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• We investigated the effects of windbreaks on PM emissions from agricultural soil erosion. • There is little impact of windbreak on PM 1 and PM 2.5 reduction. • PM 10 concentrations can be reduced significantly by windbreaks. • The settling velocity of particles has an impact on the effects of windbreaks. Wind erosion from agricultural fields contributes substantial amounts of particulate matter (PM) in the form of dust to the atmosphere, with significant impacts on air quality and human health. Vegetation barriers affect particle transport via altering air flow, yet the impact of windbreaks on PM concentrations from agricultural soil erosion is still unknown. This study describes brief campaigns to explore the effects of windbreaks on PM concentrations in Zhangbei County, Heibei Province, China. Measurements were made in arable lands with windbreaks, of which the dominant tree species was Populus , following dust events from April to May, when the trees were without leaves. We selected windbreaks with different structures and measured PM concentrations at the windward and the leeward sides of the windbreaks, using high time-resolution measurements. The effects of windbreaks were quantified by calculating the PM concentration ratios in front of and behind the windbreaks. During dust events, the average value of maximum PM 10 emissions was 109.87 μg/m3, which was above the threshold established by the World Health Organization (WHO) for air quality. The PM 10 emissions increased with air temperature and wind speed. The highest PM 10 emission was observed at a relative air humidity of 20%. PM 1 and PM 2.5 concentrations were not lower behind the windbreak than in front of the windbreak in most of the events, while PM 10 concentrations could be reduced by an average of 27%. A significant increase in PM 2.5 /PM 10 by 56.86% behind the windbreak indicates the high efficiency of the windbreak to reduce PM 10 levels. Simply planting trees can, in some cases, increase downwind PM concentrations. Vegetation configuration and avoiding locating residential areas in the immediate lee of windbreaks should be considered when planning windbreaks. [ABSTRACT FROM AUTHOR]

Highlights: [•] We proposed a method for short-term forecasting of reference evapotranspiration. [•] Temperature forecasts for 7-day horizons were used. [•] Accuracy of the proposed method was evaluated. [•] Errors were caused by errors in inputs and inherent defect of the employed model. [Copyright &y& Elsevier]

Seasonal freeze-thaw processes affect soil water migration and distribution, especially in semi-arid agricultural areas. These processes play an important role in mitigating harsh environmental conditions and wind erosion. Soil water content (SWC) and soil temperature (ST) were monitored at different depths (0–2 m) and investigated under freeze-thaw conditions from November 2018 to May 2019 in a semi-arid agro-pastoral region of northern China. The initial SWC was the main factor that affected the freeze-thaw process. During the freeze-thaw process, differences in soil thermal conductivity caused the soil to thaw faster than the freezing process, and the upper soil layer (0–60 cm) was significantly affected by temperature changes. Changes in the potential energy of water and pore pressure gradient caused the migration of soil water to the upper layer, which led to a slight decrease in SWC in each layer before ST dropped to the freezing point. The vertical migration distance of soil water exceeded 70 cm, and the SWC above a depth of 100 cm increased significantly, as water was mainly obtained from the soil layer below a depth of 200 cm. Soil compaction was reduced when affected by freeze-thaw processes and the soil particles were more fragmented, leading to wind erosion and dust events. Our results partially explain the occurrence of wind erosion in spring and provide a scientific basis for predicting soil water status and appropriate farmland management strategies. • Soil water content and soil temperature dynamic were quantified in farmland area. • Vertical migration distance of soil water exceeded 70 cm. • The initial SWC was the main factor that affected the freeze-thaw process. • Seasonal freeze-thaw processes will increase soil erodibility. [ABSTRACT FROM AUTHOR]

