Search

In order to clarify the suction characteristics of unsaturated clay under different conditions of water and salt, taking soil in western Jilin province, China as the research object, the suctions (matrix suction and osmotic suction) of samples with different water content, salt type, and salt content were determined by filter paper method. The results indicate that salt type and content have insignificant influence on the matrix suction. With the increase of water content, the matrix suction decreases at different rates in different suction regimes. When water content is constant, the osmotic suction increases with the increase of salt content, and under the condition of a constant salt content, the osmotic suction first increases and then decreases with the increase of ion concentration of the pore water, and can reach tens of MPa. The concept of suction equilibrium water content is proposed. When water content of sample is higher than this value, the magnitude of osmotic suction will always be greater than that of matrix suction. This indicates the necessity to consider osmotic suction in the presence or change of salt in soil. The applicability of the traditional models of matrix suction and osmotic suction in the full suction range of clay is discussed, and it is found that the traditional models cannot make a full explanation to the variation in suction. Based on the experimental data, an improved van Genuchten matrix suction model and an osmotic suction model, transformed by the Planck blackbody radiation formula, are proposed. [ABSTRACT FROM AUTHOR]

The aims of this paper is to illustrate the importance of grain production in China's food security strategy based on the three Northeastern provinces (NEP) in the new period, which quantitative assessment of climate change under the background of the loss caused by meteorological disasters of regional food production is clarify. In this paper, using grain planting area, yield and agricultural disaster statistics from 1981 to 2020, comparison analysis grain production and disaster characteristics between NEP and the whole country respectively. The disaster-yield assessment model was used to estimate the disaster-yield loss and final yield of the NEP by inputting disaster data in recent 10 years, and the sensitivity and stability of the disaster-yield assessment model were re-tested. The results showed that :(1) from 1981 to 2020, the grain planting area and total output in NEP increased significantly, and the proportion of the total output of NEP increased steadily, and the proportion of the total output of the three northeast provinces reached 1/5 of the total output of the whole country by 2020. (2) The disaster situation in NEP showed a significant trend of first increasing and then decreasing. The incrasing of average grain yield during the past 40 years was 65.96kg⋅ha-1 and 252.5kg⋅ha-1 per year for NEP and the whole country, while the incrasing of average grain yield during the past 10 years was 52.6kg⋅ha-1 per year for NEP significantly. (3) From 2011 to 2020, the average affected area and affected area in China were 23704.5x10³ha and 11204.7x10³ha, respectively, and 3899.1x10³disasters of the whole country and the three northeastern provinces were significantly lower than those of the previous three years, making it the decade with the least severe disasters in 40 years. (4) The simulation accuracy of the disaster-yield assessment model was high. The linear regression coefficients (R²) of simulated grain yield and measured grain yield in Heilongjiang, Jilin and Liaoning provinces were 0.98, 0.90 and 0.88, respectively. The slopes were 1.05, 1.02 and 0.98 (P < 0.01), respectively. The loss rate of grain yield due to agro-disaster was 10.4%, 17.9% and 18.0% respectively in the three province, while which was more than 8.0%, 17.0% and 16.0% for 20a.years. (5) The model slightly overestimated the grain yield of Jilin and Liaoning in recent 10 years due to the overall light disaster situation. Based on the data from 1981 to 2010, the regional grain disaster loss assessment model was proved to be able to evaluate the loss of grain yield caused by meteorological disasters well, and had the performance of predicting grain yield, and has the feasibility of operational application. The impact of meteorological disasters on the grain output in northeast China is higher than the average level of disasters in the whole country. Considering that the grain output in Northeast China accounts for a high proportion of the national grain output, preventing the risk of agro-meteorological disasters in Northeast China in the new period is of great importance to guarantee the national food security. [ABSTRACT FROM AUTHOR]

Guvermectin is a nucleoside metabolite produced by the fermentation of Streptomyces hygroscopicus. It shows antibacterial and antitumor activities and has often been used as a plant growth regulator to promote the growth of crops. In this paper, the adsorption and degradation behavior of guvermectin in soil was investigated to evaluate its environmental safety. The adsorption of guvermectin in soil was consistent with the Freundlich isotherm model, and Freundlich adsorption coefficients (KF-ads) obtained from the model were low. The soil organic matter content was significantly and positively correlated with KF-ads. The effects of surfactant, humic acid, and biochar on the adsorption of guvermectin were studied using Jilin soil. The amount of guvermectin sorbed by the soil decreased with the addition of surfactant. By contrast, the amount adsorbed gradually increased as the amount of humic acid increased. Soil adsorption test with biochar revealed that biochar can efficiently sorb guvermectin. The half-life (t0.5) of guvermectin in soil under aerobic degradation and standing water anaerobic degradation conditions ranged from 2.84 to 7.29 days and from 8.21 to 13.70 days, respectively. The adsorption and degradation tests of guvermectin in soil revealed that pollution by guvermectin is not a major risk to soil because it is not easily adsorbed, it is highly mobile, and it can be easily degraded. [ABSTRACT FROM AUTHOR]

