Cumulative Evaporation Research Articles

Estimating soil water evaporation as influenced by “dry-and green-mulch” cover beneath maize canopy

Soil evaporation reduction can improve rainfed crop production in semi-arid climates. The purpose of this study was to develop empirical models to estimate cumulative soil evaporation (∑Es) from a maize field across the basin and runoff area (BA and RA) of the in-field rainwater harvesting (IRWH) technique as influenced by different levels of stover mulch ("dry-mulch") and canopy shading ("green-mulch"). Soil water evaporation (Es) was measured with micro-lysimeters 300 mm deep and 71 mm in diameter in the BA and RA sections for three consecutive drying cycles. Four different runoff strip lengths, RSL (RSL-1, 1.5, 2 and 3m) and three mulching levels (ML) of bare, 39%, and 96% were used to estimate the Es. The coefficient crop cover (Kcover) values for full and partial canopy shade (FC and PC) on the RA were in the range of 0.46–0.97 and 0.43–0.94, respectively, while in the BA the Kcover values ranged between 0.33 and 0.92. Under IRWH, the ∑Es values from a basin area beneath a maize canopy averaged 42% of the seasonal rainfall. ∑Es proportion of seasonal rainfall is about 62, 64, and 66 percent for bare soil, but as low as 28, 30 and 32 percent for FC, PC, and unshaded canopy (UC), respectively. In conclusion, the microclimate of the cropping system changes according to surface treatments, which greatly affect the Es losses for the IRWH technique and contributes to ET partitioning. Hence, reducing unproductive water losses in dryland crop production improves water use efficiency by storing more water in the root zone for transpiration.

Implications of Watershed Management Practices on Water Availability Using Hydrus-1D Model in the Aba Gerima Watershed, Upper Blue Nile Basin, Ethiopia

The main objective of this study was to examine the implications of watershed management (WSM) on hydrological parameters in the Aba Gerima watershed in the Upper Blue Nile Basin. The Hydrus 1D model simulations were conducted in control sites and sites under WSM to estimate various components of the hydrologic cycle, using different soil physical & hydrological data under each category of experimental sites. Results were calibrated with measured soil moisture data through inverse solutions. Thus, Hydrus 1D model was found to be effective in predicting results, with R2 values of 0.73 to 0.853 and RMSE values ranging from 0.015 to 0.04. The cumulative evaporation estimated for 365 days for control sites was 37.6% higher than that of sites under WSM. Surface and bottom fluxes in the sites under WSM were 4.6% and 12.5%, respectively, higher than the control sites. This could be attributed to the increased soil water availability resulting from the implemented WSM practices in Aba Gerima, and the results of this study can be used as empirical evidence of the positive implications of WSM on water availability. Finally, WSM should be strengthened by concerned bodies and development partners in all watersheds, especially where water availability is affected by severe land degradation.

Biocrust impacts on dryland soil water balance: A path toward the whole picture.

As a crucial living feature inhabiting the soil-atmosphere boundary, biocrusts play a vital role in liquid water or vapor transport through surface soil and thus have strong effects on soil water regimes. However, it remains unclear how biocrusts affect annual or multiyear soil water budgets through the regulation of evaporation outputs and non-rainfall water (NRW) or infiltration inputs. Thus, we used automated microlysimeters to continually investigate the differences in evaporation and NRW rates between moss-dominated biocrusts and bare soil at 0-5cm depth for 2 years. The upper 30 cm of soil moisture (θ) and water storage (W) of bare soil and biocrusts were also monitored. Our results showed that the daily evaporation rate (E) of biocrusts was 17% higher than bare soil. Especially after rainfall events, biocrusts had higher E and larger cumulative evaporation than bare soil. Besides, the daily NRW of biocrusts averaged 15% higher than bare soil over 2 years. Furthermore, biocrusts increased θ by 11%-76% at 0-10cm depth but decreased θ by 32%-56% at 20-30 cm depth in comparison to bare soil, and they subsequently decreased W by 20% at 0-30 cm depth. Summarized annually, the NRW amount of biocrusts was 19% higher than bare soil, but at the same time, the cumulative evaporation of biocrusts was also 19% higher than bare soil. Finally, biocrusts resulted in more water loss at shallow depth through evaporation and lessened total W throughout 0-30 cm depth of soil. These findings demonstrate that although biocrusts input more NRW into surface soil, these water inputs partially offset their intensified evaporation. Given that all rainfall water infiltrates into the soil in our study system, our findings indicate that biocrusts may have an overall negative effect on soil water balance there, while at the same time increasing water storage and availability of the deeper soil underlying biocrusts.

