Agricultural Water Management最新文献

At present, the state has introduced the policy of forest Chinese herbal medicine planting planning, strictly prohibiting the planting of Chinese herbal medicine in basic farmland, coupled with the fact that the continuous cropping obstacles of Panax notoginseng have not yet been solved, which makes the area of arable land suitable for planting become less and less. However, the effect of soil moisture regulation on the growth of Panax notoginseng cultivated on sloping arable land has not been reported. Thus, the aim of this study was to investigate the impact of various irrigation levels and slopes on Panax notoginseng agronomic traits, physiological characteristics, disease attributes, biomass, and quality characteristics. During 2018–2020, a field experiment was conducted in the Panax notoginseng growing seasons with three irrigation levels (I1: 70–75% θ_FC, I2: 75–80% θ_FC, I3: 80–85% θ_FC) and three slopes (S1: 2.43°, S2: 6.38°, S3: 16.38°). The results evidenced that the photosynthetic characteristics, root hydraulic conductivity characteristics, biomass and PNS of Panax notoginseng reached the maximum value in the I2S2 treatment, and at the same time, the incidence rate of Panax notoginseng root rot was the lowest. Therefore, based on the results of this study, irrigation volume I2S2 should be regarded as the optimal slope and irrigation management strategies for reducing Panax notoginseng diseases and realizing stable yield and quality improvement of Panax notoginseng. A multi-objective optimization model was established through binary quadratic regression analysis. The findings evidenced that when the irrigation interval was 187–203 mm and the slope interval was 5–10.7°, Panax notoginseng had the lowest incidengce rate, and the root biomass and saponin content reached > 95% of the maximum values at the same time.

Predicting the risk of diminished wheat yields caused by drought under future climate change climate is essential for the long-term sustainability of agriculture. Although studies have explored the relationship between drought and crop yield loss, the precise thresholds triggering yield losses in the future remain unclear. In this study, we established a conditional probability framework for drought trigger thresholds at various yield loss levels in China’s winter wheat regions in the future based on copula functions. The primary drivers influencing the dynamics of drought thresholds were evaluated using a random forest model. The results revealed that the projected drought thresholds for the baseline period (1981–2020), near future (2021–2060), and far future (2061–2100) ranged from –2.1 to –1.2, –0.8 to –0.6, and –1.2 to –1.0, respectively, implying that the drought thresholds for winter wheat yield loss in the future firstly rises and then declines. This trend was primarily due to the increased contribution of precipitation (P_re) (from 24.0% to 31.5%) to the drought threshold in the far future, coupled with a decrease in the contribution of temperature (T_mean) (from 37.1% to 30.4%). This shift suggested that the increased P_re might alleviate the adverse effect of high temperature on yield in the future. The average drought thresholds for yield loss were higher in the Southwest (–1.0 to –0.6) and Xinjiang (–1.1 to –0.7) winter wheat regions, where mild drought occurrences led to a 30% yield loss (70th percentile). T_mean was the primary driving factor for the dynamic changes in future drought thresholds. The research findings provide scientific guidance for future agricultural water resource allocation and drought risk management.

Whole orchard recycling (WOR) is an emerging practice in perennial cropping systems and is an alternative to open or cogeneration burning. It is an orchard removal practice that incorporates large amounts of woody biomass back into the soil system. In this study, we utilized a soil hydrological model (HYDRUS-1D) to evaluate the seasonal effects of WOR on water movement and nitrogen (N) retention for a newly established almond orchard on a typical sandy loam soil in the Central Valley of California. Soil moisture and N content were monitored across the first five growing seasons from 2018 to 2022. The model was able to track seasonal moisture fluctuation nicely compared to observed data. Additionally, an increase in soil moisture was measured in the WOR treatments in surface soil (i.e., 0- to 15-cm depths) where biomass was incorporated, and N leaching was reduced when compared to the unamended control. Simulations suggest that with WOR, irrigation can be reduced by up to 20 % during the tree establishment stage with minimal effect on root water uptake. This reduction in applied water can increase farm water use efficiency and reduce operational expenses, e.g., cost of water and pumping. Likewise, the reduction in N leaching observed in both predicted results and laboratory analysis can further cut farm capital costs, e.g., fertilization, and lessen orchard environmental impacts. Overall, results from our simulation show a positive effect of WOR on soil ecosystem services and can potentially be a profitable strategy for orchard turnover. The results have important implications in reducing groundwater nitrate contamination in irrigated agriculture in the Central Valley of California and applicable to most parts of Southwestern United States.

