畦灌与保水剂配施对杨树根际土壤微环境特征及生长的影响

【目的】探讨畦灌与保水剂组合对杨树根际土壤微生态环境与生长的作用效果。 【方法】通过两年大田试验，研究了CK（常规畦灌）、BI₆₀（常规畦灌量60%）、BI₃₀（常规畦灌量30%）、BI₆₀S（60%常规畦灌量配施保水剂）和BI₃₀S（30%常规畦灌量配施保水剂）处理对欧美I-107杨树根际土壤中根系分泌物、理化特征、微生物数量及生长的影响。 【结果】同CK相比，BI₆₀S处理显著提高了根际土壤中根系分泌物含量，其中有机酸总量和氨基酸总量分别高出15.13%和9.23%；BI₆₀和BI₃₀处理导致根际土壤pH值显著升高，而BI₆₀S和BI₃₀S处理则使对应的pH值呈下降趋势，其中BI₆₀S处理分别比CK、BI₆₀、BI₃₀和BI₃₀S处理显著降低0.21、0.48、0.66和0.26个单位。BI₆₀S处理显著提高了根际土壤中速效氮、速效磷和速效钾含量，分别较CK提高16.72%、23.98%和20.11%；同时，BI₆₀和BI₃₀处理会导致中活性和低活性有机碳含量显著降低，而BI₆₀S和BI₃₀S处理能显著提高其活性。BI₆₀S处理亦能显著提高根际土壤细菌数，放线菌数，真菌数和微生物量碳、氮含量，其中细菌数分别较CK、BI₆₀、BI₃₀和BI₃₀S处理高出11.93%、62.74%、122.28%和16.33%。此外，该处理使欧美I-107杨林分的胸径、树高和材积平均生长率分别达到了25.37%、23.59%和64.06%，并显著高于其他处理。与BI₆₀S处理相比，BI₃₀S处理对杨树根际土壤和生长的影响效果不显著。 【结论】60%常规畦灌量配施保水剂更利于改善欧美I-107杨树根区微域的生态环境，有助于促进林分生长。

Effect of border irrigation co-applied with super absorbent polymers on micro-environment characteristics in the rhizosphere soil and growth of Populus euramericana cv.‘Neva’

Objectives] To explore effect of border irrigation co-applied with super absorbent polymers (SAP) on micro-ecological environment characteristics in the rhizosphere soil and growth ofPopulus euramericana cv.‘Neva’.Methods] A field experiment with five treatments,i.e.CK (conventional border irrigation),BI60 (60％ conventional border irrigation quantity),BI30 (30％ conventional border irrigation quantity),BI60S (60％ border irrigation quantity co-applied with SAP) and BI30S (30％ border irrigation quantity co-applied with SAP) was conducted to determine effects of different treatments on root exudate,physico-chemical characteristics,microbial population in the rhizosphere soil and growth ofPopulus euramericana cv.‘Neva’.Results] Compared with the CK treatment,the total organic acids and total amino acids in the root exudates in the BI60S treatment were significantly increased by 15.13％ and 9.23％,respectively.The BI60 and BI30 treatments obviously increased pH values in the rhizosphere soil,while the pH values appeared a decreasing trend in the treatments of BI60S and BI30S,and the pH values in the BI60S treatment were decreased by 0.21,0.48,0.66 and 0.26,respectively,compared with the treatments of CK,BI60,BI30 and BI30S.The contents of available nitrogen,available phosphate and available potassium were significantly increased by the BI60S treatment,showing 16.72％,23.98％ and 20.11％ increases compared with the CK treatment.The contents of moderate-labile organic carbon and low-labile organic carbon in the treatments of BI60 and BI30 were notably decreased,while the BI60S and BI30S treatments could apparently increase the corresponding contents.The BI60S treatment also significantly increased the populations of bacteria,actinomyces and fungi,and the contents of microbial biomass carbon and microbial biomass nitrogen,with 11.93％,62.74％,122.28％ and 16.33％ increases in bacterial population compared to the treatments of CK,BI60,BI30 and BI30S,respectively.Furthermore,the average growth rates of diameter at the breast height (DBH),tree height and volume in the BI60S treatment were 25.37％,23.59％ and 64.06％,respectively,which were also obviously higher than other treatments.However,in the BI30S treatment,fewer effects on rhizosphere soil and growth of poplar were observed compared with the BI60S treatment.Conclusions] The measure of 60％ border irrigation quantity co-applied with super absorbent polymers was more beneficial to improving ecological environment in the rhizosphere soil and promoting growth ofPopulus euramericana cv.‘Neva’.