Human activity response and prevention strategies on soil and water loss in Sichuan Province

Science in China Ser. E Technological Sciences 2003 Vol.46 Supp.91-10991Human activity response and preventionstrategies on soil and water loss inSichuan ProvinceFANG Yiping & CHEN GuojeInstitute of Mountain Hazards and Environment, Chinese Academy of Sciences and Ministry of WaterResources, Chengdu 610041, ChinaCorrespondence should be addressed to Fang Yiping (email: ypfang@imde.ac.cn)Received August 11, 2003Abstract Ten major factors have been selected to judge the degree of disturbance fromhuman activity and the corresponding relationship of the impact on soil and water loss inSichuan Province. Correlation analysis has demonstrated that stock-carrying apacity,percentage of land reclamation, population density, GDP per capita, mineral modulus andpercentage of forest coverage are the 6 most relevant human activity factors. Theanalysis on the degree of disturbance has shown that population pressure, excessive orunreasonable activities in development of resources and destructive behavior of humansare the main causes of soil and water loss. Consequently, solving the various problems inthe negative activity of humans and regulating human behavior are the first tasks thatshould be tackled in the conservation of water and soil. In the new era, the prevention andrectification of soil and water loss are measures based on the foundation of theecosystem, which is a kind of management strategy for sustainable development. Thefoundation of this method is made up of the system innovations and breakthroughs interms of aims, philosophy, measures, and aspects of the prevention and rectification ofsoil and water loss, simultaneous advance from the conceptual, policy, spatial, technicaland mode levels and system integration on the treatment strategies.Keywords: Sichuan, degree of disturbance, soil and water loss, system innovation.DOI: 10.1360/03ez00111 Basic situation of soil and water loss in Sichuan ProvinceSichuan Province is located at the upper reaches of the Yangtze River with 96.5%of the territory area of the province belonging to the Y angtze River Basin, which is a keyregion in ecosystem construction in the entire nation. Protecting and building up theecosystem in Sichuan is not only an objective requirement of the economic and socialdevelopment of Sichuan but also of extreme signifi中国煤化土he ecosystem and social-economic development of the Threand the 1e-TYHCNMH GCopyright by Science in China Press 200392Science in China Ser. E Technological Sciences 2003 Vol.46 Supp. 91-109gions of the middle and lower reaches of the Yangtze River.According to the measurements and calculations from the data of the second soilsurvey, the area of soil and water loss in the entire province has reached 199800 km*,which accounts for 40.87% of the territory area. The total annual amount of soil erosionis 950 million tons and the average soil loss is 4754 t/km2 1.21 (see table1).Table 1 Situation of soil erosion in Sichuan"CitiesArea ofArea of soil Percentage of soilMean erosionAmount of soil(prefecture) territory/km2 erosion/10* hm2 erosion area (%) modulus/t 1 km2 ! al erosion/10*tChengdu12105.0234.7128.6769432410Zigong4373.0127.4862.8462481717Panzhihua7437.5436.5349.111710625Luzhou12231.4080.8766.124937Deyang5860.4520.6935.3064291330Neijiang"13347.2291.2968.4084427707Leshan'19754.03113.8657.6459526777Mianyang20263.69101.6650.1765336642Suining5323.2536.6768.8998313605Guangyuan16313.8797.1259.5341474027Yibin13297.9281.9661.6354204442Nanchong12479.3180.3464.3873175879Bazhong2500.9877.2562.8058084487Guang' an6339.5640.812986Dachuan16579.10104.126047Ya' ar15097.0258. 1438.5142122449Aba83279.14258.1731.0025476575Ganzi152307.26440.0228.89308113557Liangshan60193.99232.3538.601912a) Ziyang City included in Neijiang. b) Meishan City included in Leshan.To different types of erosion, surface erosion accounts for a large amount and ex-tensive area in water erosion and usually occurs on cultivated hillsides, barren mountainsand slopes as well as sparse and young woodlands. This type of erosion is the main typewithin Sichuan. Approximately, 70% of the cultivated land in the region of the upperreaches of the Jialing River is found on cultivated hillsides and the degree of slope isusually between 20° and 30° with a small portion with 40° slopes. Intense soil and waterloss and damage to the soil fertility occur when it rains or there is a thunderstorm, whichhas become a major source of river sediment. The sloping field at the lower reaches ofthe Jinsha River accounts for 50%一90% of the total amount of the cultivated lands, andthe cultivated lands with a degree of slope of more than 25° account for more than 1/3 ofthe total. As for increase in gully erosion, according to a preliminary representative 1e-gional survey, the annual amount of soil loss on sloping field is as high as 9.36X 107thm2, which, when converted to the surface erosion modulus, is as high as 9000- -36000t(km-. a), and the loss along the Jialing Riv中国煤化工especiallyintense. The spatial characteristics of the erosion mi:MYHCNMHGCopyright by Science in China Press 2003Human activity response and prevention strategies on soil and water loss in Sichuan Province)3置]1000 -2000giset]2001-3000]3001-4000]4001-5000]5001- 6000Yangize]6001-7000]7001-80008001-900015500009001- 10000Fig. 1. Spatial distribution of soil erosion modulus in Sichuan.The combined erosion that is created under the combined effects of gravity and hy-dropower is another type of widespread erosion, which is usually manifest in debris flowand landslide. There are over 3000 debris flow ditches at the upper reaches of the JialingRiver with a 13854 km- area of distribution of debris flows and landslides that accountfor approximately 56% of the total area. The debris flow on the two banks of the trunkof the Jinsha River is also extremely concentrated. Not only is there a large amount ofsuspended sediment pouring into the Jinsha River each year, but there is also a largeamount of coarse materials of the bed load pouring into the Jinsha River and other riversin Sichuan as well as the Three Gorges Reservoir Area.The data analysis of the sediment runoff at the Jinsha River Basin HydrologicalStation