Interaction Of Potassium Application And Mulching On Potassium Use Efficiency And Yield, Quality Of Flue-cured Tobacco

The field experiment with two-factors split plot design was conducted, the mulching as main district, the potassium application as deputy district, to analyze and compare the effects of different treatments on K supply capacity of tobacco in the soil, agronomic characters, potassium use efficiency, physiological and biochemical indicators, yield and quality of flue-cured tobacco, the main results are as follows:1. The available K and slowly available K content in the soil had been showing a slow decline in the whole growth period, the slowly K and available K content under the straw and plastic mulching were lower than that of non-mulching. The soil available K and slowly available K increased as potassium application within a certain range. Blindly increasing potassium will lead to more potassium fertilizer converted into form of slow potassium.2. Effects of mulching on plant height, stalk perimeter and the largest leaf area reached a significant level in the various growth stages, the overall performance of the effects:plastic mulching> straw mulching> non-mulching. Effects of potassium levels on tobacco agronomic traits focused on the early growth stage.3. There had a significant effects of mulching on physiological characteristics of flue-cured tobacco. Before vigrous growth, the tobacco roots activity showed plastic mulching> straw mulching> non-mulching; straw mulching> plastic mulching> non-mulching after this stage; the NR activity of straw mulching and non-mulching firstly increased and then decreased from the flourishing to maturity and as bud period for a turning point. The plastic mulching treatment had been showing a downward trend. The SPAD value of plastic mulching reached to the maximum in prior to the bud stage, straw mulching reached to the maximum value at maturity. Mulching can increase the photosynthetic rate in early growth stage, and plastic mulching> straw mulching, but appeared as straw mulching> non-mulching> plastic mulching during the mature stage. The stomatal conductance and transpiration rate of straw mulching was higher than plastic mulching and non-mulching during the flourishing to maturity, plastic mulching was the worst performance.4. There had a significant effects of potassium application on physiological characteristics of flue-cured tobacco.With the increasing of potassium application the NR activity increased to the largest value dealing with 405 kg/hm2 (B3) in the early growth stage, there's no significant difference between three treatments in the medium-term,270 kg/hm2 (B2) treatment was larger in late, the roots activity, SPAD value, photosynthetic rate and stomatal conductance parameters from flourishing to maturity period were higher in moderate potassium level (270 kg/hm2), the transpiration rate was higher at potassium level (405 kg/hm2) in the maturity.5. In the same potassium level, stem potassium accumulation and the allocation ratio of stem potassium under the plastic mulching treatment had been higher than straw mulching and non-mulching in the whole growth period, but in the whole, the allocation ratio of leaf's K under the treatment had been less than the latter two, especially performance significantly in mature. Potassium accumulation in tobacco leaves and the allocation ratio of leaves potassium under the straw mulching treatment had been higher than plastic mulching and non-mulching in mature period, but stem K accumulation and allocation ratio of stem K under the treatment had been less than the latter two.Within a certain range, the appropriate amount potassium can increase the accumulation of potassium, but it would not increase the accumulation of potassium more than 270 kg/hm2, there may be reduced, especially in the performance significantly under plastic mulching.6. Under mulching treatment, k fertilizer utilization efficiency and total K accumulation were 17.51%～31.57% and 5.21%～12.60% higher than that of non-mulching. Intermediate or high potassium level can improve total K accumulation, but K fertilizer utilization efficiency, K utilization efficiency, K dry matter production efficiency and K economic efficiency reduced with the increase of potassium levels, When K fertilizer exceeded a certain amount, the more K fertilizer used, the greater the K fertilizer utilization efficiency rate of reduction.7. In a certain extent, mulching can increase the total sugar and reducing sugar content of flue-cured tobacco, reduced the total nitrogen content of upper leaves, potassium content of tobacco leaves was low in mulching conditions. The appropriate amount potassium can help increase the total sugar and reducing sugar content of flue-cured tobacco, especially under straw mulching. The total nitrogen and nicotine content reduced as the increase of potassium levels.8. The plastic mulching and straw mulching can improve a single leaf's weight, yield, percentage of superior tobacco leaves, output. It showed plastic mulching> straw mulching in terms of a single leaf's weight. It showed straw mulching> plastic mulching in terms of percentage of superior tobacco leaf and output. Potassium levels had little effect on a single leaf's weight and yield, but it's hepful for improving percentage of superior tobacco leaf and output to increase the appropriate amount potassium.