Competition, stress and benefits: Trees and crops in the transition zone of a temperate short rotation alley cropping agroforestry system

Abstract

Tree strips on agricultural production sites offer many economic, ecological and social advantages. However, the introduction of trees creates a transition zone between tree strips and crop land. Here, trees and crop plants compete for resources such as space, nutrients, water and light, which causes stress in the low‐competitive system. On the other hand, facilitation such as additional nutrient input through tree leaf litter and fine roots are possible. This study aims to provide indications for competition and benefits that can arise for plants growing in the transition zone of a temperate short rotation alley cropping agroforestry system (SRACS). Various climatic and plant‐growth parameters were investigated between 2013 and 2019 at different positions of an SRACS with fast‐growing poplars in northern Germany. Reduced yield of wheat, oilseed rape and silage maize close to the tree strip was associated with greater soil water tension in 30 and 60 cm soil depth due to the presence of poplar roots, reduced solar radiation due to tree shading and leaf litter coverage. In contrast, poplars growing in the outer rows produced more biomass than those in the inner rows due to the additional availability of space, light and nutrients taken from the crop field. Trees in the transition zone seem to be competitive with arable crops, but without effect on the average long‐term yield of arable crops.

Agronomic performance of soybean and sorghum in a short rotation poplar coppice alley-cropping system under Mediterranean conditions

“…Similar patterns of light reduction in relation to tree distance and height were recorded by Swieter et al (2021) in a short rotation coppice agroforestry experimental site in northern Germany. It should be noted that in our experiments the highest LAV recorded in 2018 for soybean and sorghum in the center part of the alley (an average of 94.33% at 6.75 m to the tree row) are similar to the lowest data recorded in 2019 on the East side of the alley of soybean and sorghum (an average of 94.38% at 2.5 m to the tree row).…”

“…Thus, the conversion from SRC plantation to silvoarable alley cropping-systems could become an interesting option for the transition towards sustainable agroforestry systems. Investigating the feasibility of silvoarable alley-cropping systems based on poplar short rotation coppice (SRC) has highlighted: (i) lower wood biomass production per hectare than pure poplar SRC stands, due to the reduced tree density, despite a higher growth rate per plant; (ii) tree rows significantly affect crop performance, competing for water, nutrients, and light, especially in the tree-crop interface zone (Swieter et al 2021); (iii) tree arrangement and orientation, as well as the land ratio between trees and herbaceous crops (Lamerre et al 2015;Seserman et al 2019), are key factors for the sustainability of silvoarable systems (Tsonkova et al 2012). In alley-cropping system, the choice of herbaceous crop is crucial for exploiting facilitations and limiting competition of trees.…”

Conceptualizing Multiple Stressors and Their Consequences in Agroforestry Systems

“…This study can serve as baseline knowledge for the development of agricultural production systems in the view of climate change. According to recent studies [21], and the knowledge gap, agroforestry system methods include short-duration enhanced fallows where a single horticulture crop is grown such as vegetables or medicinal plant species. The changes in the physical dimensions, life expectancies, and physiological reactions between the component species in simultaneous systems such as monoculture cropping can lead to complicated interactions between the tree and the crop species.…”

“…Pest incidence in the system can be modified by both the bottom-up effects of the abiotic environment and the top-down effects of herbivores and their natural enemies. In some systems that either induce stress (plant stress hypothesis) or improve crop vigor (crop vigor hypothesis and carbon-nutrient balance hypothesis), pest problems may increase [21].…”

Soil greenhouse gas emissions and crop production with implementation of alley cropping in a Mediterranean citrus orchard

“…However, their use is still not generalized in the Mediterranean region, and more incentives are needed to encourage farmers to adopt this practice. In this sense, alley cropping could be a suitable strategy to achieve environmental benefits but also increasing land profitability by production of complementary commodities (Swieter et al, 2021;Yang et al, 2021). Alley cropping is the agronomic strategy of growing annual or perennial crops in the alleys of tree orchards to increase farmer revenues, while increasing the land productivity by producing several commodities in the same space during the same year (Tsonkova et al, 2012;.…”