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Aims Deep soil resources was not well quantified under dryland conditions. This study aimed to quantify the changes of deep soil water, soil organic carbon (SOC), and total nitrogen (TN) in alfalfa pasture, and identify the relationships between root density and their changes.Methods Field experiment was conducted in the Loess Plateau in 2020 and 2021. Soil water, SOC, and TN contents and alfalfa root density to 1000-cm-depth were measured in alfalfa pastures and an annual crop reference field.Results Soil water depletion by alfalfa mainly occurred in the first six years with a depletion rate of 41.6, 49.1, and 62.1 mm year-1 in the shallow (0-200 cm), middle (200-500 cm), and deep (500-1000 cm) soil layers, respectively. Total depletion after six and 19 years were 916.8 and 1049.4 mm respectively. SOC content in all layers increased and peaked six years after planting, with total storage in the 0-1000-cm-profile of 74.6 kg m-2, 43.3% higher than in the reference field. TN storage in only the shallow layer continuously increased and was 52.5% higher than that in the reference field after 19 years. Root density explained the changes of soil water in the shallow and deep soil layer, SOC in the shallow and middle layer, and TN only in the shallow soil layer.Conclusions Although alfalfa pasture continuously reduced deep soil water, it showed great potential for soil carbon and nitrogen sequestration. It should be stopped early (≤6years) to increase water sustainability and maintain carbon and nitrogen sequestration efficiencies.

Fallow-winter wheat (Triticum aestivum L.) (F-W) is the major cropping system for wheat production on the Loess Plateau of China. Integrating forage crops into the summer fallow season could improve crop yield, water productivity, and rainwater use efficiency, but this process is limited by the inter- and intra- annual variable precipitation. A 3-year (2016–2019) field experiment was conducted on the Loess Plateau to investigate the effects of fallow-winter wheat, oat (Avena sativa)-winter wheat (O-W), soybean (Glycine max)-winter wheat (S-W), and vetch (Vicia sativa)-winter wheat (V-W) systems on dry matter yield, water use, water productivity, and precipitation use efficiency under three interannual rainfall scenarios: a 30% decrease in rainfall (R-30%), normal rainfall (CK), and a 30% increase in rainfall (R+30%) by a rainfall-collection-redistribution device. In 2017–2018, under the CK scenario, the F-W, O-W, S-W, and V-W system wheat yields were 3.39, 3.63, 4.30, and 3.24 t ha−1, respectively, and the system yield values were 11.28, 16.72, 16.40, and 14.27 t ha−1, respectively. Compared to the CK scenario, the F-W, O-W, S-W, and V-W system yields increased by 22.9%, 34.5%, 20.4%, and 33.8% in 2016–2017 under the R+ 30% scenario, but the system water productivity decreased by 19.9%, 41.8%, 19.6%, and 32.4% in 2017–2018 under the R-30% scenario. Compared to those of the F-W system, the O-W, S-W, and V-W system yields significantly increased by 48.2%, 45.4%, and 26.5%, respectively, and the system water productivity increased by 51.5%, 47.3%, and 25.17%, respectively, in 2017–2018 under the CK scenario. The system precipitation use efficiency also increased by 29.3%, 42.9%, and 28.9% in 2018–2019 under the R+ 30% scenario. Across the three growing seasons, the F-W system had the highest wheat yield in the dry growing season. The S-W system had the highest dry matter yield, water productivity, and precipitation use efficiency in the normal and wet growing seasons. Therefore, we recommend the F-W system for local farmers when considering saving more soil water and maintaining wheat yield in the dry growing season. In normal and wet growing seasons, we recommend the S-W system for local farmers considering that the system increases productivity and improves environmental sustainability.

In strip intercropping systems, different crop rows in a complete strip usually behave differently in growth dynamics and have distinct contribution to the final yield of the system, so resources capture and utilization processes of different crop rows should be treated separately in the performance evaluation of the whole system. This study was conducted to investigate the differences in light capture among different crop rows in wheat/maize strip intercropping systems. The field experiment comprised four planting patterns: monoculture wheat, monoculture maize, six rows of wheat alternated with two rows of maize (I62), and twelve rows of wheat alternated with four rows of maize (I124). A geometrical radiation transmission model was modified to estimate instantaneous light capture by different intercropped rows, which was tested with photosynthetically active radiation (PAR) measured above and beneath the intercrop canopy. The results demonstrated that the model accurately predicted PAR transmitted through the canopy with mean absolute error, root mean square error (RMSE) and normalized RMSE of 60.2 μmol m−2 s−1, 82.6 μmol m−2 s−1 and 5.2% respectively for I62 and of 65.9 μmol m−2 s−1, 95.3 μmol m−2 s−1 and 5.7% respectively for I124. With assistance of the model, we found that border rows in wheat strip intercepted far greater amount of both direct and diffuse PAR than the inner rows, whereas maize border rows showed no advantage in PAR absorption due to its canopy development was constrained by the competition from wheat strip. Canopy structure character showed positive effects on radiation interception in wheat border rows and all maize rows, and plant phenotypic plasticity showed positive effects on wheat border rows but negative effects on maize border rows. The radiation transmission model presented in this work was proved to be a useful tool for calculating spatial and temporal variability of radiation in strip intercropping systems and it can be further served as a base for modeling the plant growth dynamics in strip intercrops.

