| Sweet potato is potassium-like crop, from the perspective of the whole growth stage, it is found that the need of potassium fertilizer by sweet potato is highest, follows by nitrogen fertilizer, and phosphorus fertilizer was lowest. The use amount, method and time have significant effects on the yield and quality of sweet potato. Therefore, studying the potassium use law is significant to the high quality and yield sweet potato cultivation. For the sake of selecting sweet potato type with high potassium use efficiency, clearing the potassium absorption of sweet potato under different treatments, in this study, firstly, Xushu No.083228, Nanshu No.88, Xushu No.28, Wanshu No.6, Xushu No.082909, Jishu No.22and Wanshu No.5were chosen as the main study subject, different potassiumn treatments were designed, the regulatory of potassium absorption of sweet potato under different treatments was analyzed, and the projection pursuit model was used to select best sweet potato type with optimal comprehansive potassium use efficiency; then the gained best2types (Xushu No.28, Jishu No.22) were taken as main materials, potassium absorption laws of sweet potato under different soil types (yellow moisture soil and high sandy soil) and different potassium treatments (potassium application and no potassium application)were analyzed. Main study conclusions were as follows:(1) Projection pursuit model avoided the limit of using subjective weight only and effectively selected the best sweet potato type with optimal comprehansive potassium use efficiency, and the results were scientific and reasonable. The potassium absorption ability of7different sweet potato types were ordered from strong to weak as:Xushu28, Jishu No.28, Nanshu No.88, Wanshu No.5, Wanshu No.6, Xushu No.083228, Xushu No.082909.(2) From dry matter accumulation of sweet potatoes in response to the amount of potassium level, the Xushu082909is relatively poor, Jishu22is preferred varieties, Xushu28is second. For dry matter accumulation of seedling aboveground, dry matter accumulation on the upper portion of28Xushu is larger, dry matter accumulation on the middle and lower portion of Jishu22is larger. The influence of different soil types on seedling sweet potatoes total dry matter accumulation as follows:under the condition of K0, Huang Chao soil is more conducive to the accumulation of seedling sweet potatoes total dry matter; While under the condition of Kl, high sand is more conducive to the accumulation of seedling sweet potatoes total dry matter.(3) In seedling stage, potassium concentration of overground part (higher leaf, middle leaf, lower leaf, higher handle, middle handle, lower handle, higher stem, middle stem, lower stem) of Xushu No.28was more sensitive to the increase of potassium fertilizer compared to Jishu No.22, and the handle was especially obvious. Under the same condition of soil type and fertilizer amount, in seedling stage, potassium concentration of overground part of Xushu No.28was higher, while potassium concentration of root of Jishu No.22was higher. On the other hand, no matter in the yellow moisture soil or the high sandy soil, more potassium application could dramatically increased the potassium proportion in sweet potato root.(4) The potassium concentration of sweet potato in the vigorous, expand and harvest stage were different, in vigorous stage, potassium concentration of overground part of Jishu No.22was higher than Xushu No.28, potassium concentration of root part of Jishu No.22was higher in high sandy soil but lower than Xushu No.28in yellow moisture soil; in expand and harvest stage, potassium concentration of both overground part and root part of Jishu No.22was higher than Xushu No.28. The effects of soil types on potassium concentration of sweet potato could be concluded as:in vigorous and expand stage, there were no obvious effects of soil types on potassium concentration of sweet potato, but in harvest stage, yellow moisture soil was more beneficial for the increasing of potassium concentration of sweet potatoes, in comparison with high sandy soil.(5) The change laws of potassium content of sweet potato tended to bestable gradually in expand and harvest time. In expand stage, potassium content of overground part of Jishu No.22was higher than that of Xushu No.28; potassium content of root part of Jishu No.22was higher than that of Xushu No.28in yellow moisture soil but lower than that of Xushu28in high sandy soil. In harvest stage, potassium content of overground part of Jishu No.22was higher than that of Xushu No.28, while potassium content of root part of Xushu No.28was higher than that of Jishu No.22. The effects of soil types on potassium content of sweet potato could be concluded as:yellow moisture soil was more beneficial for the increasing of potassium content of overground part of sweet potatoes, while high sandy soil was more beneficial for the increasing of potassium content of root part of sweet potatoes.(6) Judging from the potassium content of root of sweet potato in harvest stage, Xushu No.28was the better sweet potato type and high sandy soil was the better cultivated soil type. |
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