The soil fertility of cultivated land in Gaomi City of Shandong Province was investigated and the spatial distribution of soil fertility was clarified. Eight soil fertility indexes, including soil pH, organic matter, total nitrogen, total phosphorus, total potassium, alkali-hydrolyzed nitrogen, available phosphorus and available potassium, were acquired by gridded sampling and analysis of surface soil. The membership value of each index was determined by the membership function model of fuzzy mathematics, and the weight of each index was determined by principal component analysis. The integrated soil fertility index was calculated using membership value and weight, and then interpolated for mapping. The results showed that the soil in the study area was mainly alkaline, accounting for 37.77% of the total samples, followed by neutral, accounting for 29.52% of the total samples. Organic matter, alkali-hydrolyzed nitrogen and available potassium were mainly insufficient, total nitrogen and total potassium were mainly medium, and total phosphorus and available phosphorus were mainly rich. The membership value of organic matter and total nitrogen were significantly lower than that of other indexes, showing they were the main limiting factors of cultivated land soil fertility. Total nitrogen had the maximum weight value and contributed the most to soil fertility. Alkali-hydrolyzed nitrogen had the minimum weight value and contributed the least to soil fertility. In the study area, the spatial distribution of integrated soil fertility index of cultivated land was mainly medium.

Reasonably guiding farmers to adopt technologies that can improve the quality of cultivated land is very important to increase soil fertility, improve soil health, and promote high yield and efficiency of crops. This study analyzed the factors influencing the improvement of cultivated land quality, reviewed the improving technologies, including straw returning, green manure planting, deep ploughing and subsoiling, organic fertilizer applying, formula fertilization by soil testing, lateral deep fertilization for rice, soil conditioner applying and water-fertilizer integrating, and summarized the advantages and disadvantages of these technologies and their applied measures. At present, the research mainly focuses on the integrated application of the technologies for improving cultivated land quality, the differences of farmers’ adoption of various technologies, and the industrial application of modern information technology platform and equipment. It is proposed that we should improve the formulation of standards for multi-function technologies, strengthen the information technology such as high-scoring remote sensing to monitor and evaluate the quality of cultivated land, boost the utilization efficiency of cultivated land resources and perfect the ecological compensation mechanism for farmers.

The management of soil acidification of cultivated land is an important measure to improve farmland quality and ensure food security. Taking Guangdong Province as an example, this paper systematically analyzed the current situation, temporal and spatial evolution characteristics and management modes of soil acidification of cultivated land in Guangdong Province. By using the methods of field investigation, analytic hierarchy process and expert consultation, the study concludes that there are some difficulties in the management of soil acidification of cultivated land in Guangdong, such as insufficient standards, management modes, policy cohesion and funds. The study puts forward suggestions on building management path of soil acidification of cultivated land in Guangdong based on developing standards and specifications, model exploration, policy incentive, public participation and the establishment of long-term mechanism, in order to ensure food security.

Cultivated land is one of the major natural resources of agricultural production development. Cultivated land fertility is a main index in the characterization of farmland quality, and it has direct impact on the development of agricultural production. The construction of cultivated land fertility evaluation index system is the key to ensure the rational utilization of farmland, which is of great significance to the protection of cultivated land, the improvement of soil fertility and the development of agricultural production. In this paper, the relevant research of cultivated land fertility assessment at home and abroad was briefly introduced. Furthermore, the development history, advantages and disadvantages of eight major technologies and methods widely used in cultivated land fertility assessment at home and abroad were summarized. The available research results show that the traditional evaluation methods have some limitations, and the laws and regulations need to be improved. With the rapid development of computer network technology and GIS technology, artificial intelligence method and GIS-based data mining method will gradually become the research hotspot, and the application of GIS and satellite remote sensing technology will be more extensive and could improve the accuracy and timeliness of farmland information. Based on the review conducted by this study, it is expected to provide theoretical and technical support for the Third National Soil Survey, as well as the development of profitable, ecological and sustainable agriculture.

Farmland is an important resource of agricultural production, and cultivated land fertility evaluation is an important guarantee for quality construction of arable land, soil nutrients interpolation techniques affect the evaluation of farmland accuracy and availability immediately. This paper took data of Licheng County as an example, the City was classified into plain and hilly region based on the landform condition. We analyzed distribution and spatial variation via the sample point data, including organic matter, available phosphorus, rapid available potassium, available zinc and available boron. This paper carried on interpolation of soil nutrients by the model of Inverse Distance Weighted and Ordinary Kriging in Licheng plain and hilly regions. Moreover, we compared the two kinds of interpolation method by the way of cross-validation and comparative analysis. At the same time, compared and analyzed the different interpolation methods based on evaluation results of farmland. In conclusion, both Inverse Distance Weighted and Ordinary Kriging had high precision, Inverse Distance Weighted was the best for interpolation of soil nutrients in hilly region but Ordinary Kriging was suitable for plain. The difference of evaluation results between the two methods for a variety of elements involved in the county farmland was small. Based on the combined principle of practicality and accuracy, Inverse Distance Weighted was the optimal choice of spatial interpolation methods for soil nutrients in cultivated land fertility evaluation.

