土壤水分含量对旱稻根系和土壤呼吸速率的影响

Effects of Soil Moisture on Soil Respiration and Root Article Number in Upland Rice

在池栽条件下比较研究了不同土壤水分含量处理(65%WHC、75%WHC、85%WHC、95%WHC和100%WHC,WHC代表田间最大持水量)对旱稻277土壤呼吸速率及根条数的影响。结果表明,土壤水分含量对旱稻土壤呼吸速率和根条数有显著影响。随着土壤水分含量的提高,土壤呼吸速率显著下降;随着旱稻生育期的推进,除100%WHC处理的土壤呼吸速率减小外,其余水分含量处理的土壤呼吸速率都呈升高趋势;随着土壤水分含量的增加,旱稻根条数逐渐降低,在分蘖前期处理间差异达到显著水平,随着生育期的推进,处理间的差异逐渐减小,且根条数与土壤呼吸速率呈显著正相关关系。土壤呼吸速率日变化在65%WHC、75%WHC和85%WHC处理下表现为逐渐增加后保持稳定,在95%WHC处理下表现为达最大值后逐渐下降,在100%WHC处理下表现为达最大值后略有下降,并一直保持在较低水平。土壤温度日变化在不同土壤水分含量下均呈现先升高再趋于平稳的变化趋势,以75%WHC水分处理下的温度最高,95%WHC和100%WHC水分处理下土壤温度较低。相关分析表明,不同水分含量处理条件下(100%WHC处理除外),土壤呼吸速率与土壤温度呈显著或极显著的二次抛物线关系,根条数与土壤呼吸速率呈显著的正相关关系。

A pond soil culture experiment was conducted to explore the effects of different soil moisture content treatments(65%WHC,75%WHC,85%WHC,95%WHC,and 100%WHC,where WHC represents the maximum field water capacity)on soil respiration rate and root number of upland rice 277.The results showed that the soil moisture remarkably affected soil respiration rate and root number.The soil respiration rate decreased significantly with the increase of soil moisture content.The soil respiration rate of 100% WHC treatment decreased gradually along with the development of growth stage,all other water treatments showed an upward trend.The root number gradually reduced with the increase of soil moisture,and the difference among the five water treatments reached to significant level in the early tillers,however,the difference among them is gradually decreased along with the passage of growth period.While extremely significant positive linear correlation was presented between soil respiration rate and root number.The daily variation of soil respiration rate showed a gradual increase and remained stable under 65% WHC,75% WHC,and 85% WHC treatments,reached its maximum value and gradually decreased under 95%WHC treatment,and slightly decreased after reaching its maximum value,and remained at a relatively low level under 100% WHC treatment.The daily variation of soil temperature showed a trend of first increasing and then stabilizing under different soil moisture contents,with the highest temperature under 75% WHC treatment and lower temperature under 95% WHC and 100% WHC treatments.Correlation analysis showed that in all of the water treatments(except 100% WHC water treatment),significant or extremely significant quadratic parabola relationship were presented between soil respiration rate and soil temperature,while extremely significant positive linear correlation was presented between soil respiration rate and root number.