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In order to explore the effect of rice seed treatment suspension (FS) on the growth of rice in dry land cultivation. In this paper, two seed treatment suspensions, i.e., sedaxane + pylocyanonitrile + metalaxyl 11% FS and clothianidin 18% FS were selected to treat rice seed (guang8you 1973). The effect of FS was assessed by standard germination, Q2 test, agronomic traits and yield. The results showed that: under laboratory conditions, germination vigor, germination percentage and increased metabolism time (IMT) of two FS with the 1 : 50 treatment (1 mL of agent is required to process 50 g of seeds, referred to as the ratio of FS to seed) had no significant effect on these parameter compare with the blank control under laboratory condition. However, the FS with the 1 : 50 treatment showed a shorter relative germination time (RGT), a higher starting metabolism rate (SMR), and the oxygen metabolism rate (OMR) was significantly higher than that of the blank control by 1.33% and 1.38% per hour, respectively. This results indicate that FS can improve seed respiration and seed vigor. The comparison between the two FS indicate that the clothianidin 18% FS had a better effect on seed vigor than the sedaxane + pylocyanonitrile + metalaxyl 11% FS under the field condition. The field performance was better than that of the blank control, among which the seedling rate of seed coatingagent treatment increased by 27.60%-33.20% compared with CK, the number of tillers increased by 71.14-97.82 per hectare, the plant height increased by 4.90-6.80 cm, the thousand-grain weight increased by 7.27%-9.09%, the effective panicle increased by 9.45-13.42 million panicles per hectare, and the actual yield increased by 529.85 kg/hm2 and 580.70 kg/hm2, and there were significant differences between them. The results showed that: coating rice seeds with sedaxane + pylocyanonitrile + metalaxyl 11% FS and clothianidin 18% FS at a seed ratio of 1 : 50 can effectively promote rice seed respiration, improve the performance and yield in dry land cultivation. [ABSTRACT FROM AUTHOR]

For revealing the spatial distribution characteristics and laws of land use on topographic gradient under different geomorphic forms in poor mountainous areas, the paper took Bijie City as the research area, which was divided into karst and non-karst areas. Based on land use data and DEM in 2009 and 2018, different characteristics of the land use change under different terrain gradients was discussed through the methods of topographic index, topographic distribution index. The results are as follows. 1) The land use types in karst and non-karst areas are hierarchical in terrain gradient. Dry land, paddy field, garden land, construction land, road and water area have certain selectivity for low terrain, while woodland, shrub land, grassland and unused land have certain selectivity for high terrain, among which land use types in non-karst areas are more widely distributed in low terrain area. 2) It has obvious effect for the terrain gradient on land use diversity in karst and non-karst areas. It had great changes as the augment of terrain gradient in 2009. And in 2018, the lower the terrain gradient was, the higher the diversity was. Compared with non-karst area, the diversity of karst area is higher in interval 1, 2 and 5 than that of non-karst area, but the opposite is true in interval 3-4. 3) The terrain gradient effect of karst and non-karst land use degree is significant, which shows the higher the terrain gradient is, the lower the land use degree is. The spatial difference is influenced by natural environment, socio-economy and policy. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to analyze the effects of sowing date and film mulching on yield and quality of direct seeding winter rapeseed to provide a theoretical basis for suitable sowing and high-yielding cultivation of winter rapeseed in dryland in southwest China. [Method] A two-factor completely randomized block design was adopted to explore the effect of sowing date(20th September, 30th September, 10th October, 20th October, 30th October, 10th November, 20th November) and film mulching (film mulching and no film mulching) on field soil temperature, dry matter accumulation, agronomic characteristics, yield and quality of Chuanyou 36. [Result] Film mulching effectively increased the 0-20 cm soil temperature, dry matter accumulation, plant height, length of main inflorscence and effective pods, thereby increasing rapeseed yield by 3.61%-44.47%, which was more obvious with the delay of sowing date. However, the sowing date delayed longer, dry matter accumulation and agronomic traits of rapeseed decreased significantly. The regression equation showed that the rapeseed yield rose first and then declined with the delay of sowing date, which had a significant polynomial relationship with sowing date. The optimal sowing date for rapeseed was 10th October, which was 2.13%, 47.97%, 74.19% and 136.64% higher than 30th September, 30th October, 10th November and 20th November, respectively. In addition, the delay of sowing date effectively reduced the content of linolenic acid, erucic acid and glucosinolates in rapeseed, but also reduced the oil content, while film mulching effectively decreased the difference in rapeseed quality resulted from the delay of sowing date. [Conclusion] 30th September to 10th October was a suitable sowing date for high yield of direct seeding rapeseed in dry land in southwest China, and a proper delay of the sowing period in combination with film mulching technology was more conducive to achieving goals of high yield, efficiency and quality. [ABSTRACT FROM AUTHOR]

