Comparative Analysis of Comprehensive Water Quality Identification Index Method Based on Different Weighting Method北大核心CSCD

【Objective】In order to analyze the water quality distribution characteristics of each water quality monitoring section of Qingshui River in Ningxia, provide a basis for water quality assessment, based on three water quality section monitoring data on Qingshui River in Ningxia from 2014 to 2016. 【Method】Using the method of Principal Component Analysis to select the evaluate data and choose representative water quality indicators to issue Comprehensive Water Quality Identification Index evaluation and combined with 3 weighting methods to do further comparative analysis.【Result】The comprehensive water quality identification index show that the Ershilipu section water quality evaluation results for class II water and remained stable. The Sanying section evaluation results meet the class III water in 2014 and 2015 years, the evaluation results meet class IV water in 2016, It shows that the water quality of this section has a trend of decrease. The Quanyanshan section evaluation results for the class II water and reduced year by year, the water quality has become the trend of further good. 【Conclusion】The three section water quality evaluation using different weighting methods reached the water function zoning requirements, there were some defects in the Standard Multiple Method and the Entropy Weight Method, and the Variation Coefficient Method was more suitable than the other two weighting methods. © 2019 Office of Journal of Irrigation and Drainage, Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences. All rights reserved.     

Sap Flow in Tropical Eucalyptus Plantation and Its Response to Environmental Changes北大核心CSCD

【Objective】Transpiration is controlled by many biotic and abiotic factors and in this paper, we studied the sap flow in tropical eucalyptus under different environments. 【Method】The experiment was conducted from January to December in 2016, and the sap flow in the eucalyptus was measured with the thermal dissipation probe under changing environment which was monitored synchronously by a small meteorological station at the Danzhou Forest Farm in Hainan province.【Result】①Temporal change of the sap flow velocity had two peaks in wet season and one peak in dry season. In wet season, the first peak 8.68 mL/(cm2·h) occurred between 11:00 to 11:30 am followed by the second peak 8.68 mL/(cm2·h) occurring between 15:00~15:30. The mean of the peaks in dry season was 7.45 mL/(cm2·h). ②The instantaneous sap flow rate lagged behind the Rh and Ta by 30 min, and the PAR by -30 min, in all seasons. ③The mean daily sap flow velocity was 2.06 mL/(cm2·h), and the maximum sap flow velocity was 4.25 mL/(cm2·h) occurring in 15th July, and the minimum was 0.14 mL/(cm2·h) occurring in 25 th November. The photosynthetically active radiation (PAR), atmospheric temperature (Ta), vapor pressure deficit (VPD) were the main factors affecting sap flow velocity. The diameter of the tree at the breast height was positively related to daily sap flow velocity. ④The monthly average sap flow velocity had a single peak, with its average in wet and dry seasons being 2.53 mL/(cm2·h) and 1.80 mL/(cm2·h) respectively. The maximum monthly average sap flow velocity was 3.42 mL/(cm2·h) occurring in July, and the minimum was 1.80 mL/ (cm2·h) occurring in February, both affected mostly by PAR, Ta and VPD.【Conclusion】The sap flow rate in tropical eucalyptus showed seasonal and diurnal period, and its daily and monthly average was affected mostly by PAR, Ta, and VPD. © 2019 Authors. All rights reserved.     

Effects of Waterlogging on Morphology and Chlorophyll Fluorescence Characteristics of Cherry Tomato at Seedling Stage北大核心CSCD

【Objective】The aim of this study was to investigate the responses of cherry tomato to waterlogging at seedling stage, and to provide reference for waterlogging resistance cultivation of off-season cherry tomato in the tropical area.【Method】Five different varieties of cherry tomatoes were used as materials in pot culture experiment, with soil waterlogging treatment and normal moisture treatment as the control (CK). The morphological characteristics indexes of shoot and root and chlorophyll fluorescence parameters in leaves of cherry tomato were measured in different days of waterlogging. And the effects of waterlogging on morphological characteristics and chlorophyll fluorescence parameters at seedling stage of cherry tomato were analyzed.【Result】Results showed that waterlogging significantly decreased the plant height, stem diameter, leaf area, leaf number and SPAD value of cherry tomato, but had no significant effect on leaf thickness. The root diameter of cherry tomato had no significant affects, but the root volume was significantly increased in HongFei 6 and TaiwanZanMei during waterlogging. Compared with CK, the root length and root surface area of HongFei 6 increased significantly, while that of QianXi decreased significantly during waterlogging. Additionally, waterlogging increased the initial fluorescence (Fo) and non-photochemical quenching coefficient (NPQ), and significantly decreased the maximum photochemical efficiency (Fv/Fm), apparent electron transfer rate (ETR) and photochemical quenching coefficient (qP) of cherry tomato leaves, besides HongFei 6.【Conclusion】The results above indicated that during waterlogging the growth and development and chlorophyll fluorescence in leaves of cherry tomato were seriously affected, but there had different effects among five different varieties . Among five varieties of cherry tomatoes, the strongest waterlogging resistance was HongFei 6, while the weakest waterlogging resistance was QianXi. © 2019 Journal of Irrigation and Drainage. All rights reserved.     

