Sheath blight (ShB) caused by Rhizoctonia solani Kühn is one of the most serious diseases in rice and is highly susceptible to climate and environmental influences, high humidity climate conditions combined with higher temperatures often lead to more severe occurrences of ShB. The heterotrophic R. solani and rice might compete for sugar at the border of interaction; however, the underlying mechanism remains unclear. In this study, we demonstrated that the expression level of Sugar will eventually be exported transporters (SWEETs) induction was higher in ShB susceptible varieties than in ShB resistant varieties by R. solani inoculation. Inoculation of R. solani revealed that most sweet mutants were less susceptible to ShB than the wild-type. Also, sugar transporters (STPs) gene expression was sensitive to R. solani infection. STPs were localized at the plasma membrane and transported hexose in yeast. Knockdown of STP4 increased the susceptibility of rice to ShB. Interestingly, sequence analysis identified two monosaccharide transporter genes (hereafter named RsMST). RsMSTs transported 2-deoxyglucose, a toxic glucose analog in yeast, suggesting their role as glucose transporter. Spray-induced gene silencing of RsMST1 or RsMST2 dramatically suppressed their expression level and reduced virulence of R. solani. These data suggested that R. solani might induce SWEETs to efflux sugar from the cytosol to apoplast, and STP and RsMSTs compete for sugar at the apoplast for host defense and pathogen virulence. This study provided important insights for ShB-resistant breeding in rice.
Rain-fed potato (Solanum tuberosum) fields in drylands significantly contribute to nitrous oxide (N2O) emissions, making them an important focus of agricultural greenhouse gas research. Film mulching and ridging are key agricultural methods in potato cultivation. Investigating the impact of these methods on N2O emissions, nitrifying/denitrifying functional genes, and microbial communities can provide a theoretical basis for soil emission reduction and more sustainable dryland agriculture. We examine the effects of flat tillage with mulching, ridge tillage with mulching, flat tillage without mulching, and ridge tillage without mulching, on potato fields under natural rainfall conditions in Wuchuan County, China. N2O emission fluxes were monitored using a static (dark) chamber and gas chromatography. Real-time quantitative PCR (q-PCR) was used to quantify abundances of nitrifying and denitrifying bacteria related to N2O emissions at various potato-growth stages. Illumina high-throughput sequencing was used to investigate microbial community structure by targeting 16S rRNA genes; related soil elements (soil temperatures and moisture) are analyzed. Mulching and ridging indirectly influence N2O emissions, nitrifying/denitrifying functional gene copy numbers, and microbial community structure by altering soil temperature and moisture. Cumulative N2O emissions and emission intensity were both consistently higher in ridge tillage with mulching during the potato-growing period. Ammonia-oxidizing archaea are the main microorganisms that control N2O emissions, with nitrification-coupled denitrification also being an important mechanism contributing to high N2O emissions during soil dry–wet cycles. Increased soil temperature and moisture elevated N2O emissions and functional gene copy numbers. The combination of mulching and ridging effectively uses the characteristics of both practices, making Nitrospira the dominant genus, and significantly increases N2O emissions.
Continuous and accurate monitoring of agricultural landscapes is crucial for understanding crop phenology and responding to climatic and anthropogenic changes. However, the widely used optical satellite remote sensing is limited by revisit cycles and weather conditions, leading to gaps in agricultural monitoring. To address these limitations, we designed and deployed a Near Surface Camera (NSCam) Network across China, and explored its application in agricultural land monitoring and achieving climate-smart agriculture (CSA). By analyzing the image data captured by the NSCam Network, we can accurately assess long-term or abrupt agricultural land changes. According to the preliminary monitoring results, integrating NSCam data with remote sensing imagery greatly enhances the temporal details and accuracy of agricultural monitoring, aiding agricultural managers in making informed decisions. The impacts of abnormal weather conditions and human activities on agricultural land, which are not captured by remote sensing imagery, can be complemented by incorporating our NSCam Network. The successful implementation of this method underscores its potential for broader application in CSA, promoting resilient and sustainable agricultural practices.
Improving smallholder farmers' adaptive capacity to climate change has become a major concern of governments and development agencies. Adaptive capacity determines the inherent ability of a system to cope with vulnerability to climate change. This paper used cross sectional survey data of 737 livestock producing households to assess determinants of adaptive capacity among Arid and Semi-Arid (ASAL) communities in Kenya. Specifically, we focused on the role of entrepreneurship orientation (risk taking, proactiveness and innovativeness) and uptake of climate smart agricultural (CSA) practices in improving adaptive capacity – a dimension which has received limited research attention. Adaptive capacity was measured using a set of indicators representing the five capitals in the Sustainable Livelihood Framework (SLF). The determinants of adaptive capacity were analyzed using fractional and censored regression models. The results revealed mixed influence of entrepreneurship orientation on adaptive capacity. While risk taking and proactiveness were positively associated with a higher adaptive capacity, innovativeness did not have any influence. Similarly, uptake of livestock CSA practices was associated with a higher level of adaptive capacity. Other factors that positively influenced adaptive capacity were age, gender, education level, diversity of income, access to extension services, credit, and collective action. The findings suggest that a strategy to promote entrepreneurial orientation, uptake of CSA, accumulation of human and financial capital would enhance livestock producers’ adaptive capacity.
