引用本文:于星辰,刘 倩,李春杰,朱 平,李海港,张福锁.根际过程和高底物浓度促进黑土有机磷矿化[J].土壤学报,2019,56(4):953-963.
YU Xingchen,LIU Qian,LI Chunjie,ZHU Ping,LI Haigang,ZHANG Fusuo.Rhizospheric Processes and High Substrate Concentration Stimulating Mineralization of Soil Organic P in Black Earth[J].Acta Pedologica Sinica,2019,56(4):953-963
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根际过程和高底物浓度促进黑土有机磷矿化
于星辰1, 刘 倩1, 李春杰1, 朱 平2, 李海港1, 张福锁1
1.中国农业大学资源与环境学院/植物-土壤相互作用教育部重点实验室;2.吉林省农业科学院农业资源与环境研究所
摘要:
土壤有机磷是植物吸收磷素的重要来源之一。大量研究表明,植物根际过程能够促进土壤有机磷矿化,提高土壤有机磷的生物有效性。以高有机质含量的黑土为研究对象,通过温室根垫培养和大田原位测定相结合的方法,旨在揭示玉米和蚕豆根际过程和土壤有机磷浓度对有机磷矿化的影响。结果表明:温室条件下,不施肥(CK)处理的蚕豆根际pH未变化,玉米根际pH上升了0.09个单位;施氮磷钾肥和有机肥(NPKM)处理的蚕豆根际酸性磷酸酶活性较玉米高93.4%;CK处理的玉米、蚕豆根际土与空白土(相同装置下不种作物的土壤)有机磷含量无差异,NPKM处理有机磷在玉米和蚕豆根际分别耗竭了138和86 mg·kg-1。根际有机磷浓度是驱动有机磷矿化的主要因素。田间玉米的根际pH与非根际相比下降了0.3~0.51个单位,酸性磷酸酶活性提高了10倍以上,施肥处理的根际苹果酸分泌量较不施肥处理高357%;根际过程与有机磷浓度可能共同调控了根际有机磷的矿化过程。因此,构建土壤高有机磷库,选择高效利用有机磷的作物品种,是维持黑土供磷能力、实现减磷增效的措施之一。
关键词:  玉米  蚕豆  根际pH  酸性磷酸酶  有机酸  有机磷矿化
DOI:10.11766/trxb201808280389
分类号:
基金项目:国家重点研发计划项目(2017YFD0200200,2017YFD0200202)资助
Rhizospheric Processes and High Substrate Concentration Stimulating Mineralization of Soil Organic P in Black Earth
YU Xingchen1, LIU Qian1, LI Chunjie1, ZHU Ping2, LI Haigang1, ZHANG Fusuo1
1.College of Resources and Environment Sciences/ Key Laboratory of Plant-Soil Interactions, MOE, China Agricultural University;2.Institute of Agricultural Resources and Environment, Jilin Academy of Agricultural Sciences
Abstract:
【Objective】 Soil organic phosphorus (P) is one of the important P sources for plants. A large number of studies have shown that rhizospheric processes improves bioavailability of soil organic P through stimulating mineralization of soil organic matter. 【Method】 In the present study, investigation were made of contributions of the rhizospheric processes of maize and faba bean to mineralization of soil organic P through an experiment combining root mat culture in greenhouse and in-situ measurement in the field, and exploration done of effect of soil organic P concentration on organic P mineralization in black soil, which is high in organic matter concentration. 【Result】No big differences were observed in dry weights of shoot and root of the maize and faba bean in greenhouse between low P (CK) and high P treatments (NPKM); Root/shoot ratio of the maize reached 0.25 in either treatment, and was 0.08 higher than that of the faba bean in CK and 0.07 higher in NPKM. Fertilization did not affect much P concentrations in shoot and root of the maize, and neither in shoot of ther faba bean. However, it did increase P concentration in root in the faba bean in NPKM by 57.6% as compared with CK. Rhizosphere pH of the maize in CK was 0.09 higher than the pH in bulk soil, and rhizosphere pH of the faba bean in NPKM was 0.11 higher than the pH in bulk soil and 0.09 higher than that of the maize. Acid phosphatase (APase) activity in rhizoshpere of the maize was significantly higher in CK than in bulk soil. No significant difference was observed in APase activity between rhizosphere and bulk soil. APase activity in rhizoshpere of the faba bean was 93.4% higher than that of the maize in NPKM. Soil organic P concentration in CK varied in the range of 214 mg·kg-1 ~ 218 mg·kg-1, and was 103%~171% lower than that in NPKM. Organic P in rhizosphere was depleted by crops in NPKM and by 138 and 86 mg·kg-1 with maize and faba bean, respectively. The organic acid anions in rhizosphere of the maize and faba bean included tartrate and malate anion. Tartrate concentration in rhizosphere of the maize was 77.0% lower in CK than in NPKM, and Tartrate concentration in rhizosphere of the faba bean did not vary much between in CK and in NPKM. In the field, rhizosphere pH of the maize was higher in CK than in NPK, NPKS and NPKM. Compared with the pH in bulk soil, rhizosphere pH of the above four treatments decreased by 0.3~0.51 units. Rhizosphere pH of the faba bean did not differ much between NPKM and NPKS. But pH of bulk soil was significantly lower in NPKM than in NPKS. But, NPK was significantly lower than all the other treatments in pH of bulk soil and of rhizosphere soil. APase activity was higher in rhizosphere than in bulk soil in all the treatments. No significant difference was observed in APase activity in rhizospheres of between the treatments. And APase activity in bulk soil did not vary much with treatment. Malate concentration in rhizosphere was higher in NPKM than in CK, but did differ much between CK, NPK and NPKS.【Conclusion】Mineralization of rhizosphere organic P was regulated by both rhizosphere processes and concentration of organic P in soil. Long-term fertilization promotes accumulation of organic P in black soil and increases concentration of the substrate of mineralization, which is beneficial to mineralization. Rhizospheric process of maize in the field enhances this process, thus maintaining P supply intensity in the root layer. Thus, building a high organic P pool and selecting crop varieties that are highly efficient in using organic phosphorus is an effective strategy to maintain P supply capacity of black soil and achieve the target of reducing P fertilization and improving its efficiency.
Key words:  Maize  Faba bean  Rhizosphere pH  Acid phosphatase  Organic acid Mineralization of organic phosphorus