The key to the operation of the cultivated land rotation and fallow system is to solve the problem of rotation and fallow subsidy. China’s crop rotation and fallow mechanism started late, and its development is not yet perfect. In terms of crop rotation and fallow subsidy, there are problems such as the lack of legal system protection, the single source of subsidy funds, the unclear subsidy target, the difficulty of determining subsidy standards, and the lack of effective supervision of the use of subsidy funds. In order to ensure further advancement of the pilot cultivated land rotation and fallow, this research proposes to improve the legal guarantee mechanism of rotation and fallow subsidy, actively broaden the sources of subsidy funds, clarify the subsidy targets, formulate reasonable subsidy standards, strengthen the supervision of the use of subsidy funds and so on.

No one thinks that there are any trouble on food security in China so far. Some relevant officials departments and agricultural specialists have been repeatedly declaring that China has been keeping sufficient in food and keeping the redline of ‘self-supply rate no less than 95%’. But our research indicates that the redline of food security has fallen long ago. The food self-supply rate in 2010 was even less than 65% and all the imported food needs 59.48 million hm2 (0.9 billion Mu) cultivated land to produce. Therefore, cultivated land deficit has been up to 0.9 billion Mu, exceeding all the cultivated land in 13 provinces of ‘Three-North’ area. It gives us a start! It is time to reconsider the thesis of the book 《Who will feed China》

As the carrier of plant growth, cultivated land is an important means of agricultural production. With the progress of the society, the role of cultivated land quality becomes increasingly prominent. Improving the quality of cultivated land is of great significance to enhance the cultivated land productivity and ensure the national food security. Based on previous studies, this paper summarized the definition of cultivated land quality, which could be understood as the comprehensive productivity of cultivated land under the combined action of cultivated land environment, cultivated land soil property, cultivated land management level and other factors. Soil property of cultivated land is the most intuitive expression of cultivated land quality and has been the focus of the research. In this paper, soil properties such as soil type, soil texture, soil fertility and plough layer structure were selected as major indexes, and their effects on cultivated land productivity were summarized. At present, the research on cultivated land quality is in the preliminary stage, and a comprehensive and systematic research should be the direction in the future.

In order to study the security status of cultivated land of Jiangsu Province to provide the basis for effective utilization, protection and administration of cultivated land, the degree of pressure of cultivated land use in Jiangsu Province and causes of that were analyzed, based on which revised data of Jiangsu province from 1971 to 2009 were selected, and the minimum area of cultivated land per capita and pressure index of cultivated land in this region during this period were calculated. The results indicated that pressure index of cultivated land showed a downward tendency in the fluctuation due to implementation of the household contract responsibility system; since the 2000s, the grain comprehensive production capacity that was decreased by natural calamities frequently occurred and the slipped grain growing activism of the peasant, began to impose pressure on the cultivated land of Jiangsu Province, but the pressure had been relieved in recent years. By the end of 2009, there had been a considerable discrepancy in the degree of cultivated land pressure between the thirteen prefecture-level cities of Jiangsu Province, among which the cultivated land of Nanjing, Wuxi, Suzhou and Changzhou had been bearing a tremendous pressure, and the cultivated land pressure of Xuzhou, Zhenjiang, Nantong had began to emerge, while that of the others had bear no pressure. The study on the cultivated land pressure based on grain security showed that there were two approaches to relive the cultivated land pressure of Jiangsu Province, one of which was to enhance the grain comprehensive production capacity of the cultivated land, while another one of which was to prevent continued loss of the cultivated land.

To provide reference and guidance for follow-up management of newly-increased farmland, soil fertility status of newly-increased farmland following land consolidation project in Heyang County of Shaanxi Province, which was part of the eastern Weibei dryland, was studied. Development of soil organic matter, total nitrogen, available phosphorus and available potassium in newly-increased farmland from 12 towns in Heyang County were analyzed and then evaluated comprehensively using the matter-element model. The results show that the soil nutrient concentration is generally low in newly-increased farmland in Heyang County with an average organic matter content of 8.66 g/kg, total nitrogen of 1.30 g/kg, available phosphorus of 18.66 mg/kg, and available potassium of 151.21 mg/kg. The content of soil organic matter is relatively low, the contents of total nitrogen and available phosphorus are moderate, and available potassium is abundant. According to nutrient evaluation grades, soil classified as Grade IV with extremely low fertility accounts for 83.4% of all the newly-increased farmland and has huge room for soil fertility improvement. Taking local economic level and typical nutrient management practices into consideration, the priority should be given to organic fertilizers while application of chemical fertilizers should be increased at an appropriate rate. With respect to cropping systems, a 3-year grain-legume rotation with 1-year of soybean and 2-year of wheat is recommended.

Arable land damage includes the following five categories: arable land surface hardening, arable land surface collapse, arable land dig loss, arable land pressure and arable land pollution. By summarizing the arable land damage types, the principle and index selection of damage identification system was put forward in this paper, such as comprehensive principle, classification guiding principle, operational principle and combined principle of arable land damage degree and recovery complexity, then the evaluation indexes of arable land damage degree were obtained, the evaluation index system of arable land damage was established by AHP (Analytic Hierarchy Process), finally, the countermeasures to arable land damage was put forward, such as laws and regulations improvement, classified management, arable land reclamation, scientific farming, strengthen arable land protection, prevention and control mechanism innovation. The paper had guiding significances for arable land damage identification, reclamation plan establishment and reclamation measures.

