Effect of Tree Presence and Soil Characteristics on Soybean Yield and Quality in an Innovative Alley-Cropping System

Abstract

Agroforestry is indicated as a farming practice suited to enhance ecosystem services generated by cropping systems. However, farmers are often reluctant to implement agroforestry systems due to the potential yield loss of crops. In a field trial, soybean was intercropped with poplar short-rotation-coppice rows in an alley-cropping system with 13.5 m wide alleys, in order to assess the effect of tree presence on soybean yield and quality. The light availability (LA) was significantly affected by the tree presence, with an increasing effect along the season due to tree growth, being at its lowest in the tree–crop interface positions (West and East). Significant effects of the tree-distance and LA were registered on soybean yield, with the highest reduction of soybean yield in the West (−78%) and East (−35%) positions. Crude fat content in soybean grain did not vary among positions in the alley, while crude protein content was the lowest in the most shaded position (West −8% than the highest value). The assessment of spatial variability among plots of measured soil characteristics highlighted no significant effect of pedological conditions upon soybean yield. Thus, in our study, the LA effect was more important than soil characteristics in determining a detrimental effect of competition for resources between soybean and poplar. Conversely, soybean quality was affected by soil characteristics, since crude fat significantly correlated with soil nutrients, pH, soil organic matter and soil texture.

Biomass Performance and Competition Effects in an Established Temperate Agroforestry System of Willow and Grassland—Results of the 2nd Rotation

“…The average height of willows was 4.47 m, with an average diameter at breast height of 2.9 cm (data not shown). Several studies [13,37,38] stated that competition for resources (water, light and nutrients) is the main reason for decreased yields of agricultural crops in AFS, especially under temperate climate [39]. These findings are confirmed by the present investigation of a transect with five TPs evenly distributed in the grassland alleyways of AFS, where significantly lower yields were determined in the border areas (TPs 1 and 5).…”

“…These findings are confirmed by the present investigation of a transect with five TPs evenly distributed in the grassland alleyways of AFS, where significantly lower yields were determined in the border areas (TPs 1 and 5). These are the areas where competition for light, water and nutrients between trees and understory vegetation is most pronounced [38,40]. Several studies [21,41] described significantly lower yields of winter wheat in proximity to the trees of an AFS, as a result of competition.…”

Agroforestry Benefits and Challenges for Adoption in Europe and Beyond

“…AFS provide a good compromise between the input-intensive monoculture for high productivity and nature-based or conservation agriculture with lower productivity, for production of food and non-food products. Due to the diversity of crop and tree species in AFS, yields are more stable in cases of adverse climatic conditions [141,142], reducing the risk exposure for the farmers. Further, there is better nutrient cycling due to the complementarity in time and space in resource use between the crop and tree species, enhancing the resource use and cycling [143] within the production system.…”

Tree–Crop Ecological and Physiological Interactions Within Climate Change Contexts: A Mini-Review

“…Agroforestry systems are also critical for rural development in lowincome regions (Montagnini, 2017;Rodríguez-Rigueiro et al, 2021) by providing determinant ecosystem services such as soil fertility enhancement, prevention of soil erosion, water, wind, and pest regulation, and pollination (Rigueiro-Rodríguez et al, 2009;Kuyah et al, 2017). In this sense, mixing crops and tree species is an excellent way to increase crop yield and yield stability, especially within adverse climatic conditions (Sileshi et al, 2012;Nasielski et al, 2015).…”