In order to examine the causes of degradation of Pinus sylvestris var. mongolica plantations on sandy land, the foliar concentrations of N, P, K and C were analyzed and compared between the field grown P. sylvestris v...In order to examine the causes of degradation of Pinus sylvestris var. mongolica plantations on sandy land, the foliar concentrations of N, P, K and C were analyzed and compared between the field grown P. sylvestris var. mongolica trees from two provenances （natural forests and plantations）. The results indicated that natural tree needles had lower N, P and C concentrations, and higher K concentrations than those of plantation tree needles. For plantation tree needles, ratios of N： P, P. K and N： K increased with tree age before 45 years old; but they were not clear for the natural tree needles. Compared with the conclusions reported on Pinus spp., we found that the foliar N and P concentrations were in the optimal range for both natural and plantation tree needles. This result suggested that N or P might not be the absolute limit factors in plant nutrient for P sylvestris var. mongolica on sandy land. However, foliar K concentrations in both natural and plantation tree needles were much lower than those reported on Pinus spp. （〉4.80 g kg-1）.The N： P ratio of natural needles was in the adequate ranges, but N： P ratio of plantation needles was out of the adequate ranges. These results indicated that there was a better balanced nutrition status in the natural forest than in the plantations. If only considering the foliar nutrient concentrations of P sylvestris var. mongolica from different provenances, it might be concluded that the degradation phenomenon of P. sylvestris var. mongolica plantations was not induced by nutrition deficiency of absolute nutrients of N and P, but might be induced by other mineral nutrients or by the effectiveness of N and P nutrients. The unbalanced nutrition status and relatively quick decomposition of needles in the plantations might also contribute to the degradation.展开更多
The biomass and net primary production of Mongolian scotch pine (Pinus sylvestris L. var mongolica) plantations of west Kerqin sandy land were measured. According to average standard trees, the biomass, netprimary pro...The biomass and net primary production of Mongolian scotch pine (Pinus sylvestris L. var mongolica) plantations of west Kerqin sandy land were measured. According to average standard trees, the biomass, netprimary production and their distributions of trunk, bark, branch, leaf and root of 16-year-old stand were analyzed.The regressive equation for the estimation of each organ biomass was established through djmensional analysis.Preferable equation with higher precision was selected. The study results showed that the total biomass of theforest community was 62.023 t/hm2 and net primary production was 5.045 V(hm2. a). which indicates that thecommunity of plantation possesses high bio-productivity.展开更多
为进一步探明陕西省榆林市樟子松人工林的土壤养分变化特征,以5年生樟子松(Pinus sylvestris L. var. mongolica Litv.)纯林和5年生樟子松-胡枝子(Lespedeza bicolor Turcz.)混交林为研究对象,分析土壤有机质、硝态氮、有效磷、速效钾...为进一步探明陕西省榆林市樟子松人工林的土壤养分变化特征,以5年生樟子松(Pinus sylvestris L. var. mongolica Litv.)纯林和5年生樟子松-胡枝子(Lespedeza bicolor Turcz.)混交林为研究对象,分析土壤有机质、硝态氮、有效磷、速效钾等理化指标以及土壤酶活性的变化特征。结果表明,樟子松纯林和樟子松-胡枝子混交林土壤有机质、有效磷和速效钾含量整体上均随着土层深度的增加呈下降趋势,全磷含量均随着土层深度的增加呈先升高后降低的趋势,硝态氮含量则均随着土壤深度的增加而增加,5个指标均表现为樟子松-胡枝子混交林高于樟子松纯林,且樟子松-胡枝子混交林各层土壤有效磷含量均显著高于樟子松纯林(P<0.05);樟子松纯林和樟子松-胡枝子混交林土壤含水率各土层间差异均不显著,樟子松-胡枝子混交林5~15 cm土层土壤含水率含量显著高于樟子松纯林(P<0.05);樟子松纯林和樟子松-胡枝子混交林土壤碱性磷酸酶活性、过氧化氢酶活性、脲酶活性均随着土层深度的增加而降低,且樟子松-胡枝子混交林过氧化氢酶活性和脲酶活性在各土层均显著高于樟子松纯林(P<0.05)。展开更多
The aim of this study was to investigate the role of rhizosphere organic phosphorus （P） in soil P supply in semiarid forests and the effects of tree species on rihizosphere organic P. We examined organic P fractions...The aim of this study was to investigate the role of rhizosphere organic phosphorus （P） in soil P supply in semiarid forests and the effects of tree species on rihizosphere organic P. We examined organic P fractions in rhizosphere and bulk soils of mono-specific Simon poplar （Populus simonii） and Mongolian pine （Pinus sylvestris var. mongolica） plantations in a semiarid sandy soil of Horqin Sandy Land in Northeast China. Total organic P （TPo） accounted for 76% of total P across the two stands. The concentration of organic P （Po） fractions decreased in the order of NaOH-Po〉Res-Po〉HCI-Po〉NaHCO3-Po in both plantations. The concentration of NaHCO3-Po was 38% and 43% lower in rhizosphere soil than in bulk soil in Simon poplar and Mongolian pine plantations, respectively. In contrast, total P, TPo and NaOH-Po significantly accumulated in rhizosphere soil in Simon poplar plantations, but no change in Mongolian pine plantations. Soil recalcitrant organic P fractions were positively correlated with soil organic carbon. The results suggest that rhizosphere labile organic P was an important source of plant-available P in this semiarid region, but the dynamic of rhizosphere recalcitrant organic P fractions varied with tree species and was correlated to organic carbon dynamics.展开更多
基金The research was supported by Innovation Research Project of Chinese Academy of Sciences (KZCX3-SW-418), and the 100 Young Researcher Project of Chinese Academy of Sciences.
