Publications

Abstract Check dams are widely used on the Loess Plateau of China to control soil and water loss, develop agricultural land and improve watershed ecology. Detailed information on the spatial distribution of check dams and the area of dam land is critical for quantitatively evaluating hydrological and ecological effects, planning the construction of new dams and repairing damaged dams. Therefore, this research presents a method that integrates deep learning and geospatial analysis to facilitate the extraction of check dam areas in broad areas from high‐resolution Gaofen‐2 (GF‐2) multispectral imageries, including red (R), green (G), blue (B) and near‐infrared (NIR) bands and digital elevation model (DEM). First, we generated three datasets with different band combinations (RGB, RGB + NIR and RGB + DEM) using GF‐2 remote sensing images combined with Advanced Land Observing Satellite—the Phased Array type L‐band Synthetic Aperture Radar DEM data to determine the optimal data combination for dam area extraction. Next, four widely used semantic segmentation networks—Fully Convolutional Network (FCN), U‐Net, PSPNet and DeepLabv3+—were modified to support the arbitrary number of input channels and evaluated for check dam area extraction. Finally, the check dam candidate areas in the Yan River basin were extracted from DEM using geospatial analysis to optimize the dam area extraction results. The results showed that all deep learning (DL) models could extract dam areas quickly and accurately with mean intersection over union and overall accuracy values >85% and >98%, respectively. PSPNet had the best performance for testing datasets with different band combinations. We also found that the DL models in the RGB + DEM images had the best remote sensing image segmentation results, avoiding many miss‐classified pixels. The F 1 scores in the RGB + DEM test dataset for FCN U‐Net, PSPNet and DeepLabv3+ reached up to 92%, or 3.3%, 2.3%, 1.9% and 3.1% higher than the corresponding values for RGB images. Potential check dam candidate regions (~3969 km 2 ) were obtained for application analysis, which reduced the original area by 50%. The DL models for the RGB + DEM images were applied in the dam candidate regions, extracting 91.9 km 2 of agricultural production dam land and 10.6 km 2 of runoff and sediment silted dam land. The extraction results will facilitate quantitative analyses of check dams, improve the management of these structures and promote the efficiency of controlling soil losses.

The chenopod Beta macrocarpa Guss (wild Swiss chard) is known for its salt tolerance, but the mechanisms involved are still debated. In order to elucidate the processes involved, we grew wild Swiss chard exposed to three salinity levels (0, 100 and 200 mm NaCl) for 45 days, and determined several physiological parameters at the end of this time. All plants survived despite reductions in growth, photosynthesis and stomatal conductance in plants exposed to salinity (100 and 200 mm NaCl). As expected, the negative effects of salinity were more pronounced at 200 mm than at 100 mm NaCl: (i) leaf apoplastic water content was maintained or increased despite a significant reduction in leaf water potential, revealing the halophytic character of B. macrocarpa; (ii) osmotic adjustment occurred, which presumably enhanced the driving force for water extraction from soil, and avoided toxic build up of Na(+) and Cl(-) in the mesophyll apoplast of leaves. Osmotic adjustment mainly occurred through accumulation of inorganic ions and to a lesser extent soluble sugars; proline was not implicated in osmotic adjustment. Overall, two important mechanisms of salt tolerance in B. macrocarpa were identified: osmotic and apoplastic water adjustment.

Ephemeral gullies are widely distributed in the hilly and gully region of the Loess Plateau and play a unique role in the slope gully erosion system. Rapid and accurate identification of ephemeral gullies impacts the distribution law and development trend of soil erosion on the Loess Plateau. Deep learning algorithms can quickly and accurately process large data samples that recognize ephemeral gullies from remote sensing images. Here, we investigated ephemeral gullies in the Zhoutungou watershed in the hilly and gully region of the Loess Plateau in China using satellite and unmanned aerial vehicle images and combined a deep learning image semantic segmentation model to realize automatic recognition and feature extraction. Using Accuracy, Precision, Recall, F1value, and AUC, we compared the ephemeral gully recognition results and accuracy evaluation of U-Net, R2U-Net, and SegNet image semantic segmentation models. The SegNet model was ranked first, followed by the R2U-Net and U-Net models, for ephemeral gully recognition in the hilly and gully region of the Loess Plateau. The ephemeral gully length and width between predicted and measured values had RMSE values of 6.78 m and 0.50 m, respectively, indicating that the model has an excellent recognition effect. This study identified a fast and accurate method for ephemeral gully recognition in the hilly and gully region of the Loess Plateau based on remote sensing images to provide an academic reference and practical guidance for soil erosion monitoring and slope and gully management in the Loess Plateau region.

