尿素及EDTA-铁对延长结缕草青绿期的影响

为了研究结缕草青绿期短的问题，旨在延长结缕草草坪使用期，在盆钵试验条件下，采用双因素随机区组试验设计，研究不同尿素浓度(0、5、10、15 g/L)和不同EDTA-铁浓度(0、20、60、100 mg/L)对结缕草叶绿素含量和可溶性糖含量的影响。在田间试验条件下，采用随机区组试验设计，研究不同施肥间隔（不施肥，每周施肥1次，每2周施肥1次，每3周施肥1次）对结缕草青绿期的影响。结果表明，最佳施肥浓度为尿素10 g/L、EDTA-铁60 mg/L。秋季叶面施肥1周1次，用量1 L/m2延绿的效果最佳，时间最长，比对照处理延长了14天。结缕草叶片电导率和根活力均弱于对照组，说明用以上浓度的尿素与EDTA-铁对结缕草进行处理，在一定程度上降低了结缕草的抗寒性。越冬后仍不能消除这种负面影响。因此，为在延长结缕草青绿期的同时，适当提高结缕草的抗寒性，可配合磷肥、钾肥的施加。

Effects of Urea and EDTA-Fe on Prolonging the Green Period of Zoysia japonica

This experiment is aimed at mitigating the problem of the short green period of Zoysia japonica and extending its green period. In greenhouse experiment, two-factor randomized block design was utilized to research on the influence of different concentrations of urea （0, 5, 10, 15 g/L） and EDTA-Fe （0, 20, 60, 100 mg/L） on the soluble sugar and chlorophyll contents of Zoysia japonica. The field experiment focused on the effect of different application intervals （non-fertilized, fertilized weekly, fertilized biweekly, fertilized triweekly） upon the green period of Zoysia japonica by randomized block design. The result indicated that the best concentrations of fertilizer applications were： 10 g/L for urea and 60 mg/L for EDTA-Fe. The best concentration and frequency of fertilizer application on leaf blades in the fall to extend the green period was 1 L/m2 and once per week, which could prolong 14 days comparing to the check. The electroconductibility and root vigor of the blades were both weaker than those of the cheek, which showed that the cold resistance of Zoysia japonica could be reduced in some way after being applied with urea and EDTA-Fe in the concentration and frequency above. Such undesired effect could not be eliminated after the winter period yet. Consequently, to prolong the green period of Zoysia japonica, meanwhile, to increase its cold resistance properly, phosphorus and potassic fertilizers could be applied as cooperation.