Evaluation of irrigation experiments with GGE biplot method and economic analysis of drip irrigation system: a case study of peanut production

Besides irrigation water quantity and quality, there is a decrease also in soil quality and fertility. Agricultural production lands are decreasing both in quantity and quality. There is a search for different operational alternatives in sandy soils with low production potentials. Drip irrigation is largely practised to get greater yields per unit area. This study was conducted under sand soil conditions, commonly preferred for peanut farming, in the 2017- 2018 growing seasons. A drip irrigation system was used in production. Two different irrigation intervals (2 and 4 days) and four different irrigation levels (I50, I75, I100 and I125, calculated based on cumulative evaporation from the class-A pan) were applied. Evapotranspiration values varied between 402-832 mm, applied irrigation water quantities between 313-783 mm, yields between 5269-8269 kg ha-1, water use efficiency (WUE) values between 0.63-1.55 kg ha-1 m-3, economic water productivity (EWP) over gross revenues between 1.29-3.81 $ m-3 and benefit and cost ratios (B/C) varied between 4.73-10.95. The GGE biplot statistical method is a useful tool in the evaluation of irrigation research where the number of applications and materials is high.

Ventilation and irrigation management strategy for tomato cultivated in greenhouses

Appropriate ventilation and water management strategy are beneficial to boost crop yield and quality in greenhouses, and their optimization is crucial for improving water use efficiency (WUE). Here, we set up three irrigation levels based on measurements of the cumulative pan evaporation (AEpan) (i.e. 0.9 AEpan, 0.7 AEpan, and 0.5 AEpan), and three ventilation modes through opening the greenhouse vents at different location (VST: open the both roof and south vents; VT: open the roof vents only; VS: open the south vents only) to reveal the effects of ventilation mode and irrigation amount on picking, yield (Y), evapotranspiration (ET), WUE and quality of tomato grown in a solar greenhouse. Nine treatments were split block design with ventilation mode as main treatment and irrigation amount as vice treatment. Each treatment was replicated three times. Results showed that harvesting time of tomato were substantially influenced by ventilation mode as a result of interior temperature differences. The VT treatment was beneficial to early maturity of tomato than the VST and VS treatments. The proportion of VT in the first three harvesting was ~36.8 % and ~26.3 % higher than of VST and VS, respectively. Irrigation amount had a marked effect on ET, Y, WUE, irrigation water use efficient (IWUE), and irrigation water compensation (Irc). Here, ET, Y and Irc of K0.9 were 51.7 % and 69.8 %, 11.0 % and 19.6 %, 7.0 % and 13.5 % higher than those of K0.7 and K0.5 treatments, respectively, while the WUE and IWUE were 13.1 % and 24.8 %, 18.6 % and 28.6 % lower than K0.7 and K0.5, respectively. However, the significant interaction between ventilation and irrigation were only found on Y, WUE and IWUE. Both ventilation and irrigation treatments had considerable effect on soluble solids (TSS), Vc and organic acid. TSS could represent the comprehensive quality of tomato, because TSS was very significantly positively correlated with the comprehensive quality scores. A better combination of ventilation and irrigation was recommended as VST × 0.7 AEpan by using the TOPSIS method based on a compromise of Y, quality and WUE.

