Improving diet quality while simultaneously reducing environmental impact is a critical focus globally. Metrics linking diet quality and sustainability have typically focused on a limited suite of ...indicators, and have not included food waste. To address this important research gap, we examine the relationship between food waste, diet quality, nutrient waste, and multiple measures of sustainability: use of cropland, irrigation water, pesticides, and fertilizers. Data on food intake, food waste, and application rates of agricultural amendments were collected from diverse US government sources. Diet quality was assessed using the Healthy Eating Index-2015. A biophysical simulation model was used to estimate the amount of cropland associated with wasted food. This analysis finds that US consumers wasted 422g of food per person daily, with 30 million acres of cropland used to produce this food every year. This accounts for 30% of daily calories available for consumption, one-quarter of daily food (by weight) available for consumption, and 7% of annual cropland acreage. Higher quality diets were associated with greater amounts of food waste and greater amounts of wasted irrigation water and pesticides, but less cropland waste. This is largely due to fruits and vegetables, which are health-promoting and require small amounts of cropland, but require substantial amounts of agricultural inputs. These results suggest that simultaneous efforts to improve diet quality and reduce food waste are necessary. Increasing consumers' knowledge about how to prepare and store fruits and vegetables will be one of the practical solutions to reducing food waste.
Nematodes are aquatic organisms that depend on thin water films to live and move within existing pathways of soil pores of 25-100 mum diameter. Soil nematodes can be a tool for testing ecological ...hypotheses and understanding biological mechanisms in soil because of their central role in the soil food web and linkage to ecological processes. Ecological succession is one of the most tested community ecology concepts, and a variety of nematode community indices have been proposed for purposes of environmental monitoring. In contrast, theories of biogeography, colonization, optimal foraging, and niche partitioning by nematodes are poorly understood. Ecological hypotheses related to strategies of coexistence of nematode species sharing the same resource have potential uses for more effective biological control and use of organic amendments to foster disease suppression. Essential research is needed on nematodes in natural and agricultural soils to synchronize nutrient release and availability relative to plant needs, to test ecological hypotheses, to apply optimal foraging and niche partitioning strategies for more effective biological control, to blend organic amendments to foster disease suppression, to monitor environmental and restoration status, and to develop better predictive models for land-use decisions.
Compost production is a critical component of organic waste handling, and compost applications to soil are increasingly important to crop production. However, we know surprisingly little about the ...microbial communities involved in the composting process and the factors shaping compost microbial dynamics. Here, we used high-throughput sequencing approaches to assess the diversity and composition of both bacterial and fungal communities in compost produced at a commercial-scale. Bacterial and fungal communities responded to both compost recipe and composting method. Specifically, bacterial communities in manure and hay recipes contained greater relative abundances of Firmicutes than hardwood recipes with hay recipes containing relatively more Actinobacteria and Gemmatimonadetes. In contrast, hardwood recipes contained a large relative abundance of Acidobacteria and Chloroflexi. Fungal communities of compost from a mixture of dairy manure and silage-based bedding were distinguished by a greater relative abundance of Pezizomycetes and Microascales. Hay recipes uniquely contained abundant Epicoccum, Thermomyces, Eurotium, Arthrobotrys, and Myriococcum. Hardwood recipes contained relatively abundant Sordariomycetes. Holding recipe constant, there were significantly different bacterial and fungal communities when the composting process was managed by windrow, aerated static pile, or vermicompost. Temporal dynamics of the composting process followed known patterns of degradative succession in herbivore manure. The initial community was dominated by Phycomycetes, followed by Ascomycota and finally Basidiomycota. Zygomycota were associated more with manure-silage and hay than hardwood composts. Most commercial composters focus on the thermophilic phase as an economic means to insure sanitation of compost from pathogens. However, the community succeeding the thermophilic phase begs further investigation to determine how the microbial dynamics observed here can be best managed to generate compost with the desired properties.
Infections of the cow udder leading to mastitis and reducing milk quality are a critical challenge facing all dairy farmers. Mastitis may be linked to the ecological disruption of an endogenous ...mammary microbial community, suggesting an ecosystems approach to management and prevention of this disease. The teat end skin represents a first point of host contact with mastitis pathogens and may offer an opportunity for microbially mediated resistance to infection, yet we know little about the microbial community of teat end skin or its potential interaction with the microbial community of intramammary milk of organic dairy cattle. High-throughput sequencing of marker genes for bacterial and fungal communities was used to characterize the skin and milk microbiome of cows with both a healthy and infected gland (i.e., udder quarter) and to assess the sharing of microbial DNA between these tissue habitat sites. The mammary microbiome varied among cows, through time, and between skin and milk. Microbiomes of milk from healthy and infected quarters reflected a diverse group of microbial DNA sequences, though milk had far fewer operational taxonomic units (OTUs) than skin. Milk microbiomes of infected quarters were generally more variable than healthy quarters and were frequently dominated by a single OTU; teat end skin microbiomes were relatively similar between healthy and infected quarters. Commonly occurring genera that were shared between skin and milk of infected glands included Staphylococcus spp. bacteria and Debaryomyces spp. fungi. Commonly occurring genera that were shared between skin and milk of healthy glands included bacteria SMB53 (Clostridiaceae) and Penicillium spp. fungi. Results support an ecological interpretation of the mammary gland and the notion that mastitis can be described as a dysbiosis, an imbalance of the healthy mammary gland microbiome.