has shown that the amount of sand in the trunk river has been on a rising trendever since the 1980s. The rates of increase for the 1970s versus that for the 1960s were0.75--1.21 and 0.83- -1.43 respectively, but the rates of increase for the 1980s versusthat for the 1970s were 1.10- -1.35 and 1.18- 2.27 respectively. To the period after1980s, it can be objectively reported that the soil and water loss at the Jinsha River Basinhas been intensified. The area of soil and water loss in the middle reaches of the JialingRiver accounts for 64% of the territory area of the region, which has been caused by therapid increase in the population and continuous red中国煤化工vated land.The total annual amount of sediment produced is a:TYH. CNMHGe“Changwww.scichina.com94Science in China Ser. E Technological Sciences 2003 Vol.46 Supp. 91- -109zhi" Project (Ecological Rehabilitation Project of the Yangtze River) that was intiated in1989, the“Tianbao" Project (protection of natural forests), and the Grain for Green Pro-ject (returning farmland to forest and grassland) that were implemented after 1998, haveproduced positive effects on soil erosion treatments and sustainable development of thesociety and economy. However, we should be clear-minded and acknowledge that thenatural environment of Sichuan is still very fragile, that is, a large area of soil and waterloss and the trends in the degradation of the ecosystem have not yet been controlled ef-fectively. The percentage of forest coverage dropped 9% in a short period of time afterthe establishment of the People' s Republic of China due to the chopping down of a largearea of forests. Though the percentage of forestry coverage has been restored to 24.23%,but less diversity in the types of forests and low efficiency in the configurations havegreatly reduced the abilities to store and retain water, protect the soil and conserve thewater resources. With an increase in the degeneration and desertification of grasslands,the degeneration and desertification area of grasslands already accounts for 20%一-30%of the useable land in the entire province and there are even some pastoral areas wherethe statistic has reached 50%4.Natural factors are latent conditions that lead to occurrences and expansion of sur-face erosion and human factors cause acceleration or deferment of natural erosion. Dur-ing the most recent 10 a, the problem of a large population contending for limitedamount of land resources in Sichuan is especially evident and the vicious cycle of envi-ronment degradation and poverty have made the controls on soil and water loss becomedifficult issues to tackle due to the relaxed enforcement of the Law on Soil and WaterConservation on engineering and construction projects, reclamation of cultivatable landon steep slopes, destruction of natural vegetation, increase in the population, urban con-struction and other human factors although the Grain for Green Project and the protec-tion projects for natural forests have been implemented.2 Relativity analysis between human activity and the level of disturbanceDegree of disturbance refers to the intensity of human activity interfering with theecosystem. The study on disturbance and the intensity that human activities have uponsoil and water loss is a key to discovering the cause of soil and water loss. Dividing thedegree of disturbance of human activities in Sichuan into different areas can help us toadjust the disturbance intensity and manner of the human activities to local conditionsfor the sake of effective control on soil and water loss and protection of the ecosystem.During the assessment, integration principle, practicality principle, dominant factorprinciple and regional integrity principle will act as the guideline to assess the mannerand degree of human activity. This assessment takes the proportion of area of soil andwater loss and erosion modulus as measurement indices for the degree of disturbanceand selects ten major factors including the percentage of sloping field, percentage ofland reclamation, percentage of forest coverage, I中国煤化工gasslands,population density, population quality, stock-carryYHCN M H Gpita (RMBCopyright by Science in China Press 2003Human activity response and prevention strategies on soil and water loss in Sichuan ProvinceYuan/person), economic density and mineral modulus to judge the impact of human ac-tivity on soil and water loss in Sichuan Province, of which the population quality is cal-culated by the number of graduates from junior colleges or secondary technical schoolsper 10000 people (# of people/ 10000 persons), economic density is calculated by GDPper unit of territory area (RMB 10000 Y uan/km^), while the mineral modulus is calcu-lated by the number of mineral employees per unit of territory area (employee/100 km),and the stock-carrying capacity is calculated by the number of raised cattle, sheep andhorse per unit of area (livestock/km), and percentage of sloping field is that of culti-vated hillsides with a gradient of more than 25° . Table 2 lists the corresponding indi-cesl4.5].Table 2 Indictor system of evaluation for disturbance degree of human activities on soil erosionl4.51Evaluation indicatorsGities. percent- percentage(prefecture) ageof of land forest grassland population populationstock-GDP economic mineralsloping reclama- coverage coverage densityqualitycarryingper capita density modulusfieldtioncapacityChengdu 12.2835.0825.291.3056130201085Zigong0.16.31.93 12.00 0.78720211004825347615Panzhihua9.614.2763.9916.11139515711184154Luzhou 22.1318.6137.303.57379i93578135230Deyang0.3335.0625.270.3563741546889915Nejiang'6.7337.569.900.04680203167216351Leshan" 10.0318.83 41.20 4.33523949358Mianyang6.4415.6553.882.672565466122157151Suining4.1432.67 17.700.0069673169222Guangyuan 15.2010.4756.440.96258285753202Yibin18.9731.750.063833963314Nanchong 10.0526.48 22 570.27568)52492142322Bazhong8.8065.1051.603.12162438336368Guang' an 4.8530.25 15.60691392901199724Dachuan 13.4517.43 41.243.2537426763040113Ya' an22.085.7469.376.11993013494949176Aba18.320.83 36.90 54.751(842881Ganzi11.4529.6C5.7702797Liangshan 14.424.9855.4722.656714)436304(a) Ziyang city included in Nejiang. b) Mcishan city included in Leshan.Before calculating the degree of