Ecological engineering in the management of an olive orchard on degraded soil

Abstract

THIS report describes the results obtained ¡n a field experiment performed on an olive orchard, in which the soil is sandy and impoverished. Our study forms part of a project whose main aim is to evalúate ecological management systems directed towards the conservation of soil in semiarid áreas. At the start of our analysis, we noted two critical points: soil erosión and a degraded soil with extremely low levéis of organic matter, N and other nutrients. To resolve these problems from a perspective of sustainable agricultura, it was decided to implant or to propitiate the growth of plant covers between rows of trees that would be capable of: controlling soil erosión, adapting to sandy soils and the rainfall regime of the semiarid climate, fixing nitrogen and undergo autoseeding. Further requirements were rapid growth, ease of handling, low cost, and a short phenological cycle, to avoid competition for water during the time of the tree's máximum needs. Species such as subclover would fulfil these requirements. We also evaluated the possibility of managing the growth of the "resident vegetation", or weeds, by carefully cutting them back such that creeping species are able to seed and remain in the soil.