| In 2008, a two-factors splitting plot experiment was employed to study the effect of irrigated in winter on the soil water content of 0～60 cm soil layer, the change of readily available nutrient of soil; the effects of irrigated in winter or before transplanting and nitrogen coupling on the dynamic change of soil water content and the alkali-hydrolyzable nitrogen of 0～60 cm soil layer, and on the growth, yield, quality and the major economic characters of flue-cured tobacco.1 The effects of irrigated in winter on the soli water content and the contents of readily available nutrientThe irrigated in winter treatment increased the water content of 0～60cm soil layer significantly, and especially played an important role on the deep subsoil water content. At different time, the content of alkali-hydrolyzable nitrogen of 0～60 cm soil layer was lower than CK, but the contents of rapidly available phosphorus and rapidly available potassium were significant higher than CK.2 The effects of irrigated in winter or before transplanting and nitrogen coupling on the growth of flue-cured tobaccoDifferent irrigation treatments all increased the maximum leaf area, stem girth, plant height, available leaves and dry material accumulation of flue-cured tobacco, also promoted the early rapid growth and the growing development of the flue-cured tobacco. Under the range of nitrogen 30～75 kg·hm-2, the all botanic characters were increased with the increasing of nitrogen-applied amount. The result of interaction of irrigation and nitrogen-applied amount was that the irrigated in winter and before transplanting treatment under the nitrogen-applied amount 75 kg·hm-2 was best for the growing development of the flue-cured tobacco.3 The effects of irrigated in winter or before transplanting and nitrogen coupling on the soil water contentDuring the whole growing period, the soil water content of 0～60 cm soil layer of different irrigation treatments were all higher than CK, and that content of the irrigated in winter and before transplanting treatment was highest. The soil water content of 0～40 cm soil layer was increased slightly with the increasing of nitrogen-applied amount, and that content of 40～60 cm was influneced more slightly by the nitrogen-applied amount. The change disciplines of the soil water content of every layer of different treatments were similar, and the change of 40～60 cm soil layer was smooth.4 The effects of irrigated in winter or before transplanting and nitrogen coupling on the content of alkali-hydrolyzable nitrogen.Only irrigated in winter and before transplanting treatment increased the content of alkali-hydrolyzable nitrogen of 0～40 cm soil layer, but also did not have significantly effect on the 40～60 cm soil layer. The content of alkali-hydrolyzable nitrogen of 0～40 cm soil layer was increased with the increasing of nitrogen-applied amount, and that content of 40～60 cm soil layer was influneced slightly by the nitrogen-applied amount. The interaction effect of irrigation and nitrogen-applied amount on that content was not significant, and only irrigated in winter and before transplanting treatment at different nitrogen-applied amount levels increased that content. The change discipline of the content of alkali-hydrolyzable nitrogen of 0～40 cm soil layer was similar, and the tend was decreased at first, then increased and decreased at last. The change of 0～20 cm soil layer was the maximum, and 40～60 cm soil layer was the most smooth.5 The effects of irrigated in winter or before transplanting and nitrogen coupling on the contents of total nitrogen and nicotine during the whole growing periodThe contents of total nitrogen and nicotine all increased with the increasing of nitrogen-applied amount. The contents of total nitrogen of all irrigation treatments were slightly lower than CK, and that effect was significant at 52.5 and 75 kg·hm-2 nitrogen-applied amount. After transplanting 30d, the contents of nicotine of all irrigation treatments were significantly lower than CK. During the whole growing period, the contents of nicotine of all irrigation treatments were all higher than CK, and that content of irrigated in winter and before transplanting treatment was highest. The contents of total nitrogen of differernt treatments decreased with the plants growing, the contont of nicotine increased with the plants growing, and increased rapidly after removing the apex.6 The effects of irrigated in winter or before transplanting and nitrogen coupling on the quality of the flue-cured tobaccoCompared with CK, different irrigation treatments all increased the contents of N, P and K of different stalk positions. The irrigated in winter and before transplanting treatment had the highest N, P and K contents in different stalk positions, while the irrigated in winter treament had highest contents of N in cutter leaves. The contents of N, P and K all increased with the increasing of nitrogen-applied amount. The result of interaction effect of irrigation and nitrogen-applied amount was that the contents of N, P and K the irrigated in winter and before transplanting treatment at 75 kg·hm-2 nitrogen-applied amount were highest.As a whole, different irrigation treantments all decreased the contents of reducing sugar and total sugar in different stalk positions, and the irrigated in winter and before transplanting treatment had the most significantly effect on those contents. Different irrigation treantments did not have sigficant efffect on the contents of nicotine in upper leaves, and those contents in cutter leaves were all higher than CK; Those contents in lower leaves of the irrigated in winter and before transplanting treatment were slightly lower than CK, whlie those contents were all higher than CK. The contents of reducing sugar, total sugar and starch all decreased with the increasing of nitrogen-applied amount, while the contents of protein and nicotine all increased with the increasing of nitrogen-applied amount.Different irrigation treatments were all favorable for inreaseing the contents of aroma consitutents of phenylalanines, Maillard reaction products and carotenoids in upper and cutter leaves, and irrigated in winter treatment were best favorable for inreaseing those contents. The aroma consitutents of cembranenoids did not appeare a obvious discipline, and different irrigation treatments were not favorable for inreaseing that contents in upper and cutter leaves. Different irrigation treatments at 30 and 52.5 kg·hm-2 nitrogen-applied amount all increased the contents of neophytadiene and the total neutral aroma components. At 75 kg·hm-2 nitrogen-applied amount, only irrigated in winter treatment increased the content of neophytadiene, while only irrigated before transplanting treatment increased the total neutral aroma components.7 The effects of irrigated in winter or before transplanting and nitrogen coupling on the black shank of flue-cured tobaccoNitrogen-applied amount did not have significant influence on the disease rate and the disease index of the black shank. Different irrigation treatments all decreased the disease rate and the disease index of the black shank, and that effects of the irrigated in winter and before transplanting treatment was best.8 The effects of irrigated in winter or before transplanting and nitrogen coupling on the major economic characters of flue-cured tobacco Compared with CK, irrigated in winter treatment and irrigated before transplanting treatment at different nitrogen-applied amount were all favorable for inreaseing the yield, average price, output value and the ratio of mid-and high-grade leaves, while the irrigated in winter and before transplanting treatment at 52.5 and 75 kg·hm-2 nitrogen-applied amount decreased the ratio of mid-and high-grade leaves. Except the irrigated in winter and before transplanting treatment at 30 kg·hm-2 nitrogen-applied amount were best for increasing the major economic characters, others irrigation treatments at 52.5 kg·hm-2 nitrogen-applied amount were best for increasing the average price, output value and the ratio of mid-and high-grade leaves. |
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