Effect of Irrigation Frequency on Water Use Efficiency and Yield of Cotton after Loosening the Deep Soil北大核心CSCD

[Objective]The objective of this paper is to experimentally investigate the responsive change in yield and water use efficiency of cotton to irrigation frequency after soil loosening.[Method]The experiment was conducted from 2016 to 2017 after deeply loosening soil. By keeping the irrigation amount the same, we compared three irrigation frequencies: Irrigating once in each 4 day (D4), 7 days (D7) and 10 days (D10) respectively. The associated irrigation times were 17, 10 and 7 respectively. In each treatment, we measured soil moisture, dry matter accumulation, water consumption, water use efficiency and the yield of the crop.[Result]After deep loosening, keeping irrigation frequency at a moderate level (D7) significantly enhanced water-holding capacity of the 0~ 20 cm soil, thereby facilitating distribution of dry matter to different organs in the bud and boll and consequently improving the water use efficiency (WUE). Compared to D4 and D10, D7 increased WUE by 15.5% and 10.5% in 2016 and 16.5% and 9.2% in 2017, respectively. Increasing irrigation frequency promoted vegetative growth and reduced distribution of the dry matter to organs in the bud and boll. In contrast, reducing irrigation frequency reduced the accumulation of total dry matter, storage of water in the top soil and water consumption. Compared to D4 and D10, D7 increased the yield by 13.8% and 7.0% in 2016, and 17.3% and 6.1% in 2017. The main mechanism underlying in yield increase in D7 was the increase in boll number and average weight of the bolls in each plant. [Conclusion]Irrigating once after each 7 days, together with deep soil loosening, can effectively promote vegetative growth and organ production from dry matter, thereby facilitating the conversion of dry matter to organs and improving cotton yield and its water use efficiency. © 2019 TEST-ZL Publishing, LLC. All rights reserved.     

Study on the Variation Characteristics of Rising Capillary Water of Layered Soil under Variation of Sand Layer and Thickness北大核心CSCD

【Objective】The purpose of this paper is to solve secondary salinization of soil in Northwest China. 【Method】the capillary water rising movement characteristics of layered soil has been analyzed through indoor test. And the variation characteristics of capillary water movement under the influence of common change of layer and thickness of sand layer has been considered in this paper, and functional relationship between groundwater recharge and height of capillary water rising with time changing has been built. Furthermore, contour distribution of groundwater recharge and capillary water rising height has been also comparative analyzed.【Result】There was a very significant positive correlation between the horizon and the volume constant and the height constant （P<0.01）. And there was a significant negative correlation between the horizon and the stable recharge rate of groundwater and the rate of steady increase of capillary water （P<0.05）. There was a significant negative correlation between the thickness of sand layer and stable recharge rate and steady rising rate（P<0.05）. When the duration of the capillary water height was rising was 0~4 days, the sandy layer was 30~50 cm, the thickness of sand layer was 0~15 cm, which has a significant effect on the change of groundwater recharge and height of capillary water. When the duration of the capillary water height was rising was 4~12 days, the sand layer is distributed in 15~30 cm, the thickness of sand layer was 15~30 cm, which has a significant effect on the change of groundwater recharge and height of capillary water. To summarize, the results of this study were of great significance for the study of water salt movement and soil salinization in layered soils.【Conclusion】The fitting parameters of the function including volume constant (v), stable recharge rate (q*), groundwater recharge time constant (τQ), capillary water rising height (υ), steady rising rate (μ*) and rising height time constant (τh) were determined by the variation of capillary groundwater recharge and capillary water height with time changing respectively. © 2019 Journal of Irrigation and Drainage. All rights reserved.     