On the geographic information system (GIS) and the second general survey soil, overlaying the current land use map with the basic farmland protection map and the soil map, forming 7609 patches, which are used as the basic management and evaluation cells. This research selected seven influencing factors from three aspects such as soil nutrient content, profile situation and land management, and the evaluation system and model of farmland fertility was built up. The grade of arable land productivity was formed according to the theory of Fuzzy Mathematics, Telphi Principle and Analytic Hierarchy Program, and the farmland fertility of the county and analysis of its spatial distribution were evaluated. The results suggested that, 90319.89 hm2 farmlands could be divided into five grades, the grade one was 3612.68 hm2, the grade two was 15856.61 hm2, the grade three was 31795.51 hm2, the grade four was 29261.32 hm2 and the grade five was 9793.77 hm2, the fertility of grade one to five account for 4%, 17.56%, 35.2%, 32.4%, 10.84%, respectively.

In order to further research and explore cultivated land quality early-warning, this paper analyzed and summarized research progress of Cultivated Land Early-Warning nearly 20 years at home and abroad from soil quality and land use change, early-warning theories and index system, early-warning model and application of cultivated land early-warning based on WebGIS. Then the comprehensive early-warning for cultivated land quality is put forward from soil fertility and quality, high standard farmland, remote sensing and farmland contamination.

The aim was to predict the population capacity level of cultivated land scientifically. This paper was a case study of the fieldwork in Pixian which was based on the accounting production capacity. It formed the cultivated land production capacity dynamic prediction model and land capacity model, then divided the region of population supporting capacity, made an holistic analysis on pixian’s Population supporting capacity of land. The results showed that: (1) the cultivated land production capacity of Pixian was 505718 t, and the population supporting capacity was large in the coming years. But it distributed uneven, and the largest capacity difference between countryside and town could be 194377. (2) Economical advanced area such as Xipu, Pitong, Hongguang, the population supporting capacity was small. The contradiction between land and population was serious. SR was more than 0.90. (3) According to the empirical study measuring method in line with the actual local, was objective and scientific.

Strictly controlled farmland refers to the cultivated land with heavy metals’ contents (cadmium, mercury, arsenic, lead and chromium) exceeding the risk control standard specified by Soil Environmental Quality Agricultural Land Risk Control Standards (GB15618-2018). This article evaluated the safety of planting edible crops in strictly controlled farmland, aiming to provide reference for cultivation structure adjustment in strictly controlled farmland, as well as the safe use of contaminated farmland. Present research indicates that the heavy metals in the seeds easily exceed the standards when oil crops, such as rape, peanut, sesame and sunflower, are cultivated in strictly controlled farmland, while heavy metals’ (such as As and Pb) contents in vegetable oil are lower than the safety limits, and the oil is safe for diet. But for Camellia oleifera seed oil, the excessive rate of heavy metals is relatively high, so it is necessary to further evaluate the heavy metals’ accumulation characteristics of Camellia oleifera varieties, and the safety of Camellia oleifera seed oil. Seed meals could be used as animal feeds and organic fertilizers after the removal of heavy metals, which could maximize the utilization of resources. Nevertheless, there is a risk of excessive heavy metals in maize silage cultivated in strictly controlled farmland, while the risk in maize grains is relatively low, and the low heavy metal accumulation maize varieties could be further screened to achieve the purpose of safe production of grains. The safety of heavy metals in tea should be further studied in strictly controlled farmland. Furthermore, it is necessary to improve the standard system of heavy metal safety limits of edible crops, strengthen the research and development of straw treatment and resource utilization technologies, and establish an ecological compensation mechanism of specific crop straw recycling in strictly controlled farmland.

In order to quantitatively measure the carbon source/sink ability of arable land resource use in Shaanxi Province, so as to provide references for the work to reduce carbon emissions in land utilization, the authors utilized data of Shaanxi Province from 2000 to 2007 to calculate the quantity of carbon absorption and emission of arable land resource use from temporal and spatial perspectives, the authors also calculated the Gini coefficient of carbon sink of arable land. The results showed that: (1)overall from 2000 to 2007 the arable land resource in Shaanxi Province acts as carbon sink and the average annual carbon sink amount was 8.16 million tons; (2)during the study period, the carbon sink of arable land showed the highest level in Guanzhong region, and a relatively high level in Shannan region, Shanbei region showed the lowest level; (3)the components of the Gini coefficient of carbon sink of arable land in different regions showed that the carbon absorbing ability of the arable land increases in both Shaanxi Province and its three regions, with the carbon sink of arable land resource use there was some advantage in Shaanxi Province, but compared with coastal areas, it still had a large gap.

