| At present,the non-timber forest-based economy is developing in full swing in China.Among the various management modes of non-timber forest-based economy,under-forest planting is the most basic and widely used mode,and many forest areas have brought new development to mountain forestry industry through under-forest planting management.At present,people pay more attention to the economic benefits of under-forest planting and management,and pay less attention to the soil quality and ecological changes after the implementation of under-forest planting and management.Under-forest soil plays an irreplaceable role in forest ecosystem,which can not only store and transform nutrients and conserve water sources,but also help maintain the healthy development of forest ecosystem.Reasonable under-forest planting management can effectively improve soil quality,at the same time,good soil quality can guarantee the growth of under-forest plants,thus increasing the under-forest biomass and indirectly affecting the economic benefits of under-forest planting management.Therefore,it is of great value and significance to study the impact of different economic planting management modes on forest soil quality.In this study,two representative understory planting and management modes,Cunninghamia lanceolata+medicinal plants(natural grass coral,artificial grass coral,Taxus chinensis,Torreya grandis)and Liquidambar formosana+tea tree,were selected in Guixi Lengshui Forest Farm,and the effects of understory planting and management on soil quality were explored in combination with their pure forest control.Among them,Cunninghamia lanceolata+medicinal plants have five treatments and three repetitions:Cunninghamia lanceolata+natural sarcandra(SCT),Cunninghamia lanceolata+artificial sarcandra(SC),Cunninghamia lanceolata+artificial sarcandra+Taxus chinensis+Torreya grandis(SCHX),Cunninghamia lanceolata+Taxus chinensis(SH)and Cunninghamia lanceolata(control)(SCK),in order to explore the different factors in plantation management of Cunninghamia lanceolata Under-forest planting pattern of Liquidambar formosana+tea trees is divided into two treatments and repeated three times according to three different altitude groups: low altitude Liquidambar formosana+tea trees(FCD)(463m),low altitude tea trees(control)(FCDCK),middle altitude Liquidambar formosana+tea trees(FCZ)(523m),middle altitude tea trees(control)(FCZCK)and high altitude Liquidambar formosana+.Through measuring the soil anti-erosion performance,water-retaining function,soil fertility,soil microbial diversity and other related indicators of each treated forest land,we can understand the impact of different under-forest planting management modes on soil quality.This will help us to further improve the comprehensive evaluation index system of under-forest planting and management,and further understand the ecological and economic value law of under-forest planting and management,and provide theoretical basis for the selection of efficient under-forest planting mode in South China.The main results of this study show that:Compared with pure forest control,Cunninghamia lanceolata+medicinal plants and Liquidambar formosana+tea trees can effectively improve soil quality under forest.The distribution laws of soil quality index values are different in different planting treatments,different altitudes and different soil depths.Cunninghamia lanceolata+Taxus chinensis(SH)is the best among Chinese fir+medicinal plants,and Liquidambar formosana+tea tree(FCD)at low altitude is the best among Chinese fir+medicinal plants.The vertical distribution characteristics of each soil quality index show that it decreases with the deepening of soil layer,and under-forest planting has the best effect on improving the surface soil(0-20 cm soil layer).(1)Compared with pure woodland control,planting medicinal plants under Chinese fir forest reduced soil bulk density by 1.87 ～ 18.55% on average and increased total porosity by 4.03 ～ 10.81% on average.Planting tea trees under Liquidambar formosana forest reduced soil bulk density by 1.65 ～ 7.32% on average and increased total porosity by0.95 ～ 5.88% on average.