粉垄深耕对长沙稻作烟区土壤物理特性及烤烟根系发育的影响

Effects of Deep Vertical Rotary Tillage on Soil Physical Characteristics and Root Development of Flue-Cured Tobacco in Paddy-Tobacco Growing Area in Changsha

为改善长沙稻作烟区土壤环境,提升植烟土壤质量。通过大田试验,设置粉垄深耕(T1)1个处理和铧式犁翻耕(T2)、直接旋耕(T3)2个常规对照,探究不同耕作方式对长沙稻作烟区土壤物理特性及烤烟根系干、鲜质量的影响。结果表明:粉垄深耕明显改善了土壤表层物理结构,在0~30 cm耕层总体范围内,T1粉垄深耕处理与T3常规处理(当地耕作方式)相比,2018年容重、紧实度平均下降8.80%,29.70%,孔隙度平均增大10.67百分点;2019年T1较T3容重、紧实度平均下降11.25%,21.45%,孔隙度平均增大12.8百分点;在烤烟移栽3-5月,T1处理0~10 cm耕层土壤平均含水率比T2高出0.62百分点,在10~20 cm耕层分别比T2和T3高出3.23,4.92百分点,在20~30 cm耕层分别高出9.43,12.3百分点,在30~40 cm耕层分别高出9.56,13.88百分点;同时,粉垄深耕相较于常规处理增加了D值,提高了土壤团聚体的稳定性。且T1处理烤烟根系干质量在团棵期、旺长期、成熟期分别高于T3处理69.75%,28.93%,28.33%,根系体积分别比T3高20.07%,55.61%,36.34%。综上,粉垄深耕改善长沙稻作烟区土壤容重、紧实度、孔隙度、土壤水分、土壤团聚体稳定性等土壤物理性状,改良了土壤环境,提高了烤烟根系的生物量、体积,为提高烟叶的产量产值奠定了基础。

In order to improve the soil environment and soil quality of tobacco planting in rice growing area of Changsha.Through field experiments,1 deep vertical rotary tillage(T1)treatment and 2 conventional controls were set up,including the ploughed furrow(T2)and direct rotary ploughing(T3),to explore the effects of different tillage methods on soil physical characteristics and dry and fresh weight of flue-cured tobacco roots in the rice-tobacco zone area in Changsha.The results showed that deep vertical rotary tillage improved the soil surface physical structure.Within the overall range of 0-30 cm surface layer,T1 deep vertical rotary tillage treatment showed an average reduction in bulk density and compactness of 8.8%,29.7%,and an average increase in porosity of 10.67 percentage points in 2018,compared with T3 conventional treatment(local tillage method).In 2019,T1′s bulk density and compactness decreased by 11.25%,21.45%on average compared with T3,and porosity increased by 12.8 percentage on average.Within 3-5 months of flue-cured tobacco transplanting,the average moisture content of the soil at T1 was 0.62 percentage points higher than that at T2 in 0-10 cm,3.23,4.92 percentage points higher than that at T2 and T3 in 10-20 cm,9.43,12.3 percentage points higher at 20-30 cm,9.56,13.88 percentage points higher at 30-40 cm,respectively.At the same time,compared with conventional treatment,the D value was increased and the stability of soil aggregates was improved.In addition,the dry mass of flue-cured tobacco roots under T1 treatment was 69.75%,28.93%and 28.33%higher at maturity than that under T3 treatment,and the volume of roots was 20.07%,55.61%and 36.34%higher than that under T3 treatment.To sum up,deep vertical rotary tillage bed improved soil physical properties such as soil bulk density,compactness,porosity,soil moisture,soil aggregate stability and so on,improved soil environment,increased the biomass and volume of flue-cured tobacco roots and laid a foundation for improving the yield and output value of tobacco leaves.