COMPARISON OF SPECIES-RICH COVER CROP MIXTURES IN HUNGARIAN WINEYARDS

Summary

Sustainable floor management has played an important role in viticulture recently. Intensive agricultural practices of past decades - like mechanical cultivation on steep slope vineyards - endanger the vineyards. Suboptimal inter-row and undervine floor management, especially coupled with extreme weather conditions can lead to heavy soil degradation. In addition, because of climate change we anticipate heavier rainstorms, which can accelerate degradation of the soil. In Hungarian viticulture, preservation of soil moisture is extremely important because of the low amount of annual precipitation (sometimes less than 500 mm per year) and evapotranspiration from June to August is typically higher than precipitation (Bauer et al., 2004). Therefore, the use of cover crops in the inter-row can be beneficial, particularly on steep slopes and in case of organic farming to provide environmentally friendly soil management. One of the most often used soil management methods in the vineyards of Hungary is mechanical cultivation. But when this is used too often or inadequately, several negative effects can be observed: dry soil caused by increased evapotranspiration, deteriorating soil structure, increased erosion and nutrient losses (Bauer et al., 2004; Aljibury and Christensen, 1972; Dijck et al., 2002). Continuous mechanical soil management can also lead to topsoil and subsoil compaction from long-term traffic (Ferrero et al., 2005; Zanathy, 2006). For soil covering, several materials (e.g. straw, reed, sedge) or cover crops can be used. The species-rich cover crop mixture helps to not only to prevent erosion and provide easier of cultivation, but has a positive effect on soil structure, soil fertility and ecosystem functioning. The growth of the roots is influenced by soil structure, so the growth of the grapevine is also influenced by compaction and soil moisture (Wheaton et al., 2008). Requirements for a suitable cover crop species are as follows: it should save the soil from erosion and compaction caused by the movement of workers and machines and it should not compete significantly with the grapevines. In addition of these parameters, the optimal mixture contains local species from local provenance.