Temporal dynamics of nutrient uptake by neighbouring plant species: evidence from intercropping

Abstract

Summary The productivity of species‐diverse plant assemblages strongly depends on the temporal dynamics of nutrient uptake by competing neighbouring plants. Our understanding, however, of how rates of nitrogen (N), phosphorous (P) and potassium (K) uptake might change through time between neighbouring plant species under field conditions is still very limited. Here, we specifically measure the temporal trajectories of N, P and K uptake by staple food plants such as wheat (Triticum aestivum L.), barley (Hordeum vulgare L.) and maize (Zea mays L.) when growing either in monocultures or in intercropping systems. We ask how (i) plant species combinations, (ii) N fertilization and (iii) film mulching might affect key indexes of N, P and K uptake over time. We fit logistic models to characterize the nutrient uptake trajectories. Maximum cumulative N, P and K uptake (kg ha−1) by wheat and barley were significantly greater in wheat–maize or barley–maize intercropping systems than in wheat or barley monocultures. Cumulative nutrient uptake by intercropped maize (either with wheat or with barley) was reduced by interspecific competition at early growth stages, but it increased rapidly after wheat and barley were harvested. Maximum cumulative N and P (but not K) uptake by intercropped maize were significantly higher than the uptake by monoculture maize, particularly when N fertilizer or film mulching was applied. Intercropping induced a significant temporal niche differentiation in maximum daily nutrient uptake rates (kg ha−1 day−1) between intercropped species. Fertilization had much stronger effects on maximum cumulative nutrient uptake of maize than that of wheat and barley. Mulching significantly increased the maximum cumulative nutrient uptake of maize and advanced the time to reach its maximum daily P and K uptake rates. Our study provides evidence of an important temporal niche differentiation mechanism (‘temporal complementarity’) in nutrient uptake rates between neighbouring plant species. A better understanding of temporal trajectories of interspecific nutrient uptake rates remains crucial if we want to maximize the nutrient‐use efficiency and sustain overyielding (i.e. high food production) in plant species‐diverse systems such as intercropping.

Nutrient Concentrations of Bush Bean (Phaseolus vulgaris L.) and Potato (Solanum tuberosum L.) Cultivated in Subarctic Soils Managed with Intercropping and Willow (Salix spp.) Agroforestry

“…In addition, willows have mutual symbioses with ectomycorrhiza and vesicular-arbuscular endomycorrhizae, allowing roots to increase the surface area for nutrient uptake, specifically N and P [19,[53][54][55]. It may be that the greater [P] in agroforestry beans and potatoes partially relate to willows facilitating P through tree root-crop root interactions and enhancing mycorrhizal fungal networks [16,18,20,56]. Additionally, willow roots may provide available P to soil by obtaining nutrients deeper in the soil profile [16,19,56].…”

Interspecies Interactions in Relation to Root Distribution Across the Rooting Profile in Wheat-Maize Intercropping Under Different Plant Densities

“…However, the mechanisms responsible for the yield advantages of intercropping over sole planting are poorly understood. Sharing of available soil water and nutrients between the two crops during the co-growth period has been found to contribute positively to the yield advantage (Pandey et al, 2013), while at the meantime the two crops compete for the available resources at specific growth stages (Ghosh et al, 2006; Xu et al, 2013; Zhang et al, 2016). Yield advantage is typically related to root growth and development (Xu et al, 2010; Wan et al, 2013), root distribution patterns across the rooting profile (Liu et al, 2015), and spatial variability in root traits.…”

Temporal Differentiation of Crop Growth as One of the Drivers of Intercropping Yield Advantage

“…It is part of nature-based solutions in land management for enhancing ecosystem services 6 . Intercropping has been widely adopted by farmers in developing countries 7–11 , especially in the single-season cropping areas because of the annual thermal limitation in most areas of northwestern China 12,13 .…”

“…Moreover, intercropping can maintain or enhance soil quality 13,23 , promote biodiversity 3,24 , control weed growth 25 , minimize the incidence of pests and diseases 26 , reduce soil erosion and runoff discharge 6 , and increase farming incomes 5,8 . To design an intercropping system with advantages in terms of efficient resource utilization it is necessary to identify the relationship between the intercropping advantages and the growth traits and resource requirements of the component crop species 3 .…”

“…To design an intercropping system with advantages in terms of efficient resource utilization it is necessary to identify the relationship between the intercropping advantages and the growth traits and resource requirements of the component crop species 3 . Previous studies show that intercropping advantages depend greatly on niche differentiation in time 12,13 and space 18,22,27,28 , or on positive interspecific interactions (facilitation) 17,23 between intercropped species, thereby moderating competition 29 .…”