► Cultivation reduced abundances of Diphtherophora, Prismatolaimus and Tylenchorhynchus. ► Application of synthetic chemical fertilizers reduced numbers of Plectus. ► Organic fertilization increased ...numbers of Cruznema, Mesorhabditus, Mesodorylaimus and Nygolaimus. ► These genera are potential indicators that can be used by non-specialists.
Nematode community indices would be more cost-effective and interpretable if ambiguous genera were removed and indices reduced to only genera with known sensitivity or response to specific types of disturbance. The objective of the present study was to perform a methodical multivariate analysis of existing datasets of high quality and enumerate the genera that respond universally consistent to a specific type of disturbance, treatment, or management worldwide. We collected 20 sources of original data from land used for agricultural purposes, whether cropland, livestock grazing or fruit orchard with manipulated treatments in cultivation, inorganic or organic fertilization or contaminated by heavy metals. Canonical correspondence analysis was performed to determine the effect of disturbance type on the composition of soil nematode communities. Genera that performed consistently in a single direction and across at least two seasons were identified. Briefly, cultivation reduced abundances of Diphtherophora, Prismatolaimus and Tylenchorhynchus. Application of synthetic chemical fertilizers reduced numbers of Plectus. Application of organic fertilizers resulted in increased numbers of Cruznema, Mesorhabditus, Mesodorylaimus and Nygolaimus. No genera met the criteria for responding positively to either cultivation or inorganic fertilization or negatively to organic fertilization. The source of nutrients apparently affected nematode communities differently. Selected nematode genera were correlated positively with the heavy metals Cd, Cu and Zn, while nematode genera correlated negatively with Cr and Se. These genera need to be verified by independent data to confirm that they respond predictably and consistently to these specific types of disturbance. Once verified, this subset of genera will improve interpretation of index values and can be the initial targets for developing molecular probes that can be made accessible to non-specialists.
Two desirable functions of healthy soil are nutrient cycling and pest suppression. We review relevant literature on the contributions of soil microarthropods to soil health through their intersecting ...roles in decomposition and nutrient cycling and direct and indirect suppression of plant pests. Microarthropods can impact soil and plant health directly by feeding on pest organisms or serving as alternate prey for larger predatory arthropods. Indirectly, microarthropods mediate the ability of crop plants to resist or tolerate insect pests and diseases by triggering induced resistance and/or contributing to optimal nutritional balance of plants. Soil fauna, including microarthropods, are key regulators of decomposition at local scales but their role at larger scales is unresolved. Future research priorities include incorporating multi-channel omnivory into food web modeling and understanding the vulnerability of soil carbon through global climate change models.
Nutrient availability greatly regulates ecosystem processes and functions of tropical forests. However, few studies have explored impacts of N addition (aN), P addition (aP) and N × P interaction on ...tropical forests N₂O fluxes. We established an N and P addition experiment in a tropical forest to test whether: (1) N addition would increase N₂O emission and nitrification, and (2) P addition would increase N₂O emission and N transformations. Nitrogen and P addition had no effect on N mineralization and nitrification. Soil microbial biomass was increased following P addition in wet seasons. aN increased 39% N₂O emission as compared to control (43.3 μgN₂O-N m(-2)h(-1)). aP did not increase N₂O emission. Overall, N₂O emission was 60% greater for aNP relative to the control, but significant difference was observed only in wet seasons, when N₂O emission was 78% greater for aNP relative to the control. Our results suggested that increasing N deposition will enhance soil N₂O emission, and there would be N × P interaction on N₂O emission in wet seasons. Given elevated N deposition in future, P addition in this tropical soil will stimulate soil microbial activities in wet seasons, which will further enhance soil N₂O emission.
