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作 者 ：鱼欢, 杨改河, 王之杰

期 刊 ：植物营养与肥料学报 2010年 16卷 2期 页码：266-273

关键词：施氮量；SPAD值；Dualex值；冠层叶绿素密度；冠层光合能力；产量；

Keywords:N application rate, SPAD reading, Dualex reading, canopy chlorophyll density, canopy photosynthetic capacity, corn grain yield,

摘 要 ：以加拿大魁北克地区推广的玉米品种Pioneer 38B84为材料，研究不同施氮量和基追比例对玉米最上一片全展开叶SPAD值、Dualex值、净光合速率（P_N）、叶面积指数（LAI）、地上部生物量、冠层叶绿素密度（SPAD×LAI）、冠层光合能力（P_N×LAI）以及产量的影响。试验设5个处理： N0（基0+追0）、N20+93 （基20 kg/hm²+追93 kg/hm²）、N45+68 （基45 kg/hm²+追68 kg/hm²）、N113 （基113 kg/hm²+追0）和SAT225［基225（播种时施氮45 kg/hm²，播种后10 d再沟施180 kg/hm²）+追0］，完全随机区组设计，重复4次，基本苗为79000 株/hm²。结果表明，追肥前，叶片SPAD值、P_N、LAI、地上部生物量、SPAD×LAI及P_N×LAI均随基肥氮量的增加而增加，Dualex值则降低。同等施氮量下，基肥配合追肥显著提高叶片SPAD值，而追肥对叶片Dualex值和P_N无显著影响。虽然基肥配合追肥处理的LAI、地上部生物量、SPAD×LAI、P_N×LAI在追肥后均显著低于氮肥一次性基施，但显著提高了玉米产量。基施氮肥20 kg/hm²与45 kg/hm²处理之间玉米产量无差异，但前者过早地表现出缺氮。总施氮量为 113 kg/hm²时，其 SPAD值、Dualex值、P_N、LAI、地上部生物量、SPAD×LAI以及P_N×LAI等指标在出苗后25～60 d与SAT225处理差异不显著，但产量却显著低于SAT225处理。本试验条件下，基肥量45 kg/hm²能较好地满足玉米前期生长，但总施氮量113 kg/hm²不能满足玉米全生育期的需求，需要进一步地评估适宜的施氮量。同等施氮量下，基肥配合追肥显著提高玉米产量； SPAD值和 Dualex值均与玉米植株氮含量显著相关，SPAD和 Dualex可以作为实时快速指导玉米追肥的有效工具。

Abstract:One year corn field experiment was conducted at a research farm of Agriculture and Agri-Food Canada, located in L‘Acadie, Quebec, Canada. The experiment was a completely randomized block design with five N treatments and four replications. The five N treatments received N 0, 20, 45, 113 and 225 kg/ha(N 45 kg/ha was applied at sowing, and N 180 kg/ha at 10 days after sowing), respectively, at sowing, and N 0, 93, 68, 0 and 0 kg/ha, respectively, at side-dressing, i.e. N0, N20+93, N45+68, N113, and SAT225. Corn density is 79000 plants/ha, and the cultivar is Pioneer 38B84. The results show that SPAD reading, P_N, LAI, aboveground dry biomass, canopy chlorophyll density (SPAD×LAI) and canopy photosynthetic capacity (P_N×LAI) are increased with basal N rates increasing before side-dressing, while Dualex reading is decreased. Compared to N113, SPAD readings in the N20+93 and N45+68 treatments are significantly increased. The split N applications have no significant influences on Dualex reading and P_N. The LAI, aboveground dry biomass, SPAD×LAI and P_N×LAI of N20+93 and N45+68 are significantly lower, but the grain yields are significantly higher than those of N113. There are no significant differences in corn grain yield between N20+93 and N45+68, however, the N deficiency is appeared earlier in N20+93 than in N45+68. No significant differences between N113, N20+93 or N45+68, on one hand, and SAT225, on the other hand, are observed in SPAD reading, Dualex reading, P_N, LAI, aboveground dry biomass, SPAD×LAI and P_N×LAI at 25-60 days after emergence, while corn grain yields of N113, N20+93 and N45+68 are significantly lower than that of SAT225. Split N application can significantly increase corn grain yield compared to only one application at sowing, and N45+68 is better than N20+93. Under our experimental condition, a total N application with N 113 kg/ha do not produce the same corn grain yield as SAT225. Both SPAD and Dualex readings show significant correlation with corn plant N concentration, and then can be used as an instant and non-destructive diagnostic tool for corn N status evaluation.

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