disturbance, the correlation between ten majorfactors of human activities and area of soil and water loss or erosion modulus of soil andwater loss was determined. Nineteen cities and prefectures of Sichuan Province wereused as samples to list the proportion of area of soil and water loss and erosion modulusas system dominant sequences, and ten index sequences including percentage of slopingfield, percentage of land reclamation, percentage of forest coverage, percentage of cov-erage of grasslands, population density, population中国煤化工acity, GDPper capita, economic density and mineral modulu:MYHCN MH Gnces, aterwww.scichina.com90Science in China Ser. E Technological Sciences 2003 Vol.46 Supp. 91-109which, the gray correlation!ol was discovered. The correlation of the index factors on soiland water loss for the above cities and prefectures in Sichuan was calculated by using acorrelation formula (table 3).Correlation formula: roi =1/19[2ro(k)]i= 1,2, .", 10.Table 3 Coefficient of correlation between human activities and soil and water lossPercentage PercentageForest Grassland PopulaionPopulation Sockcarrying GDPiRP Economic Mineralof sloping of landlandreclamationcoverage coverage density qualitycapacitycapitadensity modulusArea of0.8190.8570.838 0.7060.8300.8110.8960.839 0.751 0.827lossErosion0.8070.8330813 0.7290.8170.7870.8840.815 0.753 0.825modulusFrom the calculation results we can see that among ten human activity factors listedin table 3, the factors with the biggest impacts on soil and water loss are the followingsix factors: stock- carrying capacity, percentage of land reclamation, GDP per capita,percentage of forest coverage, population density and mineral modulus; the correlationcoefficient is above 0.825. The largest impact on the erosion modulus was also the samesix factors although the degrees of correlation of the factors are in a different order, spe-cifically: stock-carrying capacity, percentage of land reclamation， mineral modulus,population density, GDP per capita and percentage of forest coverage.Therefore, in terms of both area and the erosion modulus of soil and water loss, thesix factors of stock-carrying capacity, percentage of land reclamation, population density,GDP per capital, mineral modulus and percentage of forest coverage are human activityfactors and have the strongest correlation and display numerous common traits in thetwo dominant sequences. What should be noticeable is that soil and water loss relatesclosely with the regional economic development level GDP per capita), which is ex-actly the reason why environmental degradation and vicious poverty cycle should berectified when consideration is given to the economy.Moreover, when measuring the ten human activity factors, the correlation of impacton the erosion modulus and that of the impact on the area of soil and water loss arecommon in most aspects. It shows the justification and substitution between area anderosion modulus of soil and water loss as dominant sequences.Taking correlation coefficient as the weight for the relevant factors (indicators) ofdegree of disturbance, the sum of multiplication of weight of the indicators (W;) andcorresponding non-dimensioned indicators (V;) is the degree of disturbancell. It is indi-cated as D; and calculated by the following formula:Dj=ZW;XVj i=1,2, ., 10,j=1,2, ., 19,and the results are listed in table 4.中国煤化工From the spatial structure of the degree of disYHCNMHGies,thee-Copyright by Science in China Press 2003Human activity response and prevention strategies on soil and water loss in Sichuan ProvinceTable 4 Disturbance degree of human activitiesNon-dimensioned indicatorsCities percent- percentageforestgrass-popu- popula- stock- GDP eco-distur- distur-)f of landlandmineral(prefecture) age ofCOV-lation tion carrying per nomicmo d ime bance bancesloping reclama-eragedensity quality capacity capita densitymodulusdegree 1 degree 2tionChengdu0.5555 0.539 0.365 0.024 1.000 1.000 0.523 1.000 1.000 1.000 5.766 5.374Zigong0.007 0.490 0.173 0.014 0.880 0.328 0.935 0.371 0.320 0.622 3.481 3.425Panzhihua 0.4340.066 0.922 0.294 0.170 0.953 0.626 0.859 0.142 0.489 5.167 4.022Luzhou1.000 0.286 0.538 0.065 0.463 0.297 0.570 0.275 0.124 0.233 3.213 3.156Deyang0.0150.539 0.364 0.006 0.779 0.641 0.505 0.529 0.409 0.926 3.919 3.852Neijiang0.304 0.577 0.143 0.001 0.831 0.312 1.000 0.243 0.199 0.355 3.350 3.292Leshan0.4530.289 0.594 0.079 0.424 0.328 0.579 0.303 0.126 0.362 2.957 2 .904Mianyang 0.291 0.240 0.777 0.049 0.313 0.703 0.430 0.470 0.145 0.153 2.975 2.910Suining0.187 0.502 0.255 0.000 0.851 0.266 0.720 0.243 0.205 0.197 2.892 2.832Guangyuan 0.6870.161 0.814 0.018 0.227 0.188 0.542 0.219 0.049 0.204 2.611 2.560Yibin0.597 0.291 0.458 0.001 0.468 0.250 0.486 0.304 0.138 0.318 2.771 2.705Nanchong 0.454 0.407 0.325 0.005 0.694 0.313 0.888 0.191 0.131 0.326 3.150 3.095Bazhong0.3981.000 0.744 0.057 0.344 0.094 0.430 0.187 0.310 0.372 3.291 3.228Guang' an 0.219 0.465 0.225 0.000 0.845 0.063 0.364 0.223 0.183 0.723 2.765 2. 725Dachuan0.6080.268 0.594 0.059 0.457 0.406 0.710 0.233 0.104 0.221 3.068 3.01Ya' an0.998 0.088 1.000 0.1120.121 0.469 0.402 0.380 0.045 0.178 3.151 3.087Aba0.8280.013 0.532 1.000 0.012 0.594 0.355 0.329 0.004 0.010 2.938 2.91Ganzi0.517 0.009 0.427 0.105 0.007 0.719 0.280 0.215 0.002 0.002 1.886 1.846Liangshan 0.6520.076 0.800 0.414 0.082 0.375 0.598 0.279 0.022 0.040 2.753 2.709Weight0.8190.857 0.838 0.706 0.830 0.811 0.896 0.839 0.751 0.827coefficient 1coefficient20.807 0.833 0.813 0.729 0.817 0.787 0.884 0.815 0.753 0.825gions with the strongest degree of disturbance of human activities is concentrated on theTuojiang River Basin, lower reaches of the Minjiang River, Jialing River Basin, middleand lower reaches of the Dadu River, lower reaches of the Y along River and the middleand lower reaches of the Jinsha River (see fig. 2). This is basically consistent with thedistribution of densely populated regions, distribution of frequently developed regionsfor land and mineral resources, and spatial characteristics of soil and water loss. It showsthat the population pressure, excessive or unreasonable activities in development of e-sources and destructive behavior of humans are the main causes of soil and water loss,so resolution for the various kinds of negative activities of human is the primary task forsoil and water loss rectification of today.In order to explain the relationship between the degree of disturbance of humanactivities and soil and water loss more vividly, we have drawn the number sequence ofsoil and water loss and degree of disturbance of 19 cities and prefectures in Sichuan intoa curve (see figs. 3 and 4). According to the curve中国煤化工degree ofdisturbance of human activity, with exceptional:YHCNMH Gilar to thatwww.scichina.com98Science in China Ser. E Technological Sciences 2003 Vol.46 Supp. 91-1091.5- 2.02.0- -2.52.5- -3.0I 3.0-3.53.5- -4.0.4.0- 4.514.5-5.01:5500000I 5.0-5.5|5.5-6.0Fig. 2. Spatial distribution of disturbance degree of human activities.80r;770吧5多50-g840营30-弓20-甘Proportion of soilerosion area。