Abiotic stresses lead to an array of physiological and biochemical changes in crops which affect their growth and development leading to grain yield reductions. Oilseed Brassica species are vulnerable to heat and drought stress, especially in the early reproductive stage. We evaluated the use of several non-destructive phenomic tools to predict heat and drought tolerance at anthesis in three Brassica species, including five B. rapa, five B. napus and two B. juncea genotypes. Heat, drought or combined heat and drought treatments were applied for seven days from the beginning of anthesis, following which plants were returned to normal temperatures and well-watered conditions. Leaf and floral bud temperatures increased relative to ambient, and leaf conductance decreased in response to seven days of drought or combined treatments, but not to heat or control treatments. The drought and/or heat treatment significantly affected three photosynthesis-related parameters: the maximum carboxylation rate allowed by Rubisco (Vcmax), the photosynthetic electron transport rate and the rate of triose phosphate use. One day after the beginning of the heat and combined heat and drought treatments, Vcmax increased to more than double the basal level but remained low in the drought and control treatments. Vcmax on the first day of heat and combined treatments was positively correlated to the harvested seed yield of genotypes (r = 0.670 and 0.878, respectively), suggesting that a rapid increase in Vcmax in response to heat stress during anthesis was a positive predictor of final grain yield. The tissue volume of the whole plant, detected by plant growth imaging using a digital imaging system, was positively correlated with the above-ground fresh weight of genotypes after seven days in all treatments and was, therefore, an excellent surrogate for above-ground biomass of the whole plant. The volume of the yellow flowers after seven days in all treatments was positively correlated with the harvested seed yield of genotypes, and is a potential non-destructive phenomic screen for heat and drought stress tolerance in Brassica germplasm.

This book covers all the latest development in combating various major and minor emerging diseases in all the grain legumes.

The growth and yield of crops have been significantly affected by abiotic stresses. Although respiratory metabolism is integral to plants, its understanding within the context of stress adaptation remains limited . While the rice genome contains three Aconitase genes, their specific roles in abiotic stress tolerance and plant development remain largely unexplored. This study aimed to characterize the Aconitase gene family in rice, shedding light on the evolution of Aconitase and its involvement in diverse developmental processes, as well as its response under various abiotic stress conditions. Phylogenetic analysis indicated the evolutionary relationship between rice Aconitase genes and those of other plant species. The prediction of promoter cis-elements revealed the presence of diverse cis-acting elements associated with the response to abiotic stress within the Aconitase gene family. In addition, an analysis of public RNA-seq data indicated the potential involvement of Aconitase genes in various developmental processes and mechanisms related to stress tolerance. Further, qRT-PCR confirmed the expression patterns of Aconitase genes. Expression analysis revealed differential expression of Aconitase genes under cold, drought, ABA, and salt stresses. Elevated levels of the OsAco1 transcript resulted in a phenotype that exhibited increased tolerance to salt stress. Biochemical analysis revealed higher Aconitase activity in the overexpressed line compared to the control plant. Furthermore, the overexpressed line exhibited improved growth and lower H2O2 levels than the control plant following a 2-hour exposure to 200 mM salt stress. These findings suggest a potential role of Aconitase in enhancing salt stress tolerance. Moreover, they lay the foundation for further exploration into the precise involvement of Aconitase in plant developmental processes under various stress conditions, with the ultimate aim of developing salt-tolerant rice cultivars.

