河套灌区春玉米苗期土壤板结降水指标研究

为了完善当地气象灾害指标,更好地开展春播气象服务,笔者选用当地主栽春玉米品种‘登海605’为试验材料,利用人工模拟降水系统模拟当地春播时期自然降水过程,通过测定出苗期的土壤紧实度、出苗率、株高、根冠比等参数值,综合确定引起河套灌区春玉米苗期土壤板结的降水指标。结果表明：（1）引起土壤轻度板结的降水量级指标初步确定为2~3 mm;中度板结的降水指标为4~8 mm,≥9 mm为引起土壤重度板结的降水指标;（2）播种之后降水越早,降水量级越大,出苗时越容易形成板结,形成的板结层也越厚。

Soil Hardening at Seedling Stage of Spring Maize in Hetao Irrigation District: Precipitation Index

The paper aims to perfect the local meteorological disaster indicators and provide better meteorological service for seeding in spring. The author chose major local maize variety ‘Denghai No.605’ as material to simulate the natural precipitation process by using the artificial precipitation system, and detected the soil compaction, emergence rate, plant height, and root-shoot ratio, to determine the precipitation index causing soil hardening at seedling stage of spring maize in Hetao irrigation district. The results showed that: (1) the precipitation index causing slight soil hardening was 2-3 mm; the precipitation index causing the medium soil hardening was 4-8 mm, ≥9 mm was considered the precipitation index causing severe soil hardening; (2) the earlier and greater the precipitation was after seeding, the easier the soil hardening formed and the thicker the hardening layer became.