Soil Nutrient Status and Morphometric Responses of Guava under Drip Irrigation and High-Tech Horticultural Techniques for Sustainable Farming

In the current study, efforts were made to standardize fertigation for providing the recommended doses of fertilizers (RDF) i.e., 300, 260, and 200 g/plant/year for N, P, and K, respectively, together with optimization of irrigation scheduling so that guava plants could avoid the frequent episodes of nutritional stress, water scarcity, or overwatering. The experiment’s execution was confined to a three-factor randomized block design, with a total of 19 treatments that were replicated four times. Briefly, these treatments included drip irrigation and nutrient (NPK) application through fertigation dosages (RDF; 100, 80, and 60%) with and without silver-black plastic mulching. Different applied fertilizer dosages, together with different levels of irrigation and soil mulching, had a significant impact on the guava plant’s vegetative, reproductive, and nutritional aspects. Under silver-black plastic mulch, drip irrigation at cumulative pan evaporation (CPE) 80 and 100% of the prescribed dosage of fertilizers, better macronutrient availability in the soil, and improved plant development were recorded (M1DI2F1). Overall, using drip fertigation to provide NPK fertilizers close to the root zone increased the availability of nutrients to the plants as compared to the traditional fertigation and irrigation methods. Thus, this sustainable high-tech horticultural approach could be analyzed for its efficacy or applied to other crops to obtain adequate economic outcomes.

High-Precision Calculation of the Proportions of Water with δ2H and δ18O, the Cumulative Effect of Evaporation in the Vertical Direction and Depleted δ2H and δ18O of the Shallow Soil Water Caused by Evaporation

Exploring the water sources taken up by plants is necessary for ecological protection. The purpose of this study was to determine the exact proportions of different water sources absorbed by herbaceous plant species in the wetland of Poyang Lake in an inland humid region. This identified the water sources patterns in wetlands and provide Poyang Lake managers information about the lake water level needed to sustain vegetative life. We analysed the deuterium isotope composition (δ2H) and oxygen isotope composition (δ18O) values in the stem water of dominant herbaceous plant during its different growth stages to explore the proportions of water sources in different growth stages by using the Phillips equation, and the results supported the accuracy. The results indicate that the groundwater should not be lower than 0.13 m, otherwise the Carex cinerascens may not be able to absorb it. In previous studies, the lower slopes and intercepts of δ2H–δ18O were attributed to the secondary evaporation under the cloud, but we found that there is a cumulative evaporation effect in rainwater, soil water, and groundwater, which makes the slopes and the intercepts of δ2H–δ18O relationship lines become lower from top to bottom. In this study, the final effect of evaporation on the δ2H and δ18O values of shallow soil water is depleting the δ2H and δ18O values of shallow soil water, which is different from previous studies. The δ2H and δ18O values of groundwater varied little with changes of seasons and rainfalls. The δ2H–δ18O relationship lines established by various substances can also reflect the regulation of d-excess by large lakes through secondary sources.

No-tillage with straw mulching improved grain yield by reducing soil water evaporation in the fallow period: A 12-year study on the Loess Plateau