Sensitivity Analysis of the Reference Evapotranspiration in Ebinur Lake Oasis北大核心CSCD

【Objective】The evapotranspiration of crop depends on many factors and this paper analyzed its sensitivity to various meteorological factors in Ebinur lake oasis.【Method】Monthly ET0 in Ebinur lake oasis was calculated using the Penman-Monteith formula based on meteorological data measured from 1962 to 2016 at four meteorological stations in the region. The sensitivity of ET0 to the highest and lowest temperature, relative humidity, sunshine duration and wind speed was calculated using sensitivity analysis; and the possible existence of any trends in the ET0 was analyzed using the MK trend test. We also calculated the variation of the sensitivity coefficient for each site.【Result】The MK trend test revealed that the evapotranspiration, sunshine duration and wind speed in the region have been in decline, while the highest and lowest temperature and the relative humidity have been in rise. Analysis found that the ET0 was sensitive to meteorological factor in an order of relative humidity > the highest temperature > wind speed > the lowest temperature > sunshine duration. The sensitivity coefficient of ET0 to different meteorological factors varies spatially, with the coefficients for the highest and lowest temperature, wind speed and relative humidity being high at Alashan pass-way in northern Ebinur lake, and low at Wenquan station. Wenquan station had longer sunshine duration than Alashan pass-way.【Conclusion】ET0 is most sensitive to relative humidity in Ebinur lake oasis, and least sensitive to sunshine duration. © 2019 Authors. All rights reserved.     

Multi-factor Analysis of the Effective Precipitation for Crops in Semi-arid Region北大核心CSCD

【Objective】The purpose of this paper is to present a method to estimate the effective precipitation for crops in arid region.【Method】The model considered precipitation, soil and crop, and it was based on four modules: canopy interception, soil water tolerance, surface runoff, precipitation and deep percolation. The results calculated by the model were compared to those calculated from water balance using the data measured from the field. We applied the model to calculate spatiotemporal distribution of the effective precipitation for crops in five counties in Hebei plain.【Result】①The coefficient of determination (R2) and Nash-Sutcliffe efficiency (NSE) in all results were above 0.85, proving the reliability of the model. ②The effective precipitation for growing season of the wheat-maize in the five counties was 400.03 mm, and the infiltration coefficient of precipitation was 0.84. In wet, normal and dry year, the effective precipitation for crops was 419, 454 and 355 mm respectively, and infiltration coefficient of precipitation was 0.76, 0.86 and 0.83 respectively. The effective precipitation for crops in Luancheng and Yuanshi was higher than that for other counties.【Conclusion】The proposed model was reliable for estimating effective precipitation for crops at large scale in semi-arid region. © 2019 Authors. All rights reserved.     

Comparative Analysis of Stratified Physical Characteristics of Seasonal Snow Cover With or Without Shading北大核心CSCD

【Objective】Snow melting runoff is an important recharge component of arid inland rivers. Seasonal snow cover is very sensitive to environmental change. Therefore, it is of great significance to study and control the key factors affecting seasonal snow accumulation and snow melting process for basin safety and sustainable utilization of water resources under changing environment. 【Method】By observing the physical characteristics of seasonal snow layers under the conditions of sheltered or not (under canopy and open land) in the Urumqi River Basin experimental area on the northern slope of Tianshan Mountains in Xinjiang from November 2017 to February 2018, the differences of physical characteristics of seasonal snow layers were analyzed. 【Result】① the temperature of open land was slightly higher than that of under canopy, and the relative humidity under canopy was higher than that of open land. ②The average depth of snow under canopy was less than that of open land, and the proportion of deep frost layer to coarse snow layer was larger in stratified snow cover. ③The vertical profile of snow density under canopy was basically the same as that under open land. The snow density increased gradually from the new snow layer down to the peak of coarse snow layer (open land) and medium-sized snow layer (under canopy). ④ Snow temperature and liquid water content of layers under canopy and open land increased from new snow layer to deep frost layer. ⑤ The variation trend of snow water equivalence under canopy and open ground was basically the same during observation period. The value of snow water equivalence under open ground was obviously larger than that under canopy. 【Conclusion】Snow surface temperature is a significant factor affecting the liquid water content of snow under canopy and open land. © 2019 Office of Journal of Irrigation and Drainage, Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences. All rights reserved.     

