With regards to high ratio of spikes to tillers and low ear weight in small-spike cultivars, nitrogen application at jointing stage increased grain number by decreasing aborted florets or ovaries.

• 针对多穗型品种在高产奈件下分蘖成稳率高、穗粗重较低的特点，采取在拔节期追氮的措施能有效减少小花、子房退化，达到穗粒数增加、粒重提高的效果；