No-tillage with straw mulching (NTS) during the fallow period is an effective measure for storing precipitation and reducing soil water evaporation on the Loess Plateau of China. However, the duration of this effect of NTS during the fallow period in different cropping systems and different precipitation types is unclear. Therefore, a 12-year field experiment of two tillage methods (NTS; and conventional tillage, CT), in three cropping systems (winter wheat monoculture, WW; spring maize monoculture, MM; and winter wheat-spring maize rotation, WM) were conducted to evaluate the effect of NTS on grain yield, precipitation storage, soil water status, soil evaporation rate and cumulative soil evaporation during the fallow period in different precipitation types. Additionally, the duration for which NTS reduced soil evaporation was calculated using the linear-platform model. Our results showed that compared to CT, NTS increased precipitation storage by 35.3, 47.1 and 53.5 mm under WW, by 31.5, 31.5 and 40.4 mm under MM and by 53.2, 30.2 and 50.3 mm under WM in the wet, normal and dry fallow periods, respectively, at depths of 0–200 cm. As a result, the soil water storage at sowing was higher under NTS than that under CT. The linear-platform model showed that NTS was effective in reducing soil water evaporation for 86, 95 and 126 days under WW, 87, 81 and 110 days under MM, and 95, 104 and 121 days under WM in wet, normal and dry fallow periods, respectively. Additionally, we found that there was a large amount of cumulative soil water evaporation after the abovementioned durations in MM and WM. The path analysis indicated that NTS improved grain yields indirectly by reducing cumulative soil evaporation and increasing the soil water status at the sowing stage. Capturing precipitation when the fallow period is > 125 days may further improve yield.

Effects of attapulgite addition on soil evaporation and crack characteristics

Water is one of the most important factors limiting vegetation recovery and agricultural development in arid and semi-arid areas. The reduction of ineffective soil evaporation can improve soil water use efficiency. As a kind of clay mineral, attapulgite (ATP) plays a critical role in limiting soil evaporation due to its hydrophilicity and adsorption. In this study, three typical soils with different textures (dark loessial soil, cultivated loess soil, and sandy soil) were selected from the arid and semi-arid area of the Loess Plateau, and five ATP additions (0%, 1%, 2%, 3% and 4%) were set for conducting soil evaporation experiments under natural conditions using micro-evaporators to investigate the effects of ATP addition on different soil evaporation processes and the characteristics of evaporation surface cracks. The results showed that the cumulative evaporation and evaporation loss ratio of the same soil decreased with the increases of ATP addition when the ATP addition was <3%. When ATP was added at 3%, the cumulative evaporation and evaporation loss ratio of dark loessial soil and sandy soil decreased, while those of cultivated loess soil increased. When ATP was added at 4%, the cumulative evaporation decreased and the evaporation loss ratio increased for dark loessial soil, the cumulative evaporation increased and the evaporation loss ratio decreased for sandy soil, and the cumulative evaporation and evaporation loss ratio decreased for cultivated loess soil. The average cumulative evaporation of different soils followed an order of dark loessial soil > cultivated loess soil > sandy soil. Soil water content of ATP treatment was consistently higher than that of control throughout the whole evaporation process in the same soil. Simulations of cumulative evaporation versus the square root of time indicated that the amount of water released from the ATP-treated soil samples at the end of evaporation was higher than that of the control. After the addition of ATP, the crack area density of dark loessial soil and cultivated loess soil increased significantly, and the crack area density of sandy soil increased with the increase of ATP addition. The crack area density of all three soils reached the maximum at 4% of ATP addition. In summary, ATP addition of 3% could minimize the ineffective evaporation of soil water.

Effects of Gravity on Evaporation for Soil‐Limited Conditions

AbstractThis manuscript systematically investigates the effects of gravity during soil‐limited (Stage 2) evaporation from bare soil. Analytical and numerical solutions to the one‐dimensional Richards soil moisture flow equation are developed based on simplified hydraulic functions that depend exponentially on soil water matric potential. Semi‐infinite domains with either freely draining or hydrostatic bottom boundary conditions and finite domains with no‐flow bottom boundary conditions are considered. Cases with gravity are directly compared to those without. The simplified solutions are verified by comparison to numerical solutions with fully realistic soil hydraulic functions for two soils at the extreme ends of the range of possible soil textures. Cumulative evaporation versus time and soil volumetric water content versus depth at selected times are determined for each case from the simplified solutions. These results are reported in terms of non‐dimensional variables that are universal, spanning all soil textures and other conditions. For the semi‐infinite domain cases cumulative evaporation with gravity is reduced by several orders of magnitude for very coarse soils at times of practical interest while gravity has a negligible effect for the finest textures at those times. For the finite domain cases gravity is less important because cumulative evaporation is ultimately limited by the fixed amount of water in the profile.