To analyze the quantitative characteristics, spatial distribution and limiting factors of different types of cultivated land in Luohe City, Henan Province, and put forward specific protection measures, a comprehensive evaluation system with 17 selected indexes was constructed. By means of analytic hierarchy process and membership function method, the weight value and membership degree of each index were studied. The authors calculated the comprehensive indexes and grades according to natural breakpoint method. The results showed that: (1) the quality of cultivated land decreased from northeast to southwest in Luohe City, among which the quality of cultivated land in Linying County, Yancheng District, Yuanhui District and most of Zhaoling District was relatively high, and the quality of cultivated land in southwest Wuyang County and northern Zhaoling District was relatively poor; (2) the proportion of superior land, higher land, middle land and lower land in Luohe City was 12.48%, 39.28%, 38.58% and 9.67%, respectively, and the quality level of cultivated land needs to be further improved; (3) according to the main restrictive factors such as soil nutrient status, farmland infrastructure construction and soil barrier factors, the corresponding improvement measures were implemented. This study provides effective references for strengthening cultivated land quality construction and enhancing agricultural production capacity in Luohe City.

Constructing an efficient and standardized spatial interpolation method is an important issue for building the big data platform for cultivated land quality and serving macroscopic decision-making, and is conducive to quickly and accurately obtain the distribution map of cultivated land quality indicators of counties and even the whole country. Through literature and research review, this study summarized the current concept and process of spatial interpolation method, and clarified its precision influencing factors and application status in monitoring and evaluation of cultivated land quality. Combined with the actual application requirements of the big data platform for cultivated land quality, four in-depth research directions were put forward, including regional interpolation, geographic barriers interpolation, auxiliary variables interpolation, and module design of interpolation. The research results could provide method reference for the standardized processing of cultivated land quality data.

The study aims to clarify the process of arable land loss caused by loess slope instability, in which the loess slope stability was changed by irrigation water infiltration into soil and loess under large-scale agricultural irrigation. On the basis of statistical analysis of the loss area of arable land, the farmland area under irrigation, the number of geological disasters and the proportion of farmland loss caused by geological disasters in Tianshui of Gansu, the author collected samples of undisturbed soil and loess from typical stratigraphic sections, and tested the physical and mechanical properties and shear strength of soil under natural condition and irrigation. The slope stability was quantitatively analyzed by Swedish method based on limit equilibrium method in combination with Lizheng rock slope stability analysis system. The results showed that the slope was steady and its stability coefficient was 1.074 under natural condition, but under agricultural irrigation, with the increase of water infiltration depth, the stability coefficient decreased gradually, and the slope became unsteady. If farmland irrigation only saturated the soil layer, it would have little effect on the stability of the slope. When the thickness of loess saturated layer was greater than 2 m due to continuous irrigation water infiltration, the slope stability would be reduced by one level and became unsteady. When the thickness of loess saturated layer was greater than 10 m, the slope would be unsteady and landslides would develop, causing arable land loss.

Fallow system is an effective way to ensure the strategy of storing grain in land and technology, which s great strategic significance to the national food security. This paper summarized the background, specific implementation way and compensation method of the fallow system in United States, Europe and Japan, analyzed the uniqueness of cultivated land in resource-poor areas, destructed cultivated land areas, and weak ecological areas in China, and put forward corresponding improvement measures and fallow subsidy policies. By comparing the fallow models and analyzing the current domestic fallow system, the authors believe that the current domestic system should be enhanced by developing the prediction model, scientifically planning the fallow area, strengthening government supervision, changing current fallow subsidy mode, and motivating more research institutions and commercial companies to join in.

The study aims to clarify the abundance and deficiency of available trace elements in cultivated soil systematically in the study region, and explore the correlation between trace elements and their influencing factors, in order to provide a scientific basis for soil testing for formula fertilization, and improve fertilizer utilization rate and soil fertility in Pingliang City. The authors used Cu, Zn, Fe, Mn, B, Mo and S as the main research objects, and evaluated the abundance and deficiency of available trace elements in cultivated soil in Pingliang City. The correlation analysis and regression analysis of trace elements and their influencing factors were conducted by statistical method. The statistical results showed that the average content of available Cu, Zn, Fe, Mn, B, Mo and S was 1.04, 0.92, 13.18, 11.03, 0.51, 0.11 and 15.11 mg/kg, respectively. The content of available S had strong spatial variation, while the content of other elements were moderately variable. The results showed that the abundance and deficiency level of available Cu and Zn in cultivated soil in different regions were from low to medium, that of available Fe and Mn were from low to high, that of available Mo was from relatively low to low, and that of available B and S were from very low to relatively low. The content of available Cu in different soil types was from low to medium, that of available Zn, Fe and Mn were from low to high, that of available B was from relatively low to low, that of available Mo was from relatively low to medium, and that of available S was extremely low. There were certain correlations among soil pH, organic matter and available trace elements. In general, the cultivated soil in Pingliang City was deficient in available B, Mo and S, and available S was extremely deficient. Meanwhile, the available Cu, Zn, Fe and Mn were generally above moderate level. Therefore, according to the evaluation results and the correlation characteristics of soil pH, organic matter and available trace elements, it is suggested to take measures such as reasonable application of organic fertilizer, appropriate adjustment of soil pH, appropriate supplementation of B and Mo fertilizers according to local conditions, more application of S fertilizer, and carrying out experiments and demonstration of trace element fertilizer efficiency, to achieve the high-yield and high-quality crop production and ensure food security.

