Benefits of plant strips for sustainable mountain agriculture

Abstract

-Erosion degrades soil quality in agricultural ecosystems, thereby reducing the productivity of the land. Semi-natural vegetation and diverse cropping systems have been converted into monocultures with low tree densities, leaving the soil unprotected. We evaluated the association in soil-and water-conservation systems with production in traditional almond orchards and the beneficial impact of plant strips in mountainous agriculture. Soil loss, runoff and nutrient loss over a four-year period (2002)(2003)(2004)(2005) were monitored in hillside erosion plots with almond trees under different soil-management systems: (1) non-tillage with sage (Salvia lavandulifolia L. subspecies Oxyodon) strips 3 m wide; (2) non-tillage with rosemary (Rosmarinus officinalis L.) strips, (3) non-tillage with thyme (Thymus baeticus L. Boiss. exlacaita) strips, and (4) conventional tillage on the south flank of the Sierra Nevada (Lanjaron) in south-eastern Spain. Also, the nut yield from almond trees, and the biomass from aromatic-shrub strips were measured. The erosion plots, located on a 35% slope, were 144 m 2 in area. The plant-cover strips, 3 m wide, ran across the slope. Our results show that the most effective treatment proved to be non-tillage with thyme strips, reducing the annual soil loss by 93% and runoff by 80%, with respect to conventional tillage. Non-tillage with rosemary strips reduced soil loss by 91% and runoff by 82%, with respect to conventional tillage, while these percentages were 69% and 51%, respectively, for non-tillage with sage strips. In addition, all the treatments as a whole, in comparison with conventional tillage, revealed that the plant strips were the decisive factor in the reduction of NPK losses by surface runoff. The average nut yield from non-tillage with sage strips, non-tillage with rosemary strips, non-tillage with thyme strips and conventional tillage during the study period was 2.4, 3.2, 3.8 and 4.5 kg tree −1 , respectively, and the essential oil yield from sage, rosemary and thyme strips was 5.0, 8.7 and 10.8 L ha −1 , respectively. The non-tillage with thyme strips decreased nutrient loading in surface waters and thus had a positive impact on the environment while simultaneously maintaining reasonable almond-production levels. Thus, the combination of orchard trees with shrubs provided a viable option to conserve soil and water in hilly areas with opportunities to increase overall land productivity as well as sustainable agro-environmental measures.almond orchards / aromatic-shrub-cover strips / biomass production / hillslope erosion / mountainous agriculture / soil-management systems

Impact of Cover Crops on the Soil Microbiome of Tree Crops

“…Tillage in the row middles is common for some perennial crops, such as almonds, olives, citrus, and grapevines [11,67], and is generally performed to remove weeds to avoid water and nutrient competition, resulting in bare soil between tree rows [68,69]. Adopting no-tillage in combination with cover crops has been identified as a reliable management practice in tree cropping systems [70,71] that increases soil C sequestration and reduces N fertilization inputs compared with conventional tillage (down to a depth of 15-20 cm), primarily due to the beneficial effects on soil microbial diversity [11,14,18,23]. For example, intercropping olive (O. europea) with grasses increased bacterial diversity in no-tillage systems compared with conventional treatments, and changes in microbial diversity were positively correlated with improved olive yield [49].…”

Bioenergy farming using woody crops. A review

“…It is well known that trees grown with an intensive weed control give rise to higher erosion rates than no-till agricultural production; however, this problem may be controlled by planting cover crops between the tree rows, as demonstrated in cultivating rainfed-tree crops (Durán et al 2008). Moreover, Malik et al (2001) studied the effects of varying strip widths of four species of cover crops on the growth of sweet gum (Liquidambar styraciflua L.) seedlings planted as a short-rotation bioenergy woody crop.…”

Effect of vegetation cover on millennial-scale landscape denudation rates in East Africa

“…Over shorter time scales of up to decades or centuries, plot-scale studies provide important insights into the mechanisms through which vegetation cover affects erosion processes and denudation rates. These studies have shown that both the type and density of vegetation cover increase the resistance of soil to erosion through the binding effects of roots, the formation of soil aggregates, the resistance to flow exerted by leaf litter and stems, and the protection of the surface from rainsplash (e.g., Dunne et al, 1978Dunne et al, , 2010Wainwright et al, 2000;Gyssels and Poesen, 2003;Durán Zuazo et al, 2008). Higher infiltration rates in densely vegetated areas with thick soils also decrease the likelihood of overland flow, which can rapidly denude slopes (Horton, 1933(Horton, , 1945Abrahams et al, 1995;Prosser and Dietrich, 1995).…”