ECONOMIC ANALYSIS OF PADDY PRODUCTION WITH DRIP IRRIGATION: CASE STUDY OF DARDANELLES-TURKEY

In traditional paddy production, large water losses may occur due to drainage, evaporation and deep percolation (groundwater is highly polluted). In addition, while production costs increase, it also decreases in production areas. This study has been researched together with the usability of the drip irrigation method (DI) to reduce the global footprint of water in paddy production and its economic analysis. In the experiment, two irrigation intervals (2 and 4 days), four irrigation water levels (75, 100, 125 and 150% of cumulative Class A Pan values) and three different paddy genotypes (Baldo, Osmancik and Ronaldo) were investigated. In the research, irrigation water between 513-820 mm was applied to the treatments. Actual Evapotranspiration (ETa) values are 565-855 mm; The Crop Water Productivity (CWP) ranged from 0.84-1.35 kg ha-1 m-3 and the Irrigation Water Use Efficiency (IWUE) ranged between 0.95-1.49 kg ha-1 m-3. Economical water productivity (EWP) was calculated between 0.79-1.24 $ m-3 and the cost-benefit (B/C) ratio was calculated between 1.11-2.33. When the traditional cultivation method, the ponding method in the pan, is compared to the province, it has been determined that water savings are between 70-81%. Yield according to branches was measured as 4882-10305 kg ha-1. According to the results of the research, up to 29% yield increase was achieved under the condition of applying 150% of the cumulative evaporation every 2 days.

Ice nucleation active bacteria and its mitigation on tomato (Solanum lycopersicum)

Microbes play a vital role in ice nucleation, supporting bio-precipitation, and allowing plants to live in low-water environments. A field experiment was conducted during December 2018 with two phyllosphere microorganisms’ spraying viz., Pseudomonas aeruginosa and pink-pigmented facultative methylotrophs (PPFM) and under three moisture regimes (0.6, 0.8, 1.0 IW/CPE (irrigation water/ cumulative pan evaporation) ratio) on tomato (PKM 1) in Tamil Nadu Agricultural University, Coimbatore (Tamil Nadu). A laboratory experiment was conducted to confirm ice nucleation using two phyllosphere microorganisms’ P. aeruginosa and PPFM. The bioprecipitation impacts on tomatoes were assessed using a set of physiological parameters such as photosynthetic rate, average chlorophyll Index and the ice nucleation activity (INA) assessed using tube nucleation test and scanning electron microscope (SEM). The results showed that the mean photosynthetic rate of PPFM sprayed tomato (Solanum lycopersicum) (PKM 1) plants (40.7 μmol CO2/m2/s) at 10 DAS was significantly higher than P. aeruginosa sprayed plant (38.7 μmol CO2/m2/s) under different irrigation regimes. The average chlorophyll Index value of the P. aeruginosa sprayed tomato plants (58.1) was higher than PPFM sprayed plants (56.4). The tube nucleation tests were proved that ice crystallization induced by P. aeruginosa in super-cooled buffer at - 2 to -10°C while PPFM not catalyze the buffer even after 3hours. The scanning electron microscope (SEM) indicated the P. aeruginosa growth at the upper surface of the leaf and PPFM growth more at the lower surface of the leaf compared to without inoculation of microbes on leaves. Overall, the result revealed that P. aeruginosa may assist in ice nucleation activity that will help to make artificial rain in the near future.

