河西走廊几种盐化草地第一性生产力的研究I地上生物量与地下生物量季节动态及分配

The Primary Productivity of Saline Pastures in Hexi Corridor I The Seasonal Dynamics of Above and Underground Biomass

对河西走廊三种盐渍化草地生物量进行定位研究的结果表明：１）海韭菜草地、小灯心草草地和芦苇＋赖草草地上生物量变化均表现为单峰曲线，最大值均出现在７月上旬，其值分别为５４６．１２ｇ·ＤＭ／ｍ２，２６８．２６ｇ／ｍ２和１４０．９９ｇ．ＤＭ／ｍ２；三个草地当年地上部净生产力分别为５５９．０４ｇ．ＤＭ／ｍ２．ａ，２２６．８６ｇ．ＤＭ／ｍ２．ａ，８３．７４ｇ．ＤＭ／ｍ２．ａ．２）海韭菜草地地下生物量呈连续增长型，其最大值为７２２６ｇ．ＤＭ／ｍ２；灯心草草地和芦苇＋赖草草地地下生物量最大值于６月和７月出现，分别为４５３９．０ｇ．ＤＭ／ｍ２和１１２３．０ｇ．ＤＭ／ｍ２，三个草地的地下净初级生产力分别为３２５２．７２ｇ．ＤＭ／ｍ２．ａ，２３７７．０ｇ．ＤＭ／ｍ２．ａ和３７０．９ｇ，ＤＭ／ｍ２．ａ．３）地上部现有量最大时，上述草地地下生物量与地上生物量之比值分别为１２．００、１６．８７和７．４。根系发达，是这类草地的特点之一。

The seasonal changes of above and underground biomass were measured in the research site in Hexicorridor in 1992 and 1993.The results indicated that:1)The change of above-ground biomass showed amonopeak pattern during the growing season,and the maximum values were 546.12 g·DM/m2,268.26 g·DM/m2 and 140.99 g· DM/m2 for Trigolochin maritimun,Juncus bofonius and Phragmite communis+Leymusdasystachys respectively,which all appeared in early July;the net primary productivity was 559.04 g.DM/m2.a,26.86g.DM/m2.a and 83.74g.DM/m2.a respectively for above swards.2)The change ofunderground biomass for T.maritium Sward showed a successive increace and the maximum values are 72268,DM/m2,while J.bofonius and Phragmite communis+Leymus dasystachys swards present monopeak pattensand the maximum values were 4539 g·DM/m2 and 1123.0g.DM/m2 espectively,appearing in Jun andJuly.The net primary prod uctivity of underground biomass for above three swards was 32 5 2.729.DM/m2.a,2377.0g.DM/m2.a and 370.9g.DM/m2.a respectively.3)When above-ground biomassreaches to the peak,the ratio of under and above-ground biomass was 12,16.9,7.4 respectively for thereeswards.The flourishing root systems were the outstanding features of this type of pastures.