丘陵山区多元新型农业经营主体时空演变及产业响应

探索多元新型农业经营主体动态演变过程,明晰主体发展与产业间的响应关系,以期为构建立体式复合型现代农业经营体系,助推乡村产业振兴提供参考.以重庆市(江津)现代农业园核心区的慈云镇为例,基于2000-2019年新型农业经营主体微观面板数据,从经营主体多元化视角,解析近20年各类新型主体的进退动态发展过程,并采用标准差椭圆方法,分析各类主体时空格局演变方向,进而采用邻近性指数等方法探讨主体间的产业关联,从而揭示多元新型农业经营主体发展的过程-格局-产业响应.结果表明:①慈云镇形成了“农业企业+种植大户+养殖大户+农民专业合作社+家庭农场”多元新型主体融合发展格局,各类主体增长年际变化过程具有一致的阶段性,2000-2008年(缓慢减少、相对较枯期)、2009-2015年(快速增长、相对较丰期)、2016-2019年(缓慢减少、相对较枯期),但不同类型主体在增长速率、增长空间上表现出一定的差异,主体间发展不平衡.②不同时间阶段新增的各类新型农业经营主体空间分布均呈东北-西南方向,但空间演化存在显著差异.③多元化农业新型经营主体刺激了产业多元化发展,催生了类型多样化、规模差异化、空间邻近弱的“花-菜-果-粮-养-特色”产业发展新格局.慈云镇新型主体呈多元化发展态势,各类主体时空演变具有阶段性差异化增长特征,现阶段主体培育与产业发展相互融合,彼此响应,主体间表现出分工关联、上下游关联、市场关联、空间关联等多元化产业关系,应打造农业产业化联合体,提升主体间产业关联效应.

渝东北紫色土饱和导水率传递函数研究

为研究渝东北紫色土理化性质在垂直空间上的分布情况以及对饱和导水率的影响,进而建立饱和导水率与各理化性质间的关系函数,推求饱和导水率的传递函数,选择渝东北开州区、云阳县等7个区县内45个紫色土典型田块为研究区域,运用Excel 2013和Matlab 2015b软件统计分析后,利用多元非线性回归法推求并验证了渝东北紫色土饱和导水率传递函数模型和模型参数。研究表明:①研究区土壤饱和导水率变化范围在0.16~195.68 cm/d,变化范围广,空间变异系数大,变异性较强;同一采样点深度越大,饱和导水率越小;②土壤饱和导水率与有机质含量有显著的指数函数关系,与饱和含水量有较强的二次函数关系,与土壤容重和土壤颗粒的相关性不大;③本次试验建立的土壤饱和导水率传递函数模型及模型系数检验合格,预测值与实际测算值误差较小,精度良好,可用于渝东北紫色土饱和导水率的预测工作。

基于“三生”视角的山地丘陵区土地整治功能分区——以重庆市綦江区为例

采用"三生"功能指数测算和系统聚类分析相结合的方法,以重庆市綦江区为例,进行土地整治分区研究。结果表明:(1)各街镇地形差异较大,其"三生"功能指数随立地条件的不同呈现出明显的空间分异性。生产功能指数与立地条件指数在0.05水平上呈显著正相关(r=0.522),生活功能指数与立地条件指数在0.01水平上呈显著正相关(r=0.595),生态条件指数与立地条件指数相关性不显著,相关系数为负(r=-0.134)。(2)结合聚类结果和实际情况,将研究区分为4个土地整治区,并提出相应的整治措施。

Effects of Land Management Practices on Labile Organic Carbon Fractions in Rice Cultivation

