三种冷地型草坪草地下部分对不同水分梯度的响应

Response of the Underground Biomass of Three Cold-season Turfgrass to diverse soil water gradients

对多年生黑麦草(Lolium perenneL.)、草地早熟禾(PoapratensisL.)和苇状羊茅(Festuca arundinaceaSchreb.)3种冷地型草坪草在30%50%田间持水量(FC)、50%70%FC、70%90%FC三个水分梯度下的地下生物量进行了田间测定。结果表明,土壤水分状况直接影响草坪草根系的生长与构形分布。不同水分处理下,3种草坪草的73.4%￣92.2%的根量分布在0￣10cm的土层中,5.1%16.8%的根量分布在10￣20cm的土层中,1.7%9.8%的根量分布在20￣30cm的土层中。水分梯度对根系的垂直空间分布有很大影响,在30%￣50%FC处理下,0￣10cm层根量占0￣30cm总根量的73.4%￣89.5%;50%￣70%FC处理下,0￣10cm层根量占79.5%￣91.6%;70%￣90%FC处理下,0￣10cm层根量占78.3%￣92.2%。10￣20cm、20￣30cm层根量比例随水分梯度的增加则逐渐减小。在30%50%FC、50%70%FC、70%90%FC3个水分梯度下,3种草坪草8,9,10三个月根量累积值(g/m2)依次为,多年生黑麦草:4209.5、3416.5、3906.5;草地早熟禾:3716.6、3452.9、3447.8;苇状羊茅:5281.0、5184.5、4317.7,苇状羊茅根量最大,草地早熟禾根量最小。

Underground biomass of perennial ryegrass, Kentucky bluegrass and tall rescue under different soil moisture gradients of 30%-50% field water capacity （FC） , 50%-70%FC and 70%-90%FC in the whole experimental period was measured in field conditions. The results showed that underground biomass allocation was significantly influenced by the water gradient. 73.4%-92.2% roots distributed within the top 10 cm soil layer. 5.1% -16.8% underground biomass distributed between 10 cm and 20 cm soil layer. From 20 cm to 30 cm soil layer , about 1.7% - 9.8% root quantum existed. The underground biomass of the tree cold-season turfgrass distributed downwards in low water gradient, and distributed upwards in high water gradient. When the soil moisture gradient was 30%-50% FC,underground-biomass perpendicular allocation ratio in the soil layer of the top 10 cm, between 10 cm and 20 cm and from 20 cm to 30 cm was 73.4% - 89.5%, 7.3% - 16.8%, 2.7% - 9.8% respectively. The moisture gradient was50%-70% FC, the ratio of each soil layer was 79.5% -91.6%, 6.6% - 13.6%, 1.7% -6.9% respectively. When the moisture gradient was 70%-90%FC, the ratio of every soil layer was 78.3% -92.2% , 5.1% - 14.2% , 2.0% -6.0%.The underground biomass accumulation of perennial ryegrass under the soil moisture gradients of 30%-50%, 50%-70%FC and 70%-90%FC were 4 209.5, 3 416.5, 3 906.5 gram from August to October. The accumulative quantum of Kentucky bluegrass and tall rescue from August to October were 3 716.6, 3 452.9, 3 447.8 gram and 5 281.0, 5 184.5, 4 317.7 gram. As for underground biomass, tall rescue is the most and Kentucky bluegrass is the least.