The lack of reliable estimation of water demand in drought study has been an important obstacle in efforts for characterizing the variability of water consumption and its effects on drought monitoring and prediction, particularly over water-stressed regions. This study evaluated the performance and the contribution of three modified water demand estimates in drought modeling, including Penman–Monteith (PM) method, dual-source potential evapotranspiration model (2S PET model), and climatically appropriate for existing conditions precipitation ( P^). The results show that Standardized Moisture Anomaly Index based on P^ shows the highest correlations with different types of drought evidence, demonstrating that the P^ as a water demand metric performs the best in drought modeling over water-stressed regions. Standardized Precipitation Evapotranspiration Index based on 2S PET model performs better than that based on PM equation. Although the 2S PET model is physically superior to PM equation over agricultural or water-stress regions where the plant canopy is not “closed,” the limitations of using PET as water demand estimates in drought study still exist. Theoretically speaking, the actual water demand in non-humid regions should be highly associated with the climatically averaged water supply capability (precipitation, P), and the contributions of water demand and supply to drought indices are generally balanced in any region, which is realistically reflected by the relationships between P and P^. On the contrary, the magnitude and contribution of PET2S and PETPM were always higher than P over water-stressed regions, which could result in a water imbalance and generate more systemic errors in drought identification. Copyright © 2016 John Wiley & Sons, Ltd.

How evapotranspiration (ET) and its partitioning in agroforestry systems are influenced by canopy structure as well as soil water availability is not well explained. Modeling work was combined with field experiment in this study to investigate the interaction of ET and soil water conditions in an apple tree (Malus pumila M.) and cocksfoot (Dactylis glomerata L.) agroforestry. The experiment was conducted in 2016–2018 in an apple orchard at a spacing of 4 m × 4 m on the Loess Plateau of China. The three tested planting patterns were: monoculture apple tree with clean tillage (CT), agroforestry with 2.4-meter-wide cocksfoot strips between tree rows that harvested frequently to maintain a low coverage (LC), and agroforestry with cocksfoot of a greater coverage (GC). The multi-source ET model developed for intercropping system was improved by considering the effects of large height difference of different species in agroforestry on water vapor transporting resistances, then the improved ET model was combined with a soil water balance model to simulate ET partitioning. Soil water content in 0–200 cm layer, seasonal ET calculated with soil water balance model, and directly measured understorey ET were used to validate the model. Results showed that the root mean square error (NRMSE) for simulated soil water content ranged from 7.3% to 10.1%, and NRMSE for simulated total ET and understorey ET were only 3.9% and 4.2% respectively. Transpiration of apple tree in GC and LC was reduced by 21.3−32.5% and 12.3−24.2% after applying agroforestry, the reduction was mainly attributed to the decrease in soil water content. Planting cocksfoot also reduced soil evaporation by 21.5−27.6%, total ET in the agroforestry was only changed by − 4.9–6.7% compared to CT. Scenario simulation indicated that the negative effects of cocksfoot on apple tree transpiration linearly decreased with increase of the maximum LAI of apple tree and exponentially increased with the increase of strip width of cocksfoot. An 18-year simulation showed that GC and LC reduced the transpiration of apple tree by 7.3% and 2.1% respectively, but did not accelerate soil water depletion in the deep soil layers. Therefore, agroforestry with well managed understorey grain or cover crops is encouraged to be applied in our study area to increase the production and provide ecological services. Water transportation model developed in this study could also be used to evaluate water use and improve the design and management of other agroforestry systems.

