Low-pressure sprinkler irrigation combined with fertigation is a promising approach for sustainable agriculture. However, reducing operating pressure changes sprinkler hydraulic performance, droplet characteristics, and irrigation uniformity, which in turn affect droplet evaporation and drift, canopy interception, soil infiltration, and field microclimate, ultimately influencing crop growth and resource use efficiency. A systematic synthesis of these interconnected processes is currently missing. This review synthesizes current knowledge on low-pressure sprinkler irrigation by integrating findings from hydraulic engineering, soil physics, micro-meteorology, and crop physiology. It covers sprinkler hydraulic performance, water and nutrient transport, and crop response mechanisms. It also identifies priority directions for future research. Based on a critical evaluation of existing studies, several key findings emerge. For hydraulic performance, non-circular nozzles and flow dispersion devices can improve jet breakup and uniformity under low pressure. In particular, non-circular nozzles enhance jet instability and air entrainment via axis-switching, while water-dispersing needles and off-axis plate motion effectively improve near-sprinkler water distribution. For water and nutrient transport, low pressure increases droplet size and kinetic energy, reducing evaporation and drift losses. Canopy modifies throughfall droplets, affecting soil structure, infiltration and erosion. A notable finding is that soil water redistribution compensates for low irrigation uniformity, making root-zone soil water more uniform, whereas soil nitrogen uniformity remains close to the sprinkler irrigation uniformity. For crop responses, sprinkler irrigation improves microclimate (cooling and humidifying), enhances crop photosynthesis and reduces transpiration, thus increasing yield and water use efficiency. Importantly, reduced irrigation uniformity did not significantly reduce yield under the specific conditions reported in existing studies, benefit by lower losses and soil compensation. However, most existing microclimate studies are based on medium- and high-pressure systems; the response mechanisms under low-pressure conditions remain unclear. Future research should prioritize four areas, including long-term performance and economic feasibility of low-pressure sprinklers, coupled multi-process modelling of water and fertilizer transport and environmental risk assessment, field microclimate responses and crop physiological mechanisms under low pressure, and system regulation strategies tailored to different crops and regions. This review provides a holistic basis for optimizing water, energy, and fertilizer synergies in sprinkler irrigation.
Conventional orchard spraying often suffers from a mismatch between spraying parameters and the spatial structure of fruit tree canopies, resulting in uneven spray deposition and low spray utilization efficiency. To address these issues, this study developed a canopy feature-based profile variable-rate orchard sprayer. LiDAR was used to acquire spatial information on fruit tree canopies, based on which a mapping relationship between canopy profile characteristics and profile adjustment parameters was established. A profile adjustment mechanism consisting of a lifting platform, a translation mechanism, and a five-section profile spraying arm was designed to enable adaptive adjustment of nozzle positions and spray directions according to canopy morphology. In addition, a variable-rate spraying model was developed based on the effective canopy volume to achieve dynamic matching between spray volume and canopy spatial distribution. Field experiments were conducted in a high-spindle apple orchard to evaluate the performance of the developed sprayer. The results showed that, under the canopy-adaptive spraying mode, the average droplet coverage rate on the adaxial leaf surface was 37.65%, with a vertical coefficient of variation of 2.83%. The horizontal coefficients of variation for the upper, middle, and lower canopy layers were 11.50%, 8.03%, and 5.73%, respectively. Compared with the fixed-position quantitative spraying mode, the canopy-adaptive spraying mode reduced ground spray loss by 69.47% and water consumption by 51.93%. Overall, the canopy-adaptive spraying mode improved droplet deposition uniformity, reduced ground spray loss, and decreased spray volume, demonstrating its potential for precision plant protection in orchards.
