Promising Land Use Research Articles

Microbial electrochemical enhanced composting of sludge and kitchen waste: Electricity generation, composting efficiency and health risk assessment for land use

To realize the energy and resource utilization from organic solid waste, a two-phase microbial desalination cell (TPMDC) was constructed using dewatered sludge and kitchen waste as the anode substrate. The performance of electricity generation and composting efficacy was investigated, along with a comprehensive assessment of the potential health risks associated with the land use of the resulting mixed compost products. Experimental outcomes revealed a maximum open-circuit voltage of 0.893 ± 0.005 V and a maximum volumetric power density of 0.797 ± 0.009 W/m³. After 90 days of composting enhanced by microbial electrochemistry, a significant organic matter removal rate of 31.13 ± 0.44 % was obtained, and the anode substrate electric conductivity was reduced by 30.02 ± 0.04 % based on the anode desalination. Simultaneously, there was an increase in the content of available nitrogen, phosphorus, and potassium, as well as an improvement in the seed germination index. The forms of heavy metals shifted from bioavailable to stable residual states. The non-carcinogenic hazard index (HI) values for heavy metals and polycyclic aromatic hydrocarbons (PAHs) during the land use of compost products were less than 1, and the total carcinogenic risk (TCR) values for heavy metals and PAHs were below the acceptable threshold of 10−4. The occupational population risk of infection from five pathogens was higher than that of the general public, with all risk values ranging from 8.67 × 10−8 to 1, where the highest risk was attributed to occupational exposure to Legionella. These outcomes demonstrated that the mixture of dewatered sludge and kitchen waste was an appropriate anode substrate to enhance TPMDC stability for electricity generation, and its compost products have promising land use suitability and acceptable land use risk, which will provide important guidance for the safe treatment and disposal of organic solid waste.

An Investigation of Constraints Experienced by Homegarden Farmers of Coastal Agro-Ecological Units of Southern Kerala

Homegardens or homesteads represent a promising land use system and are common in Kerala, where the average size of farm households is small. The present investigation was carried out in the coastal homegardens of three selected panchayaths of Southern Kerala during 2021-22 to measure the constraints perceived by the coastal homegarden farmers. A total of 105 homegardens were included in the sample, with 35 homegardens purposefully selected from each identified panchayat. Farmers were interviewed using a structured interview schedule containing both open and closed-ended questions to understand the constraints. The constraints were then ranked based on the total scores obtained by summing up the individual scores for each constraint. These constraints were categorized into five main groups: Economic, Personal, Technology, Physical, and Other Constraints. Among these, "Lack of scientific knowledge," "Salinity," and "Flooding" were identified as the most critical constraints. Furthermore, the farmers provided valuable suggestions to address these constraints. These recommendations emphasized the development of tailored practices for coastal home gardens, the need for support from extension agencies, collaborative technology development, integration of traditional and scientific approaches, the establishment of market connections, the creation of accessible input centres, and the promotion of Farmer Producer Organizations (FPOs). These suggestions highlight crucial areas for future action and development, potentially enhancing the sustainability and productivity of coastal home gardens in Southern Kerala, benefiting both farmers and the broader community.

Homegarden and coffee agroforestry systems plant species diversity and composition in Yayu Biosphere Reserve, southwest Ethiopia

Agroforestry systems are among the promising land use systems that enable to address both the development and livelihood issues of the community all over the world. In southwestern Ethiopia, homegarden and coffee agroforestry systems are widely used farming systems. Despite the fact that the systems are widely used and important, there are little studies on the subject. Therefore, the objective of this study was to assess homegarden and coffee agroforestry systems plant diversity and composition in Yayu Biosphere Reserve. To achieve the study's goal, data was collected through forest inventories and household surveys. A total of 101 plant species from 49 families were identified, with 74 from homegardens (37 families) and 57 from coffee agroforestry systems (34 families). In terms of dominating plants in agroforestry systems, home gardens are dominated by herbaceous plants, accounting for 51 percent, whereas coffee agroforestry systems in the study region are dominated by trees, accounting for 72 percent. About 38 percent of household gardens and 77 percent of coffee agroforestry are made up of indigenous plant species. According to the findings, both agroforestry systems at the research site have a great diversity of plant species. As a result, the systems may be able to provide a wide range of services to farmers. Farmers, professionals, and legislators must collaborate to improve the systems' components, composition, and arrangements in order to maximize and protect the systems' multiple benefits.