Sodic soil formation, following irrigation with saline-sodic water has become a major concern due to its negative impact on soil structure, crop growth and yield. However, specifically in orchards, little knowledge exists regarding the reclamation of sodic soils. Our objective was to examine the effects of different amendments on soil reclamation and crop performance of olive grove. The study was conducted in a 14 years old olive grove, grown in a clayey soil, in which irrigation started in 2008 using saline-sodic water resulting in sodium adsorption ratio (SAR) ranging from 22 to 40 (mmol_c L⁻¹)^0.5. Six treatments were studied: control (no amendments applied), CaCl₂, MgCl₂ and H₂SO₄ that were added to the irrigation water, and gypsiferous material (GM) that was added to the soil surface prior to the rainy season and either left spread or tilled into the upper soil layer. Soil samples were analyzed for selected saturated extract properties and for aggregate stability. Additionally, plant parameters including yield, trunk expansion, fruit oil content, and tree nutritional status were measured. The results showed that the lowest SARs were observed in the GM and GM till treatments at 0–30 cm [5.0 and 3.3 (mmol_c L⁻¹)^0.5, respectively], while CaCl₂ and MgCl₂ treatments had the lowest SARs at 30–90 cm [16.2 and 17.1 (mmol_c L⁻¹)^0.5, respectively]. GM and CaCl₂ application raised the electrical conductivity (EC) levels to 6.9 and 7.6 dS m⁻¹ respectively. GM addition resulted in the most stable aggregates which was associated with a significant improvement in average tree productivity of 33 kg/tree. Conversely, MgCl₂ had the lowest average yield, of 21.3 kg/tree, which was attributed to the high concentration of Mg that led to some nutrient imbalances. In conclusion, the current study showed the efficacy of different amendments based on Ca for remediating sodic soil in drip-irrigated orchards.

Intelligent fertigation is a sustainable solution for optimising water and fertiliser input, thus minimising environmental pollution in vegetable cultivation facilities and reducing labour costs in agricultural practices. It is important to optimise irrigation scheduling parameters to specific crops to ensure water and nutrient use efficiency. A field experiment was conducted in Shouguang, Shandong Province, to investigate the effects of irrigation scheduling with different treatments (farmer drip irrigation FI, intelligent irrigation II1, and intelligent irrigation II2) on tomato growth, irrigation water and nutrient use efficiency over two growth seasons. Intelligent irrigation II1 and II2 utilised FDR sensors to control the moisture range within 80–95% and 80–85% field capacity (FC) for automatic irrigation scheduling, respectively. Intelligent irrigation (II1 and II2 treatments) reduced irrigation rate by 24.3–63.8% in comparison with FI treatment, significantly increasing total dry matter accumulation, nutrient uptake, yield and fruit quality of tomato. II2 treatment further reduced the irrigation rate by 31.6–32.3% compared to II1 treatment, with no significant difference in tomato yield and quality. Root dry matter, root-shoot ratio, 0–2 mm diameter root length and root surface area, 0–1.5 mm diameter root tips, and >3.5 mm diameter root volume were significantly increased under intelligent irrigation treatments. Positive correlations between irrigation water productivity; nitrogen, phosphorus, and potassium use efficiency; and the indices of length, surface area, tips, and volume of roots were highly significant. Intelligent fertigation system (IFS) maintained soil moisture within a suitable range through high-frequency irrigation scheduling, promoted the growth of 0–2 mm diameter roots, which were responsible for absorbing, acquiring, and transporting water and nutrients in the soil, and reduced water loss and nutrient leakage. Taken together, the intelligent fertigation system presented herein is an effective fertigation strategy to improve irrigation water and nutrient use efficiency.

