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【Objective】The intersection of big data and research on ‘three rural’ issues has created a research field with great potential. By combing the research results in this field, this paper has an in-depth understanding of its research focus and future direction, in order to provide some support for related research.【Method】 The paper used the methods of literature analysis and summary and induction to summarize and discussed the application of big data in the research of ‘three rural issues’ from three aspects: Research on agricultural issues, research on rural issues and research on farmers’ issues.【Result】With the popularization of communication infrastructure, big data such as internet usage data, communication sensor equipment data, geospatial data, organization management and operation data have been applied to the research of ‘three rural’ issues in China. At present, the application of big data in the research of ‘three rural’ in China has been constantly enriched. In the research of agricultural problems, big data has been applied to all links of agricultural production and operation, such as agricultural production monitoring and output improvement, and agricultural product market trend prediction. In the research on rural issues, the application of big data mainly focused on depicting the current situation of rural development, especially the evaluation of rural spatial environment, which can find a large number of rural spatial structures and systems driven by actual social and economic activities. In the research on farmers’ problems, the problem areas applied by big data mainly include the identification of farmers’ spatio-temporal behavior laws and the wealth and well-being of farmers reflected by them. High coverage data reflecting individual behavior, such as mobile phone use and signaling positioning data, has been the main data sources for such research.【Conclusion】The application of big data in the research of ‘three rural’ issues in China shows great development prospects in the development of agricultural industry, farmers’ lives and spatial planning, but there are also challenges in the aspects of data source and quality, method design, integration of traditional governance experience, etc. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to provide a basis for the recycling of nutrient resources of organic solid waste in urban and rural areas of China and the rational application of compost.[Method] The organic carbon (C) and phosphorus (P) characteristics of four organic waste composts, i.e., food waste (FW), garden waste (GW), chicken manure (ChM) and cattle manure composts (CaM), were systematically analyzed by Hedley P sequential fractionation method, infrared spectroscopy and thermogravimetric analysis. [Result] The obvious differences in the content and fraction of P and the content and composition of organic C among four composts were observed. The total and labile P content of animal manure composts (ChM and CaM) were significantly higher than those of plant-derived organic waste compost (FW and GW), in which the highest content of water extracted P (H2O-P) and NaHCO3 extracted P (NaHCO3-P) was observed in ChM and CaM composts, respectively. FW compost had high total organic C (TOC), but low humification index (i.e., humic C/fulvic C = 0.09) . Meanwhile, FW compost had the highest content of labile organic C (LOC), i.e., dissolved organic C (DOC), light molecular organic acids (LMOA) and amino acids (AA), the lower degree of aromatization with more carboxylic acids and polysaccharide structures, and the lowest thermal stability. GW compost had the highest content of readily oxidizable organic C (ROC) and humic substances C (HSC), and a high aromatized structure and thermal stability. Animal manure compost had the lowest HSC content and the medium DOC content. ChM compost had the highest free AA content and rich LMOA species, while the CaM compost contained a certain amount of AA and oxalic acid. Two animal manure composts had a similar aromatization degree and thermal stability, which was between FW and GW. [Conclusion] Manure composts with high P content and labile organic C can be used as a good P source to completely or partially replace chemical fertilizer. FW compost had low P content but high LOC content, which can improve the availability of P fertilizer via promoting P by C. GW compost with low P content and high stable organic C, in the long run, can improve soil fertility, which in turn can enhance soil P availability. Thus, rational application of composts according to their C and P characteristics or combined application of different composts or compost with chemical fertilizers can realize the C and P synergy and the highly efficient recycling of P nutrient resources. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aims to understand the development situation of dairy market in western China from the two dimensions of supply and demand of dairy products, and find out the specific methods and measures to further improve the food safety regulation of dairy market under the background of supply-side structural reform. [Method] Based on the panel data of dairy products supply, demand and regulation in the western provinces from 2013 to 2017, the paper constructs an index system which reflects the three levels, adopts the standard scoring method to quantitatively analyze the development degree and regulation level of dairy products market in the western region, and condenses the regulatory mode of the region. [Result] The study finds that the western region's dairy products supply and demand level showed a good development trend, by contrast, the regulatory level was low. In a certain period of time, the regulation mode of dairy products in the western provinces was relatively stable, and the type of regulation mode was gradually concentrated. [Conclusion] In order to solve the problem of limited regulatory resources, we can consider establishing trans-provincial regional regulatory agencies of the central level among provinces with the same type of regulation mode, which can improve regulatory efficiency [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 analyze the spatio-temporal evolution and trend of arable land utilization transformation in China, and to provide a theoretical reference for the transformation and protection of arable land utilization. 