Studies On Effects Of Fertilization Measures And Film-uncovering Times On The Growth And Physical And Chemical Properties Of Flue-cured Tobacco In Autumn Period Soil

In this paper we studied effects of different topdressing times, different ratios between base fertilizer and dressing and different film-uncovering time on the growth and physical and chemical properties of flue-cured tobacco autumn period soil, in order to find the suitable agronomic methods in Wenshan tobacco area, which provides vigorous scientific evidence on the tobacco productions. The main results are as follows:l.We use the local base and top dressing fertilizer method, with the total cases of topdressing unchanged, by dressing method 1 or 2 times,3 times, did some researches on effects of different topdressing times on the agronomic character sand physical and chemical properties of the flue-cured tobacco in autumn period soil. Results showed that with dressing times increased, the maximum leaf, and maximum width, stem girth, and strains height are significantly increased; except three treatments of single leaf weight have no significantly differences, other physical characters changes regularly; it can effective increase of tobacco opened tablets degrees, reduce the thickness of upper tobacco, and make tobacco more loose; also can reduce total nitrogen and nicotine content of upper leaves more obviously, improve total sugar and restore sugar content on each parts of tobacco, improve the potassium content of middle and lower leaves. It has a significant role to improve the leaf quality of upper and lower parts of tobacco, so the topdressing agronomic measures of 3 is recommended, it is more conducive to the growth and chemical substances accumulation of flue-cured tobacco, thus high quality tobacco produced.2. We use the local based dressing ratio (6:4) as CK, set different base fertilizer ratio (5:5,7:3,4:6) to study the effects of different ratios between base fertilizer and dressing on the growth and physical and chemical characters of the flue-cured tobacco in autumn period soil. Results showed that application of different ratio of base fertilizer and dressing between 30 days after the transplant and before capped, the agronomical makes little difference compared with the local routine (6:4).Different ratios between base fertilizer and dressing have great effects on chemical characters of the flue-cured tobacco in autumn period soil, among which nicotine content has particularly and regularly prominent. The nicotine content of base top dressing of 7:3 is lowest and it reduced with the increase of base fertilizer. The total nitrogen content of the upper and middle leaves of base fertilizer and dressing 7:3were significant levels (P<0.01), the lower leaves are also significant (P<0.01). The total sugar and reducing sugar content of upper and lower leaves of base fertilizer and dressing 7:3are significantly different compared to CK, reducing sugar content in middle leaves significantly but do not achieve very significant level. So we recommend fertilizer application for 70%and top dressing30%of the total amount, base fertilizer and dressing ratio 7:3 is the best, bearing in the increasing use of potassium fertilizer dosage to achieve co-ordination of water and fertilizer, in order to meet the development of the growing requirements on the uptake and utilization of fertilizers, thereby enhancing the yield and quality of tobacco.3.We use the plastic film after transplanting as CK, no plastic film and film-uncovering time differences of 30 days,40 days,60 days after transplanting as the treatments, studied on effects of different film-uncovering time on the growth and physical and chemical properties of the flue-cured tobacco in autumn period soil. There is a certain effect on agronomic and physics characters of flue-cured tobacco compared with the film-uncovering throughout the development phase, removed the plastic film after 40 days of film mulching, the maximum leaf length, the maximum leaf, stalk, leaf number of valid are larger than others, the plant height are also larger than treatments of plastic film and plastic film cover 30 days.Compared to that of film mulching whole time, the total nitrogen content of middle leaves of removed the plastic film after 40 days of film mulching are in a high level, it is lower than that of upper leaves and higher than that of lower leaves; film mulching has a positive promoting of absorption and accumulation of potassium; with the film-uncovering time goes, the nicotine content increases; removed the plastic film after 40 days of film mulching can have a good effect on the effective accumulation of sugar content, can also effectively promote the content of nitrogen, and potassium, and nicotine, and sugar, make these chemical components tend to coordination. So combines the local production situation of Wenshan tobacco area, we recommend the method of removing the plastic film after 40 days of film mulching, the internal quality of flue-cured tobacco are more compatible at the same time.