有机肥配施荧光假单胞菌肥对玉米产量与复垦土壤磷素有效性的影响

复垦土壤贫瘠,磷素含量极低,严重影响作物的生长发育。研究化肥、有机肥配施荧光假单胞菌对玉米产量和复垦土壤磷素形态以及酶活性的影响,为加速培肥矿区复垦土壤提供技术支持和理论依据。该研究在山西省晋中市采煤塌陷区进行了2a的定位培肥试验,共设置7个处理：不施肥（CK）、单施化肥（CF）、化肥配施荧光假单胞菌（CFB）、单施有机肥（M）、有机肥配施荧光假单胞菌（MB）、化肥配施有机肥（MCF）、化肥有机肥配施荧光假单胞菌（MCFB）。采集各处理土壤样品测定相关指标,并通过相关性分析和结构方程模型来探究各形态磷与有效磷以及土壤磷酸酶之间的关系。结果表明：1）在整个试验周期（2021—2022年）,与CK相比,不同施肥处理均能显著提高玉米产量以及各形态磷素。其中,以MB处理下的玉米产量、有效磷、磷活化系数、不稳定态磷以及部分不稳定态磷含量最高,与CK处理相比,玉米产量显著提高2.4倍,有效磷含量、磷活化系数值、不稳定态磷含量、部分不稳定态磷含量分别显著提高4.5倍、4.67倍、0.98倍、1.16倍。2）与CK处理相比,化肥、有机肥配施荧光假单胞菌能够显著提高土壤微生物量磷以及酸性和碱性磷酸酶活性,配施荧光假单胞菌后,微生物量磷水平和碱性磷酸酶活性均以MB较M处理提升效果最佳,分别显著提高27.08%和9.56%。3）结合相关性分析以及结构方程模型,随着荧光假单胞菌和化肥有机肥的施入,在提高不稳定态磷素含量的同时也提高有效磷的供应能力,促进磷素在农田生态系统中的循环转化,产生积极的正向影响。化肥、有机肥配施荧光假单胞菌能够一定程度上影响复垦土壤玉米产量及产量性状、各形态磷素及有效性和微生物活性,对复垦土壤脆弱的农田生态系统产生积极影响。

Effects of organic fertilizer combined with Pseudomonas fluorescein on maize yield and phosphorus activity in reclaimed soil

Reclaimed soil is characterized by the infertility and extremely low phosphorus content, thus severely impeding the growth and development of crops. This study aims to investigate the effects of chemical fertilizer and organic fertilizer combined with Pseudomonas fluorescein on phosphorus fractions and enzyme activity in reclaimed soil, in order to accelerate the soil reclamation in mining areas. A two-year targeted fertilization experiment was conducted in a coal mining subsidence area in Jinzhong City, Shanxi Province, China. Seven treatments were established: no fertilization control (CK), single application of chemical fertilizer (CF), chemical fertilizer combined with P. fluorescein (CFB), single application of organic fertilizer (M), organic fertilizer combined with P. fluorescein (MB), chemical fertilizer combined with organic fertilizer (MCF), and chemical fertilizer and organic fertilizer combined with P. fluorescein (MCFB). The soil samples were collected from the treatment plots. The phosphorus fractions, microbial biomass phosphorus, and soil phosphatase activity were measured after that. In addition, the correlation between soil phosphorus fractions and Olsen P was explored to construct the structural equation model between soil phosphorus fractions and microbial biomass phosphorus, acid phosphatase, alkaline phosphatase, and Olsen P. Results showed that: 1) Different fertilization treatments significantly increased the maize yield and various phosphorus fractions during the entire experimental period (2021-2022), compared with CK. Among them, the MB treatment was achieved in the highest maize yield, Olsen-P content, phosphorus activation coefficient (PAC) value, labile phosphorus (L-P), and moderately labile phosphorus (M-P) content. The maize yield, Olsen-P content, PAC value, L-P content, and M-P content increased significantly by 2.4, 4.5, 4.67, 0.98, and 1.16 times, respectively, compared with the CK treatment. 2) The application of chemical and organic fertilizer combined with P. fluorescein also increased the soil microbial biomass phosphorus and the activities of acid and alkaline phosphatase enzymes, in terms of microbial activity. After combined application with P. fluorescein, the levels of microbial biomass phosphorus and alkaline phosphatase enzyme activity were most effectively enhanced under the MB treatment, compared with the M treatment, indicating the significant increase of 27.08% and 9.56%, respectively. 3) The correlation analysis showed that there was the closest relationship between labile phosphorus forms (Resin-P, NaHCO3-Pi, and NaHCO₃-Po) and Olsen P. Furthermore, there was the much larger direct and positive effects of labile phosphorus on microbial biomass phosphorus, acid phosphatase, alkaline phosphatase activities, and Olsen P, according to the structural equation model. The large standardized path coefficient was found that the application of chemical fertilizer, organic fertilizer, and P. fluorescein on L-P was promoted the circulation and transformation of phosphorus in the farmland ecosystem, indicating a positive impact. In summary, the combined application of different fertilizers with P. fluorescein were promoted the yield and yield traits of maize in the reclaimed soil, together with the forms and availability of phosphorus, and microbial activity, indicating a positive impact on the fragile agroecosystem of reclaimed soil. Among them, the combined organic fertilizer with P. fluorescein significantly increased the Olsen-P content, L-P content, and M-P content, SMBP content, and ALP activity in the reclaimed soil, compared with the sole application of organic fertilizer. The finding can provide the more effective fertilization.