白羊草与达乌里胡枝子混播草地不同降雨年份土壤水分利用状况

为合理利用黄土丘陵区优良乡土草种,探索人工草地建设中乡土草种的最佳混播比例,选取白羊草(Bothriochloa ischaemum)和达乌里胡枝子(Lespedeza davurica)为研究材料,采用生态替代法,按照白羊草与达乌里胡枝子行比设置了7种组合比例(即0∶10,2∶8,4∶6,5∶5,6∶4,8∶2和10∶0),比较研究了丰水年(2011年,降雨量663.4mm)与偏旱年(2012年,降雨量458.2mm)混播草地土壤水分季节变化特征、年度生物量和水分利用效率。结果表明,白羊草与达乌里胡枝子混播草地土壤水分消耗和补充与混播比例密切相关,但主要受年度降雨量及其季节分配的影响。在2011年,充沛的降雨可补充20—260cm土层土壤水分,并弱化了不同混播比例和土层间土壤水分的时空差异。不同降雨量年份里,白羊草和达乌里胡枝子在6∶4与8∶2两混播比例下的地上生物量和水分利用效率均显著较高。

Soil Water Use of Bothriochloa Ischaemum and Lespedeza Davurica Mixture Grassland in Two Years with Different Rainfall Amounts

To rationally use native species in the loess hilly-gully region and find appropriate mixture ratio of native species for artificial grassland construction, Bothriochloa ischaemum and Lespedeza davurica were sowed by the seven row ratios of 0:10, 2:8, 4:6, 5:5, 6:4, 8:2 and 10:0 in a terraced field. The seasonal soil moisture characteristics, yearly aboveground biomass and water use efficiency were investigated and compared in two years with different rainfall amounts(663.4 mm in 2011 and 458.2 mm in 2012). Results indicated that soil water consumption and replenishment were closely related with the mixture ratio of the two species in the mixture grassland, mainly affected by yearly rainfall amount and seasonal distribution. In 2011, soil water supplement reached the 20-260 cm soil layer, and the spatial and temporal difference of soil moisture between mixture ratios and soil layers were reduced because of plentiful rainfall in the rainy season. Both in 2011 and 2012, Bothriochloa ischaemum and Lespedeza davurica mixtures at 6:4 and 8:2 ratios had higher aboveground biomass production and water use efficiency.