Soil nitrogen availability in olive orchards after mulching legume cover crop residues

Abstract

a b s t r a c tA natural source of nitrogen (N) is needed to increase soil fertility in traditional olive orchards and to maintain the N nutritional status of olive trees. With this aim, we studied the introduction of legume cover crops in two olive orchards, which were converted into mulches and left on the ground as phytomass after they had been cut. The experiments were carried out in Suç ães and Qta do Carrascal, NE Portugal, from October 2009 to January 2012. In Suç ães, the ground-cover treatments were lupine (Lupinus albus L.), a mixture of 11 self-reseeding annual legume species, natural vegetation fertilized with 60 kg N hm −2 and natural vegetation not fertilized. The treatments imposed in Qta do Carrascal were lupine, hairy vetch (Vicia villosa Roth.), a mixture of 11 self-reseeding annual legumes and natural vegetation. Soil N availability in the year following the establishment of the mulches was monitored by an in situ incubation technique. Olive yields and tree nutritional status were also measured. A peak of net N mineralization was recorded early in the autumn in the plots where the legume cover crops had been grown in the last season, in comparison with the natural vegetation plot. In the next spring, soil N availability was negligible even in the plots previously cropped with legume species. The effect of the legume cover crops on soil inorganic-N availability seems to have been slight and short-lived taking into account the high amounts of N contained in the mulched phytomass. The effect of legume cover crops on olive yield and leaf N concentration was statistically significant only in few occasions. The results of these experiments recommended some caution in the management of pure legume cover crops as a mulch in olive orchards due to the reduced transfer of N from legumes to olive trees.

Estado nutricional, produção e composição das uvas de Niágara Rosada submetidas à aplicação de composto orgânico

“…O não incremento de produção de uvas pela aplicação de composto orgânico indica que os teores naturais de nutrientes no solo somados à decomposição e liberação de nutrientes de resíduos de poda, de folhas senescentes e de plantas de cobertura depositados na superfície do solo podem conferir boa disponibilidade de nutrientes para as videiras (Brunetto et al, 2009(Brunetto et al, , 2011Rodrigues et al, 2013a). Neste caso, a aplicação de composto orgânico, tanto na linha como na entrelinha de plantio, é de pouca importância.…”

Potential of Rhizobium sullae–Sulla coronaria Symbiotic Biological Nitrogen Fixation to Supplement Synthetic Mineral Nitrogen in Olive Tree Fertilization

“…The most important limitations concern the dynamics of the organic nitrogen mineralization in the soil exploited by the olive roots, which is mainly linked to the C/N ratio of biomass and the synchrony between the period of maximum availability of mineral nitrogen produced in the soil by the microorganisms and the phenological phase of the olive plants in which the maximum nutrient concentrations are required. Rodrigues et al [26] recommended some caution in the use of pure legumes as biomass providers in olive orchards due to the reduced transfer of nitrogen from the legumes to the olive trees. However, the results of the present study indicate that olive tree fertilization with organic nitrogen from sulla green manure can compete with synthetic fertilization, but only if additional factors such as legume sowing density, use of an inoculum with a specific symbiont, and time of adding the green manure are correctly managed.…”

Effects of living mulches on the soil nutrient contents, enzyme activities, and bacterial community diversities of apple orchard soils

“…[43,44]. After the living mulch application, the soil physical and chemical properties were improved [1,2,18]. The soil organic matter input was increased, resulting the enhancement of the soil bacterial population and the alteration of the soil bacterial community composition [15,48,49].…”