The rapid development of farmers' cooperatives in rural China cannot be separated from government support. To ensure the growth of farmers' cooperatives, the Chinese government uses it as a key performance indicator for its local institutions. Superficially, rural China's cooperative population and membership size witnessed rapid growth during the first decade after the Farmers' Specialized Cooperatives Law was enacted in 2007; however, such government intervention also leads to non‐standard phenomena due to market distortion. Using nationally representative survey data from 504 cooperatives in Jiangsu, Jilin, and Sichuan provinces, this paper provides a reliable estimate of the "shell cooperative" rate around 2014. The empirical study sheds further light on the role of government during the period of rapid but chaotic growth by a subset containing 241 marketing cooperatives. Results show that direct administrative intervention leads to the emergence of many shell cooperatives (approximately 37%). Further study also confirms that task‐oriented policy support is only positively associated with the nominal coverage ratio but has no significant relationship with cooperatives' function. This study provides new insights into the formation of shell cooperatives and suggests that direct administrative intervention may not be a good strategy for promoting the sustainable development of farmers' cooperatives. [ABSTRACT FROM AUTHOR]

Mastering the spatial distribution of water retention capacity and scientifically delineating the ecological space for water conservation are of great significance to the management of regional land and water resources. In this paper, a water conservation ecological spatial delimitation framework suitable for water-deficient areas was put forward. The water retention capacity of the study area in 1983, 1990, 2000, 2010, and 2016 was evaluated by using the InVEST Water Yield model and water balance method, respectively. On this basis, a flexible inflection point model based on the contribution degree of functional units was established. Then the ecological space for water conservation was delimited. The framework was applied to the delimitation of the key water conservation areas in Jilin province, China. The results showed that: (1) the spatial distribution pattern of water conservation in Jilin province gradually decreased from east to west. The spatial difference was significant. The maximum value of water conservation in Jilin province was 730 mm. From 1983 to 2016, water conservation, which accounted for 75.71% of the area, showed an upward trend. The overall water retention capacity showed the characteristics of the overall increase and the local decline. (2) From the absolute amount of the effect of unit area change on water conservation, the intensity from the high to the low was forestland, cultivated land, grassland, unused land, buildings, and water. (3) The area of water conservation less than 474 mm accounted for more than 80% of the total study area. The overall water retention capacity was low. High importance ecological space area of water conservation was comprehensively defined as 36.97%, which was mainly distributed in the natural forest area of Changbai Mountain in the east and the south of Song Liao Plain. Therefore, this study provided a basic layout of relatively concentrated ecological spatial distribution for water conservation types at different levels in Jilin province. The study results and conclusions of this paper will provide a reference for water conservation assessment and the regional land’s natural resources management. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to test the impact of the soybean rejuvenation plan and the subsidy on farmers' land allocation decisions, which may reference policy adjustment from a micro perspective. Design/methodology/approach: The paper develops a multi-objective optimized programming model on farm-level, which simulated the land-use changes, as well as the resulting changes in benefits of the rational "typical farm". The simulation scenarios include changes in subsidy policy and production efficiency, and the baseline scenario was the production status in 2018. Findings: The results show that an increase in soybean producer subsidy will encourage farmers to allocate more land for soybean planting, which can be considered as a policy tool in promoting soybean production in China. Besides, the effect of subsidy in adjusting soybean acreage for farms is further affected by external conditions such as production technology (such as breeding technology, pesticide and fertilizer application efficiency). Meanwhile, large-scale farms show more significant land adjustments when facing changes in policies and external conditions. Originality/value: The value of this paper is to simulate the effects of soybean policy and subsidy change on farmers' land-allocation decisions through a multi-objective farmer decision-making model, which provides a micro perspective to understand the implementation effect of the soybean revitalization plan. [ABSTRACT FROM AUTHOR]