Irrigation plays a fundamental role in sustanining the productivity of agricultural systems in the inland arid area of midwestern China. Deficit irrigation can help to balance yield outcome and water input. Few studies have investigated the impact of deficit irrigation on alfalfa performance, which shows great differences from grain crops in water requirement and management strategy. The study aimed to evaluate the effect of regulated deficit irrigation on forage yield and quality of alfalfa (Medicago sativa). A three year trial was carried out with two irrigation systems (flood irrigation, FI and subsurface drip irrigation, SDI) and seven contrasting regulated irrigation treatments, and alfalfa growth, productivity and water use were measured. Under both irrigation systems, alfalfa forage yield decreased with decreasing irrigation amount under whole stage irrigation, while forage quality improved. However, the performance of alfalfa was different when deficit irrigation was applied at various growth stages. Compared with other deficit irrigation treatments, regulated deficit irrigation at single growth stage usually led to a higher yield. There was an exponential relationship between plant height and forage yield (R2 = 0.62 for FI and R2 = 0.57 for SDI) and a linear relationship between leaf area index and forage yield (R2 = 0.56 for FI and R2 = 0.64 for SDI). There was a negative correlation between forage yield and quality, which was closer to some quadratic relationships. Therefore, regulated deficit irrigation can help to achieve an ideal yield (up to 34.9 t/ha) and quality in this area. In the inland arid area of midwestern China, subsurface drip irrigation showed a higher irrigation water use efficiency (13.8–84.4 kg/(ha mm)) than flood irrigation (10.8–66.6 kg/(ha mm)) for alfalfa production. With limited water supply, deficit irrigation at single growth stage usually maintained a higher forage yield compared to slightly stressed irrigation during the whole growth. Deficit irrigation at the branching stage led to more negative effect on forage yield compared to other single stages.

Alfalfa (Medicago sativa L.) is the most widely planted forage crop on the semiarid Loess Plateau of China. It has a deep rooting system and high evapotranspiration rate, and how water content in deep soil is affected by continuous alfalfa planting and how soil water recovery responds to the conversion of alfalfa to annual crops are not fully understood. In this study, we conducted a meta‐analysis of soil water content data taken from 45 published studies conducted at 21 sites of the Loess Plateau to evaluate the effects of continuous alfalfa planting and the conversion of alfalfa to annual crops on soil water conditions in the 0−1500 cm profile. Response size (RS), the relative change in soil water content after initiating and stopping alfalfa compared to the long-term cropland, was calculated. The results show that the RS values in all soil layers from 100 to 1400 cm were significantly lower than zero (P 10-year-old alfalfa fields, respectively. After converting alfalfa into annual crops for 1–28 years, the soil water content in the 0−300 cm layer was recovered, but that in the 300−1000 cm layer was still significantly lower than that in the reference field (P

Cover cropping in orchards has been advocated on the Loess Plateau of China to prevent soil erosion and provide additional forage production; however, the effects of cover crops on water use processes in orchards have not been fully investigated and soil water sustainability in the system is still unclear. This study was conducted to investigate the effects of intercropping cocksfoot (Dactylis glomerataL.) and cocksfoot cutting management on soil water balance, evapotranspiration (ET) and its partitioning, and production in an apple orchard (Malus pumila M.). Field experiments were conducted at Qingyang experiment station in 2016-2018. The apple trees were at a spacing of 4 m × 4 m, and three soil management patterns were applied: clean tillage (CT), 2.4 m-wide cocksfoot strips set up between tree rows that were harvested with a high frequency (HF), and cocksfoot strips harvested with a low frequency (LF). The results showed that decline in soil water content in the dry season was promoted in the cover crop treatments. In tree interrow positions the soil water depletion was increased only in the 0–100 cm soil layer while in tree row positions the depletion in both the 0–100 and 100–200 cm soil layers was significantly increased (P 0.05), and 2.07–6.32 t ha-1 additional forage biomass was produced. Cocksfoot with greater harvesting frequency is suggested to be applied to conserve soil and water in apple orchards in our study area.