Soil acidification has become a limiting factor for crop growth in north China. In this paper, soil acidity of cultivated land in Henan Province was comprehensively expounded by analyzing field soil samples. The remediation measures of acidified soils were researched and promoted by means of field investigations and experimental demonstration. The results showed that soil acidification began to emerge in Henan. Adding alkaline soil conditioner, lime, calcium magnesium phosphate and alkaline fertilizer could make seasonal crop yield in severely acidified soil increase by more than 120%. At the same time, combining with agricultural resources in Henan Province, the authors summarized soil acidification regulation approaches, including an establishing soil testing and formulated fertilization system with pH value as the index, expanding straw returning to field, reasonably using livestock manure, deepening tillage to increase the depth of topsoil and so forth.

The temporal-spatial changes of construction land and arable land and the impact of construction land expansion on arable land in Changchun were studied to provide reference for rational use of land and protection of arable land in the black soil region. Land use information of the study area in 2005 and 2019 were extracted from Landsat TM/OLI remote sensing images using the object-oriented-decision tree classification method. Then the temporal-spatial changes of construction land and arable land and the impact of construction land on arable land in the aspect of quantity, quality and structure were studied. The results showed that the area of construction land had expanded by 21163.30 hm² since 2005, while the area of arable land had decreased by 19011.81 hm². Newly added construction land occupied 18170.84 hm² of arable land, accounting for 85.33% of the total area of the increased construction land. The expansion of construction land also led to an increase in the degree of fragmentation of arable land; most of the arable land occupied by construction land was originally high-quality arable land and the proportion of the area of Grade I to III could reach 72.17%. The research results are of great significance for coordinating the protection of arable land resources in rapid urbanization in the black soil region.

The study aims to comprehensively and timely grasp the cultivated land quality grade, nutrient spatial distribution characteristics and nutrient content difference of different soil types in Pingchuan District of Baiyin City, Gansu Province, and provide an effective basis for rational planting and fertilization in the future. According to the national standard of Cultivated Land Quality Grade, the cultivated land resource management information system at county scale was used to analyze the cultivated land quality grade, nutrient spatial distribution and nutrient content difference of different soil types in Pingchuan. The results showed that the cultivated land quality in Pingchuan belonged to grade five to ten, without cultivated land of grade one, two, three and four. The cultivated land of grade seven had an area of 13543.35 hm², accounting for 34.51% of the total cultivated land area in Pingchuan. The overall nutrient level of the cultivated land in Pingchuan was low, and the cultivated land with low soil organic matter content and total nitrogen content showed a bipolar distribution. The cultivated land with low content of available phosphorus was concentrated, and the cultivated land distribution of other grades was scattered. The cultivated land with high available potassium content was concentrated in the villages and towns in southern Pingchuan; and the nutrient contents of deep cultivated lime-calcium soil were overall high among the six soil types in Pingchuan, and the coefficient of variation was the lowest.

To clarify the spatial distribution of soil available microelements of cultivated land in Xi’an and provide a basis for better fertilizer management, the spatial distribution characteristics of soil available iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn) were studied by using the geostatistic method combined with GIS. The results showed that the average content of soil available Fe, Mn, Cu and Zn was 9.84, 12.95, 1.82 and 2.61 mg/kg, respectively. All these values were significantly higher than that in the second national soil survey. The contents of available Fe, Mn and Cu were moderately variable in space, however, Zn had strong variation. The optimal semi-variance model for the available Fe, Cu and Zn were spherical model and that for available Mn was Gaussian model. The analysis of the nugget coefficient showed that available Fe, Cu and Zn had strong spatial correlation, while Mn had a moderate spatial correlation. As to the spatial distribution, the contents of soil available Fe in the north and south of Xi’an were higher than that in other areas, the contents of available Cu in the west were higher than that in the east, and the spatial distribution of available Mn and Zn were complicated. In general, the contents of soil available Fe, Mn, Cu and Zn in the study area are rich. The contents of soil available Fe, Mn, Cu and Zn in most cultivated land are above the medium level, but there is still a certain proportion of cultivated land lacking available microelements. Therefore, it is necessary to take the regionalized and balanced fertilization technology in agricultural production.

Scientific calculation of grain potential productivity for country or area can provide the theory basis for reasonable formulation of approaches to ensure increase in grain production and food safety. Using the results of agriculture classification, the farmland grain potential productivity, farmland use intensity and the increase potential for future in Guanzhong were calculated. The result showed as follows: for the total of Guanzhong Area, natural potential productivity, utilization potential productivity, achievable potential productivity and real per unit area yield were 30.09 t/hm², 18.74 t/hm², 9.57 t/hm² and 7.34 t/hm², respectively. Theoretical use intensity, achievable use intensity and real use intensity were respectively 0.623, 0.511 and 0.767. Theoretical increase potential productivity, achievable increase potential productivity and real increase potential productivity were 11.35 t/hm², 9.17 t/hm² and 2.23 t/hm², respectively. The difference among counties was great. Natural potential productivity, utilization potential productivity, achievable potential productivity and real per unit area yield in Weihe River Plain were more than those in Weibei Upland and Qinling Mountains. The theoretical use intensity didn’t appear to be much different all over the Guanzhong, and that of Xianyang Region was generally higher. But the achievable use intensity appeared to be much different, and that of Tongchuan Region was generally higher, and that of Xi’an Region was generally lower. The actual utilization intensity of most counties of Guanzhong was high, and that of Xi’an Region was the maximum. There was great room for improvement of actual utilization intensity in 16 counties such as Weibin, Jintai, Wugong, Dali, etc. Theoretical increase potential productivity, achievable increase potential productivity and real increase potential productivity were great in counties of Weihe River Plain. In the future, the increase potential was mainly in the counties of Weihe River Plain.

