轮作不同高粱品种阻控设施菜田氮素损失潜力研究

为缓解华北地区设施菜田夏季休闲期氮素淋洗损失严重等问题, 提高氮素利用率及土壤生物多样性, 结合高粱的生物学特征, 选取晋杂12等6种北方常见高粱品种为供试品种, 以常规填闲作物甜玉米为对照, 筛选适宜作为北京设施菜田夏季填闲作物的高粱品种。结果表明, 从生物量、根系及养分带走量等方面来看, 晋杂12较其他品种均占优势, 成熟期生物量为11.2 t·hm^-2, 0~45 cm总根长为299 m, 作物地上部氮素带走量为139 kg N·hm^-2, 均显著高于常规填闲作物甜玉米, 可以替代甜玉米推广使用。同时研究发现冀梁2号品种在尿素施用后土壤铵态氮含量明显高于其他品种, 可能是作物根系分泌的生物硝化抑制剂减缓了硝化过程。与甜玉米相比, 高粱可能通过释放生物硝化抑制剂和根系在土壤剖面生物提氮共同起到减少氮素损失的作用。

The Potential to Reduce Nitrogen Loss Through Rotating Different Sorghum Varieties in Greenhouse Vegetable Field

In North China plain, excessive fertilization in vegetable greenhouse always results in nitrate accumulation in soil and possible nitrogen leaching with potential environmental risk. It is necessary to rotate appropriate catch crop to absorb surplus nitrogen in fallow season and reduce rootzone nitrate level. An experiment was carried out to select suitable sorghum variety as catch crop to reduce nitrogen loss in Beijing suburb. Six common varieties were used in the experiment as conventional catch crop, sweet corn as the control. The results indicated that the biomass, root growth and nitrogen accumulation in shoots of sorghum Jinza 12 were highest in the catch crops. It demonstrated that the variety Jinza 12 was an appropriate catch crop for reducing nitrogen accumulation in surface soil layer compared with sweet corn. Meanwhile, variety Jiliang 2 maintained highest proportion of soil NH4⁺-N content after urea application, which might be related to the biological nitrification inhibitors (BNI) released by the root system of sorghum. It implied that sorghum could be used as catch crop to reduce nitrogen loss through plant extraction i.e. nitrogen uptake and stabilization i.e. BNI inhibition, in comparison with sweet corn.