Benefits of plant strips for sustainable mountain agricultureVictor Hugo Durán Zuazo1, Carmen Rocío Rodríguez Pleguezuelo1, José Ramón Francia Martínez1, Armando Martínez Raya1, Lorenzo Arroyo Panadero1, Belén Cárceles Rodríguez1 and Maria Concepción Navarro Moll2
1 IFAPA Centro Camino de Purchil, Apdo. 2027, 18080-Granada, Spain
2 Departamento de Farmacología, Facultad de Farmacia, Universidad de Granada, Campus de Cartuja, 18071, Granada, Spain
Accepted 10 April 2008; published online 21 June 2008
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 (2002–2005) 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 m2 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.
Key words: almond orchards / aromatic-shrub-cover strips / biomass production / hillslope erosion / mountainous agriculture / soil-management systems
Corresponding author: firstname.lastname@example.org
© INRA, EDP Sciences 2008