水磷一体化对磷素有效性与磷肥利用率的影响

水肥一体化是发挥水肥耦合效应提高养分效率的重要途径,然水磷一体化研究较少。本文在模拟滴灌条件下研究了液体磷肥和固体颗粒磷肥(TSP)及其不同施用方法对土壤磷移动性、各形态无机磷含量动态变化的影响,比较了玉米磷素营养与磷肥利用率对不同磷源及其施用方式的响应,旨在提出滴灌条件下磷肥高效利用的最优策略。研究结果表明:1)与TSP肥料分次施用相比,液体磷肥分次施用更能提高土壤磷素有效性,在各土层Ca2-P与树脂磷(resin-P)平均含量分别提高12.4%与21.6%,且可显著提高磷在土壤中的移动性(P0.05),resin-P含量的垂直下降幅度降低56.5%;2)与TSP分次施用相比,液体磷肥分次施用的土壤中高活性无机磷含量(Ca2-P、resin-P及Na HCO3-P之和)占无机磷总量的比例提高21.0%,而低活性无机磷含量(Ca10-P与residue-P之和)占无机磷总量的比例则下降10.1%,说明液体磷肥分次施用可减小磷肥在土壤中的固定转化;3)玉米地上部干物质、叶片吸磷量和植株磷素累积吸收量均对不同磷源与施用方式有明显响应(P0.05),液体磷肥分次处理的玉米生物量、吸磷量及肥料利用率分别比TSP肥料分次处理提高27.1%、34.6%及61.4%。水磷一体化施用可提高磷在土壤中的移动性和有效性,减少磷的固定转化,显著改善玉米磷素营养,并明显提高磷肥利用率。     

Fertilizer‐use efficiency of different inorganic polyphosphate sources: effects on soil P availability and plant P acquisition during early growth of corn

Polyphosphate‐based fertilizers are worldwide in use, and their effect on crop yield is often reported to be similar to orthophosphate products, although some studies showed higher yields with polyphosphate applications. However, information on how these fertilizers may influence plant P acquisition is very limited. A pot experiment was carried out under controlled conditions with corn (Zea mays L.) growing on a sandy soil (pH 4.9) and a silty‐loam soil (pH 6.9) differing in P‐sorption properties. The objective was to evaluate phosphorus fertilizer–use efficiency (PFUE) of several polyphosphate (poly‐P) compounds (pyrophosphate [PP], tripolyphosphate [TP], and trimetaphosphate [TMP]) using orthophosphate (OP) as a reference. Focus was put on evaluating plant parameters involved in plant P acquisition, i.e., root length and P uptake per unit of root length. Furthermore, soil P availability was characterized by measuring ortho‐P and poly‐P concentrations in soil solution as well as in CAL (calcium‐acetate‐lactate) extracts. The P availability was differentially influenced by the different P sources and the different soils. In the silty‐loam soil, the application of poly‐P resulted in higher ortho‐P concentrations in soil solution. In the same soil, CAL‐extractable ortho‐P was similar for all P sources, whereas in the sandy soil, this parameter was higher after OP application. In the silty‐loam soil, poly‐P concentrations were very low in soil solution or in CAL extracts, whereas in the sandy soil, poly‐P concentrations were significantly higher. Phosphorus fertilizer–use efficiency was significantly higher for poly‐P treatments in the silty‐loam soil and were related to a higher root length since no differences in the P uptake per unit of root length among poly‐P and OP treatments were found. However, in the sandy soil, no differences in PFUE between OP and poly‐P treatments were observed. Therefore, PFUE of poly‐P compounds could be explained by better root growth, thereby improving plant P acquisition.     

不同AM菌株对酸性土壤玉米生长及磷营养的影响研究

试验研究不同AM菌株对酸性土壤玉米生长及P营养的影响结果表明,6种菌株的菌根形成、菌根效应、菌株根外菌物量均存在显著种间或生态型差异,华北菌株“BEG168”、法国菌株“BEG141”和华南菌株“BEG151”侵染率较高,达20%,而华北菌株“BEG167”次之,华中菌株“HAU-E4”和华南菌株“BEG150”最低。“BEG150”和“BEG168”显著促进玉米地上部和植株的生长,“BEG141”和“BEG151”则无促生效应,而“BEG167”和“HAU-E4”表现为负效应。除“BEG167”降低植物P素吸收外,其余菌株均对宿主P吸收有所增益,其中以“BEG168”和“BEG141”较高。除“BEG167”和“HAU-E4”外其他菌株均有一定应用价值,且以“BEG168”和“BEG150”最有望成为适应酸性土壤的高效真菌。