Abstract The application of plastic film mulch and the return and incorporation of crop straw into topsoil as independent treatments affect soil physicochemical properties, including nutrient balance/cycling. It remains unclear whether combining straw incorporation and plastic film mulch significantly affects soil physicochemical properties and bacterial communities. We conducted a two‐factor (plastic film mulch application and maize straw incorporation) randomized block design experiment with four treatments: no plastic film mulch or straw incorporation (C), plastic film mulch (M), straw incorporation without mulch (CS) and straw incorporation with mulch (MS). Soil was sampled at the end of the growing cycle after 3 years of treatment. Soil organic carbon (SOC), total nitrogen (TN) and nitrate‐nitrogen (NO 3 − ‐N) concentrations significantly improved after straw incorporation. Plastic film mulch had a significant negative effect on soil bacterial richness, whereas straw incorporation had no effect. Straw incorporation had a significant positive effect on bacterial diversity, whereas plastic film mulch had no effect. The MS and M treatments had significantly more Proteobacteria than the C and CS treatments. Formation of the soil bacterial community structure was driven by soil TN, NO 3 − ‐N and SOC in the treatments with straw incorporation, and soil ammonium‐nitrogen (NH 4 + ‐N) in the treatments without straw incorporation. In conclusion, plastic film mulch coupled with straw incorporation can significantly change the taxonomical and functional composition of soil bacterial communities and enhance soil bacterial diversity by affecting carbon and nitrogen cycling in cropland soils of farmland, especially in arid and semiarid regions. Highlights SOC, TN and NO 3 − –N concentrations significantly improved after straw incorporation Straw incorporation had a greater effect on bacterial communities than plastic film mulch Soil bacterial community structure was driven by soil TN, NO 3 − –N and SOC after straw incorporation Soil bacterial community structure was driven by soil NH 4 + ‐N without straw incorporation.

Abstract Phosphorus (P) recycling from wastewater can reduce the reliance on the primary source for P fertilisers―rock phosphate reserves. In light of this, we compared the effects of struvite (ST), a sparingly soluble P product derived from wastewater, and readily soluble KH 2 PO 4 (KP) on chickpea ( Cicer arietinum L.) and wheat ( Triticum aestivum L.) growth and P acquisition. Plants were grown in a temperature-controlled glasshouse in plastic pots containing a soil mixture with low P availability, with ST or KP applied at five P rates (7, 14, 28, 56 and 112 µg P g − 1 dry soil). Plants were harvested 56 days after sowing when there were visible differences in above-ground growth. Chickpea and wheat growth positively responded to increasing P rates of KP and ST. At low and medium P rates (7, 14, 28 and 56 µg P g − 1 dry soil) of KP and ST, the plants acquired similar amounts of P, while at a higher P rate (112 µg P g − 1 dry soil), plants supplied with ST, accumulated 1.2- to ~ 2.0- fold higher P than KP. Rhizosheath soil pH increased by ~ 0.1–0.7 units under ST than KP for both species. Wheat produced greater total root length but lower amount of rhizosheath carboxylates than chickpea under KP and ST, and wheat accumulated more P than chickpea under KP and ST. Chickpea and wheat can well access P from ST, indicating the great potential of ST as an alternative P fertiliser.

Abstract The carbon isotope discrimination (δ 13 C) of leaves has been shown to be correlated with the transpiration efficiency of leaves in a wide range of species. This has led to δ 13 C being used in breeding programs to select for improved transpiration efficiency. The correlation between δ 13 C and transpiration efficiency was determined under well‐watered conditions during the vegetative phase in six genotypes of lentil ( Lens culinaris Medikus), six genotypes of chickpea ( Cicer arietinum L.) and 10 cultivars of narrow‐leafed lupin ( Lupinus angustifolius L.). Biomass (dry matter) accumulation and water use (transpiration) varied among the genotypes in all three species and transpiration efficiency was 40% to 75% higher in the most efficient compared with the least efficient genotypes. However, δ 13 C and transpiration efficiency were not significantly correlated in any of the species. This suggests that the δ 13 C technique cannot be used in selection for transpiration efficiency in the three grain legumes (pulses) studied.