Wet peatland utilisation for climate protection – An international survey of paludiculture innovation

Drainage-base agriculture and forestry are key drivers of emissions from degraded peatlands. An important challenge of climate-oriented peatland management is an improved conservation of their huge carbon stocks. Paludiculture, the productive use of wet peatlands, is a promising land use alternative that reduces greenhouse gas emissions substantially since it requires rewetting of peatlands. As rewetting is accompanied by productive use, it offers a sustainability innovation for farmers and other land users. There is an emerging knowledge base on paludiculture but no empirical study of paludiculture and its diffusion as an international innovation. The paper closes this research gap presenting the results of a survey of paludiculture projects in a variety of global contexts. It shows paludiculture to be an emerging, science-driven and collaborative innovation that faces adverse path-dependency from drained peatland exploitation. There is a diversity of paludicultures for fuel, fodder, horticultural substrate and construction material, but these are rarely directly commercially viable. A third of initiatives see themselves in continuity with traditional but often marginalized uses of peatlands. Paludiculture is a complex, critical sustainability innovation mission calling for a multiple-objective strategy and a sustainability-oriented form of governance. As biomass from paludiculture per se can almost never compete with dryland alternatives, we recommend i) to initiate and sustain large-scale programmes to develop products that exploit the unique properties of wetland plants across market, public and communal uses, ii) to develop integrative concepts for payments for ecosystem services associated with wet peatlands, iii) a complementary focus on ending subsidies and policy support for drainage-based peatland use, as well as iv) inclusive stakeholder involvement from the start as well as sustained policy support to foster paludiculture as the productive niche within a culture of living sustainably with peatlands.

Soil organic carbon sequestration in temperate agroforestry systems – A meta-analysis

Soil organic carbon (SOC) sequestration by improved agricultural practices is an acclaimed strategy to combat climate change. Nevertheless, the aim of increasing of SOC encounters limitations, e.g. with regards to permanence of carbon storage or leakage effects in food production. Agroforestry systems (AFS) are a promising land use option that is able to sequester substantial amounts of SOC while addressing these challenges. With a focus on temperate climate zones worldwide, available information on SOC in AFS was reviewed to determine their SOC sequestration potential and respective controlling factors. From a total of 61 observations, SOC sequestration rates in soils of AFS were derived for alley cropping systems (n = 25), hedgerows (n = 26) and silvopastoral systems (n = 10). The results showed that AFS have a potential for substantial SOC sequestration in temperate climates. SOC stocks were higher in the topsoil (0–20 cm) than in the control in more than 70% of the observations, and higher within the subsoil (20–40 cm) for 81% of all observations, albeit large variation in the data. The mean SOC sequestration rates were slightly higher at 0–20 cm (0.21 ± 0.79 t ha-1 yr-1) compared to 20–40 cm soil depth (0.15 ± 0.26 t ha-1 yr-1). Hedgerows revealed highest SOC sequestration rates in topsoils and subsoils (0.32 ± 0.26 and 0.28 ± 0.15 t ha-1 yr-1, respectively), followed by alley cropping systems (0.26 ± 1.15 and 0.23 ± 0.25 t ha-1 yr-1) and silvopastoral systems showing a slight mean SOC loss (−0.17 ± 0.50 and −0.03 ± 0.26 t ha-1 yr-1). Moreover, SOC sequestration rates tended to be higher for AFS with broadleaf tree species compared to coniferous species. We conclude that temperate AFS sequester significant amounts of SOC in topsoils and subsoils and represent one of the most promising agricultural measures for climate change mitigation and adaption.