To understand current situation of farmland resource allocation and the influence of market economy on the slope of Yunnan planned tobacco area, the distribution and difference of slope types in core, high quality and suitable area were analyzed, based on the latest results of flue-cured tobacco planting zoning data and slope grid data. On this basis, combined with the data of rural per capita disposable income of each city, the impact of market economy on the slope of tobacco planting area was analyzed. The results showed that the planned area of flue-cured tobacco accounted for 47.9% of the total area of class Ⅰ and Ⅱ, and accounted for merely 18.7% of the total area of class I to III which was suitable for planting flue-cured tobacco in the whole province. However, 40.0% of the latest planned tobacco fields were in class III farming areas, and 26.3% in class IV and V areas. The percentage of class III to V flue-cured tobacco planning area in each prefecture and city was positively proportional to the per capita disposable income in rural areas, which indicated that the higher the disposable income, the more obvious the tobacco planting area developing to cultivated land with large slope. In general, under the effect of market economy, the development of flue-cured tobacco industry in Yunnan is at disadvantage in the allocation of cultivated land resources.

Effect of conservation tillage on soil structure of yellow soil was explored through setting two kinds of conservation tillage by continuous testing through 6 years to provide a theoretical basis for the conservation tillage technology application and development in yellow soil area in South China. [Method] Soil bulk density and soil aggregates were determined by ring-knife method and dry-wet sieve method. Soil mechanical composition was determined by MS2000 laser particle size analyzer, and soil porosity and aggregate failure rate were calculated. [Result]The results indicated that soil bulk density decreased and soil porosity increased in two kinds of conservation tillage of no-tillage with mulch(NTS) and sowed on ridges with mulch in furrows(LS). LS optimize the role of soil bulk density superior to NTS, and NTS optimized soil pore conditions effect is more pronounced for deeper levels of soil. The optimization process of conservation tillage on soil bulk density and soil porosity were gradually from surface to interior. Conservation tillage can increase the 0-20 cm layer of soil >0.25mm aggregate content. When it came to water stable aggregate content there"s no obvious difference between the three treatments but the content of 0-20cm layer of soil is slightly larger than 20-40cm layer. Conservation tillage can increase soil aggregate stability and reduce aggregate destruction and NTS have more significant effect to improve the stability of soil aggregates. [Conclusion] The experiment proved that the conservation tillage had some effect on the soil bulk density, porosity, aggregates and other structural traits of the yellow soil. The improvement was a very long process from the surface to the surface, which was the conservation tillage technology in the yellow soil region Application and development has laid a solid foundation.

The objective of this study is to investigate the nutrient resource of animal manure and its environmental pollution risks in Shaanxi Province. This paper estimated the time variation, regional distribution and cropland load of animal manure amount based on the provincial statistical data from yearbook and relevant literature. The environmental risk of animal manure pollution was systematically analyzed. From 2009 to 2017, the amount of animal manure in the whole province presented a trend of first increase and then decrease, with the animal manure amount and nutrients’ amount of 7118.36 × 10⁴ t and 86.76 × 10⁴ t respectively in 2014, being the maximum amount of all the years. Livestock and poultry had geographical characteristics, e.g., sheep, cattle and pigs were the main breeding in northern Shaanxi, Guanzhong and southern Shaanxi, respectively. The animal manure load in the province was 22.36 t/hm², while the nutrient load of nitrogen, phosphorus and potassium was 111.59, 58.56 and 104.22 kg/hm², respectively. The total nutrients’ amount of animal manure was about 35.63% of the amount of agricultural chemical fertilizer. The amount of animal manure in Shaanxi Province is within the allowable range of environmental carrying capacity. The risk of environmental pollution exists in Yangling Demonstration Zone, Ankang City, Hanzhong City, Xianyang City and Baoji City. The nutrient resource of animal manure has great potential to replace chemical fertilizer in Yulin City, Yangling Demonstration Zone, Ankang City, Shangluo City and Hanzhong City, while the rational use of the resource can effectively promote zero growth in chemical fertilizer use.

To study the effect of long-term reducing fertilization on soil nutrient content in protected cultivated land under different cropping systems, the soil nutrients and fertilization rate of five long-term soil nutrient monitoring points in Jinning County of Kunming City were statistically analyzed, and the effect of different fertilization treatments on soil nutrient was compared. The results showed that there was no significant difference in soil organic matter between long-term reducing fertilizer treatment and conventional fertilizer treatment, but the organic matter in long-term non-fertilization decreased significantly. Compared with those of the fertilization treatment, soil available N and available P of non-fertilization treatment decreased obviously. There was no significant difference in soil available N and available P between reducing fertilizer treatment and conventional fertilizer treatment, but available N decreased as nitrogen fertilizer decreased. Due to the long-term phosphorus fertilizer application, enrichment effect of phosphorus was significant in protected soil. Long-term reducing nitrogen application will not result in the decrease of soil organic matter, available N and available P in protected cultivated land.

