Effect Of Planting Period And Method On The Survival And Growth Of Plants In The Management Of Erosion Gully In Northeast China

The black soil area in northeast China is one of the four remaining black soil areas in the world,which is famous for its fertile soil,rich in organic matter and suitable for cultivation.However,the black soil area in northeast China is facing increasingly serious soil erosion and soil erosion,which has seriously damaged the food production capacity of the black soil area in northeast China and has become the main hazard of regional food production at present.In recent years,among the erosion ditch management models in China,plant measures have been widely adopted due to their advantages of low cost and significant ecological benefits,among which herbaceous plants and willow stumps are widely used in erosion ditch management.However,due to the short history of erosion ditch management in northeast China and even in the whole country,the research related to plant measures is less reported and the demonstration and promotion power is weak.So far,the suitable herbaceous plant species,the suitable planting period of willow stumps,and the suitable planting technology of willow stumps in the erosion ditch management in northeast China black soil area are still not very clear.In this study,eight herbaceous plants,including Trifolium repens,alfalfa,Poa pratensis,Elymus dahuricus,Astragalus adsurgens,Leymus chinensis,Achnatherum splendens,Bromus inermis and Salix matsudana willow stumps,were planted at two different planting times and eight different willow stumps,and their emergence,survival and growth indexes were investigated and analyzed,and the most suitable herbaceous plants and willow stumps for the northeast black soil area were evaluated by the affiliation function.The planting patterns of herbaceous plant species and willow stumps were evaluated by the affiliation function,aiming to provide a theoretical basis and practical reference for the plant management techniques of erosion ditches on sloping soils in the northeastern black soil area.The results of this study showed that:（1）Spring planting helped plant emergence,above-ground and below-ground growth more than fall planting of slope protection herbs,and the low temperature in fall and winter suppressed plant growth.Spring planting significantly（P <0.05）improved the seedling emergence rate of eight plants compared with fall planting,with the greatest improvement of 423% for Astragalus adsurgens and the highest emergence rate of 78% for alfalfa.The cover of plants planted in spring was higher than that planted in autumn,except for the cover of Poa Pratensis,Elymus dahuricus,and Leymus chinensis in May,and Leymus chinensis and Achnatherum splendens in June.The highest cover in August was 86.11% for alfalfa in the spring planting treatments.Among the eight plants,plant height was significantly higher（P <0.05）in the spring planting treatments than in the autumn treatments,except for Leymus chinensis,which did not differ significantly in height under the two treatments.The relative growth rate of plant height of all eight plants under the spring planting treatments was significantly higher（P <0.05）than that under the fall planting treatments,indicating that spring planting facilitates the growth and development of plant height.The number of branches of all eight plants was significantly higher（P <0.05）in the spring planting treatments than in the fall treatments,and the relative growth rate of the number of branches was significantly higher（P <0.05）in the spring planting treatments than in the fall planting treatments,indicating that spring planting was more suitable for the branching growth of the eight plants.Except for alfalfa,the relative growth rates of root length and root length were significantly higher（P <0.05）under the spring planting treatments than under the fall treatments for all plants.（2）The results of the affiliation function analysis showed that the suitability of eight slope protection plants were: alfalfa > Trifolium repens > Astragalus adsurgens >Poa pratensis > Bromus inermis > Achnatherum splendens > Elymus dahuricus >Leymus chinensis.Among them,alfalfa is the most suitable herbaceous plants for erosion ditch protection due to its high survival rate,well-developed above-ground and below-ground parts,high cover,and strong adaptability to harsh environment.（3）The survival rate,number of branches,branch length,number of roots,soluble protein content,and soluble sugar content of willow stumps were counted.Willow stumps planted in spring had better survival and growth compared to willow stumps planted in autumn.Spring planted willow stumps significantly increased their survival rate up to 126%,and among spring planted willow stumps,when planting depths were the same,the survival rate was significantly higher（P <0.05）for the bottom-tipped treatments than for the non-tipped treatments,and when bottom treatments were the same,the survival rate was significantly higher for willow stumps planted at 0.8 m depth than for those planted at 0.5 m depth.The number of branches of spring-planted willow stumps was significantly greater than that of fall-planted（P <0.05）and the number of branches of spring-planted willow stumps was significantly higher at a planting depth of 0.8m than at a planting depth of 0.5m.The branch length of willow stumps under spring planting treatments were significantly higher than that under fall planting treatments,and there was no significant effect on branch length with or without sharpening for the same planting depth.When the planting season was different and the rest of the treatments were the same,the number of roots of willow stumps under spring planting treatments was significantly higher than that of fall treatments,and the number of roots of willow stumps with the bottom end sharpened was significantly greater than that of willow stumps without the bottom end sharpened（P <0.05）.Planting willow stumps in spring significantly increased the soluble protein content of willow stumps（P <0.05）,and there was no significant difference in soluble protein content between treatments for spring and fall planted willow stumps,indicating that the soluble protein content of willow stumps was only affected by the planting season.Willow stumps planted in spring significantly increased their soluble sugar content after planting compared to before planting（P < 0.05）.The soluble sugar content of willow stumps was only related to the planting season,but not to the planting depth and the bottomtipping treatments.Through the comprehensive evaluation of membership function method,the order of suitability of the eight willow stump planting patterns is:A2B2C2>A2B1C2>A2B2C1>A2B1C1>A1B2C2>A1B2C1>A1B1C2>A1B1C1.The most suitable planting mode of willow stump is: planting in spring,planting depth 0.8m,bottom sharpened.（4）Willow stumps planted in autumn are more affected by low temperature in winter,which is not conducive to their survival and growth,and also reduces the relative growth rate of the root system and branches of willow stumps,which slows down their development and reduces the effect of soil and water conservation.Through the comprehensive evaluation of membership function method,the most suitable planting mode of willow stump is: planting in spring,planting depth 0.8m,bottom sharpened.The results showed that the survival rate and growth of both herbaceous and woody willow stakes in erosion ditches were significantly better in spring planting/planting than in autumn,with alfalfa of the legume family being the best among herbaceous plants and willow stakes being the best with proper deep planting and chipping treatments at the bottom.