Which Socio-economic Conditions Drive the Selection of Agroforestry at the Forest Frontier?

Models are essential to assess the socio-economic credentials of new agroforestry systems. In this study, we showcase robust optimisation as a tool to evaluate agroforestry’s potential to meet farmers’ multiple goals. Our modelling approach has three parts. First, we use a discrete land-use model to evaluate two agroforestry systems (alley cropping and silvopasture) and conventional land uses against five socio-economic objectives, focusing on the forest frontier in eastern Panama. Next, we couple the land-use model with robust optimisation, to determine the mix of land uses (farm portfolio) that minimises trade-offs between the five objectives. Here we consider uncertainty to simulate the land-use decisions of a risk-averse farmer. Finally, we assess how the type and amount of agroforestry included in the optimal land-use portfolio changes under different environmental, socio-economic and political scenarios, to explore the conditions that may make agroforestry more attractive for farmers. We identify silvopasture as a promising land use for meeting farmers’ goals, especially for farms with less productive soils. The additional labour demand compared to conventional pasture, however, may prove an important barrier to adoption for farms facing acute labour shortages. The selection of agroforestry responded strongly to changes in investment costs and timber prices, suggesting that cost-sharing arrangements and tax incentives could be effective strategies to enhance adoption. We found alley cropping to be less compatible with farmers’ risk aversion, but this agroforestry system may still be a desirable complement to the land-use portfolio, especially for farmers who are more profit-oriented and tolerant of risk.

Land‐use history determines stand structure and tree diversity in vanilla agroforests of northeastern Madagascar

AbstractQuestionIn human‐modified tropical landscapes, agroforestry is considered a promising land use to reconcile biodiversity conservation with production goals. The role of agroforests regarding conservation may be strongly influenced by land‐use history; however, few studies have explicitly investigated this. We therefore tested the importance of land‐use history for habitat structure and tree diversity in vanilla agroforests situated in a human‐modified tropical landscape.LocationSmallholder mosaic landscape of northeastern Madagascar.MethodsWe studied tree stand structure, diversity and composition in vanilla agroforests of contrasting land‐use history, old‐growth forests, forest fragments and woody fallows after slash‐and‐burn agriculture, which all contribute to the smallholder mosaic landscape of northeastern Madagascar. The vanilla agroforests were either derived directly from forest or otherwise from woody fallows after slash‐and‐burn agriculture.ResultsLand‐use history strongly influenced tree species diversity and composition in vanilla agroforests and also affected stand structure. Forest‐derived agroforests maintained high levels of tree species diversity and differed in community composition from fallow‐derived agroforests, which had relatively low levels of tree diversity. Additionally, forest‐derived vanilla agroforests harboured a significantly higher percentage of endemic species than fallow‐derived agroforests, and forest‐derived agroforests also shared many species with old‐growth forests and forest fragments. Fallow‐derived vanilla agroforests harboured a lower percentage of endemic species than woody fallows.ConclusionConsidering the land‐use history of agroforests is important to unfold their full potential as elements in a multifunctional human‐modified landscape. Forest‐derived agroforests are an alternative to forest conversion through slash‐and‐burn agriculture and have the potential to sustain high levels of species diversity and important habitat structures. In contrast, fallow‐derived agroforests regain stand structure on degraded historically forested land and thereby have the potential to increase canopy cover and connectivity at the landscape scale.

