Study On The Vertical Distribution And Variation Characteristics Of Soil Physical And Chemical Properties In Dadugang Tuyuan, Jinghong City

This paper intends to study the vertical distribution and variation characteristics of soil physical and chemical properties in Dadugang tea garden in Jinghong,Yunnan.Collected 13 tea garden soil profiles and 6 surrounding forest soil profiles,each with a depth of 140 cm,sampled in 11 soil layers,and collected 209 samples for testing the main properties such as water content,bulk density,pH value and organic matter.Sex profile test soil particle size composition,total nitrogen,total phosphorus,total potassium,total sulfur and other nutrients,silicon,aluminum,iron,calcium,magnesium,sodium and other major chemical elements,calculate the weathering leaching coefficient and silicon aluminum iron rate An indicator of the degree of soil development.The vertical variation characteristics of various parameters were analyzed and compared with forest profiles.The effects of tea plantation on soil physical and chemical properties were analyzed.Geostatistics and classical statistical methods were used to analyze the variability of soil physical and chemical properties in tea gardens.The following points are recognized:1.The vertical variation of soil physical properties of tea garden and forest soil is similar.The water content of 0-40 cm increases with depth,and it tends to be stable below 40 cm.The bulk density increases gradually from surface to bottom.The particle size composition is mainly composed of clay,silt and sand.The soil texture is silty clay soil,and there is no obvious change trend along the section.In the vertical variation of soil chemical properties,the pH value of tea garden soil changed with the increase of soil depth,and the pH value of forest soil increased.The organic matter,nitrogen,phosphorus,sulfur and silicon-aluminum ratio of tea garden and forest soil were from The surface layer to the bottom layer showed a decreasing trend,potassium,magnesium and iron showed an increasing trend,and the weathering leaching coefficient changed little and was stable.The total calcium in tea garden soil decreased with the increase of soil depth,and the whole forest soil Calcium does not change much in the vertical direction.2.The comparison between tea garden and forest soil showed that there was no significant difference in soil water content between cultivated layer and non-cultivated layer;bulk density was significantly different in non-cultivated layer,forest soil>tea garden soil;soil sand and clay were only There was a significant change in the non-cultivated layer below 20 cm,tea garden soil>forest soil,soil soil particles contained in the forest soil>tea garden soil in the section and there were significant differences.In the soil chemical properties,the pH value of the tea garden soil is alkalined at 0-60 cm relative to the forest soil,while the acidity trend is below 60 cm;organic matter,nitrogen,phosphorus,potassium and calcium,magnesium,sulfur,iron,etc.There were no significant differences between the chemical elements,as well as the weathering leaching coefficient and the ratio of silicon to aluminum and forest soil.3.Soil vertical variation characteristic properties of tea showed soil water content,bulk density,the degree of variation sand soil depth increased with decreasing trends change,the variation degree of organic matter and potassium,with increasing soil depth trends were enhanced.The pH value,clay and powder particles are weakly variable from the surface layer to the bottom layer;the nitrogen,phosphorus and weathering leaching coefficients are mainly medium variations.The geostatistical analysis of the A,D and K layers from the soil moisture content,bulk density,pH value and organic matter of the tea plantation is consistent with the Gaussian model,which is mainly caused by the combination of randomness and structure,and its spatial pattern is relatively complex.4.The porosity of tea garden soil decreases with the increase of depth.The surface of soil contains some fine-grained binding materials,and its ability to retain water and protect fertilizer is gradually enhanced.Surface soils have greater ability to weather and transform,while deep soils transform more slowly.The minerals in the tea garden soil are mainly quartz,mica,halloysite,chlorite,gibbsite,goethite.5.The pH value of tea garden soil was significantly positively correlated with nitrogen and sulfur,and negatively correlated with magnesium,potassium and weathering leaching index.The increase in pH of the surface soil is related to the calcium element in the organic fertilizer.There was a significant positive correlation between soil bulk density and potassium,magnesium,silicon-aluminum-iron ratio and weathering leaching coefficient,and a significant negative correlation with water content,organic matter,calcium,and sulfur.The reduction of soil bulk density is related to artificial fertilization,different land use p atterns,and farming methods.The clay is negatively correlated with the sand and positively correlated with the powder;the powder is negatively correlated with the sand,potassium and magnesium.