Evaluation and Driving Force of Water Resources Carrying Capacity in Dianchi Basin北大核心CSCD

【Objective】The purpose of this paper to explore the coordination relationship between the water resources carrying capacity of the Dianchi Lake Basin and the socio-economic development and environment of the basin. 【Method】Select the water resources, social economy and environment-related indicators to construct a comprehensive evaluation model for the water resources carrying capacity of the Dianchi Lake Basin. The trend of pressure index, bearing capacity index, coordination index and water resources carrying capacity index of the basin from 2011 to 2015 was calculated and analyzed. The factor analysis method was used to further evaluate the water resources carrying capacity of the basin, and the main factors extracted were used. The driving force model of water resources carrying capacity was constructed to identify the main driving forces that affect the water resources carrying capacity of the Dianchi Lake Basin. 【Result】The water resources carrying capacity index of Dianchi Lake Basin showed an upward trend from 2011 to 2015; The main driving forces of water resources carrying capacity in Dianchi Basin were human activity factors and natural factors, including urbanization rate, economic development factors and annual average temperature and annual. Precipitation. GDP per capita and annual precipitation wrer positive drivers, and urbanization rates and annual average temperatures are negative drivers. 【Conclusion】Based on the sustainable development of social economy and the coordinated development of water resources system, the construction of water transfer project from the outer basin to Dianchi Lake Basin should be increased to form a multi-water source combined water transfer pattern, and the population quantity should be controlled on the basis of ensuring vigorous economic development. Establish a sound water resource efficient allocation and unified scheduling scheme for multi-source water supply in the basin water resources system. © 2019 Office of Journal of Irrigation and Drainage, Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences. All rights reserved.     

Physical and Chemical Properties of Soil at Southeastern Edge of Anabasis salsa in Junggar Basin北大核心CSCD

【Objective】Soil is heterogenous and its physical and chemical properties vary spatiotemporally. The purpose of this paper is to present the results of an experimental study on the physical and chemical properties of soil in Anabasis salsa in Gobi region at the southeastern edge of Junggar basin.【Method】We measured organic matter, total phosphorus, total nitrogen, electrical conductivity, pH and water content in soil at locations 5 cm and 10 cm from the center of shrubs, and 20 cm from the outer edge of shrubs.【Result】In horizonal direction, there was no significant difference in organic matter, total nitrogen, total phosphorus, electrical conductivity, pH and water content in the 0~50 cm soil at all locations. In vertical direction, the organic matter and total phosphorus in the proximity of the Anabasis salsa decreased monotonically along the soil profile, while the total nitrogen increased first with the depth followed by a decrease. Both electrical conductivity and pH increased with depth, and soil moisture peaked somewhere within the soil profile.【Conclusion】Our results showed that the physical and chemical properties of soil in Anabasis salsa did not show significant change in lateral direction but varied erratically in the vertical direction. © 2019 Authors. All rights reserved.     

The Use of Brackish and Reclaimed Waste Water in Agriculture: A Review北大核心CSCD

Due to poor water resources management and appropriate water treatment technologies, freshwater resources depletion and water quality deterioration has made reclaimed waste water, brackish water and rainwater, called unconventional water, an important complementary resource for irrigation. However, due to its unique chemical quality, irrigating with unconventional water might lead to some detrimental impact on environment and impose health risks, which has attracted increased attention in both scientific and public community. This paper reviews the current situation of the usage of unconventional water resources for irrigation in both China and beyond, and summarized the potentially ecological risks of unconventional water, as well the national standards for regulating unconventional water irrigation. We also put forwards suggestions to improve safe and sustainable use of unconventional water resources for irrigation. © 2019 Authors. All rights reserved.     

