Trade-Off between Energy Wood and Grain Production in Temperate Alley-Cropping Systems: An Empirical and Simulation-Based Derivation of Land Equivalent Ratio

Diana-Maria Seserman,Dirk Freese,Maren Langhof,Maik Veste,Anita Swieter

doi:10.3390/agriculture9070147

Diana-Maria Seserman, Dirk Freese + Show 3 more

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https://doi.org/10.3390/agriculture9070147

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Abstract

The alley-cropping systems (ACSs), which integrate parallel tree strips at varying distances on an agricultural field can result, complementarity of resource use, in an increased land-use efficiency. Practitioners’ concerns have been directed towards the productivity of such systems given a reduced area covered by agricultural crops. The land equivalent ratio (LER) serves as a valuable productivity indicator of yield performance and land-use efficiency in ACSs, as it compares the yields achieved in monocultures to those from ACSs. Consequently, the objective of this combined experimental and simulation study was to assess the tree- and crop-yields and to derive the LER and gross energy yield for two temperate ACSs in Germany under different design scenarios, i.e., tree arrangements (lee- or wind-ward) and ratios of tree area to crop area. Both LER and gross energy yields resulted in a convex curve where the maximum values were achieved when either the tree or crop component was dominant (>75% of the land area) and minimum when these components shared similar proportions of land area. The implications of several design scenarios have been discussed in order to improve the decision-making, optimization, and adaptation of the design of ACSs with respect to site-specific characteristics.

Highlights

As a consequence of the industrialisation and specialization of the agricultural production, field sizes across Europe have expanded with negative implications for the environment, for landscape diversity and biodiversity [1,2,3]
The dry matter yields of wood and grains or seeds per cropped area are presented in Table 2, together with the inferred gross energy yield, coefficient of variation, as well as the results of t-tests where p-values were compared to a significance level of 0.05
The annual increment of tree woody biomass reported for poplar can vary with tree of light, studies performed on second rotation poplar trees planted at around 10,000 cuttings ha−1 clone of choice, weather, and other growth-limiting factors such as mortality and seasonal variation recorded biomass values in the range of 2.8–9.0 Mg dry matter (DM) ha−1 a−1 [39], 2.0–9.6 Mg DM ha−1 a−1 [40], of light, studies performed on second rotation poplar trees planted at around 10,000 cuttings ha-1 and sometimes above 20 Mg DM ha−1 a−1 [41]

Summary

Introduction

As a consequence of the industrialisation and specialization of the agricultural production, field sizes across Europe have expanded with negative implications for the environment, for landscape diversity and biodiversity [1,2,3]. The increased biomass demand for a bio-based economy will only heighten the pressure on arable lands, which will eventually compete with other land-uses in terms of food and feed production [4]. In this context, a need to redesign the agricultural landscapes towards a multifunctional land-use has been identified in order to promote ecosystem services and to ensure a sustainable and resilient agricultural production in the 21st century [5,6]. Agroforestry systems have been shown to preserve high levels of agricultural yields while delivering ecosystem services, increasing land-use efficiency [9,10], and concurrently providing effective climate change mitigation, such as reducing the atmospheric carbon dioxide [11], and adaptation measures [12,13].

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