荒漠河岸林胡杨养分状况研究

Status of Foliar Nutrients in Populus euphratica Desert Riparian Forest in Northwestern China

对荒漠河岸林胡杨叶片有机碳（C）、全氮（N）、全磷（P）和全钾（K）等化学组分在生长季不同月份和不同微生境间的变化以及它们彼此间的相关性进行了研究。结果表明,胡杨叶片C,N,P和K的变化范围分别为39.08%~46.16%,0.28%~2.81%,0.05%~0.18%和0.35%~2.03%,平均值依次为43.51%,1.49%,0.102%和1.17%。叶片C/N,C/P和N/P的变化范围分别为16.26~146.61,258.08~908.67和2.89~26.67,平均值依次是37.24,466.27和15.14。叶片平均N含量显著低于全国落叶树平均N含量,P含量与全国落叶树的平均P含量较为接近。胡杨叶片C/N明显高于全球陆生植物的C/N比值;N/P比值说明胡杨生长受到氮和磷元素的共同限制。在生长季,胡杨叶片C、N、P和K含量总体表现为下降趋势,最高值出现在5月,最低值出现在9月;微生境间,C,N,K含量和N/P比值从河岸低地,河岸平地,河岸沙堆,戈壁到沙丘间逐渐升高;C/N趋势恰好相反,P含量没有太明显的变化。叶片C含量与N、K含量均呈极显著正相关,与P含量呈弱正相关,N-K和P-K均呈显著正相关。

Contents of chemical constituents,namely organic carbon（C）,total nitrogen（N）,total phosphorus（P）,total potassium（K）,of Populus euphratica desert riparian forest in Ejina oasis of northwestern China were compared among different months in growing season and different micro-habitats,and the correlations among the chemical constituents were studied.Results showed that the ranges of C,N,P,and K contents in the leaves of P.euphratica were 39.08%~46.16%,0.28%~2.81%,0.05%~0.18%,and 0.35%~2.03%,and the mean values were 43.51%,1.49%,0.102% and 1.17%,respectively.The ratios of C/N,C/P and N/P varied from 16.26 to 146.61,from 258.08 to 908.67,and from 2.89 to 26.67,respectively,and the mean values were 37.24,466.27 and 15.14,respectively.The mean N content in the leaves of P.euphratica was significantly lower than N content in deciduous tree in China,but their mean P contents were similar.The ratio of C/N in the leaves of P.euphratica was remarkably higher than that of terrestrial plants.The ratio of N/P indicated that growth of P.euphratica was jointly limited by N and P nutrimental deficiency.The total content of leaf C,N,P,and K descended during growth season,and the maximum value appeared in May,the minimum appeared in September.The contents of C,N and K,and the ratio of N/P gradually increased from riparian lowland,flatland,sandpile,Gobi to dune,but the spatial pattern of C/N was opposite,and there was not significant spatial variation for P content.There were extremely significantly positive correlations between C content and N,K contents,respectively,and weakly positive correlation between C content and P content.The relationships of N and P with K were both significantly positive.