关键词: 春玉米, 栽培措施, 冠层结构, 干物质, 密植, 籽粒产量

Abstract:

【Objective】The objective of this study was to clarify the regulating effect of improved cultivation modes on canopy structure and population production of spring maize, and the contribution for grain yield increasing in the future.【Method】Maize cultivar “Zhongdan 909” was used as experimental materials, under 105 000 plants/hm² as planting density, setting four cultivation modes via the combination among different cultivation measures, which were subsoiling tillage (S), wide-narrow rows (W), and chemical regulator (C): (1) Traditional mode (rotary tillage 20 cm, plus 60 cm uniform plant spacing; RU), (2) Tillage improved mode (subsoiling tillage 35 cm, plus 60 cm uniform plant spacing; SU), (3) Canopy improved mode (traditional rotary tillage 20 cm, plus 80+40 cm plant spacing, and foliar spraying ECK; RWC), and (4) Synthetically improved mode (subsoiling tillage 35 cm, plus 80+40 cm plant spacing, and foliar spraying ECK; SWC). Investigated based on the differences of canopy continual sections (vertical), light distribution, photosynthesis, activity of the key sucrose synthetase enzyme, the dry matter accumulation, and grain fulling. 【Result】Compared with the traditional mode (RU; CK), the green leaf weight of tillage improved mode (SU) increased obviously, and the height and ear height of population reduced more than 30 cm under the canopy improved conditions (RWC and SWC), but the regularity degree of maize population were declined markedly; The leaves vertical distribution more uniformly, looked like “spindle type”, were the vertical height of 180-240 cm light interception and was significantly less than traditional mode (8%-37%), while the ear position (120-180 cm) was significantly higher than traditional mode (44%-129%); However, the leaves distribution of RU and SU treatments were more like “funnel type”, leaves were concentrated in the upper layer. Tillage and canopy improving synergistically could improve the canopy vertical structure significantly, promoted the chlorophyll content, net photosynthetic rate of leaves at ear position and under ear position, as well as enzyme activity own in the sucrose metabolic of ear position leaf. Maintaining the physiological activity of canopy leaves in the late growth stage, which would prolong the active accumulation period of dry matter more than 10 days. 【Conclusion】Synthetical improved mode (SWC) significantly increased the light transmission and C metabolic activity of leaves via changing the biomass spatial distribution, which promoted the canopy productivity of the functional leaves meanwhile the grain filling, then the grain yield were enhanced dramatically.

Key words: spring maize, cultivation measures, canopy structure, dry matter, high plant density, grain yield