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Soil-borne plant diseases are increasingly causing devastating losses in agricultural production. The development of a more refined model for disease prediction can aid in reducing crop losses through the use of preventative control measures or soil fallowing for a planting season. The emergence of high-throughput DNA sequencing technology has provided unprecedented insight into the microbial composition of diseased versus healthy soils. However, a single independent case study rarely yields a general conclusion predictive of the disease in a particular soil. Here, we attempt to account for the differences among various studies and plant varieties using a machine-learning approach based on 24 independent bacterial data sets comprising 758 samples and 22 independent fungal data sets comprising 279 samples of healthy or Fusarium wilt-diseased soils from eight different countries. We found that soil bacterial and fungal communities were both clearly separated between diseased and healthy soil samples that originated from six crops across nine countries or regions. Alpha diversity was consistently greater in the fungal community of healthy soils. While diseased soil microbiomes harbored higher abundances of Xanthomonadaceae , Bacillaceae , Gibberella , and Fusarium oxysporum , the healthy soil microbiome contained more Streptomyces Mirabilis , Bradyrhizobiaceae , Comamonadaceae , Mortierella , and nonpathogenic fungi of Fusarium . Furthermore, a random forest method identified 45 bacterial OTUs and 40 fungal OTUs that categorized the health status of the soil with an accuracy >80%. We conclude that these models can be applied to predict the potential for occurrence of F. oxysporum wilt by revealing key biological indicators and features common to the wilt-diseased soil microbiome.

The land use/land cover change is a local driver of environmental change having cascading impacts and implications at the global level, and therefore requires appreciable consideration when perceived from sustainability perspectives. Kerala, the southernmost state of India, has undergone a dramatic transition from a traditional agrarian economy to a modern thriving economy involving the irrational exploitation of natural resources, precisely, land and its components. The present study addresses how land is being changed along an urbanization gradient in the most agglomerative city in the state, Kochi, during the last one and half decades. High-resolution remote sensing data available from the Google Earth Pro pertaining to the four time periods, i.e., 2005, 2010, 2015, and 2020, representing urban, suburban, and rural areas, were analysed to estimate the changes in land use land cover. A semi-structured interview was conducted at the household level to identify the major drivers of land use change. The results indicated the presence of two major and divergent trends; the first one is the intensification of land use activities at the rate of 1.37% per annum, primarily driven by urbanization and infrastructure developments, and the second one is the fallowing and abandonment of land (at the rate of 0.21% per annum) driven by the increased cost of cultivation. The rates of change are more prominent in the rural areas while the urban grids are nearing saturation occupying nearly two-thirds of the area with urban features at the expense of greenery. Though the progression with respect to urbanization and infrastructure developments is expected, the fallowing and abandonment of land is unanticipated, raising serious questions in the developmental pathways to achieve Sustainable Development Goals in the State of Kerala.

Paddy fields are significant anthropogenic sources of methane (CH[sub.4] ) emissions. In southern Brazil, rice is grown in lowland flooded areas once a year, followed by a long fallow period. This study aimed to measure CH[sub.4] fluxes in a rice paddy field in southern Brazil during the rice-growing season of 2015/2016 and the following fallow period. The fluxes were estimated using the eddy covariance (EC) technique and soil chamber (SC). Diurnal and seasonal variations of CH[sub.4] fluxes and potential meteorological drivers were analyzed. The CH[sub.4] fluxes showed distinct diurnal variations in each analyzed subperiod (vegetative, reproductive, pre-harvest, no rice, and land preparation), characterized by a single-peak diurnal pattern. The variables that most influenced methane emissions were air and surface temperatures. In the growing season, the rice vegetative stage was responsible for most of the measured emissions. The accumulated annual emission estimated was 44.88 g CH[sub.4] m[sup.−2] y[sup.−1] , being 64% (28.50 g CH[sub.4] m[sup.−2] ) due to the rice-growing season and 36% (16.38 g CH[sub.4] m[sup.−2] ) due to the fallow period. These results show the importance of including fallow periods in strategies to mitigate methane emissions in flood irrigated rice-growing areas.