Integrating forage crops into traditional wheat and maize cropping systems is a potential alternative for increasing fodder supply while maintaining sustainable grain production on the Loess Plateau of China. This study was conducted to evaluate the biomass and crude protein production as well as the soil water balance and water use efficiency of oat (Avena sativa L.) and common vetch (Vicia sativa L.) intercrops compared to sole crops. Field experiments were conducted during the fallow season after wheat harvesting (mid-July to late October) in 2011 and 2012. Five cropping patterns were tested: sole oat (SO), sole common vetch (SV), and three intercrops of oat to common vetch in rows of two to one (I21), one to one (I11), and one to two (I12). Rainfall in the middle and late growing season in 2011 was abundant, but the early season was very dry. Rainfall in 2012 was less than average but distributed similarly with the long-term pattern. When harvested in late September, I21 showed the greatest aerial biomass and crude protein yield of 3.20 and 0.36 t ha−1, respectively, in 2011, and SO showed the greatest biomass and crude protein yield of 5.70 and 0.51 t ha−1, respectively, in 2012. When harvested one month later, the crude protein content of common vetch maintained a large value, while that in oat was reduced by 21 %–29 %. I21 still showed the greatest biomass and crude protein yield in 2011, and in 2012, SO had the highest biomass yield of 7.74 t ha−1 while SV showed the highest crude protein production of 0.65 t ha−1. The land equivalent ratio was above unity in all intercropping systems in 2011 and below unity in all systems in 2012. The soil water in the 0−120 cm layer in all treatments was fully recharged in 2011, but depleted in 2012, and the depletions in SV and I12 were significantly less than that of the other treatments (P

Diversifying the summer fallow (F)-winter wheat (Triticum aestivum L.) (W) cropping system by replacing summer fallow with forage crops could increase forage yield and precipitation use efficiency in the Loess Plateau region of China. However, its influence on protein productivity is unclear and it is unknown whether improvement in protein productivity will increase soil water extraction and economic input. A three-year (2011–2013) field experiment was conducted to investigate the rotational effect on system productivity, economic benefit, and sustainability when summer fallow was replaced with forage rape (Brassica napus L.) (R) and common vetch (Vicia sativa L.) (V). Results showed that the rotation system with forage crops did not alter soil water storage of subsequent winter wheat. Compared with the FWFW rotation system, the rotation system with forage crops improved precipitation use efficiency of crude protein yield (PUECP) and system water use efficiency of crude protein yield (WUECP) by 20 and 28% respectively. The greatest crude protein productivity (CPyield) was achieved with the RWRW rotation system, followed by the FWRW and RWVW systems, and CPyield with these systems was 51, 21, and 36% greater than that with the FWFW system, respectively (P

Wheat ( Triticum aestivum L.)/maize ( Zea mays L.) strip intercropping is widely practiced in arid regions of northwestern China because of its high land use efficiency. However, its sustainability has been questioned because it consumes much more water than sole cropped wheat or maize. The present study was conducted to investigate the effects of water limitation on the yield advantage and water use of this system. Three field experiments were conducted in the Hetao Irrigation District in Inner Mongolia during the growing seasons of 2012–2014. Each experiment comprised two water applications, in which one was full irrigation and the other was a period of water limitation during the co-growth period of intercropping. The interspecific competition in wheat/maize intercropping was intensified by water stress. For water limitation applied during the wheat booting/maize V5 stage (Exp. I, second irrigation was not applied), the yield advantage of intercropped wheat (IW) over sole wheat was enhanced, whereas that of intercropped maize (IM) over sole maize was reduced compared with full irrigated treatments; for water limitation applied during the wheat jointing/maize V2 stage (Exp. II, first irrigation was not applied), the yield advantages of both IW and IM were greatly reduced; for water limitation applied during the wheat grain filling/maize V9 stage (Exp. III, third irrigation was not applied), the yield advantage of IW was slightly improved, whereas that of IM was reduced. The yield advantage of intercropping under limited irrigation was 25%, 3%, and 18% in Exps. I–III, respectively, whereas that under full irrigation ranged between 22 and 24%. Under well-watered conditions, wheat/maize intercropping used 24–29% more water than the weighted means of sole crops with the water use efficiency equivalent to sole crops. After the application of water limitation, 60 mm irrigation water was saved by intercropping every year, whereas the reduction of water use ranged from 25.1 to 70.8 mm; the changes in water use of intercropping relative to sole crops was reduced to 18–24%; the changes in water use efficiency stayed at nearly zero in Exps. I and III but decreased to a value of −13% in Exp. II. These results indicated that water limitation could be applied during wheat booting or filling stage in wheat/maize intercropping to save irrigation water in our study area.

