施磷与接种丛枝菌根真菌对苜蓿产量和磷素利用效率的影响

Effects of phosphorus application and inoculation with arbuscular mycorrhizal fungi on alfalfa yield and phosphorus use efficiency

为探讨施磷及接种丛枝菌根真菌对苜蓿干物质产量、磷含量以及土壤碱性磷酸酶(AKP)活性的影响,分析接菌及施磷条件下紫花苜蓿土壤速效磷、全磷与干物质产量之间的关系,进而阐明接菌及施磷对紫花苜蓿干物质产量及各指标之间关系的影响机制。本试验采用双因素完全随机设计,设置4个施菌水平:单接种摩西管柄囊霉(Fm,T_(1))、幼套球囊霉(Ge,T_(2))、双接菌(Fm×Ge,T_(3))及未接菌处理(CK,T_(0)),在施菌条件下设置4个施磷水平,分别为:施P2O50(P_(0))、50(P_(1))、100(P_(2))、150(P_(3))mg·kg^(-1),菌磷互作共16个处理,每个处理10次重复。结果表明:1)相同接菌处理,苜蓿的干物质产量、植株叶片、茎及根部磷含量、土壤pH值及碱性磷酸酶活性均随施磷量的增加呈先增加后降低的趋势,均在P2处理达到最大值,且施磷处理显著大于未施磷处理(P<0.05)。根际和非根际土壤速效磷和全磷含量均随施磷量的增加而逐渐增加,苜蓿的磷肥农学效率随施磷量的增加呈逐渐降低的趋势。2)相同施磷处理,单接菌及双接菌处理苜蓿的干物质产量、植株叶片、茎及根部磷含量、根际和非根际土壤速效磷、全磷含量、磷素利用效率及土壤中碱性磷酸酶活性均显著大于未接菌处理(P<0.05),土壤全磷及速效磷含量均在T3处理达到最大值。双接菌处理下土壤的pH值显著小于未接菌处理(P<0.05),且在T_(3)处理达到最小值。因此,当施磷(P_(2)O_(5))量为100 mg·kg^(-1)时,混合接种两种丛枝菌根真菌可以有效促进苜蓿植株根系对土壤中速效磷的吸收,提高磷素利用效率,进而促进苜蓿干物质产量的形成。

In order to investigate the effects of phosphorus application and inoculation with arbuscular mycorrhizal fungi on dry matter yield,phosphorus content and soil alkaline phosphatase activity(AKP)of alfalfa,the soil available phosphorus and total phosphorus of alfalfa under different inoculation and phosphorus application regimes were analyzed.The relationship between alfalfa dry matter yield and inoculation and phosphorus application and the relationship between yield and various other indicators were further clarified.In this experiment,a two-factor completely randomized design was adopted.Four inoculation treatments were included:Single inoculation with Funneliformis mosseaes(Fm,T_(1)),Glomus etunicatum(Ge,T_(2)),double inoculation(Fm×Ge,T_(3))and no fungal treatment(CK,T_(0)).As the second factor,four phosphorus application levels were included:P_(2)O_(5)0(P_(0)),50(P_(1)),100(P_(2)),150(P_(3))mg·kg^(−1)making a total of 16 treatments defining the fungus-phosphorus interaction.Each treatment was repeated 10 times.It was found that:1)With the same inoculation treatment,the dry matter yield,phosphorus content of leaves,stems and roots,soil pH value and alkaline phosphatase activity of alfalfa all initially increased first and then decreased with increasing phosphorus application.All reached the maximum value in the P2 treatment,and the yield of the alfalfa P fertilization treatment was significantly greater than the no P fertilization treatment(P<0.05).The content of available phosphorus and total phosphorus in rhizosphere and non-rhizosphere soil increased gradually with increasing phosphorus application rate,and the agronomic efficiency of alfalfa phosphorus fertilizer showed a decreasing trend with increase in phosphorus application rate.2)With the same inoculation treatment,dry matter yield,phosphorus content of plant leaves,stems and roots,rhizosphere and nonrhizosphere soil available phosphorus,total phosphorus content,phosphorus use efficiency,soil alkaline phosphatase activity was significantly greater than that of uninoculated treatment(P<0.05),and the soil total phosphorus and available phosphorus contents were maximised in the T3 treatment.The pH value of soil in the double inoculation treatment was significantly lower than that in the uninoculated treatment(P<0.05),and reached the minimum value in the T_(3) treatment.Based on these results,the phosphorus application(P_(2)O_(5))treatment of 100 mg·kg^(−1),coupled with the mixed inoculation of the two arbuscular mycorrhizal fungi could could be recommended and this treatment effectively promoted the absorption of available phosphorus in the soil by the roots of alfalfa plants,improved the efficiency of phosphorus use,and enhanced dry matter yield in alfalfa.