Micronutrient Status of Grapevines at the Messina Hof Vineyard

Abstract

Texas has recently reentered the grape industry. A problem that confronts prospective vintners in Texas is that our soils have nutrition problems, especially the micronutrients. These deficiencies have led to reduced crop yields on the defective vines and therefore lower profits for the grower. The study was conducted at Messina Hof Vineyard near Bryan. The vines exhibited the classic Zn and Fe deficiency symptoms. Five varieties were tested; Champanell, Black Spanish, Ruby cabernet, Chenin Blanc and Lake Emerald. I used leaf petioles for tissue analysis, soil testing was not used. My plan of work included; visual inspection, tagging the vines, taking petiole samples, collecting harvest data and some lab work. The chlorotic vines on the average produced less total yield than did the nonchlorotic vines. I could find no correlation between the incident of chlorosis and the ions which I tested. This indicates it was a temporary deficiency which had corrected itself by the time of sampling. Last spring Messina Hof obtained a new rotary grape hoe and there was some evidence of damage to the roots. The damage occurred early in the season and that would have an influence in the amounts of nutrients the plant was able to take up. There was a direct correlation between root damage, chlorosis and yield. The exception was Ruby Cabernet which showed no signifigant difference. Ruby Cabernet was a very shy producer and is notorious for exhibiting Fe chlorosis readily. Lake Emerald did not produce. This experiment did include two visual inspections which were subjective. There is a possibility that micronutrients could have been applied and not recorded. This would have been responsible for the inconsistancy seen in the ion concentrations found in tissue analysis. The reduced yield and chlorosis were caused for the most part by damage done to the roots by the new cultivation practices. I further suggest that more care should be taken, when using the grape hoe, to disturb the roots as little as possible.