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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]

[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]