生物炭固定解鸟氨酸拉乌尔菌对紫色土磷钾有效性的影响

筛选能为解鸟氨酸拉乌尔菌（Raoultella ornithinolytica，Ro）提供适宜生存空间的生物炭，探讨固定Ro的生物炭对不同性质紫色土磷（P）钾（K）有效性的影响。采用限氧裂解法分别在不同温度（300 ℃、500 ℃和700 ℃）和原材料下（玉米秆、小麦秆和稻壳）制备生物炭。利用噻唑蓝（MTT）比色法筛选固定载体，通过傅立叶变换衰减全反射红外光谱法（ATR-FTIR）表征其性能和结构；采用室内土培试验探讨单施生物炭（BC）、Ro及固定Ro的生物炭（Ro-BC）对不同性质紫色土速效磷钾的影响。MTT结果表明，以热解温度500 ℃的玉米秸秆炭（MSC500）为最佳载体；红外光谱结果显示，500 ℃玉米秸秆炭表面官能团的C=C和－OH的伸缩振动峰较明显，C－O－C键伸缩振动峰加宽变深；室内培养试验表明，施入Ro和Ro-BC均可显著提高酸性、中性和石灰性紫色土速效磷、速效钾含量和细菌数量。以Ro-BC对土壤速效磷和细菌数量的提升效果最好，提升效果分别达61.1% ~ 276.3%和22.8% ~ 82.5%。但培养至168 h时，速效磷出现下降趋势；对速效钾而言，酸性紫色土以Ro处理对其提升效果最好（46.3%），中性和石灰性紫色土则以Ro-BC处理提升效果最好（29.8%和71.23%），针对不同Ro筛选适宜的固定载体可提高Ro菌株活性，改善土壤微环境，进而有助于提高土壤磷钾有效性。

Effect of Biochar Immobilized Raoultella Ornithinolytica on the Availability of Phosphorus and Potassium in Purplish Soil

In order to screen the biochar (BC) that can provide suitable living space for Raoultella ornithinolytica (Ro), a series of biochar carriers were obtained by maize straw (MSC), wheat straw (WSC) and rice husk (RHC) under the oxygen limited conditions by 300 ℃, 500 ℃ and 700 ℃, respectively. The effects of BC, Ro and Ro-BC on the availability of P and K in purplish soil were explored by lab-incubation with the carriers by MTT colorimetric method and ATR-FTIR method. The results showed that MSC500 was the best carrier for Ro with an obvious stretching vibration peak by the functional groups of C = C and —OH, and the stretching vibration peak of C—O—C bond was widened and deepened as well. Moreover, the application of Ro and Ro-BC significantly improved the bacteria quantity and the availability of P and K in different purplish soils. Compared with the control, Ro-BC had the best effect on the bacteria quantity and Olsen-P, which increased by 61.1% ~ 276.3% and 22.8% ~ 82.5%, respectively. However, the Olsen-P was decreased after 168h incubated. For available K, the application of Ro had the best effect on acid purplish soil (increasing by 46.3%), while the application of Ro-BC had the best effect on the neutral and calcareous purplish soils (increasing by 29.8 % and 71.23 %, respectively). In general, suitable immobilized materials for different Ro could increase the activities of Ro strains, improving soil microenvironment to promote the availability of soil P and K.