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Provisioning services, such as the production of food, feed, and fiber, have always been the main focus of agriculture. Since the 1950s, intensive cropping systems based on the cultivation of a single crop or a single cultivar, in simplified rotations or monocultures, and relying on extensive use of agrochemical inputs have been preferred to more diverse, self-sustaining cropping systems, regardless of the environmental consequences. However, there is increasing evidence that such intensive agroecosystems have led to a decline in biodiversity as well as threatening the environment and have damaged a number of ecosystem services such as the biogeochemical nutrient cycles and the regulation of climate and water quality. Consequently, the current challenge facing agriculture is to ensure the future of food production while reducing the use of inputs and limiting environmental impacts and the loss of biodiversity. Here, we review examples of multiple cropping systems that aim to use biotic interactions to reduce chemical inputs and provide more ecosystem services than just provisioning. Our main findings are the identification of underlying ecological processes and management strategies related to the provision of pairs of ecosystem services namely food production and a regulation service. We also found gaps between ecological knowledge and the constraints of agricultural practices in taking account of the interactions and possible trade-offs between multiple ecosystem services as well as socioeconomic constraints. We present guidelines for the design of multiple cropping systems combining ecological, agricultural, and genetic concepts and approaches.

Combining photovoltaic panels (PVPs) and crops on the same land unit were recently proposed as an alternative to the conversion of cropland into photovoltaic plants. This could alleviate the increasing competition for land between food and energy production. In such agrivoltaic systems, an upper layer of PVPs partially shades crops at ground level. The aim of this work was to (i) assess the effect on crop yield of two PVPs densities, resulting in two shade levels equal to 50% and 70% of the incoming radiation and (ii) identify morphological and physiological determinants of the plant response to shade. Experiments were conducted on four varieties of lettuces (two crisphead lettuces and two cutting lettuces), during two seasons. In all cases, the relative lettuce yield at harvest was equal or higher than the available relative radiation. Lettuce yield was maintained through an improved Radiation Interception Efficiency (RIE) in the shade, while Radiation Conversion Efficiency (RCE) did not change significantly. Enhanced RIE was explained by (i) an increase in the total leaf area per plant, despite a decrease in the number of leaves and (ii) a different distribution of leaf area among the pool of leaves, the maximal size of leaves increasing in the shade. Our result provides a framework for the selection of adapted varieties according to their morphological traits and physiological responses to PVP shade, in order to optimize agrivoltaic systems

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Seed number, the most variable yield component of legumes is strongly affected by heat stress (HS) and water deficit (WD). The objective of this paper is to investigate whether HS and WD reduced seed number in field pea through their negative effects on biomass production rather than by specific effects on the developing reproductive organs. Several field and glasshouse experiments were carried out in southern France, in which HS and / or WD of various intensities, durations and positions in the plant lifecycle were imposed on several pea cultivars. WD and HS reduced seed number, in an intensity-dependent manner. They also changed the distribution of seeds along the stem. Plants subjected to WD and mild HS had more seeds on the basal phytomers than did control plants, making it possible to exclude direct effects of stress on seed development. In contrast, severe HS resulted in the immediate abortion of reproductive organs. WD and HS also decreased net photosynthesis (Pn), but only during the period of constraint. Quantitative relationships between Pn and soil water status and between Pn and leaf temperature were established. Nevertheless, in all cases there was a single linear relationship between final seed number and plant growth rate during the critical period for seed set (from the beginning of flowering to the beginning of seed fill for the last seed-bearing phytomer). This reflects the reproductive plasticity of pea, which adjusts the number of reproductive sinks in an apparent balance with assimilate availability in the plant.

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