关键词: 土壤孔隙度, 土壤容重, 核桃, 间作, 农林复合系统, 小麦

Abstract: To explore the potential impacts of nitrogen deposition on lichen diversity in SnubNosed Monkey (Rhinopithecus roxellana) habitats in Shennongjia, an insitu experiment was conducted in a forest in Shennongjia Nature Reserve. Four common epiphytic lichens (Usnea longissima, Usnea betulina, Ramalina calicaris var. japonica and Parmotrema hypoleucinum) were collected, then soaked in solutions of KNO₃, NH₄NO₃, (NH₄)₂SO₄, or deionized water three times, for half an hour each time at 0, 24 and 48 h, respectively; then F_v/F_m, cell integrity (measured as solution electrical conductivity, RE) and chlorophyll OD₄₃₅/OD₄₁₅ were measured after 72 h, which are indexes indicating lichen sensitivity to nitrogen deposition. The results showed that higher nitrogen concentration led to a significant decrease of F_v/F_m and OD₄₃₅/OD₄₁₅ and a significant increase of RE. Furthermore, speciesspecific differences in sensitivity were found for different nitrogen types and different indications. Based on the response of F_v/F_m, U. longissima and U. betulina were more sensitive to KNO₃ than to NH₄SO₄ and NH₄NO₃, but R. calicaris var. japonica and P. hypoleucinum were more sensitive to (NH₄)₂SO₄ than to KNO₃ and NH₄NO₃. According to RE response to nitrogen treatment, U. longissim, U. betulina and P. hypoleucinum were most sensitive to (NH₄)₂SO₄, but there was no significant difference among responses of R. calicaris var. japonica to KNO₃, NH₄NO₃ and (NH₄)₂SO₄. As with OD₄₃₅/OD₄₁₅, U. longissim and P. hypoleucinum were more sensitive to (NH₄)₂SO₄ than to KNO₃ and NH₄NO₃, U. betulina was more sensitive to KNO₃ and (NH₄)₂SO₄ than to NH₄NO₃, but R. calicaris var. japonica was equally sensitive to the three nitrogen types. The results suggested that more attention should be paid to negative effects of nitrate deposition on habitats of SnubNosed Monkey at Shennongjia Nature Reserve, and further investigation on effects of nitrogen deposition on lichen biomass accumulation and nutrition components should be conducted to a perfect conservation of Sichuan SnubNosed Monkey.

Key words: wheat, soil porosity, intercropping, walnut tree, agroforestry system, soil bulk density