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Sensitivity analysis, calibration, and verification of crop model parameters improve crop model efficiency and accuracy, facilitating its application. This study selected five sites within the Ningxia Yellow River Irrigation Area. Using meteorological data, soil data, and field management information, the EFAST (Extended Fourier Amplitude Sensitivity Test) method was used to conduct first-order and global sensitivity analyses of spring wheat parameters in the WOFOST (World Food Studies Simulation) Model. A Structural Equation Model (SEM) analyzed the contribution of crop parameters to different simulation indices, with parameter sensitivity rankings being discussed under varying water supply and climate conditions. Finally, the adapted WOFOST model was employed to assess its applicability in the Ningxia Yellow River Irrigation Area. TMNFTB3.0 (correction factor of total assimilation rate at 3 °C), SPAN (life span of leaves growing at 35 °C), SLATB0 (specific leaf area in the initial period), and CFET (correction factor transpiration rate) showed higher sensitivity index for most simulation indices. Under the same meteorological conditions, different water supply conditions have a limited impact on crop parameter sensitivity, mainly affecting leaf senescence, leaf area, and assimilate conversion to storage organs. The corrected crop parameters significantly enhanced the wheat yield simulation accuracy by the WOFOST model ( M E = 0.9964; R M S E = 0.2516; M B E = 0.1392; R 2 = 0.0331). The localized WOFOST model can predict regional crop yield, with this study providing a theoretical foundation for its regional application, adjustment, and optimization. [ABSTRACT FROM AUTHOR]

It is crucial to understand and forecast future climate change and its impact on regional crop yield. This study employed the optimized World Food Studies (WOFOST) model and Coupled Model Intercomparison Project Phase 6 (CMIP6) data to assess the effects of climate change in different emission scenarios [ e.g. , ssp126 [sustainable development with low greenhouse gas (GHG) emissions], ssp245 (balanced development with medium GHG emissions), and ssp585 (conventional development with high GHG emissions)] on the spring wheat yield and growth period in Northwest China. Lasso regression, Support Vector Machine (SVM), Recurrent Neural Networks (RNN), Random Forests (RF), and RNN showed superior optimization performance for radiation amount surface downwelling shortwave radiation flux (RSDS), maximum temperature (Tmax), minimum temperature (Tmin), wind speed (sfcWind), and precipitation (PR). These optimizations decreased the root mean square error (RMSE) of RSDS, Tmax, Tmin, sfcWind, and PR by 1.0285, 2.6396, 2.7839, 2.3763, and 0.3020, respectively, compared to the original data. Long-term annual PR will increase by 415 mm in the ssp126 scenario, whereas the increases were estimated to be 257 mm and 249 mm under the ssp245 and ssp585 scenarios, respectively. Regarding temperature, Tmax and Tmin are expected to rise by 0.97 °C and 1.08 °C, respectively, under the ssp126 scenario. These values are also projected to be 2.29 °C/1.70 °C and 1.81 °C/3.36 °C for Tmax/Tmin under the ssp245 and ssp585 scenarios, respectively. The optimized crop parameters can effectively improve the yield simulation accuracy of the WOFOST model and reduce RMSE. Yinchuan and Huinong are projected to experience an increase of 19.8 % and 15.8 % in their average yield under the ssp585 scenario in the short-term future, compared to the average yield during the baseline period. Qingtongxia is expected to reach a 20.2 % increase under the ssp126 model, while Zhongning will undergo an increase of 12.3 % under the ssp585 model, and Litong will observe an 11.2 % increase under the ssp245 model. Qingtongxia showed the highest long-term production growth, with increases of 18.0 % and 15.3 %, respectively, under the ssp126 and ssp245 scenarios. Higher temperatures, radiation levels, and PR are typical features of the future climate in the study area. The CMIP6 data simulations and the optimized WOFOST model predict that spring wheat yield will increase soon but will not increase as much in the long run. [ABSTRACT FROM AUTHOR]

Schematic representation of the effects of salinity on root structural traits. Namely; enlarged root diameter and periderm tissue while stele smaller with larger xylem vessels. • Roots modified their structural traits to enhance salt compartmentation and exclusion. • Salts accumulated in enlarged periderm tissue allowing greater compartmentation. • Two putative apoplastic barriers were identified: around the periderm and the stele. • Xylem vessel diameter distribution shifted to allow higher hydraulic conductivity. Roots are the first plant organ to encounter, sense, and respond to soil salinity. Like for many moderately salt tolerant species, roots of olive (Olea eurpaea) trees are the principal players in salt tolerance. We studied roots of mature olive trees in order to illuminate the yet vague mechanism(s) of root salt exclusion. Root structural traits were examined in olive trees grown in lysimeters and from a long-term salinity field trial. The distribution of salts was detected in root cross-sections using scanning electron microscopy combined with energy dispersive spectroscopy. Increased soil salinity caused a continuous decline in specific root length and an increase in root diameter, periderm thickness, and specific hydraulic conductivity. While periderm cell number was not modified, cell diameter increased linearly by a total of 50 % as root zone salinity increased nearly eight-fold. Strong compartmentation of Na within the periderm was found, with highest content in the outer periderm layer and lowest content in the stele. Increase in soil salinity was associated with decrease in stele area, yet, hydraulic conductivity was doubled due to higher fraction of large diameter xylem vessels. Our results indicate significant root structural plasticity, which underlies the salt resistance mechanisms. The dominant trait enabling salt tolerance of olive trees is the enlarged periderm serving as an apoplastic barrier that enhances salt compartmentation and exclusion from the vascular tissues. [ABSTRACT FROM AUTHOR]