Relay strip intercropping of spring wheat and maize is practiced on a large scale in arid regions of northwestern China. In this study, a field experiment was carried out during 2012 and 2013 growing seasons to examine water use and crop coefficient of this system in an arid environment. The experiment comprised three treatments: sole-cropped wheat, sole-cropped maize, and wheat–maize intercropping. The grain yields of both intercropped wheat and maize were enhanced by intercropping. The gross economic profit for wheat–maize intercropping was 16.4% lower than that of sole maize and 95.4% higher than that of sole wheat. The overall land use efficiency was improved by intercropping. The time course of leaf area index in intercropping had the similar trends to those in sole crops with relatively low values, which never exceeded 3.0 m2 m−2 throughout both growing seasons. Compared to weighted means of the sole-cropping systems, wheat–maize intercropping used 26% and 24% more water in 2012 and 2013, respectively. The water-use efficiency of intercropping was nearly the same as the weighted means of the sole crops. Due to the incomplete groundcover in intercropping plots, more water was consumed as soil evaporation. Averaged over two seasons, the ratio of soil evaporation to actual evapotranspiration was 33.4, 20.7 and 24.1% for intercropping system, sole-cropped wheat and sole-cropped maize, respectively. Crop coefficient (Kc) of sole-cropped wheat was 0.19 ± 0.02, 1.05 ± 0.07, and 0.42 ± 0.09 at the initial, mid and late season in two seasons, respectively. Kc value of the sole-cropped maize was 0.22 ± 0.03, 1.10 ± 0.06 and 0.60 ± 0.02 at the initial, mid and late season, respectively. The Kc values of the wheat–maize intercropping system varied in 0.21 ± 0.03, 0.89 ± 0.05, and 0.78 ± 0.06 at the initial, middle and late wheat growing season, and in 0.85 ± 0.03 and 0.61 ± 0.01 at the middle and late maize growing season, respectively. Therefore, longer growing season and incomplete ground cover are the main factors that resulted in higher water use for wheat–maize intercropping compared to sole crops. Results of this study can help to improve the irrigation efficiency for the wheat–maize strip intercropping system.

Background Breast cancer is the most common invasive cancer to affect women in the world. Studies showed tumor-infiltrating lymphocytes can exhibit both beneficial and harmful effects on the biology and clinical outcome of breast cancer, the conclusion still remains incomplete. Here, we conducted a meta-analysis to evaluate the relationship between tumor-infiltrating lymphocytes and breast cancer. Methods A comprehensive search strategy was used to search relevant literatures in PubMed and the ISI Web of Science. The correlation among TILs and breast cancer clinicopathological features and prognosis was analyzed by using Review Manager 5.3 and Stata 12.0. Result Seventeen eligible studies consisting of 12,968 participants were included. We found that higher value of tumor-infiltrating lymphocytes had no relationship with breast cancer clinicopathological variables. Interestingly, it was correlated with response to neoadjuvant chemotherapy in majority (pooled RR 2.43, 95 % CI 1.99–2.97). Moreover, higher value of total tumor-infiltrating lymphocytes (both intraepithelial and stromal) was associated with better prognosis (pooled HR 0.88, 95 % CI 0.83–0.94), whereas some subtypes predicted a worse prognosis. Conclusion This meta-analysis indicated that high value of total TILs is not associated with breast cancer clinicopathological features, but can predict a favorable outcome for neoadjuvant chemotherapy in majority except for hormone receptor (−) subtype. And higher total TILs (both intraepithelial TILs and stromal TILs) may be the potential better prognostic indicators, while some subtypes like PD-1+ TILs and Foxp3+ TILs show a worse prognosis. Electronic supplementary material The online version of this article (doi:10.1007/s12094-015-1391-y) contains supplementary material, which is available to authorized users.

Intercropping can improve productivity per unit incident radiation by increasing the interception of solar radiation and/or maintaining higher radiation-use efficiency (RUE). This study examined the changes in radiation interception and RUE of spring wheat and spring maize after the initiation of intercropping. The field experiment comprised four treatments: wheat only, maize only, six rows of wheat alternated with two rows of maize (I62), and twelve rows of wheat alternated with four rows of maize (I124). The results demonstrated that per row, wheat in I62 and I124 intercepted 17% and 9% more radiation, respectively, than the wheat sole-cropping system and maize in I62 and I124 intercepted 28% and 26% more radiation, respectively, than the maize sole-cropping system. The RUE values were 3.10 and 3.19 g MJ−1 for maize in I62 and I124, respectively, lower than that for the maize sole-cropping system (3.51 g MJ−1). No significant difference was observed between the RUE values of intercropped and monoculture wheat. The harvest index of maize was identical in all systems, while that of the wheat was enhanced by intercropping. The grain yields of wheat in I62 and I124 were 29.2% and 10.8% higher, respectively, than that of sole wheat on per row basis and the grain yields of maize in I62 and I124 were 16.8% and 15.0% higher, respectively, than that of sole maize. Thus, increased radiation capture was the primary factor responsible for the high productivity of the wheat/maize intercropping systems. A simple model was developed to estimate radiation interception and partitioning in strip intercropping systems, considering the heterogeneity of leaf distribution in both the horizontal and vertical directions. The model may also be applicable to other strip intercropping systems.