Climate Change Mitigation through Land Use on Rewetted Peatlands \u2013 Cross-Sectoral Spatial Planning for Paludiculture in Northeast Germany

Drainage of peatlands causes severe environmental damage, including high greenhouse gas emissions. Peatland rewetting substantially lowers these emissions. After rewetting, paludiculture (i.e. agriculture and forestry on wet peatlands) is a promising land use option. In Northeast Germany (291,361 ha of peatland) a multi-stakeholder discussion process about the implementation of paludiculture took place in 2016/2017. Currently, 57% of the peatland area is used for agriculture (7% as arable land, 50% as permanent grassland), causing greenhouse gas emissions of 4.5 Mt CO2eq a−1. By rewetting and implementing paludiculture, up to 3 Mt CO2eq a−1 from peat soils could be avoided. To safeguard interests of both nature conservation and agriculture, the different types of paludiculture were grouped into ‘cropping paludiculture’ and ‘permanent grassland paludiculture’. Based on land legislation and plans, a paludiculture land classification was developed. On 52% (85,468 ha) of the agriculturally used peatlands any type of paludiculture may be implemented. On 30% (49,929 ha), both cropping and permanent grassland paludiculture types are possible depending on administrative check. On 17% (28,827 ha), nature conservation restrictions allow only permanent grassland paludiculture. We recommend using this planning approach in all regions with high greenhouse gas emissions from drained peatlands to avoid land use conflicts.

Who Adopts Agroforestry in a Subsistence Economy?—Lessons from the Terai of Nepal

Agroforestry is recognized as a sustainable land use practice. However, the uptake of such a promising land use practice is slow. Through this research, carried out in a Terai district of Nepal, we thoroughly examine what influences farmers’ choice of agroforestry adoption and what discourages the adoption. For this, a total of 288 households were surveyed using a structured questionnaire. Two agroforestry practices were compared with conventional agriculture with the help of the Multinomial Logistic Regression (MNL) model. The likelihood of adoption was found to be influenced by gender: the male-headed households were more likely to adopt the tree-based farming practice. Having a source of off-farm income was positively associated with the adoption decision of farmers. Area of farmland was found as the major constraint to agroforestry adoption for smallholder farmers. Some other variables that affected positively included livestock herd size, provision of extension service, home-to- forest distance, farmers’ group membership and awareness of farmers about environmental benefits of agroforestry. Irrigation was another adoption constraint that the study area farmers were faced with. The households with a means of transport and with a larger family (household) size were found to be reluctant regarding agroforestry adoption. A collective farming practice could be a strategy to engage the smallholder farmers in agroforestry.

Organic matter composition in density fractions of Cerrado Ferralsols as revealed by CPMAS 13C NMR: Influence of pastureland, cropland and integrated crop-livestock

Integrated crop-livestock (ICL) is a promising land use system for the Brazilian Cerrado, but little is known about what this system might change in chemical composition of soil organic matter. In three long-term experiments (9–11 years old), located on Cerrado Ferralsols in Dourados, Maracaju and Campo Grande (Mato Grosso do Sul State, Brazil), we assessed the impact of continuous cropland (CC), ICL, and permanent pasture of Brachiaria decumbens (PP) on the C concentration and composition of the free light fraction (FLF), occluded light fraction (OLF) and heavy fraction (HF) of soil in the 0–5cm layer. CPMAS13C NMR spectroscopy was used to determine the percentage of alkyl, O-alkyl, aromatic and carboxyl C types. In Dourados and Maracaju, PP had the highest concentrations of organic C in whole soil and physical fractions, while ICL was intermediate and CC lowest. In Campo Grande, soil organic C concentration was similar among management systems. Distribution of organic C across physical fractions was not affected by management nor by experimental site, and on average the FLF, OLF and HF contained 7%, 26% and 67% of the total storage, respectively. Signal peaks of the four main C types appeared in all CPMAS 13C NMR spectra, but at different intensities. O-alkyl was the major C type (about 50%), carboxyl was the minor representative (generally less than 10%) and alkyl and aromatic C were intermediates. From FLF to OLF, the alkyl and aromatic C concentrations increased, possibly due to selective preservation of waxes, resins, cutin, suberin and lignin. The HF had greater O-alkyl and lower aromatic C concentrations than OLF, which might have been related to the accumulation of microbial carbohydrates on mineral surfaces of the HF. Along the sequence CC–ICL–PP, the most evident changes were greater of O-alkyl and lower alkyl C types, practically in all fractions and sites. In FLF and OLF, these changes were attributed to greater biomass input and less seed drill-induced disturbance of soil surface (lower decomposition of residues) in the PP and ICL. Additionally, in OLF, greater O-alkyl concentration in PP and ICL was attributed to physical protection of particulate organic matter derived from grass roots occluded inside soil aggregates. Our results suggest that PP and ICL systems increased or maintained soil organic C concentrations compared to CC, associated with a qualitative increase of the chemically labile O-alkyl C type which was possibly related to greater biomass addition and less soil disturbance.