Response of hybrid fodder sorghum in relation to sulfur fertilization and irrigation regimes in semi-arid region of North West India

The animal feed nutritional value is dependent on the feed chemical composition and which could be affected by sulfur fertilization and irrigation regimes. Therefore, the present study was formulated to evaluate the effect of sulfur fertilization and irrigation regimes on fodder sorghum in semi-arid region. A two-year field experiment (2016/2017) was conducted on multi-cut hybrid sorghum with three moisture regimes (60 and 120 Cumulative Pan Evaporation (CPE), and no irrigation) and three sulfur (S) levels (0, 15 and 30 kg/ha S) as sub-plot treatment in split-plot design replicated thrice. Statistical analysis of the data revealed that individually irrigation scheduling at 60 CPE and sulfur application at 30 kg/ha resulted maximum plant height, leaf area index and number of tillers. The application of 30 kg/ha S observed with higher total green fodder yield which was 20.1% in 2016 and 16.8% more than control in 2017 and nearly, similar results were also obtained in relation to dry matter yield. Sulfur fertilization and irrigation at 60 CPE showed 39.5% mean reduction in hydrocyanic acid and the average crude protein of 10.5% and in vitro dry matter digestibility of 55.5% at 1st cut was recorded. Application of S and irrigation regimes improved the nitrogen and sulfur concentration in fodder. In conclusion, the application of sulfur @ 30 kg/ha through any sulfur source could be considered as the potential sulfur fertilizer in improving the injurious effects of water deficit condition of hybrid multi-cut fodder sorghum through alterations in nutrient uptake, yield and quality.

Impacts of moss-dominated biocrusts on rainwater infiltration, vertical water flow, and surface soil evaporation in drylands

Globally widespread biocrusts form a “living skin” on most dryland soils, helping govern fundamental ecosystem functions, particularly hydrological processes. However, the underlying mechanisms of biocrust effects on soil water infiltration and evaporation are still controversial. Biocrusts possibly regulate infiltration and evaporation due to their unique physicochemical properties and influence on surface soil moisture (θ), and these assumptions were verified in this study conducted on the Loess Plateau of China. The differences in vertical soil moisture distribution and flow patterns of infiltration water between moss-dominated biocrusts and bare soil were investigated through dye tracing experiments. The evaporation characteristics of biocrusts and bare soil were also obtained by weighing micro-lysimeters in both simulated and in-situ experiments. Results showed that biocrusts retarded deep soil water infiltration below ∼ 15 cm and significantly (F = 48.15, P < 0.001) decreased the stained area ratio (percentage of stained area to total area at the same soil depth) by 16% in contrast to bare soil. Because the infiltrated water was mostly retained in shallow soil (0–15 cm) in biocrust-covered soil, their ratios of low interaction flow (stained path width < 20 mm) and high interaction flow (20 mm < stained path width < 200 mm) were significantly higher (F ≥ 7.82, P ≤ 0.007) than those of bare soil. After the dye tracing experiments, the biocrusts modestly increased θ by 17% throughout the soil profile (0–50 cm), but they remarkably increased θ by 33%−78% in the top 20 cm of soil. Additionally, the biocrusts increased soil daily evaporation rate (E) by 27%−39% (with only the exception of the beginning) and the cumulative evaporation amount by 14% in contrast to bare soil over an 8-day field measurement. More importantly, the biocrust-affected soil properties, such as the contents of fine particles and organic matter, as well as saturated water content and field capacity, were closely correlated with E (|ρ| ≥ 0.52, P ≤ 0.08). Consequently, it was concluded that biocrusts restrict the depth of rainwater infiltration and increase surface θ, which may greatly enhance surface soil evaporation in the Chinese Loess Plateau.