Relay intercropping of spring wheat and maize is practiced on a large scale in northern China. In order to provide information on productivity and nitrogen use for spring wheat/maize intercropping, a two-year experiment under three N levels and three cropping systems (monocultured wheat, monocultured maize, and intercropped wheat and maize) was carried out in the Hetao Irrigation District of the Inner Mongolia Autonomous Region, to quantify and characterize the growth and yield of the wheat and maize and determine the uptake and use efficiency of nitrogen in two crops. The land equivalent ratio (LER) of the wheat/maize intercropping system ranged from 1.01 to 1.19, and thus land use efficiency was significantly enhanced by this intercropping system. The dry-matter yield and LAI (leaf area index) of wheat were higher in border rows than in inner rows and monocultured rows, indicating an effect of border rows in the intercropping system. The LAI was considerably lower for the intercropped than the monocultured maize, indicating that intercropping limited the vegetative growth of maize. The grain yield and nitrogen uptake of both wheat and maize in two cropping systems were significantly improved with increasing amounts of N application. The LER of intercropping system tended to increase at higher N levels. The patterns of maize growth in the monocultures and intercrops were characterized by fitting expolinear growth equations to periodic harvest data. Fitted parameters indicated a growth delay in the intercropped maize ranging from 2.39 to 8.24 d relative to the maize monoculture. The growth delays were shortest at the moderate N rate among three N levels (2.39 d in 2012 and 2.57 d in 2013). This result could be interpreted in terms of the competitive effect of wheat during the seedling phase of maize, which was weakest at the moderate N rate, causing a comparatively short growth delay. The estimated growth rate during the linear growth phase was highest in the intercrop in the high N treatment (417.5 kg ha−1 d−1 in 2012 and 376.7 kg ha−1 d−1 in 2013). The physiological nitrogen use efficiency (IE) was more favorable for monocultured wheat and intercropped maize and decreased as N rates increased. The efficiency of the use of N for the entire system was assessed by comparing the relative nitrogen yield total to the relative yield total. The relative nitrogen yield total ranged from 1.06 to 1.23, while the relative yield total ranged from 1.01 to 1.19, indicating that the intercrop used more nitrogen per unit production than did the monocultures.

Accurate estimation of reference evapotranspiration (ET0) becomes imperative for better managing the more and more limited agricultural water resources. This study examined the feasibility of developing generalized artificial neural network (GANN) models for ET0 estimation using weather data from four locations representing different climatic patterns. Four GANN models with different combinations of meteorological variables as inputs were examined. The developed models were directly tested with climatic data from other four distinct stations. The results showed that the GANN model with five inputs, maximum temperature, minimum temperature, relative humidity, solar radiation, and wind speed, performed the best, while that considering only maximum temperature and minimum temperature resulted in the lowest accuracy. All the GANN models exhibited high accuracy under both arid and humid conditions. The GANN models were also compared with multivariate linear regression (MLR) models and three conventional methods: Hargreaves, Priestley–Taylor, and Penman equations. All the GANN models showed better performance than the corresponding MLR models. Although Hargreaves and Priestley–Taylor equations performed slightly better than the GANN models considering the same inputs at arid and semiarid stations, they showed worse performance at humid and subhumid stations, and GANN models performed better on average. The results of this study demonstrated the great generalization potential of artificial neural techniques in ET0 modeling.

Zhang, Y., Wu, P., Zhao, X. and Wang, Z. 2013. Simulation of soil water dynamics for uncropped ridges and furrows under irrigation conditions. Can. J. Soil Sci. 93: 85–98. The ridge-furrow planting system combined with furrow irrigation can effectively increase soil moisture storage and improve water use efficiency in the semi-arid region of China. The precise soil water dynamics in ridge-furrow systems must be known in order to properly design ridge-furrow geometry and improve irrigation uniformity while reducing deep water percolation. The objective of this study was to investigate soil water distribution in the cross-sectional ridge-furrow infiltration, through laboratory experiments and numerical simulations. Six experimental treatments with three soil types (silty clay loam, silt loam, and sandy loam) were tested to monitor both soil water movement and cumulative infiltration in rectangular soil chambers. The HYDRUS-2D model was calibrated and experimentally validated to simulate soil water dynamics....