Scenario Analysis to Identify Viable Conservation Strategies in Paraguay's Imperiled Atlantic Forest

Carlson, M. J., R. Mitchell, and L. Rodriguez. 2011. Scenario analysis to identify viable conservation strategies in Paraguay’s imperiled Atlantic forest. Ecology and Society 16(3): 8. https://doi.org/10.5751/ES-04267-160308

INDIGENOUS PRACTICES AND SOCIO-ECONOMICS OF ARECA CATECHU L. AND PIPER BETEL L. BASED INNOVATIVE AGROFORESTRY IN NORTHERN RURAL BANGLADESH

ABSTRACT An agroforestry system based on Areca catechu L. and Piper betel L. has been gradually developed by farmers of northern rural Bangladesh since the late 1980s. This paper explores the indigenous practices and the socio-economics of this agroforestry system, seen as a promising land use strategy in the region. Data were collected by interviewing household members and visiting their agroforestry plots as well as by focus group discussions in five villages of Panchagarh district. Results indicate that farmers allocated a portion of their farmland along with homesteads for Areca and betel-based agroforestry because they felt it was both sustainable and profitable. Sustainability was ensured by the presence of different Areca and betel leaf age gradations in the plantations and by buoyant product markets. Variation was observed among farmers regarding land allocation, tree density, income, and marketing of products. Though poor farmers had less land at their disposal, they allocated the same proportion of their land to agroforestry as did the largest land holders. Poor farmers' agroforestry plots had the highest Areca tree density and also derived the highest income per hectare. Net income per farmer was directly proportional to the amount of land allotted to agroforestry.

Ecological benefits of the alley cropping agroforestry system in sensitive regions of Europe

Abstract Alley cropping is an agroforestry system that offers a promising land use alternative for the temperate zone. On the same field, the sustainable production of food and biomass is possible, while simultaneously, especially in marginal areas, the ecological function of the landscape can be improved. Thus, alley cropping corresponds with the increasing demand for renewable energy resources and for a specific adaptation to the predicted changes of climatic conditions within Central Europe. However, presently, little knowledge exists regarding the effects of alley cropping on the environment. In this study a literature survey was undertaken to provide an overview of the different ecological benefits arising from alley cropping systems within temperate Europe. Abiotic factors (nutrient cycle, microclimate), biotic factors (biodiversity) and the effects on the carbon cycle are discussed in detail. Summarising, the results showed that alley cropping may be an ecologically advantageous land use system for sustainable food and biomass production in comparison with conventional agricultural practices. As a very flexible, but low-input system, alley cropping can supply biomass resources in a sustainable way and at the same time provide ecological benefits.