Optimal Design of Vortex Pump Using Approximate Model and the Non-dominated Sorting Genetic Algorithm北大核心CSCD

【Objective】The cavity width L, blade width b2 and the number of blades Z are the most important geometric parameters affecting the performance of vortex pump. This paper aims to present a method to optimize the vortex pump. 【Method】The study was based on approximate model and the non-dominated sorting genetic algorithm II (NSGA-II), in which the pump cavity length, blade width and the number of blades were calculated using the central composite design of DoE (design of experiment). The performance of the designed pump was examined using CFD, and the effect of L, b2 and Z on vortex pump efficiency and shear stress on the blade wall was calculated using the Kriging model. The NSGA-II was used to optimize the geometric parameters.【Result】The optimal parameters calculated from the methods were L=25 mm, Z=8, b2=26.45 mm.【Conclusion】We proved that CFD and NSGA-II can be used in a combination to calculate the optimal parameters of the vortex pump, and they can significantly improve efficiency of the pump and reduce the shear stress on the blade. Our results revealed that the optimization can reduce the width of the non-blade cavity by 16.67%, and increase the number of blades of the impeller and the outlet width of the blade by 1 and 25.95% respectively. At the design flow rate, the optimal design increased pump efficiency by 1.06% and reduced the average shear stress on the blade from 274.37 Pa to 204.57 Pa. The optimal design made the shear stress on the blade more uniform, in addition to reducing the shear stress on the outlet of the blade. © 2019 Authors. All rights reserved.     

Effects of Biochar for Abating Salt Stress and Promoting Seeding Growth of Winter Wheat in a Saline Soil北大核心CSCD

The surface soil of the Yellow River Delta is rich in salt, which makes the soil salinized, compact and barren. The salinization hazard with NaCl as the main component directly affects the quality of coastal soil. Adding biochar to saline-alkali farmland can improve soil properties and promote crop growth.【Objective】The purpose of this paper is to clarify the changes of soil salt ions and winter wheat seedling growth after adding biochar to saline soil.【Method】A field experiment was conducted to investigate the effects of low dose (0~4 g/kg) of Reed carbon on soil salt ions, potassium-sodium ratio in wheat seedlings, potassium utilization efficiency and seedling biomass.【Result】The application of biochar could reduce the salt ions in soil solution, increased the potassium-sodium ratio in the winter wheat seedlings and the potassium use efficiency of the wheat seedlings, and increased the seedling biomass of winter wheat; The salt reduction and the incremental effect under the addition of 4 g/kg biochar use was the most obvious. Compared with CK, the Na+ in soil solution decreased by 9.43%, the K/Na and potassium use efficiency of seedlings increased by 56.80% and 25.48%, respectively, and the biomass of wheat seedling increased by 15.72%.【Conclusion】Biochar application can promote the increase of biomass by holding Na+ in soil solution and increasing K/Na and potassium utilization of winter wheat seedlings. The research can provide a theoretical basis for the process mechanism of biochar for salt reduction and fertilization, increase efficiency and increase yield, and provide preliminary guidance for the feasibility of biochar for salinized soil improvement. © 2019 Office of Journal of Irrigation and Drainage, Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences. All rights reserved.     

Spatial Variability of Soil Moisture at Different Scales in Sandy Loam in Northern Henan Province北大核心CSCD

[Objective]Soil moisture plays an important role in ecosystem function and hydrological processes. This paper investigated the hieratical distribution of soil moisture at different scales over a maize field.[Method] The studied site was a 50 m×50 m plot at the Experiment Station of Chinese Academy of Agricultural Sciences in Xinxiang, Henan province. We measured soil moisture in 0~100 cm soil from 36 locations at 10 m×10 m and 2 m×2 m scale, respectively.[Result]Geostatistical analysis revealed that the soil moisture was normally distributed and its confidence level at every scale was higher than that of logarithmic normal distribution. The value of the confidence level decreased as the sampling scale increased, and the difference between average soil moisture content at fine scale and moderate scale was smaller than the difference between moderate scale and large scale. In general, the confidence interval, standard deviation and coefficient of variation of the soil moisture increased with sampling scale. At large scale, the semi-variance function increased with lag distance, while at small and moderate scale, the variation function appeared to be independent of the lag distance. To achieve the same confidence level and accuracy in estimating soil moisture, the number of samples needed to be taken from the field increased with sampling scale. We also found that in estimating soil moisture, the number of samples needed to be taken depended on the required accuracy more than on the confidence level.[Conclusion]The probabilistic distribution and statistical characteristics of soil moisture in the field was scale-dependent. In estimating soil moisture, the number of sampled taken from the field needs to consider the scales to which the measured data will be applied. © The Author(s) 2019.     