Climate variability may influence olive ripening and sugar composition, complicating irrigation and nutrient management. We hypothesized that reduced irrigation would increase glucose concentrations in ‘Arbequina’ olive pulp, with responses varying according to potassium supply and harvest season. Sugar profiles and ripening-related physicochemical parameters were evaluated in ‘Arbequina’ olives across three harvest seasons (2021–2023). A 15-run Box–Behnken design combined three levels each of irrigation, potassium fertilization, and foliar copper application. Fruits were sampled monthly from May to July in each harvest season. Glucose was the predominant sugar and varied among seasons, reaching 28.12 mg g−1 in July 2021. Response surface models predicted maximum glucose concentrations of approximately 30 mg g−1 at the 75% irrigation level and 100–123.6 kg K2O ha−1 in May 2021 and 2022. Kernel principal component analysis differentiated samples by harvest month and season. Associations between the a* color coordinate and sugar concentrations were strongest in 2022 but were not consistent across seasons. Overall, the findings highlight seasonal variation in sugar composition and ripening-related physicochemical parameters. This seasonal dependence emphasizes the need to interpret agronomic management effects within their environmental context and supports the combined use of sugar profiles, physicochemical indicators, and multivariate analysis to assess olive fruit ripening.
Coal-based solid waste (CBSW; fly ash, weathered coal, coal gangue) from open-pit coal mining in extremely cold regions differentially releases salinity/alkalinity, heavy metals and acids, altering surrounding black-soil properties and reshaping its bacterial communities. We compared healthy farmland black soil (CK) with three dumping treatments—fly ash (FA), weathered coal (WC) and coal gangue (CG) (six replicates each; n = 24)—using full-length 16S rRNA sequencing (PacBio CCS), physicochemical, phospholipid fatty acid and enzyme-activity analyses. The wastes showed contrasting stress regimes: fly ash was slightly alkaline, saline and heavy-metal-enriched; weathered coal was strongly acidic and saline; and coal gangue was acidic–sulfidic. Dumping significantly altered soil pH, salinity and metal speciation, reducing organic matter by 36–61% and microbial biomass carbon by 45–74%. Alpha diversity responded in a type-specific manner: WC had the lowest Shannon index (4.72, −55.1%) and was dominated by Pseudomonadota (80.6%) with methylotrophy being enriched; FA retained the highest diversity (11.23); and CG was dominated by Actinobacteriota (45.1%). PERMANOVA and ANOSIM confirmed significant community separation. Nitrification was nearly lost under WC, while sulfate respiration was enriched under CG and sulfur respiration under FA, indicating type-specific restructuring of nitrogen and sulfur cycling. These results show that CBSW dumping drives restructuring and nitrogen–sulfur functional degradation of black-soil bacterial communities through type-specific environmental filtering, with weathered coal causing the most severe degradation, informing classified remediation.
In China’s Huaibei Plain, summer soybean and maize compete for land due to highly overlapping growing seasons. This study employs the DSSAT model under full irrigation to assess crop climatic adaptability and sowing date optimization across a baseline (2001–2020) and two future emission scenarios (SSP2-4.5 and SSP5-8.5, 2031–2050) under 13 sowing-date treatments, with 10 June as the conventional sowing date for both crops. Results indicate that future summer growing seasons will become warmer and wetter overall. Relative to the baseline, conventional sowing under future climates leads to shortened growth periods and synchronous yield declines, with maize suffering substantially larger yield losses than soybean. Sowing date optimization effectively mitigates these climate-induced yield losses, with recommended adjustments of advancing soybean by 10–15 days and delaying maize by 20 days. Following optimization, maize yield surpasses the baseline by 8.2% under SSP2-4.5 and recovers to near-baseline levels under SSP5-8.5, while soybean yield remains comparable to the baseline under SSP2-4.5 and slightly below it under SSP5-8.5. Maize maintains clear advantages in grain yield and net return, whereas soybean has higher irrigation water economic efficiency, defined as the irrigated–rainfed net return difference per unit irrigation water. Under these simulated full-irrigation conditions, we suggest maintaining a maize-dominant pattern with moderate soybean allocation and optimized sowing dates for both crops as a scenario-based reference for enhancing regional climate adaptability.