Uncertainties in estimating the potential for carbon mitigation of forest management

Forestry and agroforestry are promising land use alternatives for reducing the increasing concentrations of global atmospheric carbon (C). Various methodological approaches to estimate the impact of forestry and agroforestry on C fluxes have been proposed. Uncertainties are inevitable in any estimate of greenhouse gas (GHG) dynamics, caused by differing interpretations of source and sink category or other definitions, assumptions, and units, the use of simplified representations with “averaged” values, uncertainty in the basic socioeconomic activity data that drive the calculations, and inherent uncertainty in the scientific understanding of the basic processes leading to emissions and removals. In this study, a proposal of a forest management project was used to identify the main sources of uncertainties in the calculation of the GHG-offset impact. Errors in the calculations were related to (i) classification of land-use/land-cover (LU/LC) types, with observed differences of up to around 8% in land cover estimates, (ii) estimation of C stocks within each LU/LC type, with errors varying from around 13 to 34% in total C stock, (iii) historical evidence of LU/LC changes and related GHG fluxes applied in baselines, giving rise to uncertainties of up to about 16%, whereas varying baseline assumptions produced differences between 31 and 73% in the C mitigation calculations, with levels of uncertainty of up to 74%, and (iv) variation in parameter values to calculate C fluxes generated uncertainties of up to around 10%.

Agroforestry systems: integrated land use to store and conserve carbon

Agroforestry is a promising land use practice to maintain or increase agricultural productivity while preserving or improving fertility. From the perspective of climate change and the global carbon cycle, agroforestry practices are attractive for 2 reasons: they directly store carbon in tree components, and they potentially slow deforestation by reducing the need to clear forest land for agriculture. An extensive literature survey was conducted to evaluate the carbon dynamics of agroforestry practices and to assess their potential to store carbon. Data on tree growth and wood production were converted to estimates of carbon storage. Surveyed literature showed that median carbon storage by agroforestry practices was 9 t C ha-' in semi-arid, 21 t C ha' in sub-humid, 50 t C ha-l in humid, and 63 t C ha-' in temperate ecoregions. The limited survey information available tended to substantiate the concept that implementing agroforestry practices can help reduce deforestation.

Computer-captured expert knowledge to evaluate possibilities for injection of slurry from animal manure in the Netherlands

Surface application of slurry from animal manure substantially contributes to acid deposition in the Netherlands because of volatilization of ammonia. A qualitative physical land evaluation procedure was used to explore the possibilities for slurry injection. Expert knowledge, characteristic for qualitative land evaluation methods, was captured into the Automated Land Evaluation System (ALES) and successfully linked to a geographical information system (GIS) in which a small-scale soil map was stored. Decision trees to assess the physical suitability for slurry injection were developed within ALES. Maps are presented showing the physical suitability of the individual soil units and of agro-statistical regions. The latter were obtained by aggregation. A table is provided with the relative area for each suitability class of the agro-statistical regions. In a number of major Dutch grassland regions less than 40% of the area turned out to be suited for slurry injection, which was judged by the Dutch government to be insufficient for successful incorporation of injection in environmental legislation. A combined use of small-scale soil maps, computer-captured expert knowledge and GIS proved to be very useful in exploring land use options in a reconnaissance stage. Quick results are obtained which reduce the number of possible land use options within a short time. Thus, efforts can be concentrated on promising land use options, probably requiring application of quantitative evaluation methods.

Amazon Basin Soils: Management for Continuous Crop Production

Technology has been developed which permits continuous production of annual crops in some of the acid, infertile soils of the Amazon Basin. Studies in Yurimaguas, Peru, show that three grain crops can be produced annually with appropriate fertilizer inputs. Twenty-one crops have been harvested during the past 8(1/2) years in the same field, with an average annual production of 7.8 tons of grain per hectare. Soil properties are improving with continuous cultivation. The technology has been validated by local farmers, who normally practice shifting cultivation. Economic interpretations indicate large increases in annual family farm income and a high return on the investment of chemical inputs. Other promising land use alternatives include low-input crop production systems, paddy rice production in fertile alluvial soils, and pastures or agroforestry in rolling areas. Stable, continuous food crop production is an attractive alternative to shifting cultivation in humid tropical regions experiencing severe demographic pressures. For each hectare of land managed in a highly productive manner, there may be less need for clearing additional tropical forests to meet food demands.