【Objective】 The present paper aimed to carry out research on dynamic change characteristics of paddy field and dry land resources in Chongqing, identify the main factors driving the loss of paddy field and dry land resources, analyze the regional differences in the utilization of cultivated land resources, and provide support for improving the utilization rate of cultivated land resources, strengthening the management of provincial agricultural resources, and ensuring regional food security. 【Method】 Based on the interpretation results of historical remote sensing image data, the dynamic change characteristics and spatial differentiation of paddy field and dry land in the two historical stages of Chongqing from 1980 to 2000 and from 2000 to 2018 were quantitatively studied by using geographic gravity center analysis, cultivated land loss rate and other indicators and methods. 【Result】 The study found that areas of paddy field and dry land in each district of Chongqing decreased in the past 40 years. The loss area of paddy field was less than dry land, but the loss rate of paddy field was higher than dry land. The loss of paddy field and dry land both showed a trend from slow scattered occupation to rapid agglomeration occupation over time, and the area gravity center of both cultivated lands had gradually shifted to the northeast, indicating the shift from the western low-altitude area（with high economic growth rate and high-quality cultivated land） to the northeast hilly area（with relatively low economic growth rate and low quality cultivated land）. From 1980 to 2000, the area gravity center shift distances of paddy field and dry land were 0.58,0.97 kilometers, respectively, while that distances from 2000 to 2018 were 2.14,1.57 kilormeters. According to the result of cultivated land loss rate index, paddy field and dry land in most districts belonged to the slow loss type, and the losing rate from 2000 to 2018 was much higher than that from 1980 to 2000. Severely loss regions of paddy field were mainly located in the urban area and suburban areas. The regions of rapid loss were mainly concentrated in the northeast of Chongqing, and the severe and fast loss areas of dry land are concentrated in the urban area. Construction occupation was the primary factor of paddy field loss, and the ecological occupation was the secondary factor. Considering the loss rate of cultivated land resources and the types of cultivated land transformation, the dynamic types of cultivated land resources in paddy field and dry land could be divided into 4 categories, which were construction occupation dominated, ecological occupation dominated, no dominant type, and cultivated land type transformation. Furthermore, 10 subcategories can be identified based on their loss speed. 【Conclusion】There are regional differences in the main characteristics and driving forces of the loss of paddy field and dry land in Chongqing. It is necessary to strengthen the zoning management of paddy field and dry land based on the characteristics of regional cultivated land loss, optimize the ecological and landscape functions of existing cultivated land in the development zone, improve the resource utilization rate and comprehensive production capacity of cultivated land, and ensure food security. [ABSTRACT FROM AUTHOR]