A research trial with four land management practices, i.e., traditional tillage-fallow (TTF), traditional tillage-wheat (TTW), conservation tillage-fallow (CTF) and conservation tillage-wheat (CTW), was sampled in the 15th year after its establishment to assess the effects of different management practices on labile organic carbon fractions (LOCFs), such as easily oxidizable organic carbon (EOC), dissolved organic carbon (DOC), particulate organic carbon (POC) and microbial biomass carbon (MBC) in a typical paddy soil, Chongqing, Southwest China. The results indicated that LOCFs were significantly influenced by the combination of no-tillage, ridge culture and crop rotation. And, different combination patterns showed different effectiveness on soil LOCFs. The effects of no-tillage, ridge culture and wheat cultivation on EOC, DOC, POC and MBC mainly happened at 0-10cm. At this depth, soil under CTW had higher EOC, DOC, POC and MBC contents, compared to TTF, TTW and CTF, respectively. Moreover, the contents of LOCFs for different practices generally decreased when the soil depth increased. Our findings suggest that the paddy soil in Southwest China could be managed to concentrate greater quantities of EOC, DOC, POC and MBC.

Mountain Land Use Planning of Metropolitan Suburbs:the Case of the Jinyun Mountain and Its Surrounding area,Chongqing,China

Open space of metropolitan suburbs in mountain region,has been increasingly becoming the coupling mosaic structure of industrial actions and landscape behaviors. However,the local governments,when making land use planning,often aim at economic development,and rarely refer to the coordination of compatibilities and conflicts between industrial actions and landscape behaviors in the mosaic structure. In this study land use in the Jinyun Mountain and its surrounding area,Chongqing is adjusted by gray multi-objective programming approach and local-level decision-making process to cope with conflicts between objectives for human welfare and objectives for landscape conservation. The results indicate that: 1) the compatibilities and conflicts among different behavior characters and different landscape types result in the compatibilities of landscape to human behavior;2) a land use planning in the study area is produced based on the sustainable land use and social-eco development,which pays more attention to the resources and environment constraints and economic objectives,and follows the distribution law of rare resources;3) in the study area,cultivated land of 1,207.27 ha can meet the demands for food and byproducts by the residents there,orchard land and forestland of 632.55 ha,2,276.61 ha,respectively can provide enough space for the local people to improve their living structure and meet their demands for recreational activities,and urban residential land,rural residential land,mining land and transportation land of 1,107.60 ha,120.27 ha,162.48 ha,100.91 ha,respectively can satisfy the resident’s economic development and infrastructures;4) the equilibrium among industrial actions,landscape accessibility and ecological conservation can be obtained by analyzing the possible impacts of human activities on landscape ecological process in open space of metropolitan suburbs in mountain areas.

Land use change and its corresponding ecological responses:a review

This paper reviews the research on land use change and its corresponding ecological responses. Patterns of land use changes in spatio-temporal level are produced by the interaction of biophysical and socio-economic processes. Nowadays, the studies derived from different socioeconomic conditions and scales show that at short-term scale, human activities, rather than natural forces, have become a major force in shaping the environment, while biophysical factors control the trends and processes of land use change under the macro environmental background. Providing a scientific understanding of the process of land use change, the impacts of different land use decisions, and the ways that decisions are affected by a changing environment and increasing ecological variability are the priority areas for research： （1） explanation of scale dependency of drivers of land use change; （2） quantification of driving factors of land use change; （3） incorporation of biophysical feedbacks in land use change models： and （4） underlying processes and mechanisms of ecological impacts of land use change.

Classification and Gradation of Cultivated Land Quality in Bishan County of Chongqing, China

The conflicts among food security, economic development and ecological protection are the “sticking point” of undeveloped southwestern mountainous areas of China. The objectives of this study are to identify appropriate inte- grated indicators influencing the classification and gradation of cultivated land quality in the southwestern mountainous area of China based on semi-structure interview, and to promote the monitoring of cultivated land quality in this region. Taking Bishan County of Chongqing as a study case, the integrated indicators involve the productivity, protection, ac- ceptability, and stability of cultivated land. The integrated indicators accord with the characteristics of land resources and human preference in southwestern mountainous area of China. In different agricultural zones, we emphasize different indicators, such as emphasizing productivity, stabilization and acceptability in low hilly and plain agricultural integrative zone (LHP-AIZ), protection, productivity and stability in low mountain and hill agro-forestry ecological zone (LMH-AEZ), and acceptability in plain outskirts integrative agricultural zone (PO-IAZ), respectively. The pronounced difference of classification and gradation of cultivated land, regardless of inter-region or intra-region, is observed, with the reducible rank from PO-IAZ, LHP-AIZ to LMH-AEZ. Research results accord with the characteristics of assets management and intensive utilization of cultivated land resources in the southwestern mountainous area of China. Semi-structure interview adequately presents the principal agent of farmers in agricultural land use and rural land market. This method is very effective and feasible to obtain data of the quality of cultivated land in the southwestern mountainous area of China.

