玉米水分生理指标对覆膜比例和灌水水平的响应

为优化玉米覆盖和灌溉制度并为其提供必要的理论依据,在河西绿洲灌区,通过田间试验研究玉米各生育时期内光合速率(P_n)、蒸腾速率(T_r)、气孔导度(G_s)、叶水势(W_p)等水分生理指标对覆膜比例(70%覆盖和100%覆盖)与灌水水平(低、中、高)的响应特征及其与籽粒产量的相互关系。结果表明,2种覆盖比例对玉米水分生理指标和籽粒产量的影响不显著,但灌水水平影响显著,两者的互作效应显著。70%覆盖条件下,中灌水水平处理玉米生育期平均P_n、G_s、叶片水分利用效率(WUE)较低灌水处理分别提高22.5%、21.1%和56.1%,较高灌水分处理别提高44.5%、4.5%和18.5%;生育期内平均T_r为高灌水水平最大,比中、低灌水水平分别增大21.1%和43.2%;生育期平均Wp则为中灌水水平最高,在大喇叭口期比低灌水提高19.6%,在灌浆期比高灌水提高12.1%。此外,70%覆盖结合中灌水处理的玉米籽粒产量最高,比相同覆膜比例下低、高灌水处理分别提高13.1%和9.1%,但收获指数较100%覆盖中灌水处理显著降低。玉米P_n、WUE及G_s与玉米籽粒产量呈极显著正相关(P0.01)。因而,70%覆盖结合中灌水水平能优化玉米生育期内各项水分生理指标,可作为该区玉米生产的推荐模式,从而实现节水与增产。

Response of Plastic Film Mulching Proportion and Irrigation Quotas on Water-physiological Indexes of Maize

In order to provide theoretical basis for improving plastic film mulching and irrigation in maize production,a field experiment was conducted in Hexi oasis irrigation area to investigate the response of plastic film mulching proportion and irrigation quotas to water-physiological indexes of maize,at the same time,the study aslo analyzed the relationship between various water-physiological indexes and maize grain yield.We compared two mulching proportions,i.e. 70% mulching and 100% mulching,with three irrigation levels i.e. low (L),medium (M) and high (H). The results showed that plastic film mulching proportion had no significant effect on water-physiological indexes and grain yield of maize. However,the irrigation quota had a significant effect. In addition,the interaction effect between mulching proportion and irrigation quota were also significant. Under various treatments,the one with 70% mulching and medium irrigation level had the highest average value of P_n,G_s and leaf WUE at whole growth period. Compared with low irrigation level,P_n,G_s and leaf WUE increased by 22.5%,21.1% and 56.1%,respectively. Similarly,the three water-physiological indexes were increased by 44.5%,4.5% and 18.5% compared with high irrigation level,respectively. Among the three irrigation levels,high irrigation had the highest average T_r value at the growth period,which increased by 21.1% and 43.2% compared with the medium and low irrigation. Whereas,medium irrigation had the highest values of average leaf water potential at the growth period,which increased by 19.6% at maize big-trumpet compared with low irrigation level,and by 12.1% at grain filling compared with high irrigation level. Furthermore,the treatment with 70% mulching and medium irrigation level also had the highest grain yield,which were improved by 13.1% and 9.1% compared with the low and high irrigation level. However,the harvest index decreased compared with the medium irrigation with 100% mulching. There was a significantly (P<0.01) positive correlation between P_n,leaf WUE and G_s relative to maize grain yield. Accordingly,the integration of 70% mulching with medium irrigation could optimize the water-physiological indexes,and could be recommended as an effective model for water-saving and increasing maize grain yield.