干热河谷退化山地不同立地条件种植柱花草效应研究

Effects of Stylosanthes guianensis Plantations under Different Land Conditions in Dry-hot Valley of Yunnan Province

以云南省元谋干热河谷退化山地不同立地条件下种植的柱花草(Stylosanthes guianensis)为供试植物,研究柱花草的物候期、生长速率、生物量及覆盖效应。结果表明,在本区退化山地不同立地条件下,柱花草种植在台地及坡地均能完成其生长周期,有一定的生产力及覆盖效应。总体看,台地与坡地种植样地主要物候相差不大,台地由于保水作用强,能显著提高柱花草样地的整体生产力,草质好,柱花草的生物量、持水能力及生长量高于坡地。在改善小环境效应方面,台地和坡地柱花草种植样地由于作物覆盖地表,有效保持土壤水分,减少蒸发,在台地0～20 cm和任何立地20～40 cm土层土壤湿度均高于未种植样地,有利于柱花草抗旱及次年的萌发。同时,覆盖效应体现在能够自动调节种植样地地表温度,即在冬季保温方面,无论台地与坡地,植草样地在8:00a.m.和18:00p.m.土壤地表温度均比未种植样地高,有效地提高了土壤表层温度,有利于作物越冬;而在降温方面,台地与坡地上的植草样地在14:00p.m.土壤地表温度均比未种植样地低,有效降低土壤表层温度。从土壤容重看,在台地与坡地的样地上种植柱花草后的土壤容重均比种植前低,有效改善了土壤结构,提高土壤的透气透水性。种植柱花草样地由于固氮及枯枝落叶的腐烂与分解,土壤肥力得到了提高,且土壤微生物数量增多。

Stylosanthes guianensis was introduced to degraded mountain land in Dry-hot valley of Yuanmou County.Its major phonological periods,growth trend,biology and effects of cover in winter were studied in different land conditions.The results showed that S.guianensis could be planted in different land conditions and finish its major phonological periods.In addition,it had a good productivity and cover effect no matter in terrace or sloping field.The phonological periods in terrace and sloping field were similar.Because the water holding capacity was higher in terrace,biomass,rate of growth of S.guianensis and moisture of land surface in terrace were higher than in sloping field.Because the land surface was covered by these plants,evaporation was reduced.So it could be effective to keep moisture of land surface in terrace and sloping field.The soil moisture was higher than no-planted lands in 0~20 cm and 20~40 cm depth in both plantation conditions.It was helpful for S.guianensis to fight against drought and to re-grow in next year.In addition,S.guianensis could regulate ground temperature of plantation soil.The temperature in plantation soil was higher than no-planted soil at 8：00 a.m.and 18：00 p.m.It was helpful for S.guianensis to fight against a cold and survive through winter.Ground temperature of S.guianensis plantation was lower than no-planted soil at 14：00 p.m.and ground temperature of soil was decreased effectively by S.guianensis.Bulk density of soil planting S.guianensis was lower than before in both terrace and sloping field.The infiltration capability and configuration of planting soil were also improved.Soil fertility was increased in S.guianensis plantation due to nitrogen-fixed effect and litter decomposition.The microbial biomass was also increased.