In order to fully reflect the sustainable development situation of cultivated land resources in Henan Province, influencing factors of sustainable utilization of cultivated land resource were explored. Based on the Pressure-State-Response model, the data of cultivated land in Henan Province from 2004 to 2013 were selected and 16 indicators were extracted to conduct a comprehensive analysis of the sustainability of cultivated land resources in Henan Province using multi-factor comprehensive evaluation method. Then linear regression model was used to forecast the sustainability in the next few years. The results showed that the pressure index had the biggest change during the 10 years. The state index and the response index showed a rising trend during the 10 years. The comprehensive utilization score of cultivated land resources in Henan Province in the 10 years was 0.6-0.8, and it was mainly affected by the pressure index and the state index. The prediction results showed that the sustainability of cultivated land resources in Henan Province would have a rising trend up to 2020, and in 2020 the comprehensive score would increase by 0.14 in comparing with that of 2013 and reach a high level of sustainable utilization.

The paper aims to reflect current landscape characteristics of abandoned farmland in different types of villages. We selected 4 villages in the northwest Yixing in Heshun as the study area, and conducted the comparative analysis of landscape patch characteristics and spatial characteristics based on ArcGIS 10.1 and landscape index, and by adopting the results of the right to rural land management registration data. The results showed that: the abandoned farmland accounted for a large proportion of the total landscape area, the abandonment was serious, the patch was broken, but the shape was simple and regular and the degree of aggregation was high, so it was easy to develop and reuse; compared with the cultivated farmland landscape, the abandoned landscape was broken, the shape was complex and the distribution was dispersed, but there were exceptional individual villages; the characteristics of abandoned farmland in different types of villages were different, and the natural environment and social development characteristics of villages had great influence on abandoned farmland landscape. Through the landscape pattern analysis of the abandoned land by using the right data to rural land management registration, it is possible to accurately grasp the characteristics of abandoned land, improve the utilization rate of cultivated land, support the agricultural land transfer and consolidation work to realize the large-scale agricultural production, and develop the rural economy.

Guiding the layout of monitoring sites using basic data has become a research hotspot in recent years. Taking the monitoring of heavy metal Cd pollution in Shunyi District of Beijing as an example, monitoring site layout method for heavy metal pollution of cultivated soil under different data scenarios was developed in this study. Firstly, the basic data scenarios of heavy metal pollution monitoring in cultivated soil were divided. Secondly, the characteristics and applicable data situations of the monitoring site layout method were discussed. Finally, the even variation index and deviation index were adopted to evaluate the uniformity of monitoring sites. The research results showed that: (1) five basic data scenarios were identified based on historical and auxiliary data, namely no historical and auxiliary data, only auxiliary data, only historical data, historical and auxiliary data, and sufficiently historical data; and system/random sampling layout, unbiased sampling layout, encrypted sampling layout, encrypted/unbiased sampling layout and data refinement layout strategies were correspondingly recommended; (2) no historical and auxiliary data were in the western Shunyi District and the corresponding system sampling layout was adopted, while sufficiently historical data were in the eastern Shunyi District and the corresponding data refinement layout was used. Moreover, the even variation index of Shunyi District decreased from 0.546 to 0.490, especially to 0.468 in the eastern Shunyi District, and the deviation index was smaller than the original sampling site layout. It is confirmed that the monitoring site layout method for heavy metal pollution of cultivated soil under different data scenarios has operability and feasibility. This study can provide a theoretical basis and technical support for the sampling site layout method of heavy metal pollution monitoring in cultivated soil.

In order to understand the status of organic matter in the cultivated soil in Hangzhou, variation characteristics of organic matter content of whole cultivated soil was analyzed using soil test data recently obtained from soil fertility survey. The results showed that the level of organic matter of cultivated soil in Hangzhou was mainly medium, organic matter of most cultivated soil belonged to the level of 20-40 g/kg, and about 1/4 (27.00%) soil had a low level of organic matter. Average content of organic matter followed the order of water net plain > hills and valley plain > coastal plain. Organic matter of paddy soil decreased since the second national soil survey, while the average content of organic matter in upland increased. It was concluded that soil organic matter in Hangzhou varied greatly. Input of organic fertilizers to paddy field should be increased to prevent further decline of soil organic matter, and more attention should be paid to improve organic matter of cultivated soil in the coastal plain.

In order to improve utilization of land resources in Xinzheng City, the paper used gradual reduction model of the mechanism method to quantitatively estimate the production potential of land resources of Xinzheng City and to modify climate productive potential with the PI index of land productivity index model for soil correction coefficient, and used production potential index to evaluate arable land productivity level. The results showed that, soil correction coefficient of all towns in Xinzheng City reached an average of 0.54, arable land potential productivity reached an average of 19393.84 kg/hm², and production potential indexes reached an average of 47.39%, so there is still considerable land production potential to be exploited.

