West African mixed farming systems as meta-ecosystems: A source-sink modelling approach

Bisson, Anne; Boudsocq, Simon; Casenave, Céline; Manlay, Raphaël J.; Vayssières, Jonathan; Massé, Dominique; Daufresne, Tanguy

doi:10.1016/j.ecolmodel.2019.108803

Cited by 6 publications

(3 citation statements)

References 30 publications

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“…Taken together, trees and grasses display contrasting root foraging strategies: restricted soil exploration for grasses to locally control nutrient availability versus horizontal proliferation of tree roots to benefit from nutrients outside their canopy. Moreover, our work confirms the results of other studies (Bisson et al., 2019) parameterizing meta‐ecosystem models with field data and showing that nutrient transfers between patch types are very influential for the functioning of the meta‐ecosystem and its components (Gravel et al., 2010). Taken together, we have shown that considering savannas as meta‐ecosystems throws new insights on their functioning.…”

Section: Discussionsupporting

confidence: 91%

Spatial heterogeneity in nitrification and soil exploration by trees favour source–sink dynamics in a humid savanna: A modelling approach

et al. 2021

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Savannas are structured ecosystems characterized by a grass layer interspersed with trees. Trees strongly modify their local environment and favour nutrient accumulation under their canopies. Tree roots can also forage horizontally far beyond the canopy projection to increase nutrient uptake. In the Lamto savanna (Côte d’Ivoire), grasses are able to inhibit nitrification while trees stimulate it. Here, we used a two‐patch model simulating nitrogen (N) dynamics in a humid savanna between an open patch (without tree) associated with a low nitrification rate and a patch of tree clump associated with a high nitrification rate. The model also includes horizontal N fluxes between these two patches corresponding to horizontal soil exploration by tree roots. We analysed the impact of spatial heterogeneity in nitrification and soil horizontal exploration on N budget and plant biomass. Despite high N losses under trees due to nitrification stimulation by trees, our results show that the ability of trees to explore horizontally the open allows them to uptake more nutrients in total. This leads to an asymmetric N flux from the open to tree clumps, which contributes to nutrient enrichment under tree clumps and thereby to tree growth. Although trees have the ability to horizontally explore the soil to accumulate nutrients under their canopy, increasing the surface occupied by tree clumps increases N losses per hectare of savanna due to the increased nitrification under trees and the subsequent increase in NO3‐ leaching. While perennial savanna grasses show a restricted horizontal soil exploration to control nutrient availability, our results predict that the extension of tree roots outside their canopy increases their nutrient acquisition in the Lamto savanna. This study is the first one emphasizing the influence of horizontal exploration of trees and tree cover on savanna N budget and functioning. Overall, the proportion of tree cover and horizontal soil exploration are important factors to consider in savannas characterized by spatial heterogeneity in N cycling created by trees and grasses. These factors appear critical to the functioning of West African humid savannas and should be investigated in other savanna types. A free Plain Language Summary can be found within the Supporting Information of this article.

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Section: Discussionsupporting

confidence: 91%

Spatial heterogeneity in nitrification and soil exploration by trees favour source–sink dynamics in a humid savanna: A modelling approach

et al. 2021

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“…In traditional farms with draft cattle, they mainly depended on the fodder collected from the common rangelands. This corresponded to traditional livestock practices widely developed in SSA (e.g., Manlay et al [29] and Bisson et al [30] for West Africa). It also highlights the importance of common rangelands in biomass and nutrient flows in traditional livestock farming systems.…”

Section: Nutrient Balance At the Farm Levelmentioning

confidence: 83%

Nutrient Flows and Balances in Mixed Farming Systems in Madagascar

Fanjaniaina¹,

Stark

Ramarovahoaka

et al. 2022

Sustainability

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Mixed farming systems are still prevalent in sub-Saharan Africa. In these systems, the recycling of nutrients through crop-livestock integration (CLI) practices is crucial for the sustainability of soil fertility and crop production. The objective of this study was to analyze nutrient (N, P, K) flows and balances of mixed farming systems to assess CLI contribution to the performance of those systems. We hypothesized that more intensive farms had a better nutrient balance at the farm level, and that improved biomass management methods improved their nutrient balance. Nine farms in the Madagascar highlands were selected, some corresponding to poor traditional farms with only draft cattle; some small or medium-sized, more intensive farms with a dairy herd; and some of the latter with some improvement to management methods of livestock effluents (manure composting, liquid manure collection). The nutrient balance of the farming systems was determined, and performance indicators were calculated at both farming, livestock, and CLI levels. Results showed that nutrient recycling through CLI is significant in the functioning of the systems studied, contributing primarily to circulating nutrient flows (up to 76%) and leading to greater efficiency and productivity. Nutrient flows resulting from these practices mainly concerned animal feeding (higher than 60% of nutrient flows), even if manure management was central for crop fertilization and that manure remained a desired animal product of these types of farms (up to 100% of animal products). Large negative balances of N and K (up to 80% of inputs) were observed in traditional livestock systems with draft cattle. They were smaller (39–68%) in more intensive dairy farms. Composting of manure did not decrease negative balances, whereas their magnitude was significantly reduced by the collection of liquid manure (19% for N; 42% for K). Better management of biomass at the farm level, in particular the collection of liquid manure, seemed to substantially reduce nutrient losses in MFS.

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“…In traditional mixed crop-livestock farming systems, that are still present in some parts of the world such as in West-Africa, it is well-known that livestock plays a key role [1]; it is a vector of nutrient from rangeland to cropland that benefits to the production of the whole agro-ecosystem [2]. In occidental countries, the livestock farms are often separated from the crop fields and the livestock has thus lost its role as nutrient carrier.…”

Section: Introductionmentioning

confidence: 99%

Control of the crop-production in a network of agricultural plots

Casenave¹,

Bisson²

2020

2020 28th Mediterranean Conference on Control and Automation (MED)

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In the present paper, we propose a strategy to control the crop-production of a network of agricultural plots. The network is composed of rangeland and cropland subsystems that are connected to each other through the livestock that is a vector of nutrient from rangeland to cropland. The objective is to reach a given crop production (at the scale of the whole network) while ensuring a minimal production in each of the cropland plot. To take into account the saturation constraints on the control inputs (that are the rangeland removal rates and the manure distribution coefficients), we use a method based on a time-scale transformation. After designing the control law, we apply it on a simple numerical example to highlight the results.Index Terms-nonlinear control, input constraints, time-scale transformation, agroecosystemsCONFIDENTIAL. Limited circulation. For review only.

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West African mixed farming systems as meta-ecosystems: A source-sink modelling approach

Cited by 6 publications

References 30 publications

Spatial heterogeneity in nitrification and soil exploration by trees favour source–sink dynamics in a humid savanna: A modelling approach

Spatial heterogeneity in nitrification and soil exploration by trees favour source–sink dynamics in a humid savanna: A modelling approach

Nutrient Flows and Balances in Mixed Farming Systems in Madagascar

Control of the crop-production in a network of agricultural plots

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