A study on the characteristics of heavy metals in orange ecosystem

An investigation was conducted to identify the characteristics of heavy metals in orange ecosystem in three areas in the Three Gorge Reservoir Region by using the modified Tessier sequential extraction procedure.The contents of Cu and Pb in different speciation fractions of the soils can be ordered as the Residual(F6)>Reducible(F4)>Oxidable(F5)>Water soluble(F1)>Carbonate(F3)>Exchangeable(F2),and the contents of Zn and Ni follow the order of the Residual(F6)>Oxidable(F5)>Reducible(F4)>Water soluble(F1)>Carbonate(F3)> Exchangeable(F2),and those of Cd follow the order of the Reducible(F4)>Oxidable(F5)>Exchangeable(F2)> Carbonate(F3)>Residual(F6)>Water soluble(F1).The concentrations of Cu in the different organs of oranges follow the increasing sequence of pulp>leaf>pericarp,those of Zn and Ni following the increasing sequence of leaf >pulp>pericarp,and those of Pb and Cd follow the increasing sequence of leaf>pericarp>pulp.Correlation degrees of different forms of same heavy metals in soils are according to the order of Cu>Zn>Cd>Pb>Ni.Correlation degrees of different heavy metals in same forms are according to the order that the forms of Reducible(F4),Oxidable(F5) and Residual(F6) are higher than the forms of Water soluble(F1),Exchangeable(F2) and Carbonate(F3).There are either positive or negative correlations between heavy metals in leaves and in pulp,while there are all positive correlations between heavy mentals in leaves and in pericarp.There are significant correlations between the concentrations of some heavy metals in leaves,pericarp or pulp,and those in speciation fractions in the soils.

规划情景约束下山地丘陵区土地利用空间格局模拟——以重庆市綦江区为例

[目的]以重庆市綦江区为研究对象,通过模拟预测2010—2020年规划调控影响下研究区的土地利用空间格局变化特征,以期为目标情景下土地利用规划的空间实施提供技术支持。[方法]文章通过构建Dyna-CLUE模型分别模拟研究区在自然增长和规划约束引导下的土地利用空间格局,并对照自然情景进而分析规划约束下土地利用空间格局的表现特征。[结果]比较AutoLogistic模型与传统Logistic模型回归结果发现,除建设用地外,其他地类的ROC值都有显著提升;对比两种情景模拟结果发现,到2020年,研究区内耕地、农村居民点、未利用地较自然情景显著减少,林地、园地显著增加,城镇建设用地增长规模较自然增长情景减少171.86hm^2;规划情景约束下,2010—2015年研究区地类转移以耕地转建设用地为主,2015—2020年以耕地转林地为主,耕地转建设用地次之,再次为农村居民点转耕地。[结论]Dyna-CLUE模型模拟中,运用添加自相关因子的AutoLogistic模型代替传统Logistic模型进行空间驱动力分析,能够显著提升模型模拟精度;规划约束下,退耕还林、农村居民点复垦和农业结构调整等工作的开展是耕地减少、林园地显著增加,建设用地规模得以控制的重要原因;退耕还林成果在规划约束情景中得到较好体现,表明规划目标对于引导土地利用空间格局定向变化有重要作用,但是丘陵山地的耕地减少态势也需得到足够重视,建议推进耕地产能建设从而协调生态保护与粮食安全间的用地需求。

