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采用随机区组设计模拟氮硫复合沉降实验,以CO(NH2)2为氮源、Na2SO4为硫源,模拟试验1年后,分别采集不同氮硫沉降水平下杉木枝和叶的样品,研究杉木幼苗在不同沉降水平影响下的生长以及枝和叶营养元素氮、磷、钾、钙和镁含量的变化及其相关性.结果表明:经过1年不同沉降水平处理后,幼苗胸径和地径在不同处理间差异显著(P<0.05),均为促进作用,与对照相比,中氮低硫水平促进效果较佳;枝和叶中氮、磷和钾含量在不同处理间差异显著(P<0.05),钙和镁在不同处理间差异不显著(P>0.05);氮沉降源与叶氮、枝氮、叶磷含量相关关系极显著,相关系数分别为0.86、0.81、-0.78,与叶钾、枝镁含量呈显著负相关,相关系数分别为-0.64、-0.63;硫沉降源与叶磷(r=-0.62)含量呈显著负相关.叶中氮与磷、磷与钾、枝中氮和镁含量相关关系极显著,相关系数分别为-0.79、0.84、-0.91,叶中磷和镁、钾和镁以及枝中氮和磷、钾与钙含量呈显著相关,相关系数分别为0.65、0.70、-0.66、0.72,其他相关关系不显著.以上表明,中低氮硫沉降水平可有效提高杉木氮、磷、钾、钙、镁元素的含量.(图2表3参46)
A randomized block design was used to simulate nitrogen and sulfur composite settling experiments. CO (NH2) 2 was used as nitrogen source and Na2SO4 was used as sulfur source. One year after simulated experiment, samples of fir branches and leaves with different levels of nitrogen and sulfur were collected, The changes of seedling under the influence of different subsidence levels and the changes of nutrient elements N, P, K, Ca and Mg in the branches and leaves were studied.The results showed that after one year of different sedimentation levels, The differences among treatments were significant (P <0.05), which were all promoting effects. Compared with the control, the medium and low nitrogen levels promoted the effect better. The content of nitrogen, phosphorus and potassium in branches and leaves differed significantly among different treatments (P < 0.05). There was no significant difference in calcium and magnesium between different treatments (P> 0.05). The correlations between nitrogen deposition source and leaf nitrogen, branch nitrogen and leaf phosphorus content were significant (correlation coefficient 0.86,0.81, -0.78, Potassium and shoot magnesium contents were negatively correlated, the correlation coefficients were -0.64 and -0.63, respectively. There was a significant negative correlation between sulfur deposition source and leaf phosphorus content (r = -0.62) The correlation between nitrogen and magnesium content was significant, the correlation coefficients were -0.79, 0.84, -0.91, phosphorus and magnesium in leaves, The correlation coefficients of nitrogen, phosphorus, potassium and calcium in potassium and magnesium, and their branches were significantly correlated, the correlation coefficients were 0.65,0.70, -0.66 and 0.72, respectively, while the other correlations were not significant.The above showed that the medium and low levels of nitrogen and sulfur deposition can effectively improve Chinese fir Nitrogen, phosphorus, potassium, calcium, magnesium content (Figure 2 Table 3 Reference 46)