基质类型及烯效唑对不同秧龄晚稻机插质量和产量的影响

为明确基质类型及烯效唑对不同秧龄晚稻秧苗生理特征及本田期生长发育特性的影响,确定适宜晚稻机插育秧的基质类型、烯效唑浸种措施及秧龄,该研究以嘉58为供试晚稻品种,以2种代表性育秧介质(营养土和轻型无土育秧基质)为研究对象,采用2种(清水浸种和25 mg/L烯效唑浸种)外源生长调控措施,阐明了不同育秧介质和烯效唑浸种对不同秧龄晚稻秧苗生理特征、机插质量的影响及调控技术。结果表明,随晚稻秧龄延长,秧苗地上部分干物质量显著增加,叶片SPAD值和根系活力先增加后降低;水稻全生育期延长,大田生育期缩短。采用烯效唑浸种可提高秧苗素质,浸种处理秧苗茎基宽约增加0.1~0.2 mm,株高显著降低,叶片SPAD值和根系活力显著提高。短秧龄条件下烯效唑浸种对秧块质量和机插质量影响较小,长秧龄条件下烯效唑浸种可有效提高成苗率和大田基本苗数,降低漏插率和伤秧率。采用营养土育秧时最适机插秧龄为18 d,轻型无土基质育秧适宜机插秧龄为18~24 d。秧龄大于24 d时,烯效唑浸种可提高营养土育秧晚稻有效穗数和每穗粒数,增加晚稻产量,且秧龄越长,烯效唑浸种的增产效果越显著。烯效唑浸种对轻型无土基质育秧的产量影响较小。采用轻型无土育秧基质培育机插晚稻秧苗,产量高于常规营养土处理,适宜晚稻机插育秧。研究结果可为提升晚稻种植机械化水平提供重要参考。

Effects of substrate types and uniconazole on mechanized transplanting qualities and grain yield for late rice with different seedling ages

Abstract: The mechanized transplanting area of rice in China accounts for about 38% of the total planting area, and the area is increasing now. Preparation of nutrient soil for raising rice seedlings has become one of the obstacle factors restricting the development of rice transplanting with machine. Light soilless substrate originating from renewable resources like crop straws can solve the difficulties of getting soils and protecting environment. Few studies focus on the interaction effects between light soilless substrate, rice seedling age, and the corresponding growth regulation way. Therefore, determining the suitable substrate type, seedling age and external hormone regulation way for raising late rice will be of great importance in improving the mechanization level of transplanting late rice. In this study, 2 kinds of substrates and 2 kinds of exogenous hormone regulation ways were used in this trial to explore the effects of substrate types on physiological characteristics and mechanized transplanting qualities for different seedling-age of late rice and the regulation way. Inbred rice, Jia 58 was used in this trial as late rice cultivar. Nutrient soil and light soilless substrate were used as substrates in this trial. And 2 kinds of seed soaking concentrations for uniconazole (control and 25 mg/L uniconazole) were used in this trial as growth regulation ways. The results showed that aboveground biomass for rice seedlings was increased with the increase of rice seedling age. SPAD (soil plant analysis development) values for rice leaves and root activities for rice seedlings firstly increased and then decreased as the increase of rice seedling age. The total rice life cycle was longer and rice growth period in the field was shorter for the longer age of rice seedlings. Rice seedlings qualities were greatly improved after seeds were treated with uniconazole. After seeds were treated