Research of Protected Cultivation Techniques of Toona sinensis on Mountain Slopes

In order to prolong the supply period and increase the economic value of Toona sinensis,the protected cultivation of T. sinensis was carried out on mountainous slope to achieve stagger-season planting and the year round supply. The results showed that in late October to midNovember,the temperature was moderate( 1-10℃) and suitable for the lifting of seedlings and temporary planting dormancy. The line spacing of rooted seedlings in greenhouse was( 22-24) cm ×( 4-5) cm and planting density was 900 000-1 200 000 seedlings/ha. The line spacing of seedlings was( 14-13) cm ×( 3-4) cm and planting density was 1 950 000-2 100 000 seedlings/ha. T. sinensis began to sprout at 8-10℃ and stretch at 10-12℃. When the temperature was stable at 14℃ or above,T. sinensis started bolting and emerging leaves. The terminal buds sprouted in 40-50 d for the T. sinensis planted in greenhouse with the day temperature of 15-22℃ and night temperature over 10℃; the terminal buds sprouted in about 15 d for those planted in the greenhouse with day temperature of 20-25℃ and night temperature over 10℃. T. sinensis could be picked 3 times when planted in greenhouse,and the yield was about 24 720 kg/ha.

Automatic Monitoring of Chilling Requirement for Sweet Cherry and Its Application in Protected Cultivation

For sweet cherry, the economic benefit of protected cultivation is much higher than that of open field cultivation. However, problems such as nonuniform germination, aberrant flower, abortion, bad fruit setting and delayed maturation appear frequently due to the inaccurate regulation of chilling requirement. In order to solve the problems, an automatic system for monitoring, selecting and recording of chilling requirement in protected cultivation of sweet cherry was designed and developed. The system, which consisted of temperature detection, effective chilling temperature selection, signal conversion and output and chilling accumulation display, had been continuously used in protected cultivation of sweet cherry for 3 years and good effects had been achieved. The system monitored chilling accumu- lation accurately and made it more reasonable for the time selection of greenhouse covering, thus avoiding risks of nonuniform germination, bad fruit setting and de- layed maturation, etc. Under the coordinate application of this system with other modern measuring and controlling techniques such as automatic detection and alarming of temperature and humidity, the environment in greenhouses was regulated precisely that the uniform fruits were obtained and the expected yield, quality and harvest time were achieved.

Fruit protected cultivation in China

Protected fruit cultivation in China has developed very quickly from the early 1990s, and now it is an important branch in fruit cultivation. A brief review including fruit species, developing history, growing area, output, and distribution in the whole country is made in the paper. Characteristics of the dominant kinds of greenhouse, environmental control methods, and standards of temperature, humidity, light and CO2 for different fruit species are presented. Information on varieties, growing benefits, special management practices and other aspects of the main fruit species used for protected cultivation are also presented.

Effect of N and K Fertilizers on Yield and Quality of Greenhouse Vegetable Crops

The application of large amounts of fertilizers, a conventional practice in northern China for the production of vegetable crops, generally leads to substantial accumulation of soil nutrients within a relatively short period of time. A fixed field experiment was designed to study the effects of nitrogen （N） and potassium （K） fertilizers applied to optimize the yield and quality of typical vegetable crops. Application of N and K fertilizers significantly increased the yields of kidney bean. The largest yields were obtained in the first and second years after application of 1 500 kg N and 300 kg K20 ha^-1. In the third year, however, there was a general decline in yields. Maximum yields occurred when intermediate rates of N and K （750 kg N and 300 kg K20 ha 1） were applied. However, no significant differences were observed in the concentrations of vitamin C （VC） in kidney bean among different years and various rates of fertilizer treatments. Yields of tomato grown in rotation after kidney bean showed significant responses to the application of N and K in the first year. In the second year, the yields of tomato were much lower. This suggested that the application of N fertilizer did not have any effect upon tomato yield, whereas application of K fertilizer did increase the yield. Application of K fertilizer was often associated with increased sugar concentrations.

Water requirement pattern for tobacco and its response to water deficit in Guizhou Province