文摘In order to examine the causes of degradation of Pinus sylvestris var. mongolica plantations on sandy land, the foliar concentrations of N, P, K and C were analyzed and compared between the field grown P. sylvestris var. mongolica trees from two provenances （natural forests and plantations）. The results indicated that natural tree needles had lower N, P and C concentrations, and higher K concentrations than those of plantation tree needles. For plantation tree needles, ratios of N： P, P. K and N： K increased with tree age before 45 years old; but they were not clear for the natural tree needles. Compared with the conclusions reported on Pinus spp., we found that the foliar N and P concentrations were in the optimal range for both natural and plantation tree needles. This result suggested that N or P might not be the absolute limit factors in plant nutrient for P sylvestris var. mongolica on sandy land. However, foliar K concentrations in both natural and plantation tree needles were much lower than those reported on Pinus spp. （〉4.80 g kg-1）.The N： P ratio of natural needles was in the adequate ranges, but N： P ratio of plantation needles was out of the adequate ranges. These results indicated that there was a better balanced nutrition status in the natural forest than in the plantations. If only considering the foliar nutrient concentrations of P sylvestris var. mongolica from different provenances, it might be concluded that the degradation phenomenon of P. sylvestris var. mongolica plantations was not induced by nutrition deficiency of absolute nutrients of N and P, but might be induced by other mineral nutrients or by the effectiveness of N and P nutrients. The unbalanced nutrition status and relatively quick decomposition of needles in the plantations might also contribute to the degradation.
文摘The biomass and net primary production of Mongolian scotch pine (Pinus sylvestris L. var mongolica) plantations of west Kerqin sandy land were measured. According to average standard trees, the biomass, netprimary production and their distributions of trunk, bark, branch, leaf and root of 16-year-old stand were analyzed.The regressive equation for the estimation of each organ biomass was established through djmensional analysis.Preferable equation with higher precision was selected. The study results showed that the total biomass of theforest community was 62.023 t/hm2 and net primary production was 5.045 V(hm2. a). which indicates that thecommunity of plantation possesses high bio-productivity.
文摘为进一步探明陕西省榆林市樟子松人工林的土壤养分变化特征,以5年生樟子松(Pinus sylvestris L. var. mongolica Litv.)纯林和5年生樟子松-胡枝子(Lespedeza bicolor Turcz.)混交林为研究对象,分析土壤有机质、硝态氮、有效磷、速效钾等理化指标以及土壤酶活性的变化特征。结果表明,樟子松纯林和樟子松-胡枝子混交林土壤有机质、有效磷和速效钾含量整体上均随着土层深度的增加呈下降趋势,全磷含量均随着土层深度的增加呈先升高后降低的趋势,硝态氮含量则均随着土壤深度的增加而增加,5个指标均表现为樟子松-胡枝子混交林高于樟子松纯林,且樟子松-胡枝子混交林各层土壤有效磷含量均显著高于樟子松纯林(P<0.05);樟子松纯林和樟子松-胡枝子混交林土壤含水率各土层间差异均不显著,樟子松-胡枝子混交林5~15 cm土层土壤含水率含量显著高于樟子松纯林(P<0.05);樟子松纯林和樟子松-胡枝子混交林土壤碱性磷酸酶活性、过氧化氢酶活性、脲酶活性均随着土层深度的增加而降低,且樟子松-胡枝子混交林过氧化氢酶活性和脲酶活性在各土层均显著高于樟子松纯林(P<0.05)。
基金funded by the National Natural Science Foundation of China (41373087, 30800887)the State Key Laboratory of Forest and Soil Ecology (LFSE2013-11)
文摘The aim of this study was to investigate the role of rhizosphere organic phosphorus （P） in soil P supply in semiarid forests and the effects of tree species on rihizosphere organic P. We examined organic P fractions in rhizosphere and bulk soils of mono-specific Simon poplar （Populus simonii） and Mongolian pine （Pinus sylvestris var. mongolica） plantations in a semiarid sandy soil of Horqin Sandy Land in Northeast China. Total organic P （TPo） accounted for 76% of total P across the two stands. The concentration of organic P （Po） fractions decreased in the order of NaOH-Po〉Res-Po〉HCI-Po〉NaHCO3-Po in both plantations. The concentration of NaHCO3-Po was 38% and 43% lower in rhizosphere soil than in bulk soil in Simon poplar and Mongolian pine plantations, respectively. In contrast, total P, TPo and NaOH-Po significantly accumulated in rhizosphere soil in Simon poplar plantations, but no change in Mongolian pine plantations. Soil recalcitrant organic P fractions were positively correlated with soil organic carbon. The results suggest that rhizosphere labile organic P was an important source of plant-available P in this semiarid region, but the dynamic of rhizosphere recalcitrant organic P fractions varied with tree species and was correlated to organic carbon dynamics.
