黄河三角洲重盐碱地白刺造林技术的研究

Study on Planting Techniques of Nitraria sibirica in Yellow River Delta Region with Worst Salt-affected Soils

白刺是野生灌木,抗性强,能够在重盐碱地上生长;抗干旱,有很好的水土保持效果。选择白刺在黄河三角洲重盐碱地上进行了耐盐能力及其栽培技术的试验。结果表明白刺耐盐能力很强,在土壤含盐量达2 5%时,造林成活率仍可达90%以上,并具有明显的抑盐改土作用。整地能够提高白刺造林成活率,促进生长。造林成功的关键技术措施是在土壤含盐量0 6%以上的造林地上,以两耕两耙法进行整地,造林密度以1665～2505株/hm2为宜,在雨季进行容器苗栽植,控制杂草生长。不同种源的白刺造林结果表明,大义路种源表现最好。

In this experiment five Nitraria sibirica provenances such as Dayilu were selected to test their feature of salt-resistance, combining fixed plots with typical plot investigation, measuring survival rate and growth as main indicator. The experiments of main cultivation techniques were done on Nitraria sibirica in 4 types of site preparation, 3 types of planting, 3 designs for planting density. The Nitraria sibirica experiments for the effects of curbing salt and improving soil were conducted by testing soil nutrients, salt content, and soil physical properties as focal points in typical site of 3-or 4-year-old forests. The results shown that Nitraria sibirica could survive well at soil with salt content of 0.6%, survival rate declined distinctively as soil salt content exceeding 0.8%, high soil salt content did not influence growth in the year of planting. There were obvious differences on salt-tolerance among Nitraria sibirica provenances; the Dayilu was the best on salt-tolerance, the other four provenances had no differences, and obviously inferior to Dayilu. The thousand-fruit-weight of Dayilu (average 211.5 g) was higher than the other four Nitraria sibirica provenances (118～192 g). The different types of site preparation clearly influenced planting survival rate, conserving rate and growth. The method of two-ploughing-two-harrowing was the best among all four-site preparations. Direct seeding was largely limited, bare root seedling afforestation may be popularized when soil salt content was less than 1% and soil moisture content was optimum in spring. Afforestation with container seedling was suited in coastal saline soil in rain season. The best planting density of Nitraria sibirica was 2 505 hm^2 in Yellow River Delta area in view of effects on plant coverage, yield of fruits, and cost of forestation.