Irrigation water requirements of rice using Cropwat model in Northern Benin

Understanding crop water requirements(CWR)in semi-arid region is essential for better irrigation practices,scheduling and efficient use of water since the water supply through rainfall is limited.This paper estimated the crop reference and actual evapotranspiration(Eto and ETc)respectively and the irrigation water requirement of rice(Oryza sativa L.)in Benin’s sub-basin of Niger River(BSBNR)of west Africa,using CROPWAT model.The long recorded climatic data,crop and soil data from 1942 to 2012 were computed with the Cropwat model which is based on the United Nations’Food and Agriculture Organization(FAO)paper number 56(FAO56).The Penman-Monteith method was used to estimate ETo.Crop coefficients(Kc)from the phenomenological stages of rice were applied to adjust and estimate the actual evapotranspiration ETc through a water balance of the irrigation water requirements(IR).The results showed the BSBNR annual reference evapotranspiration(ETo)was estimated at 1967 mm.The lowest monthly value of ETo of 123 mm,was observed in August month,middle of the rainy season while the highest value 210 mm was observed in March within dry season.The crop evapotranspiration ETc and the crop irrigation requirements were estimated at 651 mm and 383 mm,respectively in rainy season and 920 mm and 1148 mm,respectively within a dry season.Irrigation projects of these seasons can then be scheduled for water use efficiency based on these findings.

Temporal variation of soil water and its influencing factors in hilly area of Chongqing,China

The paper studied the temporal variation of soil water content and its influencing factors in hilly area of Chongqing by the yearly data of 2006 and 2007.According to precipitation anomaly percentage,the year 2006 was a dry year and 2007 a normal year.In the dry year 2006,the variations of soil moisture in all three layers(0-10 cm,10-20 cm,20-40 cm)were medium(10%<CV<30%);in the normal year 2007,the variation in the layer of 0-10 cm was strong(CV>30%),and those of the two deeper layers were weak(CV<10%).Hence,the seasonal variation of soil moisture in the humid area was large in the dry year and small in the wet year.The probability distributions of soil moisture in all three layers in both dry and normal years showed single-peak shapes.However,peak locations and values varied with different layers and years.Among factors affecting the temporal variation of soil moisture in the 0-10 cm layer,during March to May,the meteorological factors including temperature,sunshine and precipitation were all inversely correlated with soil water content variation.The correlations with average temperature and accumulated temperature were both highly significant P<0.01(P=0.00).The inverse correlations with sunshine and precipitation were significant P<0.05(P=0.01).Among soil physical properties,except for bulk density which was inversely correlated with soil moisture,all other properties were positively correlated.Organic material was positively correlated with soil moisture,which suggested that organics had the sponge effect and contributed to soil water storage and movement.During the period of June to September,there was no significant correlation between soil water content and total storage.The meteorological factors of temperature,accumulated temperature and sunshine were all inversely and highly significantly correlated with soil water content P<0.01(P=0.00).

Restoration technologies of damaged paddy in hilly post-mining and subsidence-stable area of Southwest China

The paddy fields and water storage facilities are seriously damaged by the coal mine subsiding in the hilly post-mining and subsidence-stable areas in China,which make the farmers there being suffered greatly from the lack of water for traditional rice cultivation and daily life.The purpose of this paper is to find a method to restore the damaged paddy fields,thereby promoting sustainable development of land resources,and alleviating the contradiction between people and land,as well as creating a more inhabitable environment.The research methodology included field experiments,cultivated observation,and field investigation.This paper selected the Songzao Mining Area as the research area,and focused on the restoration technologies of damaged paddy fields,through the following four different measures at three experimental fields:(1)Traditional repeated cattle plowing(CK);(2)Water retention agent with repeated cattle plowing(W&C);(3)Film without holes under tilth depth(FO);and(4)Film with holes under tilth depth(FW).At last,a contrastive analysis of the four measures was made according to the results of the experiments.The results show that the use of water retaining agent with repeated cattle plowing(W&C)can be the most appropriate method to restore the damaged paddy field in the hilly post-mining and subsidence-stable area in southwest China.Compared with the other three measures,its water productivity is the maximum(0.81 kg/m3),and the net income is the highest(1403$/hm^(2)).What’s more,it is simple,short time-consuming,and low cost,which is benefit to generalize the use of this restoration technology.