Background Climate change poses a threat to the sustainability of food production among small-scale rural communities in Sub-Saharan Africa that are dependent on rain-fed agriculture. Understanding farmers’ adaptations and the determinants of their adaptation strategies is crucial in designing realistic strategies and policies for agricultural development and food security. The main objectives of this study were to identify the adaptation strategies used by smallholder farmers to counter the perceived negative effects of climate change in northern Uganda, and factors influencing the use of specific adaptation strategies. A cross-sectional survey research design was employed to collect data from 395 randomly selected smallholder farmers’ household heads across two districts by the administration of a semi-structured questionnaire. Binary logistic regression was used to analyze the factors influencing farmers’ adaptation to climate change. Results The three most widely practiced adaptation strategies were planting of different crop varieties, planting drought-resistant varieties, and fallowing. Results of the binary logit regression model revealed that marital status of household head, access to credit, access to extension services, and farm income influenced farmers’ adoption of planting drought-resistant varieties as an adaptation strategy while access to credit, annual farm income, and time taken to market influenced adoption of planting improved seeds. Gender of household head and farm income had a positive influence on farmers’ adoption of fertilizer and pesticide use. Farming experience, farm income, and access to extension services and credit influenced farmers’ adoption of tree planting. Household size, farming experience, and time taken to market had positive influence on the use of fallowing, while size of land cultivated significantly influenced farmers’ planting of different crop varieties as an adaptation strategy. Conclusion Findings of the study suggest there are several factors that work together to influence adoption of specific adaptation strategies by smallholder farmers. This therefore calls for more effort from government to strengthen the provision of agricultural extension services by improving its climate information system, providing recommended agricultural inputs and training farmers on best agronomic practices to enhance their holistic adaptation to the effect of climate change.

Cover crops have the potential to be agricultural nitrogen (N) regulators that reduce leaching through soils and then deliver N to subsequent cash crops. Yet, regulating N in this way has proven difficult because the few cover crop species that are well-studied excel at either reducing N leaching or increasing N supply to cash crops, but they fail to excel at both simultaneously. We hypothesized that mixed species cover crop stands might balance the N fixing and N scavenging capabilities of individual species. We tested six cover crop monocultures and four mixtures for their effects on N cycling in an organically managed maize-soybean-wheat feed grain rotation in Pennsylvania, USA. For three years, we used a suite of integrated approaches to quantify N dynamics, including extractable soil inorganic N, buried anion exchange resins, bucket lysimeters, and plant N uptake. All cover crop species, including legume monocultures, reduced N leaching compared to fallow plots. Cereal rye monocultures reduced N leaching to buried resins by 90% relative to fallow; notably, mixtures with just a low seeding rate of rye did almost as well. Austrian winter pea monocultures increased N uptake in maize silage by 40 kg N ha-1 relative to fallow, and conversely rye monocultures decreased N uptake into maize silage by 40 kg N ha-1 relative to fallow. Importantly, cover crop mixtures had larger impacts on leaching reduction than on maize N uptake, when compared to fallow plots. For example, a three-species mixture of pea, red clover, and rye had similar maize N uptake to fallow plots, but leaching rates were 80% lower in this mixture than fallow plots. Our results show clearly that cover crop species selection and mixture design can substantially mitigate tradeoffs between N retention and N supply to cash crops, providing a powerful tool for managing N in temperate cropping systems.

Increasing agricultural productivity while ensuring environmental sustainability are two important targets in achieving the sustainable development goals under climatic shocks. In this regard, different climate-smart agricultural (CSA) practices have been recommended and promoted to meet these goals and targets. However, the adoption of these practices remains low and variable. For the most part, low adoption has been attributed to external factors. Behavioural and psychological factors also matter but have received little empirical and policy attention. In this study, we examine the relationship between aspirations, aspiration gaps, and the adoption of CSA practices such as crop rotation, intercropping, fallowing, and organic soil amendments. Employing parametric and non-parametric estimation techniques on a pooled farm household survey from Cameroon and Kenya, we show that aspirations are associated with the use of crop rotation and organic soil amendments. We also investigate the theorized non-monotonic inverse U-shaped relationship between aspiration gaps and investments. We find evidence of this relationship for the adoption of these CSA practices, suggesting an aspiration failure for smallholder farmers. These results imply that aspirations that are ahead but not too far ahead of the current state serve as the best incentives for stimulating the adoption of CSA practices. Employing the multivariate probit model, we further highlight interdependencies in the use of these CSA practices. Specifically, we underscore significant complementarities, suggesting the bundled use of these practices. Overall, the analysis demonstrates that aspirations matter for farmer decision-making with many implications for agricultural, food, and environmental policies.

