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Agroforestry systems (AF) consisting of grapevines and trees, may lead to resource competition for water and nutrients. This study aimed to evaluate the impact of a combined cultivation on water relations, nitrogen nutrition and the resulting wine quality. 15 N-labeled inorganic nitrogen (N) sources were used to quantify net N uptake capacity. N content and δ 15 N natural abundance were analysed as integrating parameters of N nutrition. Leaf water potential (ψ leaf) was determined to evaluate the water status of grapevines. Wine quality was evaluated by chemical and sensory analyses. In result, AF system reduced leaf water potential and increased net N uptake capacity in grapevines. However, chemical composition and sensory quality of the wine were not significantly affected in the present system consisting of Riesling, Sauvignon Blanc, oak and poplar. Nitrogen availability of grapevines was favourable and water relations were improved, whereas wine quality was similar when grown with trees or without. Trees were able to reduce water and nitrogen losses without negative effects on wine quality. This work provides information on benefits and limits for intercropping of trees and grapevines in terms of performance of grapevines and wine quality compared to traditional vineyard systems.

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Background and Aims: Rootstocks play an essential role in grapevine scion growth and development. They influence water and nutrient uptake and affect biomass allocation of the scion and the grape berry composition connected with wine quality. Nitrogen (N) can be taken up by the roots in various forms such as nitrate, ammonium or urea. These N-forms and their possible differential assimilation directly and indirectly influence grapevine vegetative and generative growth. N assimilation is driven by N acquiring enzymes such as nitrate reductase (NR), nitrite reductase (NiR) and glutamine synthetase (GS). This assimilation physiology can be influenced by factors such as light conditions or substrate availability. Methods: Hydroponically grown grapevine rootstocks were fertilized with various N-forms, namely calcium nitrate (CaN), ammonium (AM), urea (UR), and glutamine (Gln). The transcript expression of the enzymes NR, NiR and GS and the enzymatic nitrate reductase activity (eNRA) were examined at various time points (0 h, 3 h, and 6 h) after N application. Results and Conclusion: The data suggest that the grapevine rootstock SO4 has the ability to assimilate the amino acid Gln. Furthermore, AM, UR, and in some organs Gln, can regulate the co-enzymes NR and NiR, both of which function as activators of the NO À 3 assimilation process. The eNRA is clearly defined by the plant organ.

Cultivation of lentils had ended by mid-20th century in Germany, but a revival was initiated in the first decade of this millennium in Southwest Germany. However, knowledge of lentil cultivation was almost lost, and today’s yields are still low. To gain an overview of current farm practices and of factors that can help lentil cultivation thrive, 25 lentil farmers (21 organic, 4 conventional) from SW Germany answered questionnaires for agronomic data on lentil cultivation in the years 2015, 2016, and 2017. Eleven farmers took part in additional semi-structured interviews about their motivation and the most important factors (economic, ecological, and social) that encouraged them to grow lentils. Neither the lentil variety (Anicia, Späth’s Alblinse I and II), nor the companion crop for the usual mixed cropping (spring barley, oat, and camelina), significantly influenced lentil yield. If lentil cultivation is to further expand, data from more farmers could be evaluated and factors that contribute to crop thriving analyzed more clearly. The cultivation techniques currently practiced are diverse, and lentils integrate well into existing structures. Farmers appear motivated to grow lentils by good examples of colleagues, by availability of marketing channels, and by the desire to promote lentils’ ecological and social benefits.