Invasive plants affect soil food webs through various resource inputs including shoot litter, root litter and living root input. The net impact of invasive plants on soil biota has been recognized; ...however, the relative contributions of different resource input pathways have not been quantified. Through a 2 × 2 × 2 factorial field experiment, a pair of invasive and native plant species (Spartina alterniflora vs. Phragmites australis) was compared to determine the relative impacts of their living roots or shoots and root litter on soil microbial and nematode communities. Living root identity affected bacteria-to-fungi PLFA ratios, abundance of total nematodes, plant-feeding nematodes and omnivorous nematodes. Specifically, the plant-feeding nematodes were 627% less abundant when living roots of invasive S. alterniflora were present than those of native P. australis. Likewise, shoot and root biomass (within soil at 0–10 cm depth) of S. alterniflora was, respectively, 300 and 100% greater than those of P. australis. These findings support the enemy release hypothesis of plant invasion. Root litter identity affected other components of soil microbiota (that is, bacterial-feeding nematodes), which were 34% more abundant in the presence of root litter of P. australis than S. alterniflora. Overall, more variation associated with nematode community structure and function was explained by differences in living roots than root or shoot litter for this pair of plant species sharing a common habitat but contrasting invasion degrees. We conclude that belowground resource input is an important mechanism used by invasive plants to affect ecosystem structure and function.
Diverting food waste from landfills to composting or anaerobic digestion can reduce greenhouse gas emissions, enable the recovery of energy in usable forms, and create nutrient‐rich soil amendments. ...However, many food waste streams are mixed with plastic packaging, raising concerns that food waste‐derived composts and digestates may inadvertently introduce microplastics into agricultural soils. Research on the occurrence of microplastics in food waste‐derived soil amendments is in an early phase and the relative importance of this potential pathway of microplastics to agricultural soils needs further clarification. In this paper, we review what is known and what is not known about the abundance of microplastics in composts, digestates, and food wastes and their effects on agricultural soils. Additionally, we highlight future research needs and suggest ways to harmonize microplastic abundance and ecotoxicity studies with the design of related policies. This review is novel in that it focuses on quantitative measures of microplastics in composts, digestates, and food wastes and discusses limitations of existing methods and implications for policy.
Core Ideas
Microplastic presence is documented in composts, digestates, and food wastes.
Lack of standardized methods for these materials complicates comparison between studies.
Existing regulations establish w/w limits on contamination which is inconsistent with many studies.
Focus on maximizing benefits of food waste diversion and minimizing risk of microplastic pollution is needed.
The primary objective of this cross-sectional observational study was to determine whether bulk tank milk quality, udder health, udder hygiene and milk production outcomes were associated with ...facility type on organic dairies. A secondary objective was to identify other management-related risk factors associated with bulk tank milk quality, udder health, udder hygiene, and milk production on organic dairy herds in Vermont. We aimed to enroll 40 farms, to compare herds using the 2 most common systems (freestalls, tiestalls) for housing organic dairy cattle in the state with those using a bedded pack during the non-grazing season (typically November–May). Two general styles of bedded packs were observed: cultivated bedded packs and untilled deep bedded packs. Due to the limited number of herds using bedded packs to house lactating dairy cattle in Vermont, we combined untilled and cultivated bedded packs to describe udder hygiene, milk quality, and udder health on these loose-housing systems deeply-bedded with organic material. The study was completed on 21 farms (5 bedded packs, 6 freestalls, 10 tiestalls) before interruption due to the COVID-19 pandemic. Data captured from Dairy Herd Improvement Association records from the test closest to the date of the farm visit included average somatic cell score (SCS), standardized 150-d milk (pounds), % cows with current high SCS (SCS ≥ 4.0), % cows with newly elevated SCS (previous SCS < 4.0 to current ≥ 4.0), and % cows with chronically elevated SCS (SCS ≥ 4.0 last 2 tests). Multivariable linear regression models were used to describe outcomes by facility type, but suffered from limited statistical power due to small group sample sizes. Unconditional comparisons failed to find statistically significant differences between farms grouped by facility type in metrics captured from Dairy Herd Improvement Association test data, bulk tank milk somatic cell count (BTSCC) and aerobic culture data, or udder hygiene scores. A secondary analysis was conducted using univariate linear regression to identify associations between herd management factors and outcomes for all 21 farms combined. Although not all differences found were statistically significant in this secondary analysis combining all farms, numeric differences that may be biologically important are reported showing farms with deeper bedding had a lower BTSCC, lower newly elevated SCS, lower chronically elevated SCS, lower elevated current SCS, lower average SCS, and better udder hygiene metrics. Farms with lower mean udder hygiene scores had numerically lower chronically elevated SCS, lower elevated current SCS, and lower average SCS. We could not reject the null hypothesis that milk quality and udder health outcomes did not differ by facility type, and this does not preclude the existence of biological differences in these outcomes between facility types. The current study provides insight on factors affecting bulk tank milk quality, udder health and hygiene measures on organic dairy farms in Vermont. Bedded packs may be a viable option for confinement housing during the winter non-grazing season for pasture-based herds interested in a loose-housing system in the Northeastern US, but more research such as longitudinal studies with a larger sample size is needed to test this hypothesis.
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