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【Objective】 Drip irrigation using brackish water is a way to relieve water shortage in arid regions such as Xinjiang, but it needs a good management to reduce its detrimental consequence. The aim of this paper is to investigate the combined effect of irrigation water quality and nitrogen fertigation on changes in soil salinity and Na+ and Ca2+ concentration in soil water with cotton planted. 【Method】 A pot experiment was conducted from June to October 2020 at Alaer in Xinjiang. There are three nitrogen treatments: 255 kg/hm2 (F1), 315 kg/hm2 (F2) and 375 kg/hm2 (F3), and three irrigation water quality treatments: 1.27 g/L (Q1), 3.03 g/L(Q2), 4.90 g/L (Q3). Irrigation with groundwater was taken as the control. In each treatment, we measured soil salt content, and concentration of Na+ and Ca2+ in soil water. 【Result】 Depending on nitrogen fertigation, saline water irrigation increased total soil salt content and Na+ and Ca2+ concentrations by 14%~78%, 42%~197% and 58%~253%, respectively, compared to groundwater irrigation. It also increased soil sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP) by 5%~109% and 48%~90%, respectively. Increasing nitrogen application to 315 kg/hm2 and 375 kg/hm2 reduced soil salinity and Na+ and Ca2+ concentrations by 11%~70%, 6%~42% and 21%~138%, respectively, and reduced soil SAR and ESP by 5%~27% and 3%~19%, respectively, compared to the control. 【Conclusion】 Soil salinity increased with the increase in irrigation water salinity, but increasing nitrogen application to 315 kg/hm2 could reduce soil salinity and Na+ and Ca2+ concentrations in soil water, thereby alleviating salinity stresses.

【Objective】 Canopy temperature varies with leaf water content and can be used as a proxy of crop water deficit. In this paper, we compare different interpolation methods for calculating spatial distribution of crop water deficit based on canopy temperature. 【Method】 The calculation was based on the 10 interpolation modules in ArcGIS. We studied two experimental sites cultivated with maize - winter wheat rotation. For each site, we analyzed the accuracy and zoning effect of canopy temperature, as well as the normalized relative canopy temperature (NRCT). The accuracy and robustness of each interpolation method was evaluated based on its characteristic value, normalized root mean square error (nRMSE) and Pearson correlation coefficient between predicted and ground-truth values, as well as spatial distributions of the predicted canopy temperature and NRCT. 【Result】 The spatial distribution of canopy temperature of the winter wheat and summer maize both has a strong autocorrelation on the two sites. The canopy temperature estimated using local polynomial and universal Kriging interpolation is spatially abnormal. The nRMSE and NRCT between the measured canopy temperature and that predicted using global polynomial interpolation are the highest, being 5.9% and 28.6% respectively; their associated Pearson correlation coefficient is 0.33. The ordinary Kriging method is most accurate in that the difference between the predicted and measured canopy temperatures is less than 0.5 ℃; its associated nRMSE (3.6%) and NRCT (17.5%) are the least with a Pearson correlation coefficient 0.8. The spatial distribution of canopy temperature calculated by the simple Kriging method, disjunctive Kriging method and empirical Bayesian Kriging method is similar to that by the ordinary Kriging method; their overlapping percentage is greater than 90%. 【Conclusion】 Considering accuracy and spatial distribution of canopy temperature and NRCT, the interpolation methods is ranked in the following order based on their accuracy: ordinary Kriging method > simple Kriging method > disjunctive Kriging method > empirical Bayesian Kriging method > radial basis function method (tension spline function) > radial basis function method(regular spline function) > inverse distance weight method. Overall, the ordinary Kriging method is most accurate for estimating crop water deficit from canopy temperature.

