施磷对灌耕草甸土无机磷形态和有效磷的影响

Effects of phosphorus application on inorganic phosphorus forms and available phosphorus in irrigated meadow soil

为探讨磷肥品种和施磷方式对灌耕草甸土无机磷形态和有效磷含量的影响,设置重过磷酸钙基施(TSP-B)、磷酸一铵基施(MAP-B)、聚磷酸铵基施(APP-B)、磷酸一铵滴施(MAP-D)、聚磷酸铵滴施(APP-D)和不施磷肥(CK)6个处理,室内培养120 d分别测定各土层无机磷和有效磷含量。结果表明:三种磷肥基施处理显著提升5~20 cm土层无机磷总量以及0~20 cm土层有效磷和Ca_(2)-P含量,而Ca_(8)-P含量仅在5~10 cm土层中显著增加(P<0.05)。TSP-B和MAP-B处理显著增加了0~5 cm和10~20 cm土层中Fe-P含量以及5~10 cm和10~20 cm土层中Al-P含量(P<0.05)。与MAP-B和APP-B处理相比,MAP-D和APP-D处理均显著增加了0~5 cm土层中无机磷总量及有效磷、Ca_(2)-P和Ca_(8)-P含量,且APP-D处理无机磷总量、有效磷含量和Ca_(2)-P含量均显著高于MAP-D处理(P<0.05)。灌耕草甸土无机磷中Ca_(10)-P和O-P占比最高,分别占无机磷总量的37.6%和35.7%,Ca_(8)-P、Al-P和Fe-P分别占14.0%、6.2%和4.8%,Ca_(2)-P仅占1.7%。Ca_(2)-P、Ca_(8)-P、Al-P和O-P与有效磷呈显著正相关(P<0.05),其贡献顺序为Ca_(2)-P>Ca_(8)-P>Al-P>O-P。研究表明,磷肥基施可明显提高灌耕草甸土耕层(0~20 cm)中无机磷总量和有效磷含量,而滴施仅能提高其表层(0~5cm)无机磷总量和有效磷含量。无机磷中Ca_(10)-P和O-P含量最高,其后依次为Ca_(8)-P、Al-P、Fe-P和Ca_(2)-P。对于深根系作物,磷肥应以基施为主,宜选用价格相对较低的酸性的TSP;对于浅根系作物(<5 cm),可采用磷肥滴施方式,且聚磷酸铵滴施效果优于磷酸-铵。

This study aimed to investigate the effects of phosphorus fertilizer varieties and application methods on inorganic phosphorus(IP)and available phosphorus(AP)content in irrigated meadow soil,in order to provide a decision-making basis for rational phosphorus application.Six treatments were set up in an indoor cultivation:basal application of triple superphosphate(TSP-B),mono-ammonium phosphate(MAP-B)and ammonium polyphosphate(APP-B),drip application of mono-ammonium phosphate(MAP-D)and ammonium phosphate(APP-D)and no phosphate fertilizer(CK).Then the IP and AP content in each soil layer were measured after 120 days.Our results showed that TSP-B,MAP-B and APP-B significantly increased AP and Ca_(2)-P content at 0-20 cm soil layer,IP content at 5-20 cm and Ca_(8)-P content at 5-10 cm(P<0.05).Meanwhile,TSP-B and MAP-B also significantly increased Fe-P content at 0-5 cm and 10-20cm,as well as Al-P content at 5-10 cm and 10-20 cm(P<0.05).Despite MAP-D and APP-D both significantly increased IP,AP,Ca_(2)-P and Ca_(8)-P content at 0-5 cm compared with treatments of MAP-B and APP-B,however,IP,AP and Ca_(2)-P content under APP-D were all significantly higher than that under MAP-D(P<0.05).In irrigated meadow soil,IP was largely composted by Ca_(10)-P and O-P,which accounted for 37.6%and 35.7%to total IP,respectively;while Ca_(8)-P,Al-P,and Fe-P accounted for 14.0%,6.2%,and 4.8%,respectively,and Ca_(2)-P only accounted for 1.7%.In addition,Ca_(2)-P,Ca_(8)-P,Al-P and O-P were significantly correlated with AP(P<0.05),the contribution order was Ca_(2)-P>Ca_(8)-P>Al-P>O-P.Our results indicated that for phosphorus,basal application could significantly increase IP and AP at arable layer(0-20 cm)while drip application only increased IP and AP at topsoil(0-5 cm).In irrigated meadow soil,IP was mostly contributed by Ca_(10)-P and O-P,followed by Ca_(8)-P,Al-P,Fe-P,and Ca_(2)-P,respectively.We suggested that for crops with deeproot systems,the best application method was basal application of TSP as it had a low price.While for crops with shallow-root systems(<5cm),APP-D was superior to MAP-D in terms of soil phosphorus content.