Knowledge regarding uptake of water and nutrients as a function of their status in the soil is critical for smart fertigation management. Of particular interest is the uptake of water and potassium (K), each as a function of root zone salinity. The objective of this study was to quantify the response of tomato water uptake (transpiration) and K uptake to varied levels of K availability combined with salinity. Two independent lysimetric experiments were conducted and used to calibrate and validate models for water and K uptake under varied soil salinity. Tomato water and K uptake were determined by water and nutrient balance using the measured soil water content and K concentration in soil and drainage solution. Tomato water uptake was affected by root zone soil K and salinity. Salinity was the dominant factor driving uptake when irrigation solution had NaCl concentration of over 3 g L–1. Potassium uptake of tomato decreased with decreasing soil K content and increasing soil salinity. The linear relationship between tomato water uptake and K uptake rate was not influenced by soil salinity, indicating that the inhibition of K uptake was probably due to passive uptake of K with the flux of water from soil to roots decreased due to salinity. Tomato water and K uptake were simulated considering the effect of soil solution K concentration under simultaneous K and salinity stresses. Simulated daily average water and K uptake rates agreed well with measured values, with root mean squared error, normalized root mean squared error, and index of agreement of 144 cm3 d–1, 20.13% and 0.99 for average daily water uptake; and 24.43 mg d–1, 29.78% and 0.98 for K average daily uptake rate, respectively. These findings can be used to predict crop water and K requirements under combined salinity and K status conditions, which should contribute to efficient and sustainable fertigation scheduling. [ABSTRACT FROM AUTHOR]

A four-year trial was set up to test the feasibility of growing oleic sunflower in a very strongly saline wasteland with drip irrigation in the Ningxia plain of Northwest China. The soil salinity expressed as electrical conductivity of the saturation paste extract (EC) was around 28 dS/m, and soil nutrient was deficient in the upper 120 cm depth. The experiment included five soil matric potential (SMP) treatments, with the SMP at 20-cm depth immediately under the emitters maintained to be higher than −5, −10, −15, −20 and −25 kPa after sunflower establishment. Drip irrigation consistently created a favourable soil moisture and low-salinity region in the root zone when the SMP was maintained higher than −25 kPa. The sunflower dry seed yield decreased by 3.8 % for each unit increase in seasonal average soil salinity in the root zone. Plant vegetative growth, yield characteristics, irrigation frequency and irrigation amount all increased with the increase in SMP from −25 to −5 kPa, and the highest irrigation water use efficiency was available when the SMP was between −10 and −15 kPa (the amount of applied water was around 750 mm). Leaching of salts by drip irrigation gradually turned the very strongly saline soil into a moderately saline soil. This research suggests that drip irrigation can be successfully used in oleic sunflower cultivation in this highly saline soil and a SMP threshold between −10 and −15 kPa is suggested for irrigation scheduling. [ABSTRACT FROM AUTHOR]

Abstract: A 4-year trial was set up to test the feasibility of growing waxy corn (Zea mays L. var. ceratina Kulesh) in a highly saline wasteland with drip irrigation in the Ningxia plain, northwest China. The original soil salinity expressed as electrical conductivity of the saturation paste extract (EC e ) averaged 28dS/m in the 0–120cm depth. The experiment included five soil matric potential (SMP) treatments in which the SMP at 20cm depth below the drip emitters was controlled higher than −5, −10, −15, −20 and −25kPa after waxy corn establishment. The results showed that drip irrigation created a favorable soil condition for waxy corn growth through forming and maintaining a high moisture and low salinity region in the root zone when the SMP was maintained higher than −25kPa. Waxy corn growth and yield parameters increased with the increase of SMP from −25kPa to −5kPa, but their responses to SMP decreased with the prolonged period of cultivation. Irrigation frequency and irrigation amount decreased significantly as SMP decreased from −5kPa to −25kPa, and the highest irrigation water use efficiency (IWUE) was available when the SMP was around −15kPa in 2005, and was between −20kPa and −25kPa in successive years. After years of cultivation and drip leaching, the highly saline soil gradually changed to a moderately saline soil. This research suggests that drip irrigation can be successfully used in growing waxy corn in dry and highly saline conditions after appropriate management strategies are adopted. [Copyright &y& Elsevier]