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In order to meet the growing food demand of the global population and maintain sustainable soil fertility, there is an urgent need to optimize fertilizer application amount in agricultural production practices. Most of the existing studies on the optimal K rates for apple orchards were based on case studies and lack information on optimizing K-fertilizer management on a regional scale. Here, we used the method of combining meta-analysis with the K application rate-yield relationship model to quantify and summarize the optimal K rates of the Loess Plateau and Bohai Bay regions in China. We built a dataset based on 159 observations obtained from 18 peer-reviewed literature studies distributed in 15 different research sites and evaluated the regional-scale optimal K rates for apple production. The results showed that the linear plus platform model was more suitable for estimating the regional-scale optimal K rates, which were 208.33 and 176.61 kg K ha−1 for the Loess Plateau and Bohai Bay regions of China, respectively. Compared with high K application rates, the optimal K rates increased K use efficiency by 45.88–68.57%, with almost no yield losses. The optimal K rates also enhanced the yield by 6.30% compared with the low K application rates.
Wenzheng Tang; Wene Wang; Dianyu Chen; Ningbo Cui; HaoSheng Yang; Xiaotao Hu. Evaluation of the Regional-Scale Optimal K Rate Based on Sustainable Apple Yield and High-Efficiency K Use in Loess Plateau and Bohai Bay of China: A Meta-Analysis. Agronomy 2021, 11, 1368 .
AMA StyleWenzheng Tang, Wene Wang, Dianyu Chen, Ningbo Cui, HaoSheng Yang, Xiaotao Hu. Evaluation of the Regional-Scale Optimal K Rate Based on Sustainable Apple Yield and High-Efficiency K Use in Loess Plateau and Bohai Bay of China: A Meta-Analysis. Agronomy. 2021; 11 (7):1368.
Chicago/Turabian StyleWenzheng Tang; Wene Wang; Dianyu Chen; Ningbo Cui; HaoSheng Yang; Xiaotao Hu. 2021. "Evaluation of the Regional-Scale Optimal K Rate Based on Sustainable Apple Yield and High-Efficiency K Use in Loess Plateau and Bohai Bay of China: A Meta-Analysis." Agronomy 11, no. 7: 1368.
Precise irrigation management of grapevines in greenhouses requires a reliable method to easily quantify and monitor the grapevine water status to enable effective manipulation of the water stress of the plants. This study describes a study on stem diameter variations of grapevine planted in a greenhouse in the semi-arid area of Northwest China. In order to determine the applicability of signal intensity of stem diameter variation to evaluate the water status of grapevine and soil. The results showed that the relative variation curve of the grapevine stem diameter from the vegetative stage to the fruit expansion stage showed an overall increasing trend. The correlations of MDS (maximum daily shrinkage) and DI (daily increase) with meteorological factors were significant (p< 0.05), and the correlations with SWP, RWC and soil moisture were weak. Although MDS and DI can diagnose grapevine water status in time, SIMDS and SIDI have the advantages of sensitivity and signal intensity compared with other indicators. Compared with MDS and DI, the R2 values of the regression equations of SIMDS and SIDI with SWP and RWC were high, and the correlation reached a very significant level (p< 0.01). Thus, SIMDS and SIDI are more suitable for the diagnosis of grapevine water status. The SIMDS peaked at the fruit expansion stage, reaching 0.957–1.384. The signal-to-noise ratio of SIDI was higher than that of MDS across the three treatments at the vegetative stage. The value and signal-to-noise ratio of SIDI at the flowering stage were similar to those of SIMDS, while the correlation between SIDI and the soil moisture content was higher than that of SIMDS. It can be concluded that that SIDI is suitable as an indicator of water status of grapevine and soil during the vegetative and flowering stages. In addition, the signal-to-noise ratio of SIMDS during the fruit expansion and mature stages was significantly higher than that of SIDI. Therefore, SIMDS is suitable as an indicator of the moisture status of grapevine and soil during the fruit expansion and mature stages. In general, SIMDS and SIDI were very good predictors of the plant water status during the growth stage and their continuous recording offers the promising possibility of their use in automatic irrigation scheduling in grapevine.
Chen Ru; Xiaotao Hu; Wene Wang; Hui Ran; Tianyuan Song; Yinyin Guo. Signal Intensity of Stem Diameter Variation for the Diagnosis of Drip Irrigation Water Deficit in Grapevine. Horticulturae 2021, 7, 154 .
AMA StyleChen Ru, Xiaotao Hu, Wene Wang, Hui Ran, Tianyuan Song, Yinyin Guo. Signal Intensity of Stem Diameter Variation for the Diagnosis of Drip Irrigation Water Deficit in Grapevine. Horticulturae. 2021; 7 (6):154.
Chicago/Turabian StyleChen Ru; Xiaotao Hu; Wene Wang; Hui Ran; Tianyuan Song; Yinyin Guo. 2021. "Signal Intensity of Stem Diameter Variation for the Diagnosis of Drip Irrigation Water Deficit in Grapevine." Horticulturae 7, no. 6: 154.
