| The experiment was carried out in the 5-year potato continuous cropping field and using the variety "Xin Daping" as test material.The difference of potato root exudates compounds and content and soil chemical properties change of potato continuous cropping were researched under the 6 different planting patterns which are harrowed bedding system without covering film(CK),harrowed bedding system with covering film(T1),completely covered alternating narrow and wide ridges with ridge planting(T2),completely covered alternating narrow and wide ridges with furrow planting(T3),plastic covered raised bedding system with bedding planting(T4)and plastic covered raised bedding system with furrow planting(T5).The results are as follows:1.GC-MS analysis identified the types of compounds of root exudates of ridge film mulching continuous cropping of potato include esters,hydrocarbons,alcohols,acids,ketones,amides,hydrazines,phenols and oximes mainly among which the relative content of esters were highest,followed by hydrocarbons.The total number of root exudates extracted by three kinds of organic solvents(methanol,ethyl acetate and n-hexane),respectively.There are 49 kinds of compounds of root exudates under the CK.There are 39 kinds of compounds of root exudates under the T1.There are 28 kinds of compounds of root exudates under the T2.There are 32 kinds of compounds of root exudates under the T3.There are 52 kinds of compounds of root exudates under the T4.There are 41 kinds of compounds of root exudates under the T5.The root exudates of potato rhizosphere soil were extracted by ethyl acetate,and more varieties and quantities of compounds could be obtained.The number of potato root exudates under 6 modes were extracted with ethyl acetate: harrowed bedding system without covering film(CK)27,harrowed bedding system with covering film(T1)21,completely covered alternating narrow and wide ridges with ridge planting(T2)15,completely covered alternating narrow and wide ridges with furrow planting(T3)21,plastic covered raised bedding system with bedding planting(T4)21,plastic covered raised bedding system with furrow planting(T5)25,Among them,the whole film ridge sowing(T2)model had the least species of root exudates.2.In the six models of potato root exudates,methyl palmitate,dibutyl phthalate and palmitic acid were detected,but the relative contents of the three allelochemicals extracted from the same reagent were different.(5.50%)and benzyl alcohol(10.90%),and the root exudates unique to the paclitaxel were found by GC-MS.(1.33%)and trans-p-isopropylcyclohexylcarboxylic acid(0.34%),the whole film ridge is unique toisopropyl myristate(4.7%),(2,6-dimethylphenoxy)-N-methylethylamine(2.13%),p-nitro-2-butanone(19.67%)and 1,3-diisopropylbenzene(1.01%),and the semi-ditch sowing is specifically 4-propylbenzaldehyde diethyl acetal(1.72%).3.Furrow planting mulch increased soil pH than harrowed bedding system without covering film planting highest 1.13 units,the whole film furrow soil pH in potato seedling growth;soil conductivity with potato growth cycle of the rise,compared with flat beds,the film ridge sowing soil conductivity in potato mature period the largest decline the biggest.4.Furrow planting mulch can promote the absorption of potato on soil available potassium and nitrogen,compared with flat beds without film,film mode ridge sowing available nitrogen absorption rate reached 17.8%,the largest increase,the whole film furrow model K absorption rate of the largest increase,reaching 29.5%.5.Ridge mulching increased the activity of soil invertase,alkaline phosphatase,catalase and urease,and increased by 15.4%~26.1%,16.8%~85.7%,53.3%~89.3% and50%~150%,respectively.Among them,the maximum increase of soil sucrase activity,alkaline phosphatase activity,catalase activity and urease activity were the whole film furrow sowing,half film furrow sowing,half film ridge sowing and whole film ridge sowing. |
