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

Alberto Mantino,Giorgio Ragaglini,Martina Micci,Giovanni Pecchioni,Marcello Mele,Simona Bosco,Iride Volpi,Federico Dragoni

doi:10.3390/agronomy10010052

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.

Highlights

Among agroforestry systems, silvoarable Alley-Cropping Systems (ACS) are characterized by the intercropping of crops and wide-row trees [1], providing a variety of products, such as food, feed, fibers, fuelwood and timber, while increasing the potential delivery of agroecosystems services [2].farmers are reluctant to implement agroforestry systems because of the potential loss of gross production due to: (i) the reduction of arable surface and (ii) the risk of lower crop yields driven by the competition for resources between crops and trees [3]
In agreement with other Canadian outcomes from a poplar–soybean intercropping two-year study [31], our result showed that a small difference in light availability (LA) between the West and East positions affected soybean yield and total biomass production at the poplar–soybean interface, suggesting that competition for light was more important than competition for water in 2018
This study evaluated the effect of tree presence on soybean yield in rainfed Mediterranean conditions and highlighted the detrimental effect on crop yield in the tree–crop interface

Summary

Introduction

Silvoarable Alley-Cropping Systems (ACS) are characterized by the intercropping of crops and wide-row trees [1], providing a variety of products, such as food, feed, fibers, fuelwood and timber, while increasing the potential delivery of agroecosystems services [2]. Farmers are reluctant to implement agroforestry systems because of the potential loss of gross production due to: (i) the reduction of arable surface and (ii) the risk of lower crop yields driven by the competition for resources between crops and trees [3]. To date, imported soybean meal for animal feeding (i) represents 70% of protein-rich feedstuff used in the European Union (EU) [8] and (ii) it is associated with an increase of environmental impacts generated by land clearing in South America [9]. Soybean represents one of the largest sources of vegetable oil and animal protein feed [10]

Methods

Results

Discussion

Conclusion