钼对含甲基营养型芽孢杆菌基质栽培甜瓜产量及氮磷钾吸收的影响

  【目的】  甲基营养型芽孢杆菌常接种于基质中以解决甜瓜生产过程中土传病害严重的问题。然而，甲基营养型芽孢杆菌对基质中微量元素的含量十分敏感，为此，我们研究了钼酸铵的适宜添加浓度，以期为甜瓜优质高效生产提供合理有效的技术参考和理论依据。  【方法】  试验于2019年5—8月在陕西省杨凌农业示范区进行，以薄皮甜瓜品种‘千玉6号’为材料，营养液中 (NH₄)₂MoO₄·4H₂O含量设置0、0.02 和0.04 mg/L 3个水平。测定甜瓜结果各时期器官干物质和全氮、全磷、全钾含量，分析结果中期甜瓜各器官对果实的养分贡献率、果实品质和果实全钼含量，统计产量并计算氮磷钾元素养分利用效率。  【结果】  甜瓜果实全钼含量随施钼水平增加而增加，而游离氨基酸、硝态氮含量、单果重及产量均在钼酸铵 0.02 mg/L水平最高，可溶性蛋白质含量在不施钼处理最高。除结果初期和中期甜瓜茎干物质量在3个施钼处理之间没有显著差异外，甜瓜各器官干物质、植株总干物质、全氮、全磷、全钾的积累量和转运量均以钼酸铵0.02 mg/L处理显著高于0和0.04 mg/L处理。0.02 mg/L钼酸铵处理通过提高营养器官中积累的氮磷钾对果实养分的贡献率，进而提高果实产量和氮磷钾养分利用效率；与钼酸铵0.02 mg/L处理相比，0和0.04 mg/L处理的果实产量及氮、磷及钾素养分利用率分别降低48.63%和17.50%、16.58%和22.44%、2.39% 和13.84%及27.34%和25.28%。  【结论】  在含有甲基营养型芽孢杆菌的基质栽培中，施用含0.02 mg/L (NH₄)₂MoO₄·4H₂O的营养液可显著提高甜瓜结果期干物质量和养分积累、转运及产量和品质。

Effects of molybdenum on yield and NPK absorption of muskmelon cultivated on substrate with B. methylotrophicus

  【Objectives】  B. methylotrophicus are often inoculated in the growth substrate to deal with soil-borne diseases in the production of melons. As the sensitivity of B. methylotrophicus activity to micronutrient contents, we studied the proper concentration of Mo in order to provide theoretical basis for preparation of high-quality growth substrate in the production of melons.  【Methods】  The experiment was conducted in Yangling Agricultural Demonstration Zone, Shaanxi Province from May to August in 2019. The thin-skin melon variety ‘Qianyu No.6’ was used as the material, and three levels of ammonium molybdate tetrahydrate (NH₄)₂MoO₄·4H₂O] at 0, 0.02 and 0.04 mg/L were set. The accumulation and contribution of dry matter and total NPK to fruit were measured at the early, middle and late fruiting stages, and the fruit quality and yield were investigated.  【Results】  The total Mo content of melon fruits increased with the increase of Mo level, while the free amino acid content, nitrate nitrogen content, single fruit weight and yield were the highest at the level of (NH₄)₂MoO₄·4H₂O 0.02 mg /L, and the soluble protein content was the highest at the level of no Mo application. Except for the dry matter content of melon stems in the early and middle stages of the fruiting, the accumulation and transfer of dry matter, total dry matter, total N, total P and total K in melon organs were all higher at 0.02 mg/L (NH₄)₂MoO₄·4H₂O. Mean while, 0.02 mg/L (NH₄)₂MoO₄·4H₂O treatment increased fruit yield by promoting the accumulation and transport of dry matter and nutrients (N, P, K) and other organs, contribution to fruit nutrients, and also improved nutrient use efficiency by increasing plant absorption and accumulation of nutrients. And compared with the 0.02 mg/L ammonium molybdate tetrahydrate treatment, the 0 mg/L and 0.04 mg/L of Mo treatment reduced the yield, N, P and K nutrient utilization rate by 48.63% and 17.50%, 16.58% and 22.44%, 2.39% and 13.84%, 27.34% and 25.28%, respectively.  【Conclusions】  The application of Mo has significant effect on increasing the accumulation and transportation of dry matter and nutrients, and enhancing the fruit yield and quality of melon grown in substrate contain B. methylotrophicus. The addition concentration 0.02 mg/L of ammonium molybdate tetrahydrate performs well.