Anti-wear and anti-oxidation abilities are two key properties of lubricants that play a crucial role in ensuring long-term stable equipment operation. In this study, we aimed to develop a base oil with good anti-oxidation and anti-wear properties for use under extreme pressure. The as-prepared metallocene polyalphaolefin (mPAO) was chemically modified using the trifluoromethanesulfonic acid (TfOH) catalysis through an alkylating reaction with triphenyl phosphorothioate (TPPT). During the experiments, when the reaction temperature exceeded 70 °C or the concentration of TfOH exceeded 2.67%, the β -scission reaction in the alkylation process became significantly more pronounced. The physical and chemical properties of TPPT-modified mPAO (T-mPAO) were evaluated by nuclear magnetic resonance spectroscopy, Fourier trans-form infrared spectroscopy, gel–permeation chromatography, and ASTM standards. T-mPAO showed significantly improved antioxidant capacity, with the initial oxidation temperature increasing by 32 °C compared to the base oil, and it exhibited the slowest increase in acid number in the 96-h oven oxidation test. The tribological tests showed that T-mPAO had the lowest friction coefficient, wear track, and wear rate (72.7% lower than that of mPAO) as well as the highest PB (238 kg) and PD (250 kg) among all tested samples. Compared to mPAO, the average friction coefficient of TPPT-modified mPAO in the four-ball friction test was reduced by 30.5%, and by 16.4% in the TE77 reciprocating friction test. Based on the experimental results, T-mPAO had strong anti-oxidation ability and excellent lubricating performance.The successful synthesis of multifunctional mPAO has enabled lubricant base oil additization, making it possible to use it in more demanding work scenarios, greatly broadening its application scope and making lubricant formulation blending more flexible. [ABSTRACT FROM AUTHOR]

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With the continuous advancement of industrial technology, higher demands have been placed on the properties of gear oils, such as oxidation stability and shear resistance. Herein, the oxidation stability of high-viscosity metallocene poly- α -olefins (mPAOs) was improved by chemical modification via aromatic amine alkylation. The modified mPAO base oils were synthesized separately with diphenylamine (mPAO-DPA) and N-phenyl- α -naphthylamine (mPAO-NPA), and their applicability in industrial gear oil formulations was evaluated. The composition and physicochemical properties of the obtained samples were assessed using 1H NMR spectroscopy, Fourier transform infrared spectroscopy, gel permeation chromatography, and the American Society for Testing and Materials standards (ASTM D445, ASTM D2270, ASTM D92, etc.) confirming the successful completion of the alkylation reaction. The oxidation stability of the samples was also evaluated using pressurized differential scanning calorimetry. The initial oxidation temperature of mPAO-NPA (230 °C) was 53 °C higher than that of mPAO, and the oxidation induction period of mPAO-DPA was nearly twice that of mPAO-NPA. Thermogravimetric analysis in air revealed the increased thermal decomposition temperature and improved thermal stability of modified mPAO. ISO VG 320 industrial gear oils were formulated using mPAO alkylated with N-phenyl- α -naphthylamine(Lub-2) and commercially purchased PAO100 (Lub-1) as base oil components. The antioxidant performance of two industrial gear oils was evaluated through oven oxidation and rotating oxygen bomb tests. The oxidation induction period of Lub-2 was 30% higher than that of Lub-1, with the latter having a lower acid number and a smaller increase in viscosity at 40 °C. Finally, the friction performance of the samples was assessed on a four-ball friction tester, revealing the synergistic effect of the mPAO-NPA base oil with the HiTEC 3339 additive, forming a more stable oil film with a smaller wear scar diameter. [ABSTRACT FROM AUTHOR]

This study was carried out to evaluate the effects of the combined application of water-retaining agents and nitrogen fertilizers on soil physicochemical properties, bacterial communities, and root growth under winter wheat planting mode in the Guanzhong area of Shaanxi Province. Based on the positioning experiment of dry farming in the loessal soil area of Shaanxi Province, four treatments were set up by using the tillage method of subsoiling + rotary tillage and straw returning: only fertilization (U), only water retention agent sodium polyacrylate (C3H3NaO2)n (S), combined use of water-retaining agent sodium polyacrylate (C3H3NaO2)n and fertilizer (US), and control group CK (no treatment). The ultra-high-throughput sequencing of 16S rRNA genes of soil bacteria was performed by the Illumina Hiseq platform, and the effects of different tillage measures on soil bacterial diversity and community structure were analyzed. In addition, the effects of these tillage measures on soil physicochemical properties and winter wheat root length density at booting and flowering stages were evaluated. The results indicated that the combination of the water-retaining agent and fertilizer markedly enhanced the contents of ammonium nitrogen, available phosphorus, and available potassium in the 0~20 cm soil layer, significantly increased the soil moisture content, and promoted the deep growth of roots. The root length density was 4.70 times higher than that of the control group at the booting stage. In addition, the combined application alleviated the decrease in soil microbial diversity caused by individual fertilization, especially significantly increasing the abundance of Gemmatimonadetes, Acidobacteria, and Planctomycetes in the 0~10 cm soil layer. This study reveals the potential of the combined use of water retention agents and fertilizers to optimize the soil environment and enhance winter wheat yield, which provides a scientific basis for improving local agricultural practices. [ABSTRACT FROM AUTHOR]