【Method】The transformation of arable land utilization, mutation point and spatio-temporal evolution were explored by entropy value method, temporal mutation point test and coupling coordination degree model. 【Result】From the perspective of time, the transformation index of cultivated land utilization transformation space, function and model in various provinces, autonomous regions and municipalities in China was generally low but continued to grow, and the transformation and development of arable land utilization was slow and low. Before 2010, in addition to Tianjin, Shanghai, Zhejiang, Fujian, Shaanxi and Xinjiang Uygur Autonomous Region, the comprehensive transformation of arable land utilization in various provinces, autonomous regions and municipalities in China was initially realized, but the transformation index was low, and there was still much room for improvement. From a spatial point of view, the transformation of arable land utilization in China has basically formed a spatial pattern in which the high-value areas mainly in the eastern region and the low-value areas in the western region as the core coexist, and the spatial migration of arable land utilization transformation showed a northeast-southwest transfer pattern, and the regional differences were obvious. The three subsystems of arable land utilization transformation space, function and mode were well coupled, but the imbalance phenomenon was becoming increasingly prominent. Overall, the transformation and development potential of arable land utilization was large, the three promoted each other, and the coupling coordination degree had a trend of ‘westward’ transfer in space, and there was a certain unbalanced trend. 【Conclusion】The transformation of arable land use showed a trend of ‘westward shift’ in space and time, and the three major subsystems of the transformation of arable land use were well coupled, but the phenomenon of dysfunction was increasingly prominent, and there was a certain degree of unevenness. Therefore, the development strategy of diversity, differentiation and regulation from the developed areas in the east to the traditional agricultural areas in the west should be implemented, to strengthen the linkage and coordination role between the 3 subsystems of spatial, functional and modal transformation of arable land use, activate factors related to agricultural development, promote the modernization of agriculture, and then achieve high-quality utilization of arable land. [ABSTRACT FROM AUTHOR]

【Objective】The present paper aimed to illustrate the potential utilization of the gene of resistance to bacterial blight and bacterial leaf streak, so as to provide reference for enriching genetic base of rice breeding.【Method】A total of 102 rice cultivars were used to screen by molecular marker for the gene xa5, which mediated the resistance for both for resistance to bacterial blight and bacterial leaf streak. The parents carrying xa5 gene and having good resistance to bacterial blight and bacterial leaf streak were used as resistant sources to cross with susceptible cultivated rice. Through pedigree method and molecular marker-assisted selection（MAS）, elite hybrid rice restorer lines were cultivated. The excellent restorer lines and sterile lines were combined with strong heterosis combinations to analyze the resistance and comprehensive agronomic traits of strong heterosis combinations.【Result】A total of 17 cultivars were screened, which carried xa5 gene from 102 rice germplasm resources（materials）. Among these cultivars, DP3, IRBB5, N36, N776, N777, N779 and P89 were well resistant to both bacterial blight and bacterial leaf streak. An elite line Y240-1 was selected from the cross between DP3 and 9311. Moreover, 998 R was crossed with elite individual Y240-1. With molecular MAS, an elite restorer line Yexiangzhan with xa5 was developed from the cross of 998 R and Y240-1, after multiple generations of selfing. Yexiangzhan was combined with sterile line Pingfeng A to produce an elite hybrid cultivar Pingfengyouxiangzhan, which showed higher resistance to bacterial blight and bacterial leaf streak in comparison with Pingfeng A. Pingfengyouxiangzhan was resistant to rice blast at moderate level and meet the 2nd class standard of fine quality issued by Ministry of Agriculture of China.【Conclusion】xa5 gene with resistance to bacterial blight and bacterial leaf streak of rice has partial dominant effect, which can be used for breeding improvement of hybrid rice; It is helpful to enrich and broaden the genetic basis of rice breeding by cultivating the superior hybrid combinations of rice with moderate resistance to bacterial blight and stripe disease with wild rice blood. [ABSTRACT FROM AUTHOR]

[ Objective] The present paper aimed to identify the causal agents of Camptotheca acuminata leaf spot, and to test the inhibitory activity of different fungicides against the pathogen, so as to provide scientific evidence for the prevention and treatment of the leaf spot disease of C. acuminata. [ Method] The pathogen of the C. acuminata leaf spot was isolated by conventional tissue isolation method and subjected to pathogenicity test. Combining the morphology observation and rDNA-ITS sequence analysis, the pathogen was identified and the toxicity of 12 fungicides to the pathogen was determined by mycelial growth rate method.[ Result] A fungus was isolated from C. acuminata leaf spot in the Chinese Herb Garden of Guangxi Agricultural Vocational University, and the strain was named as XS-1. After pathogenicity test, morphological observation and molecular identification, it was confirmed that Corynespora cassiicola was the causal agent of the C. acuminate leaf spot, which is reported for the first time in China, and the disease was named as Corynespora leaf spot disease. The results of the inhibitory activity test showed that the selected 12 fungicides had a certain inhibitory effect on the growth of strain XS-1 mycelium. Among them, 20% difenoconazole and prochloraz ME had the strongest inhibitory effect with EC50 of 0.098 mg/L, followed by 20% penconazole EW, 50% carbendazim WP, 20% imazalil EW, 250 g/L propiconazole EC, 10% difenoconazole WG with EC50 of 0.3737, 0.4557, 0.4878, 0.5746 and 0.5956 mg/L, respectively.