沙封覆膜种植孔促进盐碱地油葵生长

为了提高盐碱地油葵的出苗率及存活率,提高油葵产量,在河套灌区选择土壤盐分较高的地块,地膜覆盖种植油葵时改传统的土封种植孔为沙封种植孔,在油葵播种期、出苗期和幼苗期测定不同封孔方式对种植孔根际、地膜覆盖区、地膜间露地0~40.0 cm土层土壤水分、盐分及油葵出苗率、存活率、产量等的影响。结果表明,从播种到幼苗期,0~15 cm土层土壤水分逐渐降低,土壤盐分逐渐升高,且不同时期存在显著或极显著差异。出苗期和幼苗期沙封种植孔根际0~10.0 cm土层土壤水分比土封种植孔分别降低3.86%和4.83%,比地膜覆盖区分别降低4.79%和9.73%;0~15.0 cm土层土壤盐分比土封种植孔分别降低16.46%和40.99%,比地膜间露地分别降低30.53%和33.72%;比地膜覆盖区则分别提高17.86%和29.89%。土封种植孔根际0~10 cm土层土壤水分在幼苗期比地膜覆盖区降低5.15%,出苗期和幼苗期比地膜间露地分别提高3.44%和4.42%;出苗期根际0~15.0 cm土层土壤盐分比地膜间露地降低16.84%,幼苗期则提高12.32%,出苗期和幼苗期则比地膜覆盖区分别提高41.07%和120.11%。沙封种植孔缩短了油葵的出苗天数,极显著提高了油葵的出苗率、存活率,促进幼苗生长。沙封种植孔的油葵单株产量低于土封种植孔,单位面积产量则提高了62.00%,增收58.60%。河套灌区土壤含盐量较高的地块,地膜覆盖种植油葵时采用沙封种植孔,可提高油葵的出苗率及幼苗存活率,提高油葵产量及产值。在河套灌区盐碱危害较严重的地块,地膜覆盖种植油葵时应采用沙封种植孔。

Planting hole sealed by sand promoting growth of oil sunflower in saline-alkaline fields mulched with plastic film

Abstract: Oil sunflower is a pioneer crop growing in saline-alkaline soil. However, its germination rate and seedling growth can be inhibited when soil salinity is extremely high and thus its yields can be decreased. In order to improve germination rate and survival rate of oil sunflower, increase its yields and outputs, a field experiment was conducted to investigate the effect of two planting hole sealing methods (sealed by soil and sealed by sand) on rhizosphere soil moisture and soil salinity in severe saline-alkaline soils of Hetao irrigation area, Inner Mongolia, China. Eight rhizosphere soil samples at depth of 0-40 cm were taken with 5 cm as a sampling layer from the plots of planting hole sealed by sand and planting hole sealed by soil at the sowing, germination and seedling stages of oil sunflower to determine the soil moisture and salinity. Meanwhile, soil moisture and soil salinity under the plastic film mulch and in open field between plastic film mulching were also detected. Germination rate, seedling survival rate, seedling growth, yields, and output from the plots of planting hole sealed by sand and planting hole sealed by soil were calculated. The results showed that the soil moisture at depth of 0-15 cm decreased but soil salinity increased from sowing stage to seedling stage, and significant or extremely significant differences were detected between different growth stages. In seedling germination and seedling stage, rhizosphere soil moisture at 0-10 cm depth in the treatment of planting hole sealed by sand decreased by 3.86% and 4.83% than that in the treatment of planting hole sealed by soil, decreased by 4.79% and 9.73% than that in the treatment of plastic film much, while the rhizosphere soil salinity at 0-15 cm depth in the treatment of planting hole sealed by sand decreased by 16.46% and 40.99% than that in the treatment of planting hole sealed by soil, decreased by 30.53% and 33.72% than that in the treatment of open field between plastic film mulch, and increased by 17.86% and 29.89% than that in the treatment of plastic film mulch. At the germination stage, the rhizosphere soil moisture at 0-10 cm depth in the treatment of planting hole sealed by soil was almost same as that in the treatment of plastic film much, increased by 3.44% than that of open field between plastic film mulch, and its rhizosphere soil salinity at 0-15 cm depth decreased by 16.84% than that of open field between plastic film mulch, increased by 41.07% than that of plastic film mulch. At the seedling stage, the rhizosphere soil moisture of planting hole sealed by soil at 0-10.0 cm depth decreased by 5.15% than that of field mulching with plastic film, increased by 4.42% than that of open field between plastic film mulching, and its rhizosphere soil salinity at 0- 15 cm depth increased by 12.32% and 120.11% than that of open field among and in plastic film mulching. The treatment of planting hole sealed by sand significantly shorted the germination days, improved germination rate and seedling survival rate, and promoted seedling growth of oil sunflower. The yields per plant in plots of planting hole sealed by sand were significantly lower than those of planting hole sealed by soil, but its yields per unit increased by 62.00% and output increased by 58.60%. This study indicated that planting hole sealed by sand significantly decreased rhizosphere soil salinity at seedling germination stage and seedling stage of oil sunflower, improved germination rate and survival rate, promoted seedling growth, and increased oil sunflower yields and output value per unit area. Planting hole sealed by sand should be an optimum method for sowing oil sunflower in severe saline-alkali land of Hetao irrigation area.