Disturbance degree of10human activiesggiuuggauggFig. 3. Correlation between disturbance degree of hu中国煤化工aYHCNMHGCopyright by Science in China Press 2003Human activity response and prevention strategies on soil and water loss in Sichuan Province)9120006-一Modulus of soil10000erosion5- r - Disturbance degree ofhuman activies8000440002000Fig. 4. Correlation between disturbance degree of human activities and soil erosion modulus.for the area and erosion modulus of soil and water loss and this similarity can be ex-pressed to 0.814 or 0.824 respectively by the correlation coefficient. It is obvious thatthis relationship is very close, suggesting the sensitivity of impact of human activity onsoil and water loss and the effectiveness of soil and water loss rectification by regulatingand controlling human activities and behaviors, in which the key lies in the adjustmentof positive behavior or action of human activity to minimize the pressure on the ecosys-tem and resource utilization and to reduce soil erosion resulting from functional defectsof the ecosystem caused by human activities. So the method and way for rectification ofsoil and water loss should be shifted from focusing on resource configuration, essentialprograms and engineering construction to rectification ideas and guidelines that focus onimprovement of human survival conditions and living quality and realize comprehensiveinnovation in philosophy, policies, spatiality, technology and mode levels.3 Prevention and rectification strategies for soil and water loss3.1 Philosophy levelIn the new era, the prevention and rectification of soil and water loss is based onthe ecosystem; it is a kind of management method based on the scientific “ecosystem"philosophy; and it is a management strategy for the comprehensive control on humanactivity, land, water and biological resources, and promotion of the sustainable utiliza-tion and sustainable development in a fair and just manner. This method is a kind of sci-entific method based on the key point of applying the highly active, sustainable func-tions and the coordinative mechanisms of various leqwel中国煤化工lure, humanand organic environment'8. Therefore, from the p>phy level,the traditional outdated thought should be cast a\JMHCNMHGndbreak-www.scichina.com100Science in China Ser. E Technological Sciences 2003 Vol.46 Supp. 91-109throughs should be achieved in such aspects as aims, philosophy, methods and field ofthe prevention and rectification of soil and water loss.The breakthroughs in the aims for the prevention and rectification of soil and waterloss should be achieved from increasing the vegetation coverage to improving the ecolo-gic functions and raising the income of farmers. To increase the vegetation coverage byartificial afforestation is only a means to realize its objectives. The former single preven-tive rectification should be changed into the integrating maintenance of ecosystem. Weshould pay attention not only to the protection of natural resources, but to the rationaldevelopment and application of those resources as well. Integrate rectification and de-velopment; not only to help farmers poverty alleviation but also to become better off.These measures will effectively increase the income of the farmers and spark their en-thusiasm in rectification. The experience in developing eco-agriculture and eco-tourismin some areas demonstrates that it will encourage the rising and lasting enthusiasm of thefarmers and bring vitality and energy for soil and water conservation in the case that thelong-term, medium-term and short-term interests are closely combined and theshort-term interests are subject to long-term ones9.The breakthroughs should be achieved in the field of prevention and rectification ofsoil and water loss from the rebuilding and restoration to readjusting the manners ofhuman activity. According to the above-mentioned analytical results, the main cause ofsoil and water loss lies in the irrational development activities of humans and their nega-tive behaviors. Therefore, the scientific thought of soil and water conservation should bechanged from the field of artificial restoration and rebuilding into that of readjustinghuman activities and criterion of conduct.The breakthroughs for the philosophy in prevention and rectification of soil andwater loss should be achieved from the departmental segmentation to systematic integra-tion. The scientific notions of soil and water conservation shall be a complete and 0r-ganically connected system. Integrated analysis and unified management should beadopted for various elements of soil and water conservation to maintain the unificationand integrity of the management system for soil and water conservation. Breakthroughsin the traditional soil and water conservation, separation of the forest ecosystem, grass-land ecosystem, water ecosystem and wild animals and plants and other elements and, inaddition, departmental segmentation for relevant work for classified management andrestoration of construction layout are necessary.The breakthroughs should be achieved for the method of the prevention andrectification of soil and water loss from the bioengineering to the combination of crite-rion of human conduct with bioengineering. The most effective traditional measures andways to settle the soil and water conservation lie in biological and engineering measures,carrying out ecologic construction and human intervention; while the scientific