Retrieving Soil Moisture Using Spectral Mixture Analysis of Landsat8 and the Moderate Resolution Imaging Spectroradiometer北大核心CSCD

【Objective】Soil moisture plays a critical role in many hydrological and ecological processes and understanding its spatiotemporal changes is imperative to ecosystem management and irrigation design. This paper presents and tests a method to estimate soil moisture distribution using satellite technologies.【Method】We took Guangli Irrigation District at Jiaozuo in Henan Province as our study area. The Landsat-8 and MODIS imageries from the area were used to retrieve soil moisture with the apparent thermal inertia and vegetation water supply index, respectively. Using the abundance of vegetation and soil moisture decomposed by the spectral mixture analysis as weighting factors, we retrieved the soil moisture distribution in the area using the two methods.【Result】The correlation coefficient between the measured soil moisture and the retrieved using the vegetation water supply index method and the apparent thermal inertia method was 0.47 and 0.51 respectively. We found that combining the two methods could improve the correlation coefficient between the measured and retrieved soil moisture to 0.73. 【Conclusion】Our results showed that the proposed method is reliable and can adequately estimate soil moisture in irrigation district grown with a diverse of crops. © 2019 Authors. All rights reserved.     

Autumn Irrigation Alerted the Geochemistry of Groundwater in Hetao Irrigation District：Take Yichang Irrigation District as an Example北大核心CSCD

【Objective】Surface infiltration could change biogeochemical reactions in groundwater thereby alerting its chemical compositions. The aim of this paper is to investigate the responsive change in chemical composition of groundwater to infiltration following the autumn irrigation in irrigation districts.【Method】The experiment was conducted in Hetao Irrigation District, during which we measured the change in concentration of Na+, K+, Ca2+, Mg2+, SO42-, Cl-, HCO3- and CO32- and then statistically analyzed them.【Result】The irrigation increased the concentration of Cl-, SO42-, KNa, Mg2 and HCO3-, but slightly reduced the concentration of Ca2+. The TDS was higher in south and lower in north of the irrigation district. The Piper diagram showed that the Cl-Na was the dominant groundwater type, accounted for 75% and 61% of the studied area before and after the irrigation respectively. Irrigation turned groundwater in 16.7% of the studied area to Mg-SO4-Cl type. The Gibbs model and ion proportional coefficient diagram revealed that the chemistry of groundwater in the studied region was mediated by evaporation, weathering and leaching of silicate and evaporite, and is independent of precipitation. 【Conclusion】The mean TDS in the groundwater increased by 32.9% after the autumn irrigation, indicating the impact of soil leaching. Improving drainage after the autumn irrigation is hence essential. © 2019 Journal of Irrigation and Drainage. All rights reserved.     

Using Biogas Slurry to Regulate Growth,Field and Fruit Quality of Greenhouse Tomato and Nitrogen Dynamics in Root Zone北大核心CSCD

【Objective】The physiological development of tomato is affected by a number of integrative abiotic and biotic factors and the purpose of this paper is to investigate how irrigation with biogas slurry alerts the yield and fruit quality of greenhouse tomato.【Method】The experiment was conducted in a greenhouse from autumn in 2017 to spring in 2018 by irrigating the tomato with a mixture of fresh water and biogas slurry at volumetric ratio of 1∶8, 1∶6 and 1∶4 at flowering stage and fruit-elongation stage respectively. In each treatment, we measured growth, yield, and fruit quality of the tomato, as well as the dynamics of total nitrogen in the root zone. 【Result】The tomato growth was positively related to the biogas slurry ratio at significant level, and the 1∶6 and 1∶4 ratio gave the highest total dry matter at the flowering stage and the fruit expansion stage respectively. The 1∶6 treatment gave the best return, and compared to CK (without biogas slurry), it increased the return by 12.93% in autumn and 12.31% in spring respectively. Irrigating with 1∶4 ratio at fruit elongation stage gave the highest yield, and compared to CK, it increased the yield by 26.59% in autumn and 27.71% in spring respectively. The 1∶4 treatment gave 4.32% increase in yield compared to chemical fertilizer application in spring. T5 and T6 treatments improved soluble sugar and solid, as well as and sugar-acid ratio, while T2 and T3 treatments increased titratable acid and vitamin C content.【Conclusion】Irrigation by mixing biogas slurry and freshwater at 1∶6 and 1∶4 volumetric ratio at flowering-fruiting stage and fruit expansion stage can considerably improve yield and quality of tomato. © 2019 Authors. All rights reserved.     