Post-anthesis water use is important for grain yield in wheat under drought because this water is immediately used for grain filling. The aim of this study was to determine whether root capacity for water uptake from deeper layers in the soil profile differed between two genotypes with contrasting stomatal behaviour under terminal drought. The wheat cultivar Drysdale and the breeding line IGW-3262 were grown in 1m deep pots in a glasshouse under well-watered conditions until anthesis, when three watering treatments were imposed: (i) watering maintained at 90% pot soil water capacity (WW), (ii) watering withheld but supplementary watering supplied to the bottom 30cm of the pot to keep this layer of the soil profile wet until physiological maturity (WB) and (iii) watering completely withheld (WS). Stomatal conductance, post-anthesis water use and water use efficiency, and grain yield were measured. Post-anthesis water use in Drysdale was similar in the WB and WW treatments, while in IGW-3262 it was 30% less in the WB treatment than in the WW treatment. In the WB treatment as the top soil dried, stomatal closure was faster in IGW-3262 than in Drysdale, which may have affected the capacity of roots to uptake available water at depth. The reduction in post-anthesis water use in IGW-3262 resulted in a decline in grain yield.

ABSTRACT Acidity limits plant growth, particularly when the growing medium has a pH below 5, a challenge that is particularly relevant for certain plants like switchgrass ( Panicum virgatum ). Although adding biochar to the growing medium has been shown to improve plant growth by modulating acidity, its specific impact on switchgrass remains largely uninvestigated. Thus, we conducted a pot experiment to assess how different biochar application rates (0%, 1%, 2.5%, 5%, 10%, and 20% w/w), derived from mushroom residue through muffle furnace pyrolysis at 350°C for 2 h, affect the physicochemical attributes of phosphogypsum and subsequent switchgrass growth. Our findings revealed that adding biochar to phosphogypsum significantly alleviated acidity and enhanced moisture, organic matter, total nitrogen, total phosphorus, total potassium, available phosphorus, and available potassium contents. Notably, the 10% biochar treatment had the most positive impacts on germination rates, while the 5% treatment had the greatest improvements in shoot length, tiller number, and total weight compared to the control. Structural equation modeling illustrated that biochar indirectly contributed to switchgrass health by altering the physicochemical properties of phosphogypsum, with pH as the pivotal regulator. Our study demonstrated the potential of mushroom residue biochar as an effective amendment for acidic substrates/matrix (e.g., soil), offering a promising strategy to improve physicochemical conditions and stimulate plant growth.

Drought stress is the main limiting factor for global soybean growth and production. Genetic improvement for water and nutrient uptake efficiency is critical to advance tolerance and enable more sustainable and resilient production, underpinning yield growth. The identification of quantitative traits and genes related to water and nutrient uptake will enhance our understanding of the mechanisms of drought tolerance in soybean. This review summarizes drought stress in the context of the physiological traits that enable effective acclimation, with a particular focus on roots. Genes controlling root system architecture play an important role in water and nutrient availability, and therefore important targets for breeding strategies to improve drought tolerance. This review highlights the candidate genes that have been identified as regulators of important root traits and responses to water stress. Progress in our understanding of the function of particular genes, including GmACX1, GmMS and GmPEPCK are discussed in the context of developing a system-based platform for genetic improvement of drought tolerance in soybean.

Predictions from climate simulation models suggest that by 2050 mean temperatures on the Loess Plateau of China will increase by 2.5 to 3.75°C, while those in the cropping region of south-west Australia will increase by 1.25 to 1.75°C. By 2050, rainfall is not expected to change on the Loess Plateau of China, while in south-west Australia rainfall is predicted to decrease by 20 to 60 mm. The frequency of heat waves and dry spells is predicted to increase in both regions. The implications of rising temperatures are an acceleration of crop phenology and a reduction in crop yields, greater risk of reproductive failure from extreme temperatures, and greater risk of crop failure. The reduction in yield from increased phenological development can be countered by selecting longer-season cultivars and taking advantage of warmer minimum temperatures and reduced frost risk to plant earlier than with current temperatures. Breeding for tolerance of extreme temperatures will be necessary to counter the increased frequency of extreme temperatures, while a greater emphasis on breeding for increased drought resistance and precipitation-use efficiency will lessen the impact of reduced rainfall. Management options likely to be adopted in south-west Australia include the introduction of drought-tolerant perennial fodder species and shifting cropping to higher-rainfall areas. On the Loess Plateau of China, food security is paramount so that an increased area of heat-tolerant and high-yielding maize, mulching with residues and plastic film, better weed and pest control and strategic use of supplemental irrigation to improve rainfall-use efficiency are likely to be adopted.