| Due to excellent features and favorable properties, Forage-type annual ryegrass (Lolium multiflorum.Lam) has became one of the largest grass planting in the agricultural region. However, it has relatively weak resistance of saline-alkali. In view of this, this character limits the annual ryegrass introduction to the development of saline areas in China.The first study was conducted to evaluate the salt tolerance of 10 annual ryegrass by multipie statistics analysis at seed germination stage. The results showed that, more than 150mmol/L NaCl, seed germination had been greatly inhibited. We choose ten significant indicators which are classified into three categories by using cluster analysis. Salt tolerant groups includes Abundant and Common; intermediate groups includes Splendor, and sensitive groups includes the others.Next experiment in which 15N labeling technique was applying, mainly investigates dry matter accumulation, nitrogen accumulation and utilization of Abundant, Splendor, Guicao 1 under salt stress of NaCl. The results showed that salt stress inhibited dry matter and nitrogen accumulation. With the increasing nitrogen fertilizer, it can ease the symptoms of salt stress, improve dry matter and nitrogen accumulation. During early growth, nitrogen absorption is mainly dominated by fertilizer, opposite in the latter growth. At the 35th day after topdressing fertilizer, dry matter and nitrogen achieve the maximum accumulation in Abundant and Splendor, while Guicao 1 at the 21th day after topdressing fertilizer. With the increasing amount of nitrogen, the nitrogen form fertilizer is incresed and from siol is decreased, which utilization of fertilizer and soil show the opposite way. Fertilizer nitrogen accumulation from topdressing was increased, reducing the amount of basal fertilizer. Comprehensive consideration of yield, nitrogen utilization, adjusting the proportion of topdressing and basal dressing, the amount of nitrogen available for production can refer to 240kg/hm2. |
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