The water requirement pattern for tobacco（Yun 85） was identified based on analysis of data obtained from pot experiments in a canopy at the Xiuwen Irrigation Test Central Station in Guizhou Province, China. The results showed that the tobacco water requirement and the tobacco water requirement intensity throughout the growth period in pot experiments were significantly lower than those in field production. In pot experiments, the tobacco water requirement throughout the growth period ranged from 159.00 to 278.90 mm, with a reduction in the range of241e441 mm, as compared with that in field production. Also, the average water requirement intensity at the vigorous growing stage was1.97 mm/d, and the water requirement and water requirement module were 33.80e72.60 mm and 16.39%e33.09%, respectively, at the group stage, almost equal to their values at the vigorous growing stage. The patterns of the tobacco water requirement and water requirement module in pot experiments were different from those in field production. In pot experiments, the tobacco water requirement and water requirement module ranked the highest at the mature stage, followed by those at the group/vigorous growing and rejuvenation stages, while the water requirement intensity ranked the highest at the vigorous growing stage, followed by those at the mature, group, and rejuvenation stages. The pattern of the water requirement intensity in pot experiments was consistent with that in field production. In addition, the response of the tobacco water requirement to water deficit was also analyzed. Serious water deficit at the vigorous growing stage and continuous water stress at the group,vigorous growing, and mature stages can greatly influence the tobacco water requirement. Water deficit led to reductions in the water requirement and water requirement intensity at each growth stage. The vigorous growing stage exhibited the highest sensitivity to water deficit.The lower limit of moderate soil water stress at the vigorous growing stage was 65% of the field capacity. Results of this study can help to establish a reasonable irrigation schedule for tobacco production in Guizhou Province, China.

The Scale of Constructing Mountainous Cities in Yunnan Province based on “Benchmark” Farmlands

In 2011, Yunnan provincial committee and government proposed the strat- egy of constructing mountainous cities in order to protect farmlands and guarantee crop safety, which makes full use of hills and gentle-slopes and transforms land use pattern. However, social and economic development performs unevenly in Yun- nan, supplemented by varied geographical conditions, so that constructing mountain- ous cities should proceed as per local conditions. The research proposed the con- trol of constructing mountainous cities provided crop safety under the principle of farmland protection and measured the quantities of demanded construction lands ac- cording to science of population prediction and ekistics, based on which the control scales of constructing mountainous cities were determined by multiplying basic farm- land coefficient and the area of newly increased construction lands. The research is of significance for guiding the construction of mountainous cities and avoiding the occupation of construction lands on farmlands.

Analysis of Temporal and Spatial Changes of Cultivated Land in Karst Areas of Southwest Guangxi Based on Landscape Pattern Indices

Affected by topographical conditions,the distribution of cultivated land in karst areas is relatively fragmented.More effective cultivated land protection measures can be taken in a targeted manner by grasping the spatial and temporal distribution characteristics of regional cultivated land.In this study,with the cultivated land of four county-level administrative regions(Debao County,Jingxi City,Daxin County,and Tiancheng County)in typical karst landform areas in southwestern Guangxi as the research object,combining with the spatial analysis function of the GIS software platform,the spatial distribution characteristics and temporal and spatial changes of cultivated land in the study area were investigated from 2009 to 2020 using the quantitative analysis method of landscape pattern indices,revealing the main problems of cultivated land utilization,and the multi-dimensional management ideas of cultivated land protection in karst areas under the background of rural revitalization strategy were proposed.

Prediction and Protection of Cultivated Land in China

[Objectives]To protect cultivated land and ensure national food security and to forecast the cultivated land area of China and the provinces(cities)in 2030,2035 and 2050.[Methods]Based on the cultivated land area data of the whole country and provinces(autonomous regions and municipalities)from 2009 to 2017,the OLS model is used to forecast the cultivated land area of China and the provinces(cities)in 2030,2035 and 2050.[Results]The results show that the predicted area of cultivated land in 2030,2035 and 2050 is 134.0886,133.7856 and 132.8764 million ha,respectively,showing an obvious decreasing trend.The national cultivated land scale predicted in this paper can meet the requirements of the 2030 national cultivated land retention target set in the National Land Planning Outline(2016-2030).However,in the total area of existing cultivated land,there is still a certain area of sloping cultivated land(accounting for about 4%of the total cultivated land area,it is appropriate to gradually return farmland to forest).At the same time,nearly 20%of the cultivated land has been polluted,and the low-quality cultivated land accounts for about 22%of the total cultivated land.[Conclusions]The situation of cultivated land protection in the whole country is not rosy.For this reason,some measures and suggestions are put forward:strengthening land consolidation,striving to improve the quality of cultivated land,and appropriately increasing new cultivated land;strengthening the protection of cultivated land resources and strictly controlling the reduction of cultivated land.

Design of Trinity Framework for Cultivated Land Protection

Starting with the goals and tasks of quantity,quality and ecological protection in different scales,this paper constructs a"trinity"framework of cultivated land protection system,and puts forward the key points of cultivated land protection in different scales.Finally,a preliminary evaluation is made on the quantity,quality and ecological protection of cultivated land on a macro scale in China.