Climate nutrient management for various sources and levels of fertilizers on soil nutrients, growth and yield of maize (Zea mays l.) in Madurai district, Tamil Nadu, India

Global climate change is expected to soil processes and properties, which are important for restoring soil fertility and low productivity. The field experiment was conducted at Research Farm, Agricultural College, and Research Institute, Madurai district, Tamil Nadu, during Kharif season 2021 to study of various sources and fertilizers' levels to influence under deficit and excess water conditions on soil fertility, growth, and yield of maize (Zea mays). The study revealed that excess and deficit water condition in moisture regime irrigations at Irrigation water / Cumulative Pan Evaporation (IW/CPE) ratio of 1.0 along with nutrient management practices (N8) 125 % Soil Test Crop Response (STCR) - NPK soil application by 1 % foliar spray of micronutrient mixture. Significantly higher of mean values available nitrogen (225 kg ha-1), available phosphorous (20.81 kg ha-1), available potassium (351 kg ha-1), dry matter production (DMP) (16,404 kg ha-1), plant height (250 cm) and yield (9,030 kg ha-1) and was comparable with IW/CPE ratio of 0.8, 0.6 along with others nutrient management practices at 100 % and 75 % STCR - NPK followed by foliar sprays 2 % NPK (19:19:19) and Pink-pigmented facultative methylotrophs (PPFM) 1 %. Hence, under a normal water availability situation, irrigation at an IW/CPE ratio of 0.8 was good enough to produce a higher yield, while under deficit and excess water conditions IW/CPE ratio of 1.0 along with125 % STCR-NPK by foliar spray of micronutrient mixture of 1 % was suitable for obtaining optimum nutrient management for enhancing soil fertility, growth and yield of maize.

Effects of Variable Proportions of Concrete Fragments on Urban Soil Moisture Transport: An Experimental and Simulation Study

In order to investigate the effects of typical anthropogenic concrete fragments on moisture infiltration and evaporation in urban soils, the effects of typical anthropogenic concrete fragments on wetting peak transport distance, cumulative infiltration, cumulative evaporation, evaporation rate, and soil profile moisture at four levels (0, 5%, 10%, and 20%) were investigated by indoor soil column experiments. The results showed that the presence of concrete fragments promoted the wetting peak transport distance and cumulative infiltration, and the promotion effect increased gradually with the increase of the ratio, but there was a threshold value, and the promotion effect was least when the ratio was 20%. When the evaporation period was 35 d, concrete fragment treatment can increase the cumulative evaporation and promote the evaporation of urban soil moisture; the promotion effect increases with the increase of the proportion, but there is a threshold value; when the proportion is 20%, the promotion effect is the smallest. The evaporation rate was consistent with the different stages of evaporation process during evaporation. The concrete fragment treatment reduced the time required for moisture to reach the same depth during infiltration; the moisture coefficient of variation of the concrete fragment treatment during evaporation showed a trend of decreasing, then increasing, and then decreasing, which increased the uncertainty of moisture in the evaporation process. The model simulation results show that the models such as the power function, Kostiakov model, and Rose model fit well, and the coefficient of determination R 2 is greater than 0.99, among which the Kostiakov model fits best. The research results can provide a theoretical scientific basis for building an efficient ecological city.

Numerical study of the impact of climate conditions on stability of geocomposite and geogrid reinforced soil walls

Geosynthetic-reinforced soil (GRS) walls using marginal soils can operate under unsaturated conditions depending on climate conditions and drainage inside the reinforced zone. Geocomposite reinforcements have been suggested to act as internal drainage layers, but their hydraulic behavior can also be strongly affected by climate conditions. Numerical analyses were conducted to observe the impact of four distinct tropical climate conditions (arid, semi-arid, humid subtropical and humid tropical) on suction profiles and stability of reinforced soil walls constructed using geogrid and geocomposite reinforcements. The climate simulation involved the incorporation of a soil-atmosphere interaction on water balance and on the unsaturated transient infiltration. Results indicate the GRS walls can operate under relatively high suction levels under arid climates in which cumulative evaporation overcomes infiltration. Any climate that has rainy seasons with consecutive rainfalls with intensities close to the infiltration capacity of soil and/or monthly cumulative precipitation higher than 200 mm/day led to critical conditions in terms of soil water saturation and stability. Under unsaturated conditions of soil, the drainage effectiveness of geocomposites is significantly reduced and adverse capillary break effects become critical.

