| 4years field experiment was conducted to study differences in dry matteraccumulation (DMA) and the reason in five different rotation systems (rape-tobacco,fallow-tobacco, green manure-tobacco, barley-tobacco and wheat-tobacco) as K326variety for material, in Shilin county,2006～2007, Xundian county,2006～2007,2009～2010and2010～2011, Yunnan province. Meanwhile, in order to makeflue-cured tobacco more early growth, timely maturing, improve the yield and qualitycombination of the law of high-quality tobacco DMA to study effects of differentnutritional regulation measures of DMA of flue-cured tobacco in different precedingcrops, in Xundian county,2010～2011, in Songming and Luquan county,2012.4～2012.10. The results showed that:Different growth stage biomass, net of dry matter accumulation (NDMA), drymatter accumulation contribution rate(DMACR) and dry matter accumulationcumulative intensity(DMACI) were rotation of greenmanure-tobacco>fallow-tobacco>rape-tobacco> barley-tobacco and wheat-tobacco.Soil N supply sufficient were green manure-tobacco>fallow-tobacco>rape-tobacco>barley-tobacco and wheat-tobacco.Soil N supply sufficient with green manure-tobacco and fallow-tobacco, so thatabsorbed more nutrients, especially the last part of the growth nitrogen supply remainsbullish, DMA is more, vigorous growth, tobacco leaves were hard to maturing and fallyellow. Lesser N application when the preceding crops were green manure and fallow,especially green manure. Rape-tobacco DMA is relatively more in the middle of thegrowth, later relatively less, but soil nitrogen supply still more, should be less nitrogenfertilizer. Although the middle of the growth wheat and barley DMA is relatively small,timely maturing and fall yellow. Available potassium after harvest preceding crops, Kbalance in the soil too much to uptake of flue-cured tobacco, lesser application of Kwhen the preceding crop was wheat or barley, to ensure DMA consistent with the lawof high-quality flue-cured tobacco DMA. 91%,83%and75%of the total nitrogen amount conventionally recommendedwere applied to the tobacco plants when preceding crops were rape, fallow and greenmanure respectively, while for tobacco plants with barley and wheat as precedingcrops respectively, potassium were both supplied with90%of the recommended rate.The results showed compared with Conventional fertilization. After Nutritionalregulation dry matter accumulation regularity more in line with the law of high-qualitytobacco DMA. However, compared with conventional fertilization, fallow-tobaccorotation system was not good.Reducing fertilizer had no adverse effect on growth and maturity of tobaccoplants with rape, green manure, barley and wheat as preceding crops. Moreover, leafyield, economic value and profit were all higher in the treatments with reducingfertilizer than those with normal fertilization in four rotation systems, includingrape-tobacco, green manure-tobacco, barley-tobacco and wheat-tobacco. Leaf qualitywere all found better in treatments with reducing fertilizer in rape-tobacco, greenmanure-tobacco, barley-tobacco and wheat-tobacco rotation systems. From the abovedifferent preceding crops have consistent rule. However, for the tobacco plants infallow-tobacco rotation system, reducing fertilizer resulted into the poor growth andundesirable quality. Leaf yield, economic value and profit decreased respectively.Follow-tobacco in Songming and barley-tobacco in Luquan, made a furthervalidation of the nutrition regulation effect, in2012. The results showed thatbarley-tobacco and fallow-tobacco nutrition regulation effect is better, had no adverseeffect on growth of tobacco plants with follow as preceding crops. Its should berelative with different varieties,In conclusion, nitrogen fertilizer could be reduced25%and9%for the tobaccoplants compared with the normal fertilization rate in green manure-tobacco andrape-tobacco rotation systems, while for those in barley-tobacco and wheat-tobaccosystems, potassium could be supplied at90%of the recommended rate. For those infallow-tobacco rotation system, more research work is needed for the determination ofthe rational nitrogen amount. |