Response in Growth,Quality and Water Consumption of Greenhouse Tomato to Change in Matric Potential at 20 cm below the Emitter of Drip Irrigation北大核心CSCD

[Objective]Irrigation schedule needs to know the spatiotemporal dynamics of soil moisture in root zone. The objective of this paper is to investigate the feasibility of using matric potential measured at 20 cm below the drip emitter as a proxy for soil moisture in the root zone to schedule irrigation.[Method]The experiment was conducted in a greenhouse and the model plant was tomato. We compared seven matric potential (SMP) thresholds in that whenever the measured soil matric potential dropped below them, drip irrigation was resumed. The values of the SMP thresholds varied from flowering and fruit-setting stage to fruiting stage, and the seven combinations (flowering and fruit-setting stage/fruiting stage) were -15 kPa/-15 kPa (S1), -15 kPa/-30 kPa (S2), -15 kPa/-45 kPa (S3), -25 kPa/-25 kPa (S4), -30 kPa/-15 kPa (S5), -30 kPa/-30 kPa (S6), and -30 kPa/-45 kPa (S7). In each treatment, we measured growth, fruit quality, water consumption and water use efficiency of the tomato.[Result]Stem diameter increased with SMP threshold at both flowering and fruit-setting stage and fruiting stage, whereas the plant height was only responsive to SMP at flowing and fruit-setting stage. The relative chlorophyll content in leaf (SPAD) did not show significant difference between treatments at flowering and fruit-setting stage but inversely increased with the SMP threshold at fruit setting stage. Decreasing the SMP threshold at flowering and fruit-setting stage could reduce the percentage of defective fruits and increase soluble solids content. Yield increased inversely with SMP threshold at fruit setting stage, peaking when SMP was -45 kPa. Lowering the SMP threshold increased irrigation amount and hence water consumption, thereby decreasing water use efficiency. [Conclusion]Our experimental results suggest that setting the SMP at -30 kPa at the flowering and fruit-setting stage and -45 kPa at the fruiting period appears to be optimal to best balance yield, fruit quality, irrigation water use efficiency and water use efficiency for winter-spring tomato grown in solar greenhouse in North China. © The Author(s) 2019.     

Efficacy of Fertilization in Improving Soil Aggregation,Carbon and Nitrogen in Soil Reclaimed from Subsided Areas Caused by Coal Mining北大核心CSCD

【Objective】The objective of this paper is to present experimental results on efficacy of fertilization in improving aggregation and carbon and nitrogen accumulation in soil reclaimed from subsided areas caused by coal mining.【Method】The experiment was conducted under conventional irrigation with non-fertilization as the CK. We compared three treatments: applying organic fertilizer, inorganic fertilizer, and mixture of organic and inorganic fertilizer. For each treatment, we measured the size of soil aggregates, and carbon and nitrogen content in 0~20 cm and 20~40 cm soil in a coal mining-induced subsided area at Jincheng City in Shanxi Province.【Result】Compared to CK, organic fertilizer significantly increased the content of macro-aggregates sized >1 mm, and reduced the content of micro-aggregates sized < 0.25 mm. Inorganic fertilization enhanced formation of micro-aggregates, compared to organic fertilization. Applying organic fertilizer significantly increased the average weight diameter (MWD) and geometric mean diameter (GMD) of the aggregates, and reduced the fractal dimension D of the aggregates. The content of organic carbon and total nitrogen in soil under organic fertilization was the highest, followed by organic-inorganic fertilization. The content of carbon and total nitrogen in soil with a single application of inorganic fertilizer was much lower than that under organic fertilization. Majority of organic carbon and total nitrogen were found in aggregates > 0.2 mm, 1～2 mm and 0.25～1 mm, especially under organic and organic-inorganic fertilization. The C∶N ratio in all aggregates (except those in 0.053～0.25 mm) was much lower under organic and organic-inorganic fertilization than under CK, and C∶N ratio in CK and inorganic fertilization was comparable.【Conclusion】Fertilizations, especially organic fertilizer, can enhance macro-aggregation in reclaimed soil from subsided areas induced by coal mining. It also increased the content of organic carbon and total nitrogen in the aggregates. © 2019 Authors. All rights reserved.