Suitability Evaluation Of Soil For Organic Farming In Major Zizyphus Jujube Cv. Jinsi-xiaozao Production Area Of Hebei Province

Environmental protection,food safety and sustainable development has caused widespread discussion and concern with deterioration of agricultural production environment,decline of food quality and gradual depletion of non-renewable energy sources.Developing organic agriculture and organic food was an effective method to prevent degradation of production environment,ensure food safety and improve product competitiveness.The aim of this study was to plan suitable area for organic farming through assessing soil environmental quality in major Zizyphus jujube cv.Jinsi-xiaozao production area of Hebei province.On this basis,prior development region and suitable region for farming organic Jinsi-xiaozao were delineated according to the growing conditions of Jinsi-xiaozao.This thesis would provide the basis for selection and layout of organic Jinsi-xiaozao and other organic products origin.Over all,the main results showed as follows:1.Heavy metals contents except Cd in surface soil of study area were very close to background contents of Hebei province (A level); compared to national soil background values(A level), all elements except Cd, Hg had little differences .The variation coefficient of elements showed middle degree variation,which ranged from 10.98% to 52.29%.2.The Exponential model was selected as the fitted semi-variance function model of Cd, As,Pb,Cr,Zn,Ni.The Gaussian and Spherical model as that of Hg,Cu respectively.The nugget effect of elements ranged from 18.45% to 55.86%.The nugget effect of Cr,Zn,Ni with a strong space correlation were less than 25%.Their space variation was mainly caused by the structural factors.Cd,Hg,As,Cu,Pb showed middle level space correlation. Their space variation were effected by structural factors and random factors.3.The spatial interpolation maps of soil heavy metals were tending to plaques shape.The distribution of all elements except Hg exists common feature,namely,there was a high content belt in the north east-south west of research area,especially to Pb,Cr,Zn,Ni.Cr and Ni were very similar in the spatial distribution;Cr,Zn,Ni were roughly similar;Pb and Zn also had many similar characteristics.4.Only thinking about soil heavy metals pollution,all area of four counties could be as pollution-free agricultural products base;all area basically could be as green food base; most regions could be as organic food base.Cd,Cu,Ni,As in soil of the research area were the restrictive factors for organic farming .5.The fruit color,weight of simple fruit,soluble total sugars,titratable acid, Vc, sugar-acid ratio were selected to divided comprehensive quality of Jinsi-xiaozao into two levels of quality and the non-quality. The soil target elements which effected comprehensive quality of Jinsi-xiaozao were:Cu,B,Zn,Cl.6.The prior development zone,suitable zone and unsuitable zone of organic Jinsi-xiaozao were divided with the method of maps overlay.According to the statistic, the area of the prior development zone was 352.27 km~2 and the suitable zone was 2085.37 km~2.