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试验在扬州市郊区沿江高沙土上进行。对少(免)耕小麦吸氮动态及生长动态进行数学模拟结果表明,江苏沿江地区扬麦5号小麦的吸氮速率最大期和生长速率最大期分别在叶龄余数2.7～0.2和孕穗末至始穗之间。乳熟以后,植株累积吸氮量常因氮素损失而减少,以致吸氮速率可能出现负值。吸氮速率最大期的累积氮量、全生育期的吸氮总量、生长速率最大期的累积生物量以及生长最大速率均与产量密切相关,其中生长速率最大期的累积生物量是小麦生长最重要的指标。拔节肥的作用主要在于减缓吸氮速率最大期以后吸氮速率的下降程度,防止早衰,以促使生长速率最大期的累积生物量能达到一定的高产指标。吸氮速率最大期的累积生物量与高产小麦同期累积生物量指标的差数,是确定拔节肥施氮量的主要依据之一。高产小麦吸氮速率最大期(叶龄余数2.1左右)是追施拔节肥的最适时期。
The experiment was carried out on the high sandy soil along the Yangzhou suburb. The results of mathematical simulation of nitrogen uptake and growth of less (free) tillage wheat showed that the maximum and maximum growth rates of nitrogen absorption rate of wheat in Yangmai 5 along the Yangtze River in Jiangsu Province were between 2.7 and 0.2, Between the beginning of the ear. After milking, the accumulated nitrogen uptake of plants often decreases due to the loss of nitrogen, so that the nitrogen uptake rate may be negative. The cumulative nitrogen uptake in the maximum period of nitrogen uptake, the total amount of uptake of nitrogen during the whole growth period, the cumulative biomass in the maximum growth period and the maximum growth rate were closely related to the yield. The cumulative biomass in the maximum growth period was the highest in wheat Important indicator. The main role of jointing fertilizer is to slow down the decline of nitrogen absorption rate after the maximum nitrogen absorption rate and to prevent premature aging so that the cumulative biomass of the maximum growth rate can reach a certain high yield index. The difference between the cumulative biomass at the maximum nitrogen absorption rate and the accumulated biomass at the same period of high-yield wheat was one of the main bases for determining the amount of nitrogen applied to jointing fertilizer. The maximum period of nitrogen absorption rate of high-yield wheat (leaf age remainder 2.1 or so) is the most suitable time for topdressing fertilizer.