Based on the theories of mass conservation and coalbed methane (CBM) adsorption/desorption, this paper first establishes a novel reservoir pressure model for CBM production, following which, the CBM concentration and production models are also proposed. Then, these models are programmed and solved by means of the finite element method. Taking the Hunchun CBM field in Jilin province, China, as an example, the reservoir pressure, gas concentration, and production characteristics under different hydraulic fracture forms are simulated and investigated. In conclusion, the reservoir pressure decreases very rapidly in a small region near the fracture tip, which we called the "reservoir pressure singularity". The existence of a hydraulic fracture greatly reduces the reservoir pressure in the process of CBM exploitation. The permeability sensitivity coefficient of reservoir pressure, Rpk, is defined to quantitatively describe the influence of coal seam permeability on the evolution of reservoir pressure. Rpk decreases logarithmically as the distance from the CBM extraction well increases. The reservoir pressure and CBM recovery rate characteristics in the presence of multiple hydraulic fractures are also investigated. We believe these results could contribute to the design of hydraulic fracturing wells and the evaluation of gas production in a CBM reservoir. [ABSTRACT FROM AUTHOR]

Fault section diagnosis (FSD) is a critical part of the power system dispatching and control. To diagnose the faulty section(s) correctly, an improved binary variant of gaining‐sharing knowledge‐based algorithm (GSK) named LOBGSK is presented in this paper. It stretches the original GSK over binary search space so as to solve the 0‐1 integer programming FSD problem. In LOBGSK, individuals are encoded by binary numbers and logical operations instead of real arithmetic operations are designed to update the individuals. By this, LOBGSK can avoid transcoding in solving the FSD problem. To validate the effectiveness of LOBGSK, it is first applied to a 4‐substation test system considering various fault scenarios. Then it is further implemented to the IEEE 118‐bus system and an actual fault event occurred in a practical power grid in Jilin province of China. In addition, the influence of three key parameters of LOBGSK is also investigated. Simulation results show that LOBGSK is robust against its key parameters and can offer a 100% successful rate to diagnose different faults quickly, which is demonstrated by the reported results of some published FSD methods. Furthermore, it outperforms seven state‐of‐the‐art metaheuristic algorithms and the original GSK in solving the FSD problem of power systems. [ABSTRACT FROM AUTHOR]

In recent years, China and Japan are cooperating in the destruction of the Japanese army abandoned chemical weapons in China (JACWs). During the long-term burial of JACWs, As-containing agents leaked into the environment due to the corrosion of the shell, resulting in soil As pollution. This paper studied the fraction, speciation, and composition of As in the soil polluted by the As-containing agent in Jilin, China. The results showed that As was mainly distributed in the forest soil in the study area, with the highest concentration of 110 mg/kg, and had the trend of migration to the downhill farmland soil. As mainly accumulated in the amorphous Fe/Al oxides bounded fraction and residual states, the proportion of potentially risky fractions in the soil of downhill farmland is higher than that of uphill farmland. The speciation of As in the soil is mainly As(V), with an average content of 25.02 mg/kg. The transformation behavior of As in the horizontal migration of topsoil is mainly the oxidation of As (III). The residual organic As in soil mainly includes 2-chlorovinylarsonic acid, triphenylarsine, phenylarsine oxide, and diphenylarsonic acid. Similar to the influence factors of As, both speciation and organic compounds of As are significantly affected by Fe/Al/Mn-oxides, and degradation and transformation reactions such as redox occur during migration. • As mainly existed in amorphous Fe/Al oxide bound fraction and residual fraction. • The organic-As in soil mainly includes CVAOA, TPA, PAO, and DPAA. • DPAA showed a significant negative correlation with TP, Ca and Mn. [ABSTRACT FROM AUTHOR]

Mastering the lodging risk of planting environment is of great significance to the optimal layout of maize varieties and the breeding of lodging resistant varieties. However, the existing lodging risk models are still at the stage of single or multi-factors independent analysis, and lack of assessment for different lodging types. To address this issue, based on the mechanism of different lodging types, the Archimedean copula function was used to describe the joint probability distribution of wind speed and precipitation, and the lodging risk assessment model of maize was established. By comparing the goodness of fit, when the rank correlation coefficient of these two is positive and negative, the corresponding optimal joint probability distribution functions are the Gumbel copula and Frank copula. According to the spatial distribution of lodging risk, the area from Liaodong Bay northward to Tongyu, Jilin province in the Northeast and the North China Plain has a high frequency of lodging, in which the probability of stalk lodging is two to four times that of root lodging. Finally, we discussed how to apply the lodging risk distribution results to optimize the maize variety test sites to improve the efficiency and reliability of the existing test system. The method proposed in this paper comprehensively considers the synergistic effect of multiple factors and can provide technical support for other risk assessment. [ABSTRACT FROM AUTHOR]