In order to ensure food security and promote the sustainable use of cultivated land in western border region, quality evaluation system of cultivated land was established and basic farmland layout was optimized in typical border county Yingjiang. The farmland was classified by the method of analytic hierarchy process, expert scoring and GIS, combined with the actual situation and the evaluation index system of Yingjiang County, basic farmland partition was conducted by the evaluation results. The results showed that the farmland could be divided into 4 grades, the first- grade farmland occupied 22.92% , the second- grade farmland occupied 37.46%, the third-grade farmland occupied for 27.55% and the fourth-grade farmland occupied 12.07%, and the measures for farmland quality improvement and the basic layout of farmland were proposed. Basic farmland partition based on farmland classification met the requirements of quality and quantity of farmland in Yingjiang, it could also provide theoretical basis for the further improvement of basic farmland productivity.

In order to improve the compensation mechanism for farmland occupied by non-agricultural construction projects, the National Food Strategic Reserve Base has sufficient reserves. This study used spatial analysis, empirical research, and other methods to analyze the changes in the increase and decrease of cultivated land from 2000-2014 in each administrative bureau of Heilongjiang Reclamation. It is found that there are problems such as lack of the system, "dominance and inferiority", unreasonable use of land by farmers and limitations of natural conditions during the implementation of the policy of compensating for the balance of cultivated land. By drawing on the innovative experience of the Jiansanjiang Administration"s compensation for arable land, and perfecting the specialized system and regulations in the reclamation area, it is not simply to use the number as a criterion for measuring the balance of arable land, but also to use the modern technology to realize the full use of the topsoil to help the reclamation area and even the rest of the country. The region fully realizes the balance of arable land compensation, so as to achieve the sustainable development of arable land and safeguard national food security.

To fully understand the effect of different amendments on the physical properties of newly cultivated land, a greenhouse culture experiment was carried out on three kinds of newly cultivated land soil with different texture. The effects of 14 amendments, including polyacrylamide, β-cyclodextrin, potassium fulvic acid, bentonite, kaolin, vermiculite, zeolite, diatomite, limestone powder, commercial organic fertilizer, rice straw, Chinese milk vetch, and biochar and peat, on soil structure, water retention and water permeability of the three kinds of soil were compared. The results showed that most of the amendments could improve the soil water stability aggregates, bulk density, saturated water holding capacity, wilting water content, saturated water conductivity and effective water range. And the effect of applying polyacrylamide, β-cyclodextrin, potassium fulvic acid on the physical properties was the most obvious, while the application of peat and commercial organic fertilizer also had a better effect on the physical properties of the soil. Compared with the control, the water stability aggregates of the soil with the application of polyacrylamide, β-cyclodextrin, potassium fulvic acid increased by 42.88%-299.38%, 41.15%-239.69% and 55.39%-207.70%, respectively. The application of peat and commercial organic fertilizer had better improving effects on the soil of newly reclaimed land in low hilly region, the water stability aggregates increased by 31.90%-119.69% and 35.19%-71.05%, respectively. Bentonite, Chinese milk vetch and rice straw could obviously improve the water stability aggregates of sandy soil and loamy soil. The application of kaolin and vermiculite could obviously improve the water stability aggregates of sandy soil, but they had little effect on the water stability aggregates of clay and loamy soil. Biochar had little effect on the content of water stable aggregates, but it could increase the saturated water holding capacity, saturated hydraulic conductivity and effective water range, and reduce the wilting water content. In general, the organic amendments, such as polyacrylamide, β-cyclodextrin, potassium fulvic acid, peat and commercial organic fertilizer, can effectively improve the overall physical properties of the soil, and are more suitable for being applied to the newly reclaimed land in low hilly regions.

In order to analyze the driving factors of the cultivated land change in Kunming, correlation analysis, regression analysis and path analysis were used to explore the factors. The study was based on the condition that area of cultivated land was diminishing and area of construction land was increasing in Kunming from 2000 to 2010. The results showed that the main driving factors were economic, population and technical factors. Economic factors (Kunming GDP, the total value of industrial production, fixed asset investment) were the most important. Population factor (total population) was the indirect effective factor. Technical factor (the total power of agricultural machinery) was more and more important. Economic and population growth led to the reduction of cultivated area per capita. Reduction in arable land and increase of population exacerbated the contradiction between people and land, and had a significant impact on ecology and environment.

[Objective]The fragmentation of cultivated land exists widely in the urderdeveloped areas of agriculture, caused by natural factors and the average allocation rule of cultivated land under the household contract responsibility system, restricting the development of agriculture. In order to solve this problem and achieve large-scale production in agriculture, a new method based on hierarchical cluster analysis was proposed to classify and exchange rural plots. [Method]In this study, wenzhuang village of Taigu County in Shanxi Province was taken as an example. Eight factors were employed to evaluate the cultivated land quality, including plot area, slope of land, shape index of plot, continuity of plot, regularity of plot, traffic accessibility, farming distance and plot yield, Through the analysis for those eight factors utilizing rural land ownership database and hierarchical cluster analysis method, the plots were divided into 5 categories according to the characteristic of farmland operation in the area studied.[Result] Research indicates: the same classified plots in wenzhuang village were distributed around residential area in the form of circular circle; on the basis of the right of village collectives’ farmland contract and management, the same classified plots can be exchanged among the farmers of their own accord, and the land management right of the different classified blocks can be adjusted according to the average yield level, through which the land with the same management right can be gather together as much as possible and improve the farming efficiency. [Conclusion]This method is suitable for the interchange of cultivated land inside village collectives and provides a new way for the adjustment