Precise irrigation management of grapevines in greenhouses requires a reliable method to easily quantify and monitor the grapevine water status to enable effective manipulation of the water stress of the plants. This study evaluated the applicability of crop water stress index (CWSI) based on the leaf temperature for diagnosing the grapevine water status. The experiment was conducted at Yuhe Farm (northwest China), with drip-irrigated grapevines under three irrigation treatments. Meteorological factors, soil moisture contents, leaf temperature, growth indicators including canopy coverage and fruit diameter, and physiological indicators including SPAD (relative chlorophyll content), stem water potential (φs), stomatal conductance (gs), and transpiration rate (E) were studied during the growing season. The results show that the relationship between the leaf-air temperature difference (Tc-Ta) and the plant water status indicators (φs, gs, E) were significant (P < 0.05), and the relationship between gs, E and Tc-Ta was the closest, with R2 values ranging from 0.530–0.604 and from 0.545–0.623, respectively. CWSI values are more easily observed on sunny days, and it was determined that 14:00 BJS is the best observation time for the CWSI value under different non-water-stressed baselines. There is a reliable linear correlation between the CWSI value and the soil moisture at 0–40 cm (P < 0.05), which could provide a reference when using the CWSI to diagnose the water status of plants. Compared with the Tc-Ta value, the CWSI could more accurately monitor the plant water status, and above the considered indictors, gs has the greatest correlation with the CWSI.
Chen Ru; Xiaotao Hu; Wene Wang; Hui Ran; Tianyuan Song; Yinyin Guo. Evaluation of the Crop Water Stress Index as an Indicator for the Diagnosis of Grapevine Water Deficiency in Greenhouses. Horticulturae 2020, 6, 86 .
AMA StyleChen Ru, Xiaotao Hu, Wene Wang, Hui Ran, Tianyuan Song, Yinyin Guo. Evaluation of the Crop Water Stress Index as an Indicator for the Diagnosis of Grapevine Water Deficiency in Greenhouses. Horticulturae. 2020; 6 (4):86.
Chicago/Turabian StyleChen Ru; Xiaotao Hu; Wene Wang; Hui Ran; Tianyuan Song; Yinyin Guo. 2020. "Evaluation of the Crop Water Stress Index as an Indicator for the Diagnosis of Grapevine Water Deficiency in Greenhouses." Horticulturae 6, no. 4: 86.
In this paper, the hydraulic characteristics of side weirs, such as Froude number distribution, water profiles, velocity distribution and discharge coefficient were investigated. Experiments and simulations with FLOW-3D software were performed on side weirs with four different crest angles under different conditions. The results showed that the simulated and the observed water depths were similar with a relative error below 5.63%. The relationships between discharge coefficient and its parameters were studied based on dimensional analysis, and regression models were established under different working conditions with a maximum relative error of 9.25%, which met the common requirements of flow measurement in irrigation districts. The hydraulic characteristics of trapezoidal sharp-crested side weirs was preliminarily characterized, which provided useful information on the performance of flow measurement devices placed in water inlet of field.
Yingying Wang; Wene Wang; Xiaotao Hu; Fulai Liu. Experimental and numerical research on trapezoidal sharp-crested side weirs. Flow Measurement and Instrumentation 2018, 64, 83 -89.
AMA StyleYingying Wang, Wene Wang, Xiaotao Hu, Fulai Liu. Experimental and numerical research on trapezoidal sharp-crested side weirs. Flow Measurement and Instrumentation. 2018; 64 ():83-89.
Chicago/Turabian StyleYingying Wang; Wene Wang; Xiaotao Hu; Fulai Liu. 2018. "Experimental and numerical research on trapezoidal sharp-crested side weirs." Flow Measurement and Instrumentation 64, no. : 83-89.
Danjie Ran; Wene Wang; Xiaotao Hu. Three-dimensional numerical simulation of flow in trapezoidal cutthroat flumes based on FLOW-3D. Frontiers of Agricultural Science and Engineering 2018, 1 .
AMA StyleDanjie Ran, Wene Wang, Xiaotao Hu. Three-dimensional numerical simulation of flow in trapezoidal cutthroat flumes based on FLOW-3D. Frontiers of Agricultural Science and Engineering. 2018; ():1.
Chicago/Turabian StyleDanjie Ran; Wene Wang; Xiaotao Hu. 2018. "Three-dimensional numerical simulation of flow in trapezoidal cutthroat flumes based on FLOW-3D." Frontiers of Agricultural Science and Engineering , no. : 1.
The use of portable short-throat flume in the field is an emerging technique developed for water discharges measurement of inlet in the field. Based on the principle of critical flow and RNG k-ε three-dimensional turbulence model along with the TruVOF technique, experiments and corresponding simulations were performed for 16 working conditions on the 76 mm width flume with discharges up to 40.01 L/s to determine its hydraulic performance. Hydraulic performance of the flume obtained from simulation analyses were later compared with observed results based on time-averaged flow field, flow pattern, Froude number and velocity distribution. Comparison yielded a solid agreement between results from two methods with relative error below ±10%. Regression models developed for upstream depth versus discharge under different working conditions were satisfying with the relative error of 9.16%, which met the common requirements of flow measurement in irrigation areas. Compared to the long-throat flume, head loss of portable short-throat flume in the field was significantly less. Further, head loss under the free flow condition was less than that under the submerged flow condition of portable short-throat flume with a flat base in the field.
Yizhou Xiao; Wene Wang; Xiaotao Hu; Yan Zhou. Experimental and numerical research on portable short-throat flume in the field. Flow Measurement and Instrumentation 2016, 47, 54 -61.
AMA StyleYizhou Xiao, Wene Wang, Xiaotao Hu, Yan Zhou. Experimental and numerical research on portable short-throat flume in the field. Flow Measurement and Instrumentation. 2016; 47 ():54-61.
Chicago/Turabian StyleYizhou Xiao; Wene Wang; Xiaotao Hu; Yan Zhou. 2016. "Experimental and numerical research on portable short-throat flume in the field." Flow Measurement and Instrumentation 47, no. : 54-61.