Water Evaporation Reduction Using Sunlight Splitting Technology

The imbalance between precipitation and water evaporation has caused crop yield reduction, drought, and desertification. Furthermore, most parts of the world are short of water, including China. We proposed a low-cost polymer multilayer film to reduce water evaporation by only passing through several sunlight wavelengths necessary for photosynthesis. A series of experiments were conducted to characterize the influence of partial sunlight on the reduction of water evaporation. Evaporation containers and evaporation pans were placed in open-air (CK), under a glass shed (GS), and under a glass-shed covered with multilayer films (GMF). Our results showed a significant reduction in water evaporation under GMF. Cumulative soil surface evaporation of CK, GS and GMF over 45 days was 80.53 mm, 68.12 mm, and 56.79 mm, respectively. Under GMF, cumulative water evaporation from soil and pan surfaces decreased by 29% and 26%. The slope (β1≠0) of simple linear regression showed a significant relationship between evaporation time and cumulative water evaporation (p = 0.000 &lt; α = 0.05 shown in the ANOVA table). The correlation coefficient was more than 0.91 in all treatments, suggesting a strong positive linear relationship. This study may contribute to future drought resistance and agrivoltaic sustainability development.

The evolution of early-age cracking of cement paste cured in low air pressure environment

In recent years, infrastructure constructions have rapidly developed in plateau areas. The research on the surface cracks of cement-based materials in low air pressure environment in plateau areas is critical in improving the long-term durability of concrete structures as well as the harmony between the building and environment. In this work, the evolution of early-age cracking in cement pastes cured in low air pressure environment was examined by drying measurement, thermogravimetric analysis (TG), nitrogen adsorption-desorption, and micromorphology. The cumulative moisture loss and evaporation rate, total crack area, degree of hydration, and microstructure analyses were evaluated to analyze the evolution mechanism of early-age cracking. The results indicate that the development of early-age cracking on cement paste surfaces is related to air pressure. The moisture evaporation of cement paste accelerates in low air pressure environment, making early-age cracking and pores more noticeably exposed to the cement paste surface. Further, the cement hydration decreases and the volume of micropores and mesopores of cement paste increases in low air pressure environment, forming a loose and porous microstructure and increasing the risk of early-age cracking on the cement paste surface.

Effect of irrigation and nitrogen management on water productivity and nutrient uptake of aerobic rice

Water and nitrogen fertilizer are the two important inputs for rice cultivation. A field experiment was carried out in split plot design, with three water management treatments, irrigation at (i) 75 % Cumulative Pan Evaporation (CPE), (ii) 100% CPE, (iii) 125% CPE in the main plot, and four nitrogen management strategies, (i) 100% nitrogen applied through chemical fertiliser, (ii) 75% through chemical fertiliser + 2.5 t ha-1 vermicompost, (iii) 50% through chemical fertiliser + 5.0 t ha-1 vermicompost, and (iv) 25% through chemical fertiliser +7.5 t ha-1vermicompost in subplot. The grain yield, straw yield, water productivity, nutrient uptake and economics of aerobic rice were considerably affected by irrigation and nitrogen management. Crops receiving irrigation at 125% CPE had the highest grain yield (3618 kg ha-1), which was comparable to crops receiving irrigation at 100 % CPE. Regardless of irrigation and nitrogen management, the straw yield of aerobic rice ranged from 4127 to 5092 kg ha-1. The highest total NPK uptake by grain was recorded with nitrogen at 100 % N through fertiliser (N1), which was significantly greater than what was obtained from other nitrogen treatments and irrigation management at 100 % CPE (I100) and 125 % CPE (I125) was significantly better than irrigation at 75 % CPE (I75). Irrigation management at 125 % CPE yielded the highest gross return, net return, and B: C ratio of aerobic rice, which was comparable to 100 % CPE and 100 % N through fertiliser, 75 % N through fertiliser + 2.5 t ha-1 vermicompost, and significantly higher than other nitrogen treatments.