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ARS Home » Plains Area » Lincoln, Nebraska » Agroecosystem Management Research » Research » Publications at this Location » Publication #207048
Title: Leaf stable isotopes (delta 13C and delta 15N) relative to biomass production in two fertilized merlot vineyards

Author
item STAMATIADIS, S - GOULANDRIS/GREECE
item CHRISTOFIDES, C - GREECE
item TSADILA, E - GREECE
item TASKOS, D - GREECE
item TSDILAS, C - GREECE
item Schepers, James

Submitted to: American Journal of Enology and Viticulture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/7/2007
Publication Date: 6/6/2007
Citation: Stamatiadis, S., Christofides, C., Tsadila, E., Taskos, D., Tsdilas, C., Schepers, J.S. 2007. Leaf stable isotopes (delta 13C and delta 15N) relative to biomass production in two fertilized merlot vineyards. American Journal of Enology and Viticulture 58:67-74.

Interpretive Summary: Grapes are frequently grown on soils that are relatively infertile and difficult to manage. Nutrient and water deficiencies at certain times during the growing season result in differential quantity and quality of the wine produced. Trying to relate grape production parameters such as vine vigor and pruning weight to the spatially variable patterns in soil properties and leaf nutrient concentrations was not fruitful. However, variations in isotopic nitrogen and carbon in leaves explained 71% of the spatial variation in pruning weight. Variations in isotopic nitrogen in leaves helped explain the relative contribution of soil organic matter and fertilizer to the nitrogen supplied by soil. Likewise, differences in isotopic carbon helped explain differences in water storage and water use efficiency. This study demonstrated that the isotopic signature in grape leaves may be a useful tool in developing site-specific management practices.

Technical Abstract: Grapevines (Vitis vinifera L.) are often cultivated under sub-optimum conditions for both water and nutrients in order to enhance the quality of the grapes for making wine. Since water supply and nitrogen nutrition are major determinants of photosynthetic activity, this study investigated the potential of leaf '13C and '15N in explaining spatial variations in biomass production as a function of water use efficiency and fertilizer N uptake, respectively. The combined isotopic signal of the leaves, along with pruning weight, leaf nutrients and soil properties, was measured in randomly selected field positions over two growing seasons in two fertilized but differing, Merlot vineyards. Significant correlations of surface soil properties and leaf nutrients with pruning weight were not great enough to explain spatial patterns in biomass production. In contrast, leaf '13C and '15N, when used as independent variables in multiple regression, explained 71% of the spatial variation of pruning weight across both fields and growing seasons. Most of the explained model variability was attributed to leaf '15N (r2=0.54), but within single years leaf '13C was better correlated to biomass. The negative correlation between these two isotopes and pruning weight was high only within the vineyard that had steep topographic features and spatially variable growth patterns. It indicated a response of vines to adverse soil conditions by a progressive reduction of WUE and an increase in fertilizer N uptake downslope from the low- to the high-biomass areas of this field. If these relationships persist in other fertilized and water-stressed fields, the isotopic signature of the leaves may be an important tool for the application of site-specific management practices within single vineyards.