Soil wind erosion is the main cause of land degradation in arid and semi-arid areas in northern China, which is mainly affected by surface type, climate and so on. Strong soil wind-erosion will not only accelerate regional desertification and influence the quality of human life, but also cause serious ecological and environmental problems. Since the 2000 s, our country has gradually strengthened the control of land desertification and carried out a series of sand control works, which effectively improved the overall ecological environment of the sandy land. But in recent years, there are some common phenomenon that extensive grassland and brushland was turned into cultivated land in the southeast and southwest of Mu Us sandy land. However, in the dry and windy winter or spring, these new reclaimation land is usually so exposed that it is vulnerable to suffer from strong wind erosion. Therefore, it is great significance to study the characteristics of soil wind erosion in new reclaimation land and find out the control methods. Based on the above question, this paper selected the southern part of Mu Us sandy land (38°05′27″-38°13′58″N, 107°24′28″-107°37′30″E) as the research area, as well as set up 5 observation points on different surfaces, which were represented respectively by A, B, C, D and E. Point A was on the brushland, point B was on the middle of the grassland, and other three points were respectively on different parts of the cultivated land. On the day with strong wind activity, 12 groups simultaneous observation of wind and sand were made at these 5 points (A, B, C, D, E), with each observation time at least 20 minutes. After these observations, the material of the sand samplers were weighed with an electronic balance of 1/1 000, and the material of surface and sand samplers on cultivated land were analyzed by Mastersizer2000 Laser Particle Size Analyzer. The results showed that the soil wind erosion intensity increased exponentially after grassland and shrubland were cultivated; on cultivated land, with the increase of height, the sediment transport rate decreases with exponential function within 0-10 cm height and power function within 10-20 cm height. Due to the height of the sand collector used in this paper is 20cm, lower than the height of the sand flow layer. In order to obtain the total sediment transport rate of the surface of the cultivated land, this paper must calculate it through the function simulation obtained from the above result. After calculating the total sediment transport rate, fitting it with the wind speed. We found that the total sediment transport rate has a good power function relationship with the wind speed in the cultivated land with sufficient erodibility particles. Based on the formula of the relationship between wind speed and total sediment transport rate, as well as the wind speed data of the meteorological stations in the region, the wind erosion modulus of the new reclaimation land can be preliminarily calculated. The result shows that the wind erosion modulus of the new reclaimed land is 9 657 t/(km2·a). Through the results obtained in this paper, combined with the former research results, this paper argues that the emergence of new reclaimed land has an important impact on regional desertification, and its area should be used as an important index when evaluating regional desertification. Meanwhile, Controlling cultivated land area, establishing windbreak and sand fixation forest, as well as retaining stubble at a certain height can effectively control soil wind erosion in newly reclaimed land. [ABSTRACT FROM AUTHOR]

[Objective] In order to comprehensively maintain and improve the production, ecological and living functions of the farmland ecosystem, under the different types of cultivated land, the present paper analyzed the spatial and temporal evolution trajectory and characteristic differences of the quantity and quality of the water and dry land in the cultivated land based on the perspective of the ’trinity’ protection for quantitative and quality ecological development.[Method] Taking the Jiangjin District of the Three Gorges Reservoir as an example, the land use status and cultivated land quality grade evaluation result data, the standard deviation ellipse, landscape pattern index, nearest neighbor index method, etc. were used to study the quantity, the spatial and temporal evolution pattern of quality and ecology. [Result]（i） Quantity, the distribution of flooded and dry land in Jiangjin District had a trend of further expanding to the hinterland of Jiangjin District. The evolution path of dry land changes from northwest to southeast, and the evolution path of paddy field changed from southwest to southeast;（ii） Quality, the overall quality of the paddy field was higher than that of the dry land. The grade of the paddy and dry land was gradually decreasing from the central and western regions to the north and south.（iii） Ecological, the shape of the paddy and dry land was complex and fragmented, with reduced connectivity and significant aggregation.[Conclusion] The implementation of arable land zoning and types of protection measures, to achieve the development momentum of characteristic agriculture according to local conditions, provides reference for the protection of arable land resources in this area, the formulation of ’tri-in-one’ protection policies and the optimization of the layout of arable land. [ABSTRACT FROM AUTHOR]

