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为探明玉米超高产(≥13 500kg.hm-2)群体在本地的形成规律,以苏玉20为试材,通过不同的施氮水平及3:6:1的基肥、穗肥、粒肥施氮方案的试验,实现籽粒最高产量15 663.4kg.hm-2的目标。苏玉20超高产群体形成的规律为:促开花期有较大的LAI(达到7.0以上),并减缓灌浆期LAI下降速率,同时提高粒叶比;加大吐丝期干物质积累量和灌浆前期干物质积累速率,以促使整个生育期内总干物质积累量达到30 000kg.hm-2以上;减缓灌浆期净光合速率下降到40%以下。精确施氮可有效调节超高产群体质量,增加总粒数,进而提高产量。苏玉20籽粒产量(y)与施氮量(x)的关系为y=-0.472 1x2+430.79x-83 670(R2=0.985 6),其最佳施氮量、超高产施氮范围分别为456.2、407.9～504.6kg.hm-2。
In order to find out the local formation law of super-high-yielding maize (≥13 500kg.hm-2) population, Suyu 20 was used as test material, with different N application rates and 3: 6: 1 basal, Nitrogen program to achieve the highest grain yield of 15 663.4kg.hm-2 goal. Suyu 20 super-high-yield population formation law is: to promote flowering a larger LAI (up to 7.0 above), and slow down the grain filling rate of LAI, while increasing grain-leaf ratio; increase silt dry matter accumulation and grouting The accumulation rate of dry matter in the early stage will promote the accumulation of total dry matter over 30 000kg.hm-2 in the whole growth period, and decrease the net photosynthetic rate below 40% in the filling stage. Accurate nitrogen application can effectively regulate the quality of super-high-yielding population, increase the total number of grains, and then increase the yield. The relationship between grain yield (y) and nitrogen application rate (x) in Suyu 20 was y = -0.472 1x2 + 430.79x-83 670 (R2 = 0.985 6) 456.2, 407.9 to 504.6 kg.hm-2.