The effects of cover crops and conventional tillage on soil and runoff loss in vineyards and olive groves in several Mediterranean countries

Abstract

Cover crops (CC) in vineyards and olive groves provide an alternative to conventional tillage (CT) for land management. Runoff, sediment and nutrient loss from six sites in France, Spain and Portugal were compared over 3–4 yr. In general, runoff loss was not significantly reduced by the CC alternatives: average annual runoff coefficients ranged from 4.9 to 22.8% in CT compared with 1.9–25% in the CC alternatives. However, at two sites, reductions in average annual runoff coefficients were greater for CC: 17.2 and 10.4% in CT, 6.1 and 1.9% in CC. Nutrient loss in runoff followed a similar pattern to runoff, as did pesticide loss on the one site; reductions occurred when runoff losses were significantly reduced by CC. The lack of differences at the other sites is thought to be due to a combination of soil conditions at the surface (compaction and capping) and sub‐surface (low‐permeability horizons close to the surface). In contrast, CC always resulted in reductions in soil erosion loss, plus similar reductions in nutrients and organic matter (OM) associated with sediment. Soil erosion loss ranged from 1.4 to 90 t/ha/yr in CT compared with 0.04–42.7 t/ha/yr in CC. Overall, reductions in runoff and associated nutrient and pesticide loss from vineyards and olives occurred with the introduction of CCs only when soil permeability was sufficiently high to reduce runoff. In contrast, reduction in soil erosion and associated nutrients and OM occurred even when the amount of runoff was not reduced. In the most extreme encountered situations (highly erodible soils in vulnerable landscape positions and subject to highly erosive rainfall), additional conservation measures are needed to prevent unsustainable soil loss.

Improvement of soil carbon sink by cover crops in olive orchards under semiarid conditions. Influence of the type of soil and weed

“…Experimental fields and depth erosion in the five fields was 67.7% and 80.4% respectively; this reduction was less than that observed by Gómez et al (2011) under similar conditions, especially for the OC (95.2%), and slightly lower for erosion (97.4%). With regard to erosion and OC loss, the higher the reduction in erosion, the greater the reduction in OC output from the system.…”

Soil and Water Conservation in Rainfed Vineyards with Common Sainfoin and Spontaneous Vegetation under Different Ground Conditions

“…In Mediterranean vineyards, several studies have demonstrated the positive effects of VC on soil, nutrient and water conservation, such as in Italy [10,26,30,31], Spain [12,22,[32][33][34] and France [13,35,36]. On average, VC reduces the total volume of runoff yield, offering an adequate protection against erosion in comparison with bare soil management [22,32].…”

“…In Barcelona province, NE Spain, Ramos and Martínez-Casasnovas [11] estimated an average rate of 10.9 Mg ha −1 y −1 in levelled vineyards, whereas Bienes et al [12] measured average rates between 0.4 and 1.8 Mg ha −1 y −1 in Central Spain (Madrid and Cuenca) under conventional tillage and during a low rainfall erosivity period, and between 0.02 and 0.32 Mg ha −1 y −1 with different vegetation covers (Brachypodium distachyon, spontaneous vegetation, rye and barley). In southern France, Gómez et al [13] observed in three experimental sites over three years average soil loss rates between 4.5 and 90 Mg ha −1 y −1 under conventional tillage and between 0.7 and 42.7 Mg ha −1 y −1 with cover crops. In Israel, Pipan and Kokalj [14] observed increased soil erosion owing to the conversion of terraced vineyards into recent plantations in slopes without terraces.…”

“…In addition, some techniques usually adopted in vineyards' installation and management (e.g., intense tractor traffic throughout fixed paths) deteriorate soil structure and produce soil surface compaction [26]. In the literature, the benefits of VC in vineyards, fruit-tree orchards and reclaimed soils has been widely evaluated in a variety of soil and climate conditions throughout the world [13,[27][28][29].…”

Relationship Among Crop Systems, Soil Cover, and Water Erosion on a Typic Hapludox

“…The benefits of using cover plants were also demonstrated by Gómez et al (2011), who concluded that they significantly reduced water erosion in comparison to traditional tillage practices in Southern France, Spain, and Portugal. Cover plants with corn intercropping was recommended by Ngome et al (2011), who stated that Mucuna and Arachis increased corn yields in Kenya.…”