Cassava ( Manihot esculenta Crantz) is an important crop for humans due to its staple and industrial values. Currently the demand is more than the supply as the current output falls below the expected. This necessitated the breeding of superior genotypes that are high yielding. These superior genotypes also requires a fertile soil for optimum production. However, this has been primarily achieved through the application of organic manures and inorganic fertilizers. It is then important to evaluate four newly released cassava varieties in an organically enriched soil relative to the local best variety. Four newly released cassava varieties, Hope, Obasanjo2, Baba 70, and Game changer, and one Local Best (LB) was planted in 5-years fallowed farm lands at three plots (A, B and C) for 2 seasons. It was a three-way factorial (5-varieties*3-farms*2-seasons) arranged in a randomized complete block design and replicated three times. Data were taken on the Fresh Tuber Weight (FTW) and Stem Height (SH) per variety, and pre and post soil status. Data were analyzed using analysis of variance, while differences in varietal means were separated using least significant differences at 5% level of significance. The FTW and SH differed significantly across varieties, years and interaction between variety, farms and year, and ranged from 19.2 ± 0.5 (LB) to 41.0 ± 0.5 (Obasanjo2), 32.1 ± 0.4 (farm C) to 34.1 ± 0.4 (farm A), 30.4 ± 0.3 (year two) to 35.0 ± 0.3 (year one), and the interactions between variety and year, farms and year, and variety, year and farms were significant. The soil macro and micro elements declined in the post relative to the pre status. The fresh yield of the improved varieties Baba70, Game change, Hope and Obasanjo2 was 74%, 80.8%, 81%, and 113% higher than the local best, respectively. Yield declined in the second season due to decline inherent soil nutrient hitherto compensated by shifting cultivation in the farming community.

We examine the impact of ambiguous and contested land rights on investment and productivity in agriculture in Akwapim, Ghana. We show that individuals who hold powerful positions in a local political hierarchy have more secure tenure rights and that as a consequence they invest more in land fertility and have substantially higher output. The intensity of investments on different plots cultivated by a given individual corresponds to that individual's security of tenure over those specific plots and, in turn, to the individual's position in the political hierarchy relevant to those specific plots.

High soil strength is a problem in grain production systems worldwide. It is most severe in deep sands where the high strength occurs at greater depth, and is therefore more difficult to remedy. High strength is not an intrinsic soil physical property but the outcome of abiotic, biotic, climatic and management factors. Consequently, soil strength needs to be measured in situ with a penetrometer which, despite imperfections, provides approximate benchmarks. Following examination of laboratory, glasshouse and field literature, we hypothesise that the primary effect of high soil strength on crops is a reduction in tillering or branching, resulting in reduced radiation interception, crop transpiration and grain density (grains m− 2). This effect appears to be manifest via strigolactone hormones. While deep tillage allows deeper root growth and access to more water in deep soil layers, we contend that it is the direct effects of hormones on shoot development which has the largest effect on yield. The development of high soil strength cropping environments is not simply a function of soil properties and increased machinery mass and traffic frequency, it arises from a confluence of these with the farming system, the climate and perhaps plant breeding activities. An improved understanding of the relative importance of the unintended consequences of breeding, the effects of changes in fallowing practices, crop rotation, soil fertility, climate and traffic, along with a better understanding of the possible importance of bio- and macropores types provide avenues for improved management of high soil strength in grain crop production systems.

Irrigated agriculture dominates freshwater consumption globally, but crop production and farm revenues suffer when water supplies are insufficient to meet irrigation needs. In the United States, the mismatch between irrigation demand and freshwater availability has been exacerbated in recent decades due to recurrent droughts, climate change and overextraction that dries rivers and depletes aquifers. Yet, there has been no spatially detailed assessment of the potential for shifting to new crop mixes to reduce crop water demands and alleviate water shortage risks. In this study, we combined modelled crop water requirements and detailed agricultural statistics within a national hydrological model to quantify sub-basin-level river depletion, finding high-to-severe levels of irrigation scarcity in 30% of sub-basins in the western United States, with cattle-feed crops—alfalfa and other hay—being the largest water consumers in 57% of the region’s sub-basins. We also assessed recent trends in irrigation water consumption, crop production and revenue generation in six high-profile farming areas and found that in recent decades, water consumption has decreased in four of our study areas—a result of a reduction in the irrigated area and shifts in the production of the most water-consumptive crops—even while farm revenues increased. To examine the opportunities for crop shifting and fallowing to realize further reductions in water consumption, we performed optimizations on realistic scenarios for modifying crop mixes while sustaining or improving net farm profits, finding that additional water savings of 28–57% are possible across our study areas. These findings demonstrate strong opportunities for economic, food security and environmental co-benefits in irrigated agriculture and provide both hope and direction to regions struggling with water scarcity around the world.Farmer livelihoods and food production are impacted by water shortages in many regions globally. These shortages can be mitigated by changing the mix of crops produced in water-scarce regions, potentially resulting in reduced irrigation needs of 28–57%.