[Objective] The objective of the paper is to provide the scientific basis for rational fertilization in Jianhe County of Guizhou Province and similar areas. [Method] The effects of soil nutrient indexes(total N .organic matter, available N .available K, available P, total P and total K)on soil fertility are explored by using variation coefficient method, correlation coefficient method and weighted mean method, and then the soil fertility in paddy field and dry' land is evaluated by using improved Nemerow comprehensive evaluation method combined with the weight coefficient mean value of the three methods. [Result] The soil available k in paddy field and total P in dry land were at a lower level, while other nutrient indexes were at a medium-high, high and higher level. The soil available N content in six dry' land sampling sites with different plants was high. Soil total P and available k fluctuate greatly among sampling sites, while organic matter content fluctuates less. The soil available P in fertility factor weighted coefficient of paddy field and dry land was the highest, respectively 0. 2710 and 0. 2358 comparing the mean value of the three weighted method weighted coefficient. The available P is the main factor influencing soil fertility in paddy field and dry' land and soil fertility indexes is 1.52 and 1.63 separately. The soil comprehensive fertility was at a fertile level. [Conclusion] The soil fertility of paddy field and dry land in Jianhe County is at a fertile level, and available P is the main factor influencing soil fertility in paddy field and dry land. The soil N content in paddy field and dry land is high, which can meet the demand of crop production. Therefore, N fertilization should be reduced in production. The soil K content in paddy field is low, and the corresponding fertilization measures should be taken to improve K supply level in paddy field. [ABSTRACT FROM AUTHOR]

In this paper, the geochemical signatures were employed to investigate factor controlling on groundwater geochemical evolution in the Shule River basin in northwestern China, where groundwater extensive extraction occurs for agriculture and domestic supply. The results show that the TDS concentrations of groundwater gradually increases from the Qilian Mountains front to the Guazhou basin. Springs in the mountain front of the Qilian Mountains, the Yumen-Tashi groundwater, and the Guazhou groundwater were Ca-HCO3, Ca-Mg-HCO3-SO4 and Na-Mg-SO4-Cl types, respectively. Geochemical evolution in groundwater was possibly due to a combination of mineral dissolution, mixing processes and evapotranspiration along groundwater flow paths，but the mineral dissolution was the main cause. [ABSTRACT FROM AUTHOR]

Freshwater and energy are indispensable resources for human survival and social developments. However, fresh water scarcity is expanding and intensifying around the world because of rapid population growth, industry development, abnormal climate and urbanization. Especially, the shortage of useful water has become more obviously for isolated or arid regions. Great amount of groundwater in these regions found in wells usually remains brackish water. To obtain safe and pure drinking water, various brackish water distillation technologies have been increasingly recommended as a viable alternative. However, conventional distillation processes have indicated highly energy consumption, and potential environmental impacts due to the utilization of fossil fuels. It is necessary to utilize solar energy for the brackish water distillation, in order to meet the high requirement of potable water and agriculture in the remote and arid regions blessed with ample amount of solar energy. This paper therefore designed a novel multi-effect solar brackish water distillation device based on vertical tube falling film, which allows testing of four operational modes, i.e., single-effect, double-effect, triple-effect and four-effect. Compared with conventional solar brackish water distillation device, some advantages can be achieved, such as falling film evaporation, multi-effect operation, smaller thermal resistance, and higher efficiency of thermal utilization. The working principle was introduced for the four-effect device and structure. A theoretical analysis of heat and mass transfer process of the device was carried out. The water yield, evaporation temperature and condensation temperature of the device for four operation modes were tested under the fixed heating power operation. The effects of the different operation effects on the water yield per energy and GOR (Gain Output Ratio) were investigated, together with the economic analysis of the multi-effect devices. The results demonstrated that when the heating power was 200W, the water yield per energy and the total water production of the four-effect device were 1.45 g/kJ and 1.039 kg/h, indicating an increase by 36.80% and 35.88% than that of the triple-effect device, respectively. The steady-state operation temperature was 83.76 ℃, while the total temperature difference of evaporation and condensation was 19.07 o C in the four-effect device. The GOR of four-effect device can reach 3.36. The payback period of four-effect device was 5.69 years. Performance and economic analyses of the devices indicated a wide applicability of the system, especially for remote and arid regions. [ABSTRACT FROM AUTHOR]