(2)Planting medicinal plants under Cunninghamia lanceolata forests increased the average R0.25,MWD and GMD of soil water-stable aggregates by 2.19 ～ 8.60%,3.38 ～25.01% and 5.13 ～ 34.43%,respectively,and the failure rate of soil aggregates(PAD)increased on average Planting tea trees under Liquidambar formosana forest increased the average R0.25,MWD and GMD of soil water-stable aggregates by 3.64 ～ 20.04%,7.47 ～21.78% and 1.64 ～ 14.28%,respectively,and the average failure rate of soil aggregates decreased(3)Planting medicinal plants under Cunninghamia lanceolata forest increased the maximum soil water holding capacity,capillary water holding capacity,field water holding capacity and permeability coefficient K10 by 8.08 ～ 30.98%,3.67 ～ 23.08%,5.08 ～20.16% and 43.69 ～ 166.10%,respectively.The planting of tea trees under Liquidambar formosana forest increased by 3.63 ～ 9.75%,3.15 ～ 9.14%,3.78 ～ 12.44% and 5.77 ～96.46% respectively.Soil water characteristics are distributed in different models,different altitudes and different soil layers.Soil water holding capacity and soil permeability of Chinese fir+Taxus chinensis treatment are significantly higher than those of other treatments.(4)Planting medicinal plants under Cunninghamia lanceolata forest increased soil p H by 0.58 ～ 6.14%,soil organic carbon by 8.94 ～ 46.13%,soil total nitrogen by 2.22 ～104.44%,soil total phosphorus by 6.56 ～ 44.83% and soil total potassium by 7.22 ～ 32.03.Planting tea trees under Liquidambar formosana forest increased soil p H value by 0.74 ～1.26%,soil organic carbon content by 3.36 ～ 29.64%,soil total nitrogen content by 3.81 ～27.19%,soil total phosphorus content by 5.41 ～ 35.38%,soil total potassium content by11.26 ～ 20.40%(5)There are 114 phyla,227 classes,433 classes,609 families,863 genera,381 species and 41287 OTUs in high-throughput sequencing.There are differences in the structure and diversity of soil flora among different treatments,but they are not significant.Planting under Cunninghamia lanceolata can improve the structure and diversity of soil flora,and the best improvement effect is under Cunninghamia lanceolata plus Taxus chinensis(SH).Altitude affects the flora quality of Liquidambar formosana+tea tree forest land to a certain extent,but it is not the main factor.Redundancy analysis showed that ammonium nitrogen,p H value and average weight diameter(MWD)of soil water-stable aggregates had the greatest influence on soil bacterial community,and dominant bacterial species had significant correlation with them.(6)Correlation analysis shows that the physical index of forest soil moisture,aggregate stability index and chemical property index have good correlation with each other.Soil bulk density has significant or extremely significant negative correlation with soil porosity index,water holding capacity index and infiltration index(P < 0.05 or P <0.01).There is a significant or extremely significant positive correlation between soil organic matter and soil aggregate index(P < 0.05 or P < 0.01).(7)Principal component analysis showed that the comprehensive evaluation scores of soil quality of Chinese fir plantation with medicinal plants and Liquidambar formosana plantation with tea trees were higher than those of pure forest control.Chinese fir+Taxus chinensis(SH)has the best effect on improving soil quality among the medicinal plant types planted under Chinese fir forests,and the specific score order is SH>SC>SCHX>SCT>SCK.The improvement effect of Liquidambar formosana+tea trees on soil quality at different altitudes is the best at low altitude,followed by high altitude and the worst at middle altitude.The ranking of specific scores is FCD>FCG>FCZ>FCZCK>FCDCK>FCGCK.To sum up,planting under Cunninghamia lanceolata and Liquidambar formosana in Guixi Lengshui Forest Farm can reduce soil bulk density,improve soil porosity,improve soil aggregate composition structure,enhance soil water holding capacity,improve soil permeability,increase soil nutrient content and protect soil microbial and bacterial diversity.It has a good effect of improving fertility and soil,and can significantly improve the quality of soil under forests and increase the comprehensive benefits of forests.Large-diameter Cunninghamia lanceolata forest+Taxus chinensis model(SH)and large-diameter Cunninghamia lanceolata forest+artificial grass coral model(SC)have the most obvious effects on improving soil quality. |
PDF Full Text Request