Growth of Vegetables in an Agroecological Garden-Orchard System: The Role of Spatiotemporal Variations of Microclimatic Conditions and Soil Properties

Abstract

Garden-orchard systems (GOS) consist in intercropping various vegetables with fruit trees. They are very promising to produce fruits and vegetables in sufficient quantity and of adequate quality while limiting environmental impacts. We assessed the effects of apple trees on the spatiotemporal variations of microclimatic conditions and soil properties, and their influence on the growth of two vegetables (radish and lettuce). We performed measurements on five vegetable beds situated at different distances from apple tree rows (from 1.5 to 5 m). Vegetable beds near the apple trees received on average 8% less radiation. Air temperature near the trees was on average 1.5 °C lower during daytime while air relative humidity was up to 5% higher. Apple trees improved the soil surface properties. Soil organic matter was up to 40% higher in the vegetable beds near the rows whereas soil bulk density was 16% lower, N mineralization was up to two times faster. Mineral N and bulk density were the primary limiting factors for the growth of radish while lettuce growth was mainly affected by microclimate. Our results provide a framework to define a spatial arrangement of GOS that optimize the ecosystem services of fruit trees and, therefore, the productivity of GOS.