notionsof soil and water conservation is to readjust the hu中国煤化工rs. The in-tegrated legal, economic, administrative, and engil:YHCNMH Gst forcefulCopyright by Science in China Press 2003Human activity response and prevention strategies on soil and water loss in Sichuan Province101measures in effecting results.3.2 Policy levelThe systems and policies are the key to ensuring that the innovation of thought andphilosophy of soil and water conservation can be carried through. Table 5 lists the majorpolicies and systems for the rectification of soil and water loss.3.3 Spatial levelSeven regulation areas are classified for soil and water conservation in SichuanProvince according to the water system, that is, Jialing River Basin, Minjiang River Ba-sin, Yangtze Trunk River Basin, Tuojiang River Basin, Y along River Basin, Jinsha RiverBasin, Heihe & Baishuihe River Basin of the Yellow River Water System21The Jialing River Basin Regulation Area covers a total 50 counties and cities (dis-tricts) with a total area of 100900 km' including all the counties of Guangyuan, Bazhong,Nanchong, Dazhou, Suining and Guang' an City and part of the counties of Deyang City,Ziyang City, Aba Prefecture, etc., where the soil and water loss is most serious in Si-chuan and the area of soil and water loss reaches 59400 km", covering 58.8% of the totalbasin area.The Minjiang River Basin Regulation Area covers total 54 counties (cities and dis-tricts) with a total area of 122400 km- including all the counties of Leshan and Ya' anCity, most counties of Chengdu City, Meishan City, Aba Prefecture, etc. and part of thecounties of Liangshan Prefecture, where the area of soil and water loss is 44700 km',covering 36.5% of the total basin area.The Yangtze Trunk River Basin Regulation Area covers total 13 counties (districts)with a total area of 17800 km^ including most counties of Yibin and Luzhou City, wherethe area of soil and water loss is 1 1600 km*, covering 65% of the total basin area.The Tuojiang River Basin Regulation Area covers total 25 counties (cities) with atotal area of 26300 km^ including all the counties of Zigong and Neijiang City, mostcounties of Deyang and Ziyang City and part of the counties of Chengdu, Luzhou, Me-ishan City, etc., where the area of soil and water loss is 14900 km', covering 56.7% ofthe total basin area.The Yalong River Basin Regulation Area covers total 17 counties (cities) with a to-tal area of 128200 km- including most counties of Ganzi Prefecture and part of thecounties (cities and districts) of Panzhihua City, where the area of soil and water loss is33700 km, covering 26.3% of the total basin area.The Jinsha River Basin Regulation Area covers total 21 counties (districts) with atotal area of 74700 km2 including most counties of Liangshan Prefecture and PanzhihuaCity and part of the counties (districts) of Ganzi中国煤化工where thearea of soil and water loss is 30900 km', coveringTYHCNMH G"www.scichina.com102Science in China Ser. E Technological Sciences 2003 Vol.46 Supp. 91-109Table 5 Major policies and security systems for the rectification of soil and water lossPolicies and systemsParaphraseNatural forest protection andFor natural forest protection program, continue to carry out the policy of centralreturning farmland to forestfinance transfer payment; return the farmland to forests and grasslands for culti-and grassland policyvated hillsides over 25° and continue to carry out the policy of grain subsidy, seed-lings planting subsidy and educational subsidy policy for returmning farmland toforest and grasslandScientific and technologicalOrganize the research and development of personnel to tackle key problems andsystemstrive for new breakthroughs around the bottleneck problems of prevention andrectification of soil and water loss, especially the breeding selection for improvedvariety, the comprehensive technology for soil and water conservation, the tech-nology of grassland rectification, rectification of desertification and control tech-nologies, comprehensive treatment technology for small river basirs, runoff for-estry technology, water conservation, drought fighting and afforestation technol-ogy, water-saving irigation technology, and so on. Construct testing demonstrationsites for cultivating and popularizing the demonstration sites of soil and water lossbased on the methods of testing, demonstration and popularization.Reserves area managementEstablish the significant nature reserves at the important headwater conservationareas, flood control areas and flood basins, wind proofing and mobile sand controlareas, key fishing zones, etc. of the Jinsha River, Yalong River, Dadu River, Tuoj-ang River, Jialing River, etc. Practically protect the ecological commonweal forestand ecosystem such as water-resource retaining forest, soil and water conservationforest, etc by way of establishing the ecological function reserves to prevent fromthe damage to ecosystem and soil and water loss, as well as to ensure the safety ofthe whole Yangtze River Basin and national ecosystem.Compilation system of erThe development activities for various kinds of natural resources must comply withvironmental impact assess-the formality of ecologic environmental impact assessment. The scheme of soil andment and soil & waterwater conservation should be compiled and reported for the key construction pro-conservation schemejects of resource development.Management system for Adjust the indutries that consume a large amount of water in area that lack water.projects that consume a largeThe new water storage, water diversion and irigation projects that will increase theamount of waterwater ecosystem disturbance should be stopped at the areas where the cut off in theriver flow occurs, lake diminishes and ground water is over exploited; at the areaswhere the ground water is seriously over exploited, the forbidden zones should bedefined to avoid the large - scale underground funnel or surface collapse.Land-use control and com-Define the ecosystem protection responsibilities of the land contractors; freeze thepensation systemland acquisition of the grasslands, forestland and wetland with significant ecologi-cal functions; report for approval as per the laws and regulations and cary out thesystem