Early Warning of Cultivated Land Quality Based on Multiple Indicators

At present,the quality protection and early warning of cultivated land in China are actually based on the increase and decrease of the quantity of cultivated land and the change of its quality.The early warning of cultivated land quality based on this is easy to cause the problem of missing and wrong alarm.Based on the quality and productivity change of regional cultivated land,early warning on the regional cultivated land quality is conducted in this study respectively,and the results of the two early warning are compared.Moreover,a multi-indicator cultivated land quality early warning based on the quality change,productivity change and auxiliary indicators is proposed.The results show that:early warning of cultivated land quality based on quality and productivity change of cultivated land has certain limitations.Based on multi-indicator early warning,the number of counties with heavy,medium and light warnings in Henan Province is 52,8 and 11 respectively.The multi-indicator early warning result of cultivated land quality is more accurate,which can provide a basis for cultivated land protection and management assessment,and has great application value.

Effects of Arbuscular Mycorrhizal Fungi Communities on Soil Quality and the Growth of Cucumber Seedlings in a Greenhouse Soil of Continuously Planting Cucumber

A pot experiment was performed to determine the effects of arbuscular mycorrhizM fungi （AMF） communities on soil properties and the growth of cucumber seedlings in a degraded soil that had been used for continuous cucumber monoculture in a greenhouse for 15 years. In the experiment, AMF communities （created by combining various AMF species that were found to be dominant in natural farm soil） were inoculated into the degraded soil, and then the soil was planted with cucumber. Inoculation with AMF communities did not affect soil pH but increased soil aggregate stability and decreased the concentrations of salt ions and electrical conductivity （EC） in the soil. Inoculation with AMF communities increased the numbers of culturable bacteria and actinomycetes but reduced the number of fungi. AMF communities increased plant growth, soluble sugar content, chlorophyll content, and root activity compared to non-mycorrhizal or a single AMF species treatments. Improvements of soil quality and plant growth were greatest with the following two communities： Glomus etunicatum ＋ G. mosseae ＋ Gigaspora margarita ＋ Acaulospora lacunosa and G. aggregatum ＋ G. etunicatum ＋ G. mosseae ＋ G. versiforme ＋ G. margarita ＋ A. lacunosa. The results suggested that certain AMF communities could substantially improve the quality of degraded soil.

Impact of farmer households＇ livelihood assets on their options of economic compensation patterns for cultivated land protection

With rapid urbanization and the socio-economic transformation, cultivated land protection has gradually become a major concern in China. The economic compensation plays a crucial role in promoting cultivated land protection and improving the utilization ratio of cultivated land. Farmer household＇s satisfaction has a great influence on the effectiveness of compensation. Therefore, households＇ willingness to select the economic compensation pattern for cultivated land protection has been considered and re-examined. By employing Participatory Rural Appraisal method （PRA）, 3 villages and 392 households were investigated and sampled in mesa and hilly areas of Chongqing. Then a quantitative analysis framework of household livelihood hexagon has been developed to quantify the livelihood assets of differ- ent farmer households. Finally, the Gray Relation Model and Probit Regression Model have been employed to explore the coupling relationship between the household livelihood assets and their compensation pattern options. The results show that there are both qualitative and spatial heterogeneity in household livelihood assets. We found that the inequality of livelihood assets is evident for five household types. There is a spatial trend that the higher the eleva- tion, the less livelihood assets are. In addition, their options of economic compensation pat- tern vary from Chengdu Pattern to Foshan Pattern due to their difference in livelihood assets and difference in location. In detail, there is a coupling relationship between household live- lihood assets and their compensation pattern; negative correlation is observed between natural assets value and household pattern options, while the other livelihood assets have positive impacts on compensation pattern in varying degrees, which from the top are psy- chological assets, human assets, physical assets, financial assets, and social assets respec- tively. A conceptual compensation pattern system has been designed to meet the demands for farmer households mainly according to their shortage in livelihood assets. In addition, compensation method, compensation standard, the basis of compensation and the source of compensation funds have been proposed accordingly.

Drivers of farmers’behavior toward compensation scheme for cultivated land protection in chengdu pilot area,China

Studying farmers’behavior affected by economic incentive is necessary to promote positive behavior among farmers toward protecting the quantity,quality,and ecological environment of cultivated land.In this study,we investigated the current situation regarding economic incentive policies for cultivated land protection,which has attracted the attention of Chinese government.Then,we focused on the earliest pilot scheme(i.e.,Cultivated Land Protection Fund,CLPF)implemented in the west of China since 2008 to empirically analyze farmers’behavior.Statistical analysis and path analysis methods were applied,with data collected from 296 questionnaires.Our results showed that positive actions,including the enhancement of initiatives to protect cultivated land,the improvement of ecological environment of cultivated land,and the investment in agricultural infrastructure,have been adopted by farmers since the implementation of the CLPF.Furthermore,gender,education level,labor force size,cultivated land area,migration out of traditional farming areas,average annual household income,and farmers’knowledge of the policy impacted significantly on farmers’behavior.On the premise of comprehensive consideration of the diversity of farmers’livelihoods,new communication technologies and sufficient funds,we suggested that a long-term and sustainable project should be established at the national level to effectively compensate farmers.