海水养殖废水灌溉条件下山东滨海盐土溶质迁移及其平衡研究

在半干旱的山东莱州地区,利用小型蒸渗装置研究海水养殖废水灌溉下滨海盐土溶质迁移特征以及溶质平衡。结果表明:在耐盐作物-菊芋的水分临界期(6月初)和水分最大效率期(9月初)海水养殖废水灌溉两次,根区土壤中的盐分对于不同淋洗分数的处理分别增加了89 78,92 35,96 10和102 85g,部分盐分被淋出土体,淋洗效率分别达到17 3%,24 4%,31 1%和36 8%。海水养殖废水灌溉后,土壤中的养分如硝态氮、氨态氮和活性磷酸盐均有所增加,其迁移能力分别为硝态氮>活性磷酸盐>氨态氮,说明硝态氮极易淋失。在选择较小淋洗分数(0 1和0 2)的情况下,大部分的氨态氮和活性磷酸盐被保留在土壤中成为作物的有效养分。此外,大强度的降雨对盐分的淋洗也起到关键性的作用,但也会导致养分的淋失。因此,适时适宜矿化度的海水养殖废水结合适当的淋洗分数补充灌溉耐盐植物,有效地增加了土壤养分,而盐分不会过量累积。

Solute Movement and Balance on Shangdong Coastal Saline Soil under Mariculture Wasterwater Irrigation

In semi-arid area of Laizhou(Shandong province), fifteen lesimeters were used to study solute movement and balance on Shandong coastal saline soil under mariculture wasterwater irrigation. There are five treatments in this experiment, i.e, CK(non-irrigated) and the treatments of leaching fraction(LF) being 0.1, 0.2, 0.3 and 0.4. The results showed that, total desolved salts (TDS) at root zone for the treatments of leaching fraction being 0.1, 0.2, 0.3 and 0.4 increased by 89.78,92.35,96.10 and 102.85 g, respectively, when irrigated two times during the key developing stages of Helianthus tuberosus L. Some were leached blow the root zone and leaching proficiency reached 17.3%, 24.4%,31.1% and 36.8% respectively. After mariculture wastewater irrigation, nutrients such as nitrate, ammonium and reactive phosphorus, increased at root zone. Amounts of nutrients being retained at root zone were different due to the differences of the movement abilities among the three solutes. Nitrate was apt to leaching blow the root zone, however, ammonium and reactive phosphorus be retained. Additionally, heavy rain helped to leach the soluble salts out of the root zone, but the nutrients were also being leached.Therefore, we concluded using mariculture wastewater to irrigate salt-tolerant crop could increase soil nutrients, while the total desolved salts would not be excessively accumulated.