of balance of construction-occupied land and reclamation of primary culti-vated land8]Carrying capacity constraint The stock carrying capacity is the key factor among those that impact the soil andystemwater loss. When developing the stock raising, it should be strictly adhered to“determining the livestock number according to the carrying capacity of the grass-land" in order to avoid overgrazing; for overgrazing, the stock-carrying capacityshould be verified and the livestock number should be reduced within a fixedperiod; strictly carry out a system that forbids use in forbidden zones and rotatesgrazing for the grassland in order to acelerate the restoration rate of the grassland.Forbidden mining system for Mining in reserves, at famous scenic sites and in forest parks is forbidden. Quarry-key zonesing，sand exploitation and soil borrowing is strictly forbidden in the dangerousareas where there are collapses and landslides and in the areas where the debrisflow is easy to occur and in the areas where it is easy to lead to damage to naturallandscape; the precautions should be taken against the occurrence of secondarygeologic hazard and soil and water loss during the development of mineral re-sourcesl!].中国煤化工-next page)MHCNMH GCopyright by Science in China Press 2003Human activity response and prevention strategies on soil and water loss in Sichuan Province103(Continued)Policies and SystemsParaphrase“Four Types of Barren"The policy of“who will rectify, manager, and beneficiary" for the rectification andreform systemdevelopment of the“Four Types of Barren" (wasteland, barren ditch, waste-hillsideand barren sand) should be carried out. It is allowed to break through the adminis-trative boundary and allow the main bodies with different economic sectors to buythe right of use and development. Protect the rectification achievements of“FourTypes of Barren” and the rectifier' s lawful rights and interests during a specifiedperiod according to the laws. For the rectification by way of contraction, leasingand stock cooperation, inheritance, transfer or subleasing should be allowed. Recti-fiers who buy the right of use should enjoy the rights of inheritance, transfer,mortgage or stock and joint operationI2l .Investment security systemPersist in attracting funds from the state, local, collective and personal investment.Raise funds in multi-channel, at multi-level and in many ways. Besides the neces-sary support from the central government, the local government must have thethree-level supporting funds with sufficient ratios. But acording to the stage 4implementation of“Ecological Rehabilitation Project of the Yangtze River”, exceptthe sufficient supporting funds at the provincial and district (autonomous prefec-ture) levels, those at the county level are hard to be made available; the rate ofavailability in some counties is less than 10%. Therefore, the supporting funds atthe provincial, city (prefecture) and county levels must be ensured; they should beincluded into the financial budget at different levels and listed and paid as ear-marked funds. Adhere to a policy of“whoever conducts afforestation will beawarded the land and whoever jointly conducts will share it'". Fully mobilize theenthusiasm of the nongovernmental sectors and general public to participate in thesoil and water conservation and maintain ecosystem.Supervision system for soilThe departments of agriculture, forestry, land and construction, etc. shouldand water lossstrengthen the planning coordination at the provincial, city (prefecture) and countylevels. Conduct multi-level, multi-tier and multi-objective supervision and man-agement upon the control planning of soil and water loss, restoration retification,information processing and feedback system.Heihe & Baishuihe River Basin Regulating Area of Yellow River Water System (inSichuan Province) covers 2 counties of Aba Prefecture with a total area of 18600 km,where the area of soil and water loss is 4700 km^, covering 25.3% of the total basin area.According to the implementation plan of soil and water conservation, the nationalecosystem construction planning and various degrees of disturbance by human activity,all the 180 counties in Sichuan Province are included in the key counties for soil andwater conservation in upper reaches of Yangtze River, among which 12 are in the firstbatch (1998一2003), 26 are in the second batch (2004一2010) and 139 are in the thirdbatch (2010- -)21 (see fig. 5); in addition, the key prevention and supervision area of soiland water conservation at state and provincial levels are established correspondingly(see fig. 6).3.4 Technology levelThe comprehensive treatment technology for small river basin: the systematic plan-ning and technical design will be conducted according to the upper, middle and lowerreaches of the river basin. The desertification pre中国煤化工and bio-logical control works should be set up in upperYHCNMHGthe slopewww.scichina.com104Science in China Ser. E Technological Sciences 2003 Vol.46 Supp. 91-109First stageI Second stage550000Final stageFig. 5. Key counties of stage treatment for soil erosion.500000State-level中国煤化工Fig.6. State and provincial-level areas:MYHCNMH GCopyright by Science in China Press 2003Human activity response and prevention strategies on soil and water loss in Sichuan Province105of the river bed; the river bed consolidation and river rectification works should be con-structed in middle and lower reaches to stabilize the toe of slope at both banks, consoli-date the flow center, avoid longitudinal erosion, strengthen the ground water supply andmaintain the natural ecosystem; the debris flow alarm facilities should be set in smallbasin in lower reaches where the landslide and debris flow might occur. The spirit ofcomprehensive treatment should be embodied from upper reaches to lower reaches, fromprotection to development, from application to improvement, from rectification to pre-vention for mountain, water, farmland, forest and roadlo. According to the practice ofthe national and provincial key regulating areas where the outstanding achievements inrectification are made and both stopgap measures and radical measures are taken,“NineCombinations" are paid attention to in the rectification: combining