Given the current scarcity of freshwater resources, it is imperative to explore new agricultural management options to sustainably enhance food production. Desalinated seawater (DSW) presents a promising solution for irrigation in water-stressed regions. However, its application in perennial crops has been poorly assessed, potentially posing challenges to existing cultivation practices due to higher associated costs, salinity, and the presence of potentially harmful elements, notably boron (B). To address these uncertainties, a three-year experiment was conducted to evaluate the short-term effects of irrigation with DSW on a ‘Rio Red’ grapefruit orchard. Four irrigation treatments were assessed: DSW, freshwater (FW), a 1:1 mixture of DSW and FW (MW), and DSW with reduced B concentration (DSW–B). At present, the young age of the trees (3.5 years) and their grafting onto a five-year-old rootstock at the beginning of the experiment likely facilitated rapid foliar mass development and prevented the accumulation of phytotoxic elements up to critical levels. However, local DSW consistently exceeded recommended citrus thresholds for B (0.5 mg L^–1), sodium (Na⁺; 115 mg L^–1), and chloride (Cl^–; 250 mg L^–1) in irrigation water, resulting in significant concentrations of B (2.1 mg kg^–1), Na⁺ (504 mg L^–1) and Cl^– (476 mg L^–1) in soil. Moreover, these levels led to concentrations in leaves close to defined thresholds in the case of Na⁺ (0.25 g 100 g^–1), and exceeded them in the case of B (>250 mg kg^–1). Although fruit quality remained unaffected, variability in yield among trees and the cost disparity between water resources, resulted in slight fluctuations in the income-outcome balance during initial cultivation years. Our findings offer insights into the irrigation of sensitive crops with DSW, aimed at mitigating potential soil and plant harm from early accumulation of phytotoxic elements. Further research is warranted to explore the impact of both single and sustained DSW usage for irrigation purposes.

This paper highlights the evolution and impact of the SWAP model (Soil – Water – Atmosphere – Plant), which was initiated by R.A. Feddes and colleagues fifty years ago, in 1974. Since then, the SWAP model has played a crucial role in the advancement of agrohydrology. This paper highlights some major advances that have been made, especially focussing on the last fifteen years. The domain of the SWAP model deals with the simulation of the soil water balance in both unsaturated and saturated conditions. The model solves the Richards equation using the water retention and hydraulic conductivity functions as described by the Van Genuchten – Mualem equations. Bimodal extensions of the Van Genuchten - Mualem relationships have been implemented, as well as modifications near saturation and addressing hysteresis. An important sink term in the Richards equation is root water uptake. Crop development plays an important role in a robust simulation of root water uptake. That is why a link has been made with the dynamic crop growth model WOFOST. Instead of using a prescribed crop development, a distinction between potential and actual crop development is calculated by reducing the potential photosynthesis as a result of water or oxygen stress. Since the early days of SWAP, empirical and macroscopic concepts have been used to simulate root water uptake. Recently two process-based concepts of root water uptake and oxygen stress have also been implemented. Another important sink-source term in the Richards equation is the interaction with artificial drains. In SWAP, drainage can be simulated by either using prescribed or simulated drain heads and simulation of controlled drainage with subirrigation is possible. Finally, we briefly elaborate on three studies using SWAP: water stresses in agriculture in the Netherlands, regional water productivity in China, and controlled drainage with subirrigation. We finish discussing promising developments for the near future.

Water-stressed regions like Kenya rely on saline water sources, which can pose serious health hazards if not treated. While desalination is a burgeoning solution, safe disposal of desalination brine is often infeasible or too expensive. To circumvent this disposal challenge, we examine the maximum desalination recovery ratio (RR_max) for which desalination brine can safely be reused for many agricultural applications. Water samples from the Mara Triangle and data from past studies were collected and analyzed to measure contaminant concentrations against established safety limits of salinity and potentially hazardous elements for multiple agricultural use cases. The results suggest that high water recoveries were possible in the Mara Triangle, with the maximum recovery ratio reaching greater than 94% and 98% for crop irrigation and livestock watering, respectively. Brine reuse in this region was mostly limited by salinity, with Boron content ranking second. The most salt-tolerant crops (i.e., barley, sorghum, and wheat) were shown to be cultivable in all locations. According to calculations of the Heavy Metal Evaluation Index, groundwater in the Mara Triangle was generally safer for direct use by all users than the surface waters sampled in the past Lake Victoria and Nairobi studies.