【Objective】The objective of the paper is to provide a reference for soil nutrient management and sustainable operation in Karst areas.【Method】The soil samples were collected from woodland and dry land in Baiduo Village(dolomite areas) and Shiqiao Village(limestone areas) in Shibing County,Guizhou Province,and then the soil nutrient was analyzed.【Result】The soil developed from dolomite was featured with higher organic matters,total N,available P,available K and hydrolysable N.The soil developed from limestone was featured with higher total P and total K.Total N was positively and very significantly related to hydrolysable N and organic carbon in soil developed from limestone and dolomite.Hydrolysable N was positively and significantly related to organic carbon in limestone areas.Hydrolysable N was positively and very significantly related to organic carbon in dolomite areas.Land use patterns had obvious effects on nutrient content in soil developed from limestone and dolomite.Soil total K,total N,hydrolysable N and organic carbon content in limestone woodland was higher than dry land,and available K,total P,available P and pH was lower than dry land.Soil total P and available P in dolomite woodland are lower than dry land,and other indexes are higher than dry land.The organic matter,total N,total P and total K content in dolomite-developed soil was Grade II,Grade I,Grade VI and Grade III respectively.The organic matter,total N,total P and total K content in limestone-developed soil was Grade II,Grade I,Grade V and Grade I separately.【Conclusion】Soil nutrient was not only affected by soil forming rock,but also affected by land use pattern. [ABSTRACT FROM AUTHOR]

Drought is a natural hazard caused by long-term precipitation deficiency and high evaporation resulted from high temperature, which is among the most common disasters around the world. In recent decades, with the intensification of climate change and human activities, drought occurrence is becoming more frequent in China, causing negative impacts on agricultural production, ecological environment and social economy. Therefore, it is significant to explore the impact of drought on vegetation for agricultural production and healthy development of ecological systems. In this paper, the response and sensitivity of vegetation to drought in different climatic zones in China were analyzed, and the effects of different climatic factors, including water balance (precipitation-potential evapotranspiration), annual precipitation, mean temperature and sunshine hours, on the relationship between different vegetation types including forestland, grassland and cultivated land and drought were explored, so as to reveal the response mechanism of ecological vegetation to drought from a macro perspective. Using the self-calibrating Palmer drought severity index (scPDSI) and normalized difference vegetation index (NDVI) data for the period of 1982-2015, the response rule and sensitivity of different types of vegetation to drought were analyzed by applying time-delay correlation method, and the influence of various climate factors on the relationship between vegetation and drought was analyzed by applying linear regression method. The results of the research showed that in northwest China, Inner Mongolia, north China plain and southern Qinghai-Tibet plateau, the correlation of shorter lag time scPDSI (1-3 months) and NDVI was close (Rmax>0.4), which indicated that vegetation growth was more sensitive to drought in these regions and that vegetation biomass were influenced mainly by the spatiotemporal characteristics of the water availability. In the humid areas of south China, including the middle and lower reaches of the Yangtze River and the Pearl River basin, the precipitation is abundant so that the correlation between NDVI and scPDSI was negative, and the response of vegetation was not sensitive to drought. The growth of vegetation is mainly controlled by energy factors such as temperature and sunshine hours. The relationship between vegetation and drought was significantly affected by the average annual water balance, precipitation, sunshine hours and temperature, among which the annual water balance was the main water controlling factor (R²=0.45). It can be concluded that the change of water availability was the key factor behind the change of vegetation vigor. Sunshine hours were the main energy controlling factor. When average annual temperature was less than 5, the effect of ℃ temperature on the correlation between scPDSI and NDVI was also significant. The sensitive areas of drought impact on vegetation were mainly in the northern arid regions, while the southern humid areas had strong resilience and resilience to drought. The sensitivity of different types of vegetation to drought varied greatly, and the order of sensitivity is grassland >forestland>cultivated land. The results can provide a scientific basis for the evaluation of the impact of drought on ecological vegetation in different regions of China, and thus help to guide agricultural and environmental production, protect vulnerable ecosystems and provide implications for sustainable socioeconomic development. [ABSTRACT FROM AUTHOR]