the upper, middle andlower reaches of the river basin; combining engineering measures with biological meas-ures; combining the grass planting with afforestation; combining timber forest withnon-timber product forest; combining slope treatment with ditch treatment; combiningurban regional treatment with rural regional treatment; combining the soil and water lossrectification with regional economic development; combining the soil and water lossrectification with industrial development; combining the soil and water loss rectificationwith casting off poverty and becoming better off.Slope treatment and maintenance technology: due to the special natural environ-ment such as topography, landform, and climate, as well as the great man-land conflictand wide range of poverty in Sichuan, many slopes have become the development spacefor industries in various places of Sichuan. Therefore, in addition to strict implementa-tion of the policy of returning farmland to forest and grassland, the combined system offarmland and forestland, as an acknowledged effective form for the optimized applica-tion of slopes both in home and abroad, is widely applied to slope improvement, i.e. toselect and plant the species of trees and grasses with strong root system, soil conserva-tion, slope protection functions and economic values on the slope to establish a biologi-cal protection belt; and to plant grain crops in the gentle slope farmland to carry out theplanting of forest-grain network belt and develop combined agro-forestry production.Compared with pure farmland, the combined layering system of agro-forestry estab-lished on the slope in the middle of Sichuan Basin, according to the study of Xiangh' ",can raise the efficiencies of light energy, auxiliary energy utilization and comprehensivebenefits of energy by 9.8%- -14.1%, 17.6%一 -21.5% and 6.4%- -15.3% respectively.The study on the combined system of agro-forestry on the slope in hilly area in Sichuanmade by Fei Shimin shows that: compared with the farmland system, the biomass of thecombined system is 4.24 times over that of the comparative system and its efficiency oflight energy utilization can be raised by 12.09%;, in addition, it can effectively preventfrom the soil and water loss and has great use and value in popularization.Eco-agriculture development technology: the eco-agriculture development not onlydoes good to the local economic development and中国煤化工rmers, butalso can effectively protect ecosystem and prevent!YHCNMHGoss.Itisawww.scichina.com106Science in China Ser. E Technological Sciences 2003 Vol.46 Supp. 91-109mode by which the sustainable utilization can be realized. The eco-agriculture develop-ment technology mainly includes the water-saving, fertilization, comprehensive controlover pests, multi-faceted breed aquatics, comprehensive utilization of agricultural andsideline products, edible fungus cultivation, biomass energy utilization, alkaline land andflood land improvement, land treatment techniques in ecological engineering of waste-water, etc. Establish a good soil and water conservation system by way of combinationof agriculture, forest and grass; establish good drainage and irrigation systems for farm-land by way of combination of drainage, water storage and water diversion; establish agood eco-agricultural development system by way of combination of agriculture, stockraising, marsh gas and processing. Make the agriculture have the functions of productiv-ity, livelihood and ecology in order to promote the overall development of regionaleconomy, raise the farmer' s income, and give full play to the efficiency of the mainte-nance for the integrated water and soil resourcesl12.Urban soil and water conservation technology: the urban soil and water loss mainlyoriginates from the piling of rubbish with no soil and water conservation measures andthe loss of spoil and discard slag during the old city reconstruction. The correspondingtechnical measures include garbage treatment and restoration of the vegetation by COV-ering with soil after the recycling of the waste. Combining the beautification of urbanenvironment and the overall planning of the city, select the species of trees, flowers andgrasses with strong adverseness proofing, cold resistance, drought endurance, leannessproofing, trampling proofing, being evergreen and with long growth duration for green-ing and beautification. During the course of construction of the development zone of thecity, the system of“tri-simultaneity and one-scheme”(simultaneous design, simultane-ous construction, simultaneous production and compiling scheme of environmental im-pact assessment and soil & water conservation) should be completely carried through,the corresponding civil engineering and vegetation restoration project should be per-formed, the atheistic effect of the city should be strengthened through environmentaldesign to embody the artistic style and cultural sentiment of the modern city accordingto the Report on the Proposal of Soil and Water Conservation compiled and reported bythe Soil and Water Conservation Department.Soil and water conservation technology in industrial and mining areas: the indus-trial and mining areas are the key regulating areas to soil and water conservation; forexample, the production capacity of gangue in large-scale coal mine and iron mine inPanzhihua city reaches 180 td. As the comprehensive utilization rate is low, and the en-gineering measure is lacking for the ailings treatment, when the rainstorm comes, thtailings and gangue debris flow may arise and directly flow into Jinsha River. Therefore,the land rectification, secondary cultivation and vegetation restoration should be con-ducted by combining their own economic strength; the key points of soil and water con-servation are to conduct the construction of solid waste treatment, flood control, shelterbelt construction in industrial and mine areas, spoi中国煤化工omprehen-sive utility of gangue works. For the spoil yards th2| Y片CNMHGnecessaryCopyright by Science in China Press 2003Human activity response and prevention strategies on soil and water loss in Sichuan Province107measures should be taken to raise the land utilization rate, such as secondary cultivationof agriculture, forestry, animal