| Red soil region is an important agricultural planting area in China.Because of the influence of regional climate and soil characteristics,it causing uneven distribution of water and heat,make the problem of seasonal drought increasingly prominent,which has a negative impact on crop growth.Ramie,as a cash crop in South China,has excellent soil and water conservation performance.Studying the water retention performance and soil physical and chemical properties mechanism of different root types of ramie is helpful to understand the difference of water retention performance among different root types of ramie and its main influencing factors.It is of great significance to explore the way of drought resistance of red soil and improve soil moisture performance.In this paper,the water storage capacity,soil physical and chemical properties and their effects on water performance of different root types of ramie in different periods were studied.Based on the yield data of two harvest periods,the root types and varieties of Ramie with strong comprehensive ability were screened out,which provided a scientific theoretical basis for soil and water conservation,seasonal drought prevention and promotion of ramie planting in red soil region.Under the condition of using stem-broken ramie,three kinds of shallow,medium and deep ramie root types were selected,and threevarieties were selected for each root type.Surface water content,soil water storage rate,surface water content and soil water storage capacity of different root type ramie were measured in the high water period,the low water period,the yield of Second Harvest and Third Harvest were measured,and the bulk density,field water holding capacity,water stability aggregates > 0.25 mm and the presence of water-stable aggregates were measured during the test period.The changes of soil physical and chemical properties such as organic matter were analyzed,and the excellent materials with better soil and water conservation performance and higher yield were screened by synthesizing various properties of different root-type ramie varieties.The main results are as follows:During the wet season period,on the water Retention of Ramie Surface Water Content,deep-rooted ramie was the best,medium-rooted ramie was the second,and shallow-rooted ramie was the worst.Shallow-rooted ramie can reach a higher water content in the surface soil in a short time after rain,but after a few days,the surface water content of shallow-rooted ramie began to drop to the lowest,and the water content of deep-rooted ramie increased to the highest in different soil layers,and gradually approached the long-term rule that the surface water-holding capacity of deep-rooted ramie was the best.During the low water period,the surface water content and soilwater storage of deep-rooted ramie were the best,followed by medium-rooted ramie and shallow-rooted ramie,and there were significant differences between shallow-rooted ramie and deep-rooted ramie(p < 0.05).Deep-rooted soil has the best water retention performance in all soil layers,and the deeper the soil layer,the more obvious the advantages of deep-rooted soil in water retention performance.The deeper the ramie root system is,the stronger the correlation between soil water storage is,and the closer the relationship between soil water storage and soil water storage is.In terms of soil physical and chemical properties,the ability of deep-rooted ramie to reduce bulk density and improve field water holding capacity,aggregates and organic matter were the strongest,while the ability of medium-rooted ramie and shallow-rooted ramie was weaker.The change of soil organic matter content is the main factor affecting the change of soil physical and chemical properties and the difference of water storage and retention capacity of ramie.The factors of bulk density,aggregates and field water holding capacity also have different effects on the formation of soil physical and chemical properties and water retention capacity of ramie at different stages.Through the analysis of water-holding mechanism,it can be seen that different root-type ramie can improve the physical and chemical properties of soil in varying degrees,and the change of soil organicmatter content is the dominant factor affecting the changes of soil physical and chemical properties and the differences of water-holding capacity of different ramie.Through the increase of organic matter content,the soil bulk density is reduced,and the field water-holding capacity and aggregate content are increased.Finally,by improving the physical and chemical properties of the soil,the water performance of the soil was improved.Deep-rooted ramie has the strongest ability to improve soil physical and chemical properties and the best water performance in different periods because of its root length.In the yield measurement of Second Harvest and Third Harvest,the middle-root type ramie showed the best physical properties and yield results,followed by shallow-root type and deep-root type;the two highest yield varieties were BD0717 of medium-root type,and the largest increase was DaFangYuanMa of shallow-root type.From Second Harvest to Third Harvest,the yield of shallow,medium and deep roots increased by 34.67%,32.68% and 34.74% respectively.Scoring and screening of different ramie varieties showed that deep-rooted ramie had outstanding ability in water storage and water conservation and improving physical and chemical properties,and its yield was relatively general,with higher overall score;medium-rooted ramie had better performance in yield,while water storage and water conservation ability and physical and chemical properties were slightlyweaker,followed by shallow-rooted ramie in all aspects;shallow-rooted ramie had poorer performance.The overall score was the lowest.Starting from practical application,deep-rooted BaZhongQingGanMa is recommended for soil moisture conservation;deep-rooted HuangBaiMa is recommended for improving soil structure;medium-rooted BD0717 is recommended for increasing yield and high yield;and deep-rooted XiangZhu YiHao is recommended for balancing the above three factors. |
