黄化是石灰性土壤上水稻膜下滴灌常见的营养障碍,显著影响作物生长发育和产量。以水稻品种T-43为试验材料,采用两因素裂区试验研究播期和土壤局部酸化对改善膜下滴灌水稻苗期缺铁黄化的作用。主区设置三种不同的播期,即在土温达到12℃(T1)、15℃(T2)、18℃(T3)时播种;副区为不同的土壤酸化剂:硫酸铵+硝化抑制剂(AS)、磷酸(PP)、柠檬酸(CA)和对照(CK)。结果表明,三种酸化剂处理均显著降低土壤pH值,提高了土壤有效铁含量,其中AS效果最显著。AS、PP和CA处理的苗期水稻叶片中有效铁含量较CK分别提高14.4%、11.3%和9.2%。三种酸化剂提高了水稻苗期根系活力和根系的根长、表面积、根体积,以AS处理效果最好。晚播较早播显著提高了水稻苗期根系活力,增加了水稻根系的根长、表面积、根体积。晚播使水稻苗期叶片活性铁含量提高了11.2%,叶片SPAD值显著增加。酸化剂的施用有助于克服水稻苗期缺铁黄化,以硫酸铵(生理酸性盐)结合硝化抑制剂最佳,适当的推后播期也能有效改善膜下滴灌水稻缺铁黄化。

Rice seedling chlorosis is a common symptom in calcareous soil under drip irrigation,limiting rice growth and yield. A two-factor split-plot experiment was carried out to reveal the effects of sowing date and soil acidification on rice chlorosis caused by iron deficiency under drip irrigation with plastic film mulching(DIPM) by using T-43 (Oryza sativa L.)as material. The sowing date was the primary factor and sowing was conducted at soil temperature of 12℃(T1),15℃(T2),18℃(T3). The subplot was soil acidifiers: ammonium sulfate with nitrification inhibitor (AS), phosphoric acid (PP), citric acid (CA), and contrast (CK). The results showed that acidifier application significantly reduced soil pH value and increased soil iron availability with AS being the most effective one. Compared with CK the active iron concentration in rice leaf increased by 14.4%, 11.3% and 9.2%, respectively under As, PP and CA application. Acidifier application also improved root activity at seedling stage, root length, root surface area, and root volume, especially AS. Late sowing improved root activity of rice at seedling stage, increased root length, root surface area, and root volume. The active iron concentration in rice leaf under DIPM increased by 11.2% and SPAD value was significantly improved. In conclusion, application of acidifier helps overcome rice leaf chlorisis under DIPM, as well as delayed sowing date,with As showing the best effect.