【摘要】 [目的]研究石灰性土壤上磷肥减施结合硫铵替代尿素措施的效果,为夏玉米—冬小麦体系合理施用磷肥和维持作物高产提供依据。[方法]在陕西关中设置3年田间定位试验,实施夏玉米—冬小麦轮作模式,共含有对照（CK,不施磷肥）、常规施磷（CP,年施磷量180kg P₂O₅/hm²,撒施）、减施磷肥（RP,年施磷量134kg P₂O₅/hm²,条施）、减磷结合硫铵替代尿素（RPSA,施磷量与RP相同,条施）4个处理。作物收获期采集植物和土壤样品,测定玉米和小麦产量、磷肥效率、p H及土壤磷水平。小麦拔节期测定根系形态、菌根侵染率等指标。[结果]与CK相比,施磷处理（CP,RP和RPSA）的玉米和小麦籽粒产量均显著提高,增幅分别为17.3%～24.8%和5.1%～19.0%;土壤有效磷（Olsen-P）和微生物量磷（MBP）显著提高;除RP外,施磷处理的土壤p H均显著降低。施磷处理间,2018—2019年度RP较CP产量显著降低14.6%,磷回收率和偏生产力显著提高。RPSA较RP土壤p H显著降低,有效磷、微生物量磷含量和根系形态及菌根侵染率均显著提高。土壤p H与土壤磷水平、小麦根系形态指标和产量均呈显著负相关。RDA结果表明:土壤p H是影响小麦菌根侵染率、根系形态和产量的最重要环境因子。[结论]磷肥减施结合硫铵替代尿素调控措施可以降低石灰性土壤pH,提高土壤有效磷和微生物量磷含量,促进小麦根系生长并提高菌根侵染率,是石灰性■土夏玉米—冬小麦体系有效的磷肥减施增效措施。更多还原

【Abstract】 [Objective] The aims of this study are to examine the effect of phosphorus fertilizer reduction combined with ammonium sulfate substitution of urea measure, and provide the basis for rational application of phosphorus fertilizer to maintain high crop yields under summer maize-winter wheat cropping system on calcareous Eum-Orthic Anthrosols. [Methods] A 3-year field experiment was set up under summer maize-winter wheat cropping pattern in the field with calcareous Eum-Orthic Anthrosols in Guanzhong, Shaanxi Province. The four treatments were included: control（CK, no P fertilizer applied）, conventional phosphorus application（CP, annual P application rate of 180 kg P₂O₅/hm², spreading）, reduced phosphorus fertilizer（RP, annual P application rate of 134 kg P₂O₅/hm², strip-localized application）, and reduced phosphorus fertilizer combined with substitution of ammonium sulphate for urea（RPSA, the P application rate was the same as that of RP, strip-localized application）. Crop and soil samples were collected to determine yields, phosphorus fertilizer efficiency and soil phosphorus levels at harvest stage. The root morphology and mycorrhizal infection rate of wheat were measured at the jointing stage. [Results] Compared with CK, the grain yields of maize and wheat were significantly increased in all phosphorus application treatments（CP, RP and RPSA） by 17.3%～24.8% and 5.1%～19.0%, respectively. The soil pH was significantly reduced for all treatments applied phosphorus except for RP. In all phosphorus application treatments, compared with CP, crop yield of RP decreased significantly by 14.6% in 2018—2019, whereas the phosphorus recovery rate and partial productivity increased. Compared with RP, RPSA significantly reduced soil pH, increased soil available phosphorus（Olsen-P） and microbial biomass phosphorus（MBP） content, and increased the densities of root length, root surface area, root volume, root dry weight, and mycorrhizal infection rate of wheat root. The Pearson correlation analysis showed that there was significant negative correlation between soil pH and phosphorus level, root morphology and yield. The results of RDA showed that soil pH was the most important environmental factor affecting the mycorrhizal infection rate, root morphology and yield of wheat. [Conclusion] The phosphate fertilizer reduction combined with ammonium sulfate instead of urea can reduce the pH of calcareous soil, increase the content of available phosphorus, microbial biomass P, the growth of wheat roots and the mycorrhizal infection rate, which is an effective regulating measure to reduce phosphorus fertilizer application amount and to increase the P efficiency under summer maize-winter wheat cropping pattern on calcareous Eum-Orthic Anthrosols.更多还原