• Windbreaks can effectively reduce wind erosion on agricultural fields by 20 %. • Windbreaks can attenuate the spike of PM concentrations. • The dispersion of PM 10 to downwind areas could be reduced by windbreaks. • Windbreak have little impacts on dispersion of PM 2.5 and PM 1 concentrations. Particulate matter (PM) emissions from farmlands due to wind erosion have resulted in serious land degradation, air pollution, and human health problems. Although windbreaks have been traditionally planted on farmlands to reduce soil erosion, only a few studies examining wind erosion and PM emissions on farmlands utilizing windbreaks have been undertaken. In our study, the performance of windbreak patches and strips used for mitigating wind erosion and PM pollution were examined in-situ between 2017 and 2019. Soil loss and PM emissions from farmlands with and without windbreaks were measured using sediment traps, dust monitors and samplers during high wind events in a non-foliage period. Results indicated that soil loss in windbreak patches was 20 % lower than that on farmlands; compared to farmland, windbreak patches resulted in wind speed reductions of 27 % and 30 % at heights of 0.2 m and 2 m, respectively. The use of windbreak strips resulted in a reduction of PM 10 dispersion in downwind areas, recording a steeper decline of PM 10 concentrations in the open transect than in the vegetated transect. For PM 2.5 and PM 1 , the rate of decline was similar between the two transects. Windbreak strips were also recorded to reduce vertical PM 10 flux, with average values of 0.68 and -2.81 μg m−2 s-1 on the windward and leeward side, respectively. Shelter effects of windbreaks were highest when windbreak porosities were between 40 %–60 %, during which the shelter distance was between 7–9 times tree height. Results from this study can be used to assess wind erosion and PM emissions from farmlands with windbreaks, enabling suitable positioning of the windbreaks to maximize their effects. [ABSTRACT FROM AUTHOR]

• Shelter forests mortality and its relationship with precipitation and soil water content was quantified. • Lower mortality of poplar (<32%) above 230 mm (precipitation) and an SWC > 16.56%. • A threshold response was evident when precipitation was 60% of normal. • Wind speed, low temperature, and stand density had effects on the mortality of shelter forests. Shelter forests in the agricultural field are critical ecological barriers against harsh environmental conditions and agricultural soil erosion in northern China; however, shelter forests have been extensively degraded in the past decades. It is unknown how patterns of mortality of shelter forests relate to highly variable spatial precipitation and soil water content (SWC). Here, we explore the relationships of precipitation and SWC with the mortality of Populus simonii Carr (poplar) shelter forests in the semi-arid Bashang Plateau, northern China. Mortality of poplar shelter forests and its relationship with precipitation and SWC are spatially quantified in an area with an uneven distribution of precipitation by combining standard field plot measurements, precipitation, and SWC spatial distribution grid data. The mortality patterns of poplar shelter forests revealed threshold responses to precipitation and SWC, with lower mortality (<32%) above 230 mm (precipitation) and an SWC > 16.56%. Results indicate that a threshold response is evident when precipitation is 60% of the average precipitation. In addition, our results show that wind speed, low temperature, and stand density also had significant effects on the mortality of poplar shelter forests. Our results show how precipitation and SWC patterns within a region influence the mortality of poplar shelter forests. Moreover, this study reveals other factors influencing stand structure and landscape heterogeneity, which have been largely overlooked in previous studies. [ABSTRACT FROM AUTHOR]

Abstract: The dehumidifier and regenerator are key components in liquid desiccant air conditioning systems. Many researchers have developed mathematical models of the coupled heat and mass transfer processes in the dehumidifier or regenerator, and most of the models were solved numerically. Compared with numerical solutions, analytical solutions have more advantages in analyzing the parameters that affect the heat and mass transfer performance. This paper presents analytical solutions of the air and desiccant parameters inside the parallel flow, counter flow and cross flow dehumidifier/regenerator under some reasonable assumptions based on the available heat and mass transfer models. The analytical solutions of the air and desiccant parameters within the dehumidifier/regenerator show good agreement with the corresponding numerical results, and the analytical solutions of the enthalpy and moisture efficiencies agree well with experimental findings. The method developed here can be used in the optimal design of the dehumidifier or regenerator. [Copyright &y& Elsevier]