[ Conclusion] Based on pathogenicity test, morphology observation and rDNA-ITS sequence analysis, the pathogen causing C. acuminata leaf spot is identified as C. cassiicola. 20% difenoconazole and prochloraz ME, 20% penconazole EW, 50% carbendazim WP, 20% imazalil EW, 250 g/L propiconazole EC and 10% difenoconazole WG have strong inhibitory effect on the growth of strain XS-1 mycelium, and can be used as an important reference for the control of Corynespora leaf spot on C. acuminata in the field. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to explore the effects of different types of fruit bags on the formation of fruit quality and the change of peel pigment of Qiumitao No. 1, so as to provide reference for the high-quality production of Qiumitao No. 1 in southern China. [Method] Taking the fruit of Qiumitao No. 1 as the experimental material, four different types of fruit bags (yellow outside and black inside, single yellow bag, single white bag, single semi white translucent bag) were bagged after the first physiological fruit drop. The changes of pigment content in single fruit weight, vertical and horizontal diameters, fruit size, peel pigment, and pulp glyc acid content and relative enzyme activities were measured and analyzed every 7 days (5 times), before plucking fruit, and the change rule was analyzed. [Result] The results showed that the surface of fruit covered with yellow outside and black inside double-layer bag was smooth, the chlorophyll content was significantly lower than that of single-layer bag and showing white jade color (P < 0. OS, the same as below), the longitudinal diameter, transverse diameter and single fruit weight were higher than those of the other three treatments, and the content of quinic acid, malic acid, sucrose, sorbitol and total sugar of fruit covered with yellow outside and black inside double-layer bag were significantly lower than those of other single-layer bag treatments, which match with the light taste at maturity. Among the three single-layer bags, the yellow singlelayer bag had higher sucrose and fructose content, lower citric acid and quinic acid content, the highest total sugar content, the lowest total acid content and the highest sugar acid ratio. The results of correlation analysis showed that there was no significant correlation between the acid invertase activity and neutral invertase activity with sucrose content at late stage of fruit development (P > 0. OS). [Conclusion] Qiumitao No. 1 bagged with double-layer yellow outside and black inside has low pigment content and beautiful appearance, but the content of sugar and acid was lower, and the taste was lighter; the peel pigment content of Qiumitao No. 1 bagged with single-layer yellow fruit bag was higher than that of double-layer bag, and the fruit appearance was green and dull, but the content of sugar and acid in the fruit was higher than that of other bagged fruits. In production and markting, the type of fruit bag can be selected according to the needs of sales, which can improve the overall economic benefits. [ABSTRACT FROM AUTHOR]

[Objective] The present paper aimed to understand the genetic diversity of the cultivated Salvia miltiorrhiza populations, the phylogenetic relationship based on the internal transcribed spacer (ITS) regions of the rDNA,and to find out the single nucleotide polymorphism (SNP) fingerprints for the identification of S.miltiorrhiza populations. [Method] PCR amplified, sequenced and compared the ITS sequences of the 42 S.miltiorrhiza populations collected from 33 different regions in China. [Result] The lengths of ITS1,5.8 S rDNA and ITS2 regions in rDNA of S.miltiorrhiza were 203-229,164 and 226-229 bp, respectively; There existed relatively larger difference in length in ITS1,while more nucleotide variations occurred in ITS2;SNP variation sites occurred only in the ITS1 and ITS2 regions with 19 and 37 variation sites and 8.30% and 16.16% variation rates respectively. [Conclusion] Based on the SNP fingerprints of ITS, only 3 cultivated populations could be discriminated from the rest. The phylogenetic trees based on various regions of ITS showed that the cultivated S.miltiorrhiza populations were not genetically related to their geographical sources. [ABSTRACT FROM AUTHOR]

[Objective] Castanea henryi is one of the important woody grains in southern China. The present paper aimed to study the effect of different rootstock ages on the growth and photosynthetic characteristics of grafted seedlings. [Method] C. henryi' Huali 3' was grafted with 2-year-old and 4-year-old rootstocks of Chinquapin, respectively. Then the growth, Pn-PFD response curve and diurnal variation of photosynthesis of the grafted seedlings were measured. [Result] The new shoot length and diameter of seedlings grafted with 4 -year-old rootstock was the highest. The average length of the new shoot of 2 -year group was 92.41 cm, and the average diameter was 11.49 mm. The average length of the new shoot of 4-year group was 131.69 cm, and the average diameter was 14.55 mm. The light saturation point (LSP), apparent quantum efficiency ( AQY), maximum net photosynthetic rate (Pmax), light compensation point (LCP) and dark respiration rate (Rd) of the 4-year-old rootstock grafted plants were all higher than 2-year-old rootstock grafted paints. The diurnal variation curve of Pn of the two groups of rootstock grafted C. henryi new shoots was of double peak type. At 14 :00 pm, there was a valley value, showing a more obvious phenomenon of photosynthetic noon break. When the rootstock was more older, and its the average daily net photosynthetic rate (Pn) was higher than that young rootstock. [Conclusion] The present study indicated that the grafted seedlings with older rootstocks had advantages over growth rate of new shoots, the ability of photosynthesis and light use efficiency. [ABSTRACT FROM AUTHOR]