播种深度和种子来源对羊草种苗出土的影响

Effects of sowing depth and seed source on seedling emergence of Leymus chinensis

研究了5种播种深度下2种种子来源的羊草（野生和栽培）出苗情况。结果表明：播种深度和种子来源都显著影响羊草出苗率、出苗速率和种苗首次出土时间。羊草出苗率、出苗速率与播种深度成反比。播深1cm时出苗最多，野生和栽培羊草的出苗率分别为84％和91％；覆土2cm次之，分别为74．5％和84．5％；覆土6cm出苗最低，为33％和24．25％；不覆土与覆土1cm的相比分别下降了50．25％和45．25％。野生和栽培羊草的出苗速率分别由覆土1cm时的6．46和8．46下降到覆土6cm时的2．41和1．65。种苗首次出土时间随着播种深度的增加而延长，播种深度1～2cm时，两种羊草9～10d都可出苗；不覆土的处理种苗首次出土所需时间最长，分别需要21．25d和21d。总体上，栽培羊草的出苗率和出苗速率高于野生羊草的出苗率和出苗速率，栽培羊草首次出苗时间早于野生羊草。

In this paper, two seed sources （wild and cultivar） and five different sowing depths were used to study their effects on L. chinensis emergence. It may help to provide some practical management regimes for degraded grassland restoration and reconstruction. The results indicated that both the sowing depth and seed source had significant influence on L. chinensis seedling emergence （P 〈 0.01）, emergence rate and emergence time. The emergence percentage and rate declined as the sowing depth increased. The optimal sowing depth was 1 --2 cm for the two seed sources L. chinensis. The highest emergence percentage for wild and cultivar L. chinensis was 84% and 91%, respectively, at lcm sowing depth; the emergence percentage was the lowest to 6cm earth up, was 33% and 24.25%, respectively. The difference between them was 3-- 4 times. Both seeds of wild and cultivar L. chinensis could not emerge from sowing depth at 8cm. The highest emergence rate occurred at 1 cm depth, was 6.46 （wild） and 8.46 （cuhivar）, respectively; and the emergence rate was lowest at 6cm sowing depth （2.41, wild; 1.65, cultivar）. In general, the seedling emergence percentage and rate of cultivar＇s L. chinensis was higher than wild L. chinensis, while to 4--6 cm earth up, it got the contrary tendency. Too deep sowing depth or surface-sown delayed the first seedling emergence time. For the surface-sown treatment, the first emergence time was 21--21.25 d. However, at 1 --2 cm depth, the first emergence time was 9- 10d. Thus the control of sowing depth is critical in the restoration sites and, at times, may be more important than seed source.