In both arid and semi-arid regions, adopting field mulching can effectively optimize soil moisture distribution, enhance crop yields, and improve water productivity. While acknowledging its advantages, field mulching seems insufficient for maintaining high crop productivity due to the increasing frequency of extreme weather. Furthermore, drought often coincides with critical crop growth stages, necessitating the implementation of agricultural irrigation to ensure normal crop growth. Accordingly, we conducted a three-year field experiment from 2021 to 2023 including three typical field mulching methods (no mulching, NM; straw mulching, SM; plastic film mulching, FM) and three supplementary irrigation strategies (irrigated at the branching stage (V4), W1; irrigated at the pod-filling stage (R2), W2; irrigated at both the V4 and R2 stage, W3). Throughout the entire growth period, we monitored soil moisture conditions for each treatment, measured leaf physiological parameters at crucial growth stages, and assessed soybean yields and water productivity (WP). Our findings indicated that, relative to SM and NM, FM maintains optimal soil moisture balance, augments chlorophyll content, and enhances photosynthesis, resulting in an average yield increase of 17.0% and 38.3% over three growing seasons. Additionally, supplementary irrigation also significantly affects the growth and seed yield of soybean. FMW2 achieved the higher seed yield (4307.5 kg ha⁻¹, 3-year averaged), had insignificant difference with the highest seed yield of 4568.6 kg ha⁻¹, both significantly higher than other treatments. Similarly, the leaf area index, chlorophyll content, net photosynthetic rate (P_n) and transpiration rate (T_r) also presented insignificant difference between FMW2 and FMW3, while WUE_leaf (P_n/T_r) of FMW2 obviously higher than that of FMW3. As a result, FMW2 achieved the highest WP of 12.2 kg ha⁻¹ mm⁻¹ over the three growing seasons, compared to the three-year average of the other treatments, the increase ranges from 5.6% to 46.7%. In summary, the FMW2 treatment optimized water distribution to meet the water demands of soybeans during the reproductive growth stages, achieving a beneficial balance between soybean seed production and WP by regulating leaf functional parameters. Future research will explore more specific irrigation scheduling techniques (e.g., precision irrigation, deficit irrigation, and sensor-based irrigation management systems) while integrating innovative agricultural film materials (e.g., biodegradable films) to further enhance crop resilience and productivity under evolving climatic conditions.

Adopting drought-tolerant (DT) cultivars is an effective strategy to sustain maize (Zea mays L.) production under water shortage. Optimizing plant density is an important management practice for improving maize yield. In a two-year field trial, the response of yield, actual evapotranspiration (ET_{c act}), and water productivity (WP) to plant density (6, 7.5, 9 plants m⁻²) was assessed under irrigated and rainfed conditions using a DT (ZD958) and a drought-susceptible (DS, ZY309) maize cultivar, and additionally, the comparison of soil water depletion will be conducted among soils growing different DT maize varieties. Under rainfed, average yield, ET_{c act}, and WP were 24.7%, 8.6% and 14.8% greater in ZD958 than ZY309, respectively. When density increased from 6 to 9 plants m⁻², for ZD958 and ZY309 ET_{c act} remained relatively constant, whereas their yield and WP first increased and then decreased and ultimately reached their maximum at 7.5 plants m⁻². Under irrigation, increasing density (6–9 plants m⁻²) significantly increased yield and WP for ZD958, but for ZY309, yield and WP were not significantly impacted. Yield across seasons did not differ between cultivars at 6 and 7.5 plants m⁻², and ZD958 had a 10.2% yield advantage over ZY309 at 9 plants m⁻². The findings imply that DT cultivar showed greater high density tolerance than DS cultivar and thus higher optimal density under irrigation. Under rainfed, both cultivars had similar density tolerance and optimum density, whereas DT cultivar had stronger drought tolerance than DS cultivar, which could explain DT cultivar’s greater yield and WP. This study indicate that DT cultivar showed higher and more stable yields than DS cultivar across rainfed and irrigated conditions when grown at optimal densities. Thus, sustainable maize production could be achieved by adopting DT cultivars and optimizing density for different conditions in the study region.