Soil organic carbon (SOC) dynamics under elevated atmospheric CO2 concentration has been widely reported, however, in which the behaviors of active and passive fractions remain inadequately explored. Here we studied this issue using three pairs of active and passive fractions of SOC under a 10-year free-air CO2 enrichment experiment (550 ± 17 ppm) in a cropland in the North China Plain. We found that decadal elevated CO2 increased the root biomass, root exudation rate and microbial biomass, but had little effects on SOC pool size. Elevated CO2 increased the readily oxidizable organic carbon (ROOC) and particulate organic carbon (POC) due to the increments of root C input, but decreased their paired passive fractions possibly because of the carbon input-induced positive priming effect. Our results indicate the reduced stability of SOC pool under elevated CO2. This is significant for better predicting SOC feedback to future climate change.
To mitigate the impact of climate change, farmers are increasingly opting for more efficient energy allocation in agricultural production. This study aims to evaluate the effectiveness of these methods employed by maize growers in Benin, while identifying the constraints associated with their implementation. A survey was conducted among 230 maize growers in Benin to achieve the objectives of the study. The Data Envelopment Analysis method was utilized to measure farmers' technical efficiency, followed by the application of the Tobit model to identify the factors determining this efficiency. The comparative analysis of efficiency indices reveals that farmers who prioritize increased utilization of agricultural inputs exhibit higher levels of technical efficiency while maintaining constant yields. In terms of technical efficiency at varying yields, farmers who increase their labor input demonstrate the highest level of efficiency. Subsequently, farmers who choose to augment the quantities of agricultural inputs exhibit greater scale efficiency. The Tobit model reveals that age, experience, maize production area, utilization of insecticides and NPK fertilizers are significant determinants influencing the efficiency levels of maize growers. Maize growers encounter challenges in accessing improved maize seeds and agricultural machinery, as well as facing financial constraints.
In the Everglades Agricultural Area (EAA), Florida, cultivating rice in flooded paddies is becoming increasingly popular to conserve water and soil health. Flood depth is a critical factor affecting the discharged water quality, soil carbon, and yield production. However, few studies have comprehensively investigated the optimal flood depth in EAA, considering multi-functional indices. To address this gap, we investigated drainage water quality, water quantity, nutrient uptake, soil carbon, and rice yield in rice paddies in histosol soils over a two-year period at four flood depths (5, 10, 15, and 20 cm). For each flood depth, averaged over two years, total outflow loadings of suspended solids, nitrogen, phosphorus, and potassium were significantly reduced by 40 %, 38 %, 36 %, and 32 %, respectively, compared to inflow water loadings (p < 0.001). Total phosphorus uptake averaged ∼11.21 kg ha−1 in rice shoots and 0.48 kg ha−1 in roots, while total potassium uptake averaged ∼4.28 kg ha−1 in shoots and 0.13 kg ha−1 in roots. Soil organic carbon (SOC) in 5, 10, 15, and 20 cm flood treatments increased annually at a rate of 3.85 %, 5.64 %, 6.86 %, and 6.86 %, respectively; for these same treatments, soil active organic carbon (AOC) decreased annually at rates of 11.75 %, 8.63 %, 20.07 %, and 8.48 %, and rice grain yield was 4488, 5103, 5450, and 5386 kg ha−1, respectively. Overall, considering the water quality, SOC, AOC, and rice yield production, irrigating rice paddies at a flood depth of 15 cm most effectively improves water quality, increases carbon sequestration, reduces active carbon, and yields more rice than other flood depths. By evaluating the effects of flood depth on the soil–water–plant nexus in a holistic manner, we propose a more sustainable and environmentally friendly mode of rice cultivation within the EAA.
This study examined the resilience to climate change of smallholder family farms in the Centre Region of Cameroon. Data were collected using a mixed-methods strategy and analyzed using descriptive, multivariate, and inferential statistics. Family farms exhibited a mean climate resilience index of 0.46 (medium), with the Ntui, Mbangassina, Batchenga, and Obala regions scoring 0.42, 0.44, 0.47, and 0.51, respectively. Family farmers had a high transformation capacity (59.07 %), a low adaptation capacity (32.10 %), and a very low absorption capacity (8.82 %). Logistic regression revealed significant causal relationships (p < 0.05) between the capacity of the farms to adapt to climate fluctuations and change and annual income, access to agricultural inputs, access to agricultural machinery, and membership in a farmers organization. These are the primary factors that could significantly increase climate resilience in Cameroonian family farms. Consequently, policymakers in these regions and beyond should consider these as indicators when developing policies to strengthen the climate resilience of local agricultural systems. In doing so, they should also consider community monitoring and indigenous knowledge, which can help bridge the gap between local adverse impacts and the necessary adaptations to climate change.
Agriculture, broadly defined to include crop and livestock production, forestry, aquaculture and fishery, represents a key source or sink of greenhouse gas emissions. It is also a vulnerable sector under climate change. The term climate-smart agriculture has been widely used since its inception in 2010, but no clear and unified understanding of its scientific meaning exists. Here, we systematically analyzed the relationship between agriculture and climate change and interpreted the scientific definition of climate-smart agriculture. We believe that climate-smart agriculture represents a modern production approach to coordinatively promote food security, climate mitigation benefits and agricultural adaptation to climate change towards the Sustainable Development Goals. In addition, due to the worsening global climate change situation, we expounded on the urgency and major challenges in promoting climate-smart agriculture.