husbandry and water resources.Soil and water conservation technology in hydropower and road engineering pro-jects: it mainly includes the slope protection, bioengineering and land reclamation bycovering soil technique. The landscape engineering and shelter-forest engineering forside slope should be applied in highway, railway, channel projects and the peripheralregions of spoil yard. The species of trees with beautiful form, pest proofing, strong ad-verseness and pollution resistance should be selected for greening. The vegetationplanting and engineering measures should be combined in the slope protection of thebioengineering construction. The rags and block stones grouting slope protection andgrass protection should be adopted for the higher cut surface, subgrade and side slopeabove the highway, railway and channel in order to ensure the stability of the side slope.The bare land caused by the project construction should be conditioned before plantingtrees and grass, afforestation on side slope and excavating contour furrow so as to im-pound the flood and reduce the scouring.3.5 Mode levelSince reform and opening up， the local governments at various levels of Sichuanand the farmers have created a series of modes during the course of practice in soil andwater loss rectification, mainly the farm household rectification mode, joint householdmode, joint rectification mode by company and household, stock cooperative rectifica-tion mode, enterprise rectification mode, community coordination rectification mode,and government coordination rectification mode. The above-mentioned six modes areused in different ranges of rectification, but according to the requirement of establishinga socialist market economic system, and from the lower level to upper level, the order ofpriority should be: the farm household rectification mode- cooperative rectificationmode- stock cooperative rectification mode- enterprise rectification mode- commu-nity rectification mode - government rectification mode. For example, Panzhihua cityadopts the preferential policies, such as buying the land use right for 30 a (or 50 a), in-heritable development right, supporting the key persons (companies) in development andrectification by government loans and interest discounts, the government being respon-sible for settling the water resource infrastructures, and water and power supply. At pre-sent, there are about 200 private-owned enterprises, self-employers or farmers of jointcontraction that participate in purchase or contraction of barren mountains and slopes;the area of land with 30 a of management right sold is about 1350 hm'. In terms of thesoil and water loss rectification of Meiziqing Small River Basin, under the managementof operational mechanism in the“Company + Farm Household" mode, the area of slopetransformed into terraced field is 270 hm'，and many fancy fruits such as longan, mango,litchi, and loquat are planted. It is estimated that after 5 a, the company will gain netprofits by share of more than RMB 2000000 Yuan中国煤化工thanRMB300000 Yuan of tax levied on agricultural and fiYHCN M H Gthe amualwww.scichina.com108Science in China Ser. E Technological Sciences 2003 Vol.46 Supp. 91-109financial revenue will be gained and the farmers will also acquire evident befitsl131.4 Summary(i) This paper chooses a comprehensive human activity index system to reflect im-personally and wholly the general characteristics of soil and water loss in Sichuan Prov-ince and the impact of human activities on it, in which the spatial characteristics of hu-man activity in degree of disturbance basically complies with the reality of the soil andwater loss. Therefore, in terms of both the area and erosion modulus of soil and waterloss, the six factors of stock-carrying capacity, percentage of land reclamation, popula-tion density, GDP per capita, mineral modulus and percentage of forest coverage arehuman activity factors that have the strongest correlation and display numerous commontraits in the two characteristic sequences. Therefore, with regard to the single factor, theultimate approach of solving man- land conflict and maintaining man-land harmony liesin decreasing the stock-carrying capacity, increasing land output efficiency, contollingpopulation growth, lessening the pressure of population upon resource environment andobeying the order of nature.(i) The correlation between soil and water loss and human activities and the spatialstructure of degree of disturbance show that population pressure, excessive or unrea-sonable activities in development of resources and destructive behavior of humans arethe principle reasons for soil and water loss, so resolution of the various kinds of nega-tive activities of humans is the primary task for soil and water loss rectification of today.(ii) In this new era, the prevention and rectification of soil and water loss is basedon the ecosystem; it is a kind of management method based on the scientific“ecosys-tem”philosophy. This approach lays its foundation on the following aspects: innovationand breakthrough in terms of the aims, philosophy, measures, and aspects of the field ofprevention and rectification of soil and water loss, simultaneous advance from the con-ceptual, policy, spatial, technical and mode levels and system integration on the treat-ment strategies by combining the upper, middle and lower reaches of drainage area, en-gineering measures with biological measures, growing grass with afforestation, timberforest with non-timber product forest, slope treatment with channel treatment, urban re-gional treatment with rural regional treatment, soil and water loss rectification with le-gional economic development, soil and water loss rectification with industrial develop-ment, and water and soil rectification with casting off poverty and becoming better off.The preferred order of selection is the farm household rectification mode- cooperativerectification mode 一stock cooperative rectification mode 一enterprise rectificationmode- community rectification mode- government rectification mode.Acknowledgements This work was supported by the National Key Technologies R&D Program (Grant No.2001 BA901A40).References中国煤化工1. 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