of the first year study conducted in 2009 indicated that the marketable tomato yield obtained under the calcium thiosulfate treatment (73 tons/ac) was significantly higher (P < 0.05) than that observed for the other treatments.  However, no significant differences were observed in the occurrence of blossom-end rot, soil Ca and Na concentrations among the treatments.  Results of the second year study conducted in 2010 will also be presented.