Corn is one of the main grain crops in China, and it is also an important part of farmers' income source. In recent years, in order to achieve the goal of increasing agricultural maize income, corn planting areas in the middle east of Gansu have used a technology called the double-furrow sowing with whole plastic film against the drought, and it provides an effective technical approach for a steady increase in the yield of maize in arid regions. According to statistics, by the end of 2013, the rate of corn mechanical harvest was 49%, and till 2016, the rate of corn mechanical harvest reached 63% in China. On the whole, the corn mechanization level in China has been greatly improved, but the harvest of maize in Gansu Province is mainly based on artificial harvesting, and mechanized harvest has lagged behind the national average level. Except some small plots that can not use combine harvester, plastic film has become one of the main reasons limiting the application of corn combined operation machinery. If we continue to use the machine with horizontal roller commonly used in China at present for harvesting, then after stripping the collection process of corn stalk can not be completed. Therefore, the ordinary type of corn combine harvester with horizontal roller is not suitable for agricultural production in arid regions. To adapt to the cropping patterns of the whole plastic film and double-furrow sowing in arid regions, and solve the problem that the corn plant can not be fed continuously into the header of the harvester during the harvesting process, as well as the high loss rate issue of traditional corn harvester, a kind of self-propelled corn combine harvester for harvesting ear and stalk was designed in this paper. This machine cut 2 rows at one time, and used the vertical snapping rolls to grab the corn ear from the corn stalk, and the corn ear was delivered at the middle of the cutting platform; behind the vertical snapping rolls there was a shredding device, and the corn stalk chopped by the shredding device was conveyed by the conveyer on the side of the combine harvester. This arrangement on the cutting header realized whole plastic film mulching on double ridges for two-row cutting and reaping both corn ear and stalk for corn combine harvester, and grain loss was reduced. Because of the existence of plastic film, the corn stalk after picking could not be smashed and returned to the field with corn stubble. However, the vertical snapping rolls could solve this kind of defect. When the vertical snapping rolls worked, the stalk was output from the vertical snapping rolls, so it was suitable to recycle the stalk. Compared with the horizontal snapping rolls, the vertical snapping rolls can reduce the weight of the cutting platform and shorten the length of the machine. At the same time, the turning radius is reduced correspondingly, the turning is more flexible, and the machine can walk better on the double ridges. In addition, the gripping delivery mechanism adopts a holding and convey chain on one side, and the other side is an eccentric elastic tooth type shifting wheel, so the weight of the cutting platform is further reduced. And the machine can complete the function of corn ear's picking, conveying, peeling and collecting at one time, as well as the stalks cutting, kneading, chopping, throwing and collecting. The field experimental results showed that the grain loss rate was 1.8%, the ear loss rate was 2.4%, the grain damage rate was 0.77%, the qualified rate of cutting corn stalk was 92.6%, and the husking rate of corn was 95.1%, when the machine speed was 4.5 km/h, the speed of vertical snapping rolls was 1 100 r/min, and the speed of shredding device was 1 584 r/min. And the experimental results meet the design requirements of combined operation machine. [ABSTRACT FROM AUTHOR]

Coal mining in Jurassic coalfields of the arid Northwest area has damaged the local water resources greatly. Basing on the analysis of diachronic changes of the drainage and water balance of Jinjie Coal Mine, the paper gave some explanations of the changes of circulation patterns of groundwater before and after the mining. According to the changing characteristics of the water levels of pore water, fissure water and mixed water of double aquifers before and after mining, it was believed that the variation of the hydraulic properties of the roof aquifer in the mining area is mainly induced by the unified evolution of the transmission and closing property of roof aquifuge during the promoting process of mining face. The variation of the transmission and closing property of roof aquifuge changes the circulation pathways of mine groundwater, and the heavy-water deposits could be formed in the arid area. Also, the paper holds that the prediction method of real-time mine inflow based on variations of roof hydraulic properties will be one of the key issues in the future studies of deposit hydrogeology. [ABSTRACT FROM AUTHOR]