| Clear water and green mountains are golden hills and silver mountai-ns.Ecological rejuvenation is the key to rural rejuvenation.In recent years,the economy under the forest has developed vigorously.As one of the innovati-ve agricultural modes of underforest economy,underforest ecological chicken raising has obvious advantages of good ecological,economic and social benefit-s.However,in order to one-sided pursue the maximum economic benefit,individual farmers ignore the protection of ecological environment,resulting in the lack of sustainability of mountain farming,especially in the karst mountain where the ecological environment is fragile.Excessive forest farming has a great impact on the ecological environment.Guizhou is a typical mountainous agriculture province.The ratio of sown area of crops to non-mountainous area is 414.54%,far higher than the national average of 75.06 %.By 2020,the population density of Guizhou was 206 people ·km-2,higher than the national level of 148 people ·km-2.At the same time,Guizhou is the region with the largest karst distribution area in China.The special and fragile geological and geomorphologic background makes the contradiction between man and land in Guizhou extremely acute.The unreasonable underforest economic development will accelerate and aggravate the occurrence of rocky desertification in the karst area.Therefore,in order to protect the ecological environment safety and reasonably develop the ecological industry of underforest breeding,this study took Puding County as an example to select the forest land with the canopy density of 0.5 ~ 0.7,the stand age of 5 years and the pure peach(Prunus Per-sica)stand in the karst mountain area.Three chicken density treatments,name-ly 600(T1),1 200(T2)and 2 400(T3)·hm-2,were set,and three different densities of underforest breeding plots and one CK without chicken were set.By analyzing different undergrowth chickens density on quality of surface soil and vegetation,the influence of equivalent factor method and function value method before and after the contrast calculation breeding value of ecosystem services,determine reasonable karst mountain forests breeding density,build scientific and reasonable Lin Qin compound management pattern,in order to promote the development of karst mountain forests economy sustainable green.The results showed that:(1)In terms of physical properties,there was no significant change in soil bulk density under T1 and T2 treatments,but the saturated water conductiv-ity and the maximum water holding capacity showed an upward trend.Soil bulk density of T3 treatment increased by more than 10%,and its saturate-d w ater conductivity and maximum water holding capacity showed a decreasing tre nd.Compared with the average values before culture and CK treatment,the va riation ranges of soil porosity of each culture treatment were-4.02 %,-0.41 %and-12.63 %,respectively.Among them,soil hardening appeared in T3 treatment.In terms of nutrient content,the nutrient content of TN,TP,TK and SOC in other treatments increased to varying degrees compared with that befo re culture except that the nutrient content of TK decreased slightly in T1 treat ment.Compared with the mean values of CK and before culture,the vari-ation ranges of TN nutrient contents in T1,T2 and T3 treatments were 23.00%,69.01% and 51.09%,respectively.Compared with the mean value of CK and before culture,the variation range of TP nutrient content in each treatment was6.12%,7.48% and 29.25%,respectively.Compared with the mean value of CK and before culture,the variation range of TK nutrient content in each treat-ment was-0.34%,18.21% and 36.76%,respectively.Compared with the mean value of CK and before culture,the variation range of SOC nutrient content in each treatment was 18.49%,89.28% and 61.39%,respectively.(2)The restoration ability of herbaceous vegetation species diversity decreased with the increase of cultivation density.The effect of cultivation density on herbaceous vegetation species diversity was not significant in T1 treatment,but the dominant species changed dramatically before and after cultivation,and Conyza canadensis had the strongest survival ability.After raising chickens under forest,the biomass of herbaceous vegetation in each treatment decreased by more than 95 % on average.After 4 months of restoration,the biomass of herbaceous vegetation under different treatments was 41.21%,3.47% and 1.48% compared with that before culture,respectively.(3)From the perspective of the change of ecosystem service value,the values of ecosystem service units treated by CK,T1,T2 and T3 were 560800,449700,512700 and 635,700 yuan ·hm-2·a-1,respectively.The supply service value accounted for 3.48%,20.26%,31.74% and 48.13% of the ecosystem serv-ice value,respectively.Food production and raw material production can be directly converted into economic benefits,and their economic benefits and ecol-ogical benefits ratios are 1:33,1:4,1:2 and 1:1,respectively.(4)According to the comprehensive analysis,the optimal eco-economic benefit ratio is 4:1 under the breeding density of 600 chickens ·hm-2.The economic benefit and ecological benefit can be taken into account in the underforest bree ding,and the sustainable development path of underforest breeding can be followed.The density of 1 200 chickens·hm-2 raised under forest had the greatest effect on soil nutrient improvement,but it had a strong damage on biodiversit y and affected soil environmental quality.Therefore,in the areas with low requirements for biodiversity conservation and environmental quality,it is advis-able to control the density of chickens at 600·hm-2 after dividing the forbidden grazing areas and rotating grazing areas.Under this density condition,raisin-g chickens under the forest can improve the physical and chemical properties of the soil,and the herbaceous vegetation can be recovered quickly.It can also obtain better economic and ecological benefits,which is conducive to the ecological environment protection and green and sustainable development of the karst mountain area. |
