Effects Of Vertical Deep Rotary Tillage Technique On The Emission Of Greenhouse Gas From Potato Farmland Soil

In order to clarify the impact of vertically rotary subsoiling tillage technique?VRT?on the soil temperature,humidity and emissions of greenhouse gas?CO₂ and N₂O?of potato farmland soil,and analyze their relationship.4 treatments included VRT with mulching potatoes?VRT-P?,the rotary tillage?TT?with mulching potatoes?TT-P?,VRT without mulching or crops?VRT-FL?,TT without mulching or crops?TT-FL?,the moisture,bulk density,temperature and greenhouse gas emission of the soil were investigated,to understand the effect and mechanism of VRT on annual cumulative emission and diurnal variation emission of greenhouse gas from potato farmland.The results showed that:?1?During the growth period of potato,VRT could break the plow pan,loosen the soil,improve soil permeability and soil porosity,resulted in a better soil structure.The soil bulk density of VRT decreased by 11.79%¹3.18%significantly,as compared with TT.VRT increased the moisture content and water storage in 0³0cm soil profile by 5.47%⁵.61%and22.96%²5.23%compared to TT,respectively.the accordingly soil temperature was increased by 2.10%².79%.In the diurnal variation,the soil moisture content and the soil temperature of VRT increased by 4.63%⁶.51%and 6.62%⁶.98%,as compared with TT.?2?In the annually accumulative emissions,the emissions of N₂O and CO₂ of VRT increased by 39.50%⁶5.47%and 4.81%²7.15%compared with TT,the significant difference were observed in N₂O.The emission of N₂O in TT-P,VRT-P,VRT-FL and TT-P in planting season increased by 149.09%,239.06%,556.54%and 370.32%respectively compared to that in fallow period,the correspondingly CO₂ emission increased by 526.12%,532.03%,385.96%and 318.12%respectively,and all of them represented significant differences.In the planting season,the emission of N₂O and CO₂ of VRT significantly increased by 51.48%⁷4.25%and21.85%²4.64%,as compared with TT.During the fallow period,the emission of N₂O and CO₂of VRT increased by 11.28%²4.82%and 4.84%²3.48%compared to TT,the significant difference were observed in N₂O.?3?The emission of N₂O and CO₂ in potato farmland under different tillage methods represented obviously diurnal variation characteristics,which was basically consistent with the diurnal variation of temperature.Both emission of N₂O and CO₂ during the day were more than that at night.According to the correction coefficient and the regression analysis of the average and cumulative emission of greenhouse gas,the reasonable measuring time at 8:00¹0:00am.?4?The emission of N₂O and CO₂ were positively correlated with soil temperature in0²5cm profile significantly,and it were also significantly positively correlated with moisture content in 0³0cm profile.Under different tillage conditions and times,the comprehensive warming potential of greenhouse gases in potato farmland soil was significantly different among treatments?P<0.05?.In the 100a scale,VRT increased by 36.28%⁵3.04%compared with TT,and it was increased by 94.36%in TT-P compared with TT-FL,it was also increased by 164.88%in VRT-P compared with VRT-FL,and all differences were significant.?5?SPAD value of potato leaves treated in VRT-P was significantly higher than that of TT-P,which increased by 12.27%,5.55%and 12.31%in seedling stage,flowering stage and bulking stage,respectively,the significant differences were observed.The aboveground biomass of potatoes in VRT-P increased by 21.62%,and the underground biomass increased by62.07%,and both of which had significant differences,as compared with TT-P.VRT-P was not only promoted ontogenesis,but also improved potato population growth significantly,the LAI was 25.42%higher than that of TT-P treatment.The yield of VRT-P treatment increased by10.49%compared with that of TT-P,while the WUE increased by 6.44%.Because VRT optimized the structure of the arable layer soil,increased the water storage,moisture content of0³0cm soil,and the water consumption of potatoes.These were benefited to potato roots development,caused the promotion of potato nutrients uptake,resulted in the increased dry matter accumulation,potato population,and tuber yield.