【作者】 李静；

【导师】 张锡洲； 李廷轩；

【作者基本信息】 四川农业大学 ， 植物营养学， 2014， 硕士

【摘要】 烤烟是重要的经济作物之一,烟叶的产量、品质以及生产投入决定着烟草生产的经济效益。钾是烟草的重要品质元素,含钾量不仅对烟叶的可燃性有明显作用,而且影响烟草的其它品质性状。烟叶含钾量低一直困扰着我国烟草生产,成为我国生产优质烟叶的主要限制因素之一。因此,研究植烟土壤钾素形态转化特征和烤烟钾吸收分配规律对提高我国烟叶含钾量及其品质具有重要的意义。本研究针对四川烤烟种植规模最大的凉山州植烟区,选取当地主栽烤烟品种云烟87和云烟85,通过土培试验与田间试验系统研究了烟草钾素吸收、积累和分配特性,以及植烟土壤中钾素的形态转化特征,从而提出最佳钾肥施用量、施用时期和基追肥比例,为烟草钾肥的合理施用提供科学依据。主要结果如下：(1)植烟土壤中速效钾和缓效钾含量及其占全钾含量的比例均随钾肥用量的增加而增大。增施钾肥增加了土壤可利用钾素的供应量,但过量施用钾肥,不利于钾肥利用率的提高。当钾肥用量超过180 kg hm-2时,施入土壤中的钾肥盈余量较高,烤烟采收后土壤的速效钾和缓效钾含量均高于植烟前。盆栽试验条件下,施钾270 mgkg-1时云烟85采收后土壤的速效钾和缓效钾含量分别比植烟前提高了52.4%和81.3%,钾肥利用率在烤烟的三个烟叶成熟期分别比施钾180mg kg-1时降低了3.1、8.0和4.9个百分点。大田试验条件下,施钾360kg hm-2时云烟85采收后表层土壤的速效钾和缓效钾含量分别比植烟前提高了77.2%和78.9%。(2)烤烟的产量、含钾量、钾积累量和钾分配率均随钾肥用量的增加先升高后降低。当钾肥用量为158 kg hm-2(约为常规用量的75%)时,云烟85的烟叶产量(2238.2kghm-2)与最高产量(2239.1 kg hm-2)、钾积累量(52.16 kg hm-2)与最高钾积累量(53.47 kg hm-2)之间差异较小。在土壤速效钾含量处于丰富(≥200mg kg-1)或以上水平时,降低25%左右的钾肥用量可提高种植云烟85的经济效益。(3)随烤烟移栽后天数的延长,云烟85的钾积累量在现蕾(移栽后65 d)和中部叶成熟(移栽后95 d)时出现峰值,钾积累速率的变化呈双峰曲线,旺长后期(移栽后50-65 d)和中部叶成熟期(移栽后85-95 d)为钾积累高峰期。钾肥追施时期调整至钾积累高峰期之前,有望提高成熟期烟叶的含钾量。(4)钾肥施用总量158kghm-2条件下,烤烟进入旺长后期(移栽后55 d左右)和中部叶成熟期(移栽后80 d左右)之前,分别追施钾肥总量的15%～20%,打顶后烟叶钾积累量的降低比例在5 d和10 d内分别比常规施肥减少了37.2～42.0和15.4～60.3个百分点；成熟期中、上部烟叶的含钾量显著增大,分别达3.21%和3.37%；施入土壤中钾肥的利用率比常规施肥提高了12～18个百分点。表明在烤烟进入钾积累高峰期之前追施钾肥,能有效减少打顶后烟叶钾素外溢,提高成熟期的烟叶含钾量和钾肥利用率,以达到优质高产目的。更多还原

【Abstract】 As the important economic crop, the economic benefit of flue-cured tobacco is determined by tobacco leaf yield, quality and production input. The quality elements of tobacco is K, not only combustibility is good, the other quality indicators are more appropriate when the K content is high in tobacco leaf. But K content in tobacco leaf is generally low in China. Therefore, in order to improve K content and quality of tobacco leaf in our country, the characteristics of K transformation in soil, the lows of K uptake and distribution in tobacco were studied. According to the largest flue-cured tobacco area Liangshan prefecture in Sichuan, the main flue-cured tobacco cultivars yunyan85 and yunyan87 were used in the soil culture and field experiment. The characteristics of K absorption, K accumulation, K distribution in tobacco and the characteristics of K transformation in tobacco soil were studied to proposes a relatively optimal K application rate, time and ratio of basal and topdressing. Provide a theoretical basis for rational fertilization. The main results are as follows:(1)The content and proportion in total K content of available and slowly available K in tobacco soil were increasedas the K. application rate increased. K supplying enhanced when increased K application rate, but the excessive application of K goes against the increase of K using efficiency. When the K application rate was exceed 180 kg ha-1, available and slowly available K content in the soil after planting were higher than preplant soil. Especially the soil planted yunyan85. In the pot culture experiment with the K application 270 mg kg-1, available and slowly available K content in the soil after planting were 52.4% and 81.3% higher than preplant soil, and the K using efficiency in the three maturities were decreased 3.1,8.0 and 4.9 percent point when compared with the K application 180 mg kg-1. In the field experiment, available and slowly available K content in the soil after planting were 77.2% and 78.9% higher than preplant surface soil under the K application 360 kg ha-1.(2) The yield, K content, K accumulation and K distribution rate of flue-cured tobacco were all increased at the first, and then decreased with the increase of K application rate. The yield (2238.2 kg ha-1) and K accumulation rate (52.16 kg ha-1) were equivalent to the highest yield (2239.1 kg ha-1) and K accumulation (53.47 kg ha-1) of tobacco leaf when the K application rate was 158 kg ha-1 (About 75% of the conventional K rate). When the available K content of soil is rich (=200 mg kg-1) or above level, decrease the appropriate K application rate can improve the economic benefits of plant yunyan 85.(3) The peaks of K accumulation for yunyan85 were appeared when the flower budded (65 days after transplanting) and middle leaf matured (95 days after transplanting). The change of K accumulation rateshowed a double-peak curve with the extension of days after transplanting, peak periods were in the later vigorous growth stage (85-95 days after transplanting) and middle leaf maturity (85-95 days after transplanting). Adjust the period of K topdressing to the peak of K accumulation rate can increase the K content of tobacco leaf.(4) When the total K application was 158 kg ha-1, the method of K topdressing stage was before the later vigorous growth stage (85-95 days after transplanting) and middle leaf maturity (85-95 days after transplanting), each stage used 15%-20% K fertilizer of total K application rate, the reduced proportion of K accumulation in tobacco leaf were 37.2-42.0 and 15.4-60.3 percent point within 5 days and 10 days after topping when compared with conventional fertilization. K content of middle and upper leaf has reached 3.21% and 3.37%. K using efficiency has increased 12-18 percent point. It shows that applied K fertilizer before the peak of K accumulation rate for flue-cured tobacco could shut down the spillover rate, increase K content of tobacco leaf and K using efficiency.更多还原