两种类型中粳稻吸氮分析及施肥技术研究

The Analysis of Nitrogen Uptake and the Study on Fertilization Technique in Two Types of Japonica Rice

对4个中粳稻品种(包括多穗和大穗两个类型)吸氮规律研究表明:分蘖期多穗型品种吸氮量多于大穗型品种,而长穗期则少于大穗型品种;以氮的相对累积速卒(RARN)表示吸氮强度,4品种均为分蘖期吸氮强度最高,长穗期次之,灌浆结实期最低,大穗型品种各生育阶段吸氮强度均大于多穗型品种;群体总吸氮量与施氮量呈正相关,产量与群体总吸氮量呈二次曲线方程。本试验产量最高时(亩产稻谷500公斤左右)的群体总吸氮量为每亩11.6公斤,其中58—68％来自土壤本身的氮素。据两年结果,将水稻各生育时期土壤供氮量及相对应的植株累计吸氮量配合带常量(土壤基础肥力)的双曲线回归方程,得亩产450—500公斤稻谷的大田各时期土壤供氮指标,以此指标,可进行“补差施肥”。

Four cultivars of midseason japonica rice, which belong to multi-ear type or large-ear one, were studied on the law of nitrogen uptake and the fertilization technique. The results are as follows: At the tilling stage, the multi-ear type rice takes up more nitrogen than large-ear type rice does. On the contrary, at ear primordium stage, the nitrogen uptake of large-ear type was more than that of multi-ear type. For all the cultivars, at the tilling stage the relative accumulation rate of nitrogen(RARN), which is used to indicate the nitrogen uptake intensity, is the highest, and at the ear primordium stage the RARN ranks behind the previous one; at the grain filling stage it is the lowest. At each developmental stage, the nitrogen uptake intensity of large-ear type is higher than that of multi-ear type. It is suggested that the total nitrogen uptake of the plant is positively correlated with the fertilizer norm. The relationship between the yield and the total nitrogen uptake of the plant shows a quadratic equation curves. In this experiment, when the yield per mu was about 500kg, the total nitrogen uptake of the plant was 11.6kg per mu, 58-68 per cent of the nitrogen coming from the soil.