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This article explores the use of field experimentation in presenting an account of input inventory, material quantities, and the process flow for shea butter production in Ghana. The shea fruit is a non-timber forest product (NTFP) that is indigenous to ecosystems in semi-arid regions of Africa. Current methods and equipment for processing shea kernel into butter impose a dilemma of excessive harvesting of fuel wood for heating and the use of large quantities of water. Thus, the nature of input requirement and production process presents implications for conflict over natural resource use and for sustainability as more processing takes place. Material flow analysis was applied to the data generated from the processing experiments. The outcome was discussed in focus group discussion sessions and individual interviews as a way of data triangulation to validate study parameters. Results from this experiment showed that the quantity of water used in urban processing sites was higher than that used in rural sites. On the other hand, fuel wood use and labor expended were found to be higher in rural sites per unit processing cycle. The nature of the processing equipment, accessibility to input resources, and target market for shea butter were key determinants of the varying resource quantities used in the production process.

Phosphate-solubilising microorganisms (PSM) are often reported to have positive effects on crop productivity through enhanced phosphorus (P) nutrition. Our aim was to evaluate the validity of this concept. Most studies that report ‘positive effects’ of PSM on plant growth have been conducted under controlled conditions, whereas field experiments more frequently fail to demonstrate a positive response. Many studies have indicated that the mechanisms seen in vitro do not translate into improved crop P nutrition in complex soil–plant systems. Furthermore, associated mechanisms are often not rigorously assessed. We suggest that PSM do not mobilise sufficient P to change the crops’ nutritional environment under field conditions. The current concept, in which PSM solubilise P ‘for the plant’ should thus be revised. Although PSM have the capacity to solubilise P to meet their own needs, it is the turnover of the microbial biomass that subsequently provides P to plants over a longer time. Therefore, the existing concept of PSM function is unlikely to deliver a reliable strategy for increasing crop P nutrition. A further mechanistic understanding is needed to determine how P mobilisation by PSM as a component of the whole soil community can be manipulated to become more effective for plant P nutrition.

Laboratory experiments are a widely used methodology for advancing causal knowledge in the physical and life sciences. With the exception of psychology, the adoption of laboratory experiments has been much slower in the social sciences, although during the past two decades the use of lab experiments has accelerated. Nonetheless, there remains considerable resistance among social scientists who argue that lab experiments lack \"realism\" and generalizability. In this article, we discuss the advantages and limitations of laboratory social science experiments by comparing them to research based on nonexperímental data and to field experiments. We argue that many recent objections against lab experiments are misguided and that even more lab experiments should be conducted.

Late wilt disease, caused by Cephalosporium maydis in maize plant, is one of the main economical diseases in Egypt . Therefore, to cope with this problem, we investigated the potentiality of plant growth promoting rhizobacteria in controlling this disease. Six strains ( Bacillus subtilis , B. circulance , B. coagulanse, B. licheniformis , Pseudomonas fluroscence and P. koreensis ) were screened for siderophore production, and using dual plate culture method and greenhouse experiment, antagonistic activity against C. maydis was studied. Using two superior strains, single and dual inoculation treatments in maize were applied in field experiment during the 2018 and 2019 seasons. Results indicated that B. subtilis and P. koreensis strains had shown the most qualitative and quantitative assays for siderophore production and antagonistic activities. In greenhouse, the most effective treatments on the pre- and post-emergence damping off as well as growth promotion of maize were T3 treatment (inoculated with B. subtilis ), and T8 treatment (inoculated with P. koreensis ). In field experiment, T5 treatment (inoculated with a mixture of B. subtilis and P. koreensis ) showed significant increases in catalase (CAT), peroxidase (POX) and polyphenol oxidase (PPO) activities, as well as total chlorophyll and carotenoids than control treatments during the two growing seasons. In the same way, the highest effect in reducing infection and increasing the thickness of the sclerenchymatous sheath layer surrounding the vascular bundles in maize stem was observed and these results were a reflection of the increase in yield and yield parameters.

ContextGrasslands provide a variety of ecosystem services (ESs) for humans. While much ES research has focused on forests and wetlands, synthesizing the currently somewhat sporadic studies of grassland ecosystem services (GESs) is much needed.ObjectivesWe aimed to review the scope, major methods, and key findings of GESs, and identify knowledge gaps and future directions.MethodsWe conducted a systematic review of articles published during 1970–2018 (including 380 peer-reviewed articles from Web of Science and 32 book chapters from Google Scholar).ResultsThe number of GES studies has accelerated in recent decades, with China (31%) and the United States (18%) together accounting for almost half of them. A total of 33 GESs were mentioned in the searched articles, of which carbon sequestration, forage production, and water erosion control had the highest frequencies. Methods for evaluating GESs include field survey, field experiments, and statistical and process-based modeling. Grasslands are the primary source of meat and dairy products, account for about one-third of the total carbon of all terrestrial ecosystems, and provide numerous other ESs, such as night cooling, soil erosion control, and flood mitigation.ConclusionsThis review presents the state-of-the-science of GESs, and identifies several future research directions. To move forward, we propose a framework with a 3-M methodology: (1) “Multi-scales”—understanding GESs from various spatiotemporal scales; (2) “Multi-methods”—evaluating GESs with multiple statistical and modeling techniques using multiple data sources; and (3) “Multi-perspectives”—assessing GESs from ecological, social, and economic perspectives for sustainability.

Soil organic carbon (SOC) is primarily formed from plant inputs, but the relative carbon (C) contributions from living root inputs (i.e. rhizodeposits) vs litter inputs (i.e. root + shoot litter) are poorly understood. Recent theory suggests that living root inputs exert a disproportionate influence on SOC formation, but few field studies have explicitly tested this by separately tracking living root vs litter inputs as they move through the soil food web and into distinct SOC pools. We used a manipulative field experiment with an annual C4 grass in a forest understory to differentially track its living root vs litter inputs into the soil and to assess net SOC formation over multiple years. We show that living root inputs are 2–13 times more efficient than litter inputs in forming both slow-cycling, mineral-associated SOC as well as fast-cycling, particulate organic C. Furthermore, we demonstrate that living root inputs are more efficiently anabolized by the soil microbial community en route to the mineral-associated SOC pool (dubbed ‘the in vivo microbial turnover pathway’). Overall, our findings provide support for the primacy of living root inputs in forming SOC. However, we also highlight the possibility of nonadditive effects of living root and litter inputs, which may deplete SOC pools despite greater SOC formation rates.

• Despite widespread anthropogenic nutrient enrichment, it remains unclear how nutrient enrichment influences plant–arbuscular mycorrhizal fungi (AMF) symbiosis and ecosystem multifunctionality at the global scale. • Here, we conducted a meta-analysis to examine the worldwide effects of nutrient enrichment on AMF and plant diversity and ecosystem multifunctionality using data of field experiments from 136 papers. • Our analyses showed that nutrient addition simultaneously decreased AMF diversity and abundance belowground and plant diversity aboveground at the global scale. The decreases in AMF diversity and abundance associated with nutrient addition were more pronounced with increasing experimental duration, mean annual temperature (MAT) and mean annual precipitation (MAP). Nutrient addition-induced changes in soil pH and available phosphorus (P) predominantly regulated the responses of AMF diversity and abundance. Furthermore, AMF diversity correlated with ecosystem multifunctionality under nutrient addition worldwide. • Our findings identify the negative effects of nutrient enrichment on AMF and plant diversity and suggest that AMF diversity is closely linked with ecosystem function. This study offers an important advancement in our understanding of plant–AMF interactions and their likely responses to ongoing global change.

Culturomics is an emerging field of study that seeks to understand human culture through the quantitative analysis of changes in word frequencies in large bodies of digital texts. Culturomics research can help practitioners in nature conservation respond to cultural trends, building and reinvigorating its societal relevance. We identify five areas where culturomics can be used to advance the practice and science of conservation: (1) recognizing conservation‐oriented constituencies and demonstrating public interest in nature, (2) identifying conservation emblems, (3) providing new metrics and tools for near‐real‐time environmental monitoring and to support conservation decision making, (4) assessing the cultural impact of conservation interventions, and (5) framing conservation issues and promoting public understanding. More generally, culturomics opens up an exciting new area of research, equipping conservationists with novel tools to explore and shape human interactions with the natural world.

• Trees may survive prolonged droughts by shifting water uptake to reliable water sources, but it is unknown if the dominant mechanism involves activating existing roots or growing new roots during drought, or some combination of the two. • To gain mechanistic insights on this unknown, a dynamic root-hydraulic modeling framework was developed that set up a feedback between hydraulic controls over carbon allocation and the role of root growth on soil–plant hydraulics. The new model was tested using a 5 yr drought/heat field experiment on an established piñon-juniper stand with root access to bedrock groundwater. • Owing to the high carbon cost per unit root area, modeled trees initialized without adequate bedrock groundwater access experienced potentially lethal declines in water potential, while all of the experimental trees maintained nonlethal water potentials. Simulated trees were unable to grow roots rapidly enough to mediate the hydraulic stress, particularly during warm droughts. Alternatively, modeled trees initiated with root access to bedrock groundwater matched the hydraulics of the experimental trees by increasing their water uptake from bedrock groundwater when soil layers dried out. • Therefore, the modeling framework identified a critical mechanism for drought response that required trees to shift water uptake among existing roots rather than growing new roots.

Arbuscular mycorrhizal fungi (AMF) are ubiquitous in agroecosystems and often stated to be critical for crop yield and agroecosystem sustainability. However, should farmers modify management to enhance the abundance and diversity of AMF? We address this question with a focus on field experiments that manipulated colonisation by indigenous AMF and report crop yield, or investigated community structure and diversity of AMF. We find that the literature presents an overly optimistic view of the importance of AMF in crop yield due, in part, to flawed methodology in field experiments. A small body of rigorous research only sometimes reports a positive impact of high colonisation on crop yield, even under phosphorus limitation. We suggest that studies vary due to the interaction of environment and genotype (crop and mycorrhizal fungal). We also find that the literature can be overly pessimistic about the impact of some common agricultural practices on mycorrhizal fungal communities and that interactions between AMF and soil microbes are complex and poorly understood. We provide a template for future field experiments and a list of research priorities, including phosphorus-efficient agroecosystems. However, we conclude that management of AMF by farmers will not be warranted until benefits are demonstrated at the field scale under prescribed agronomic management.