创造适合郁金香正常生长的栽培环境，尽量延长生长期，可提高郁金香切花品质及产生新球的数量和质量。
By providing appropriate cultivation and by prolonging the vegetative period to the greatest extent, the quality of cut flowers can be improved, and the number of new seed bulbs can be increased.
结果表明，这些牧草的越冬率均接近100%，抗寒性很强，适应性随栽培年限延长而提高。
The results showed that the over-wintering rate of these three forages were all about 100 percent, the resistance to cold were very well and adaptability increased with prolonging of cultivated time.
随着地膜覆盖栽培年限的延长，由于残膜回收率低，土壤中残膜量逐步增加，造成地膜污染。
Along with mulching fixed number years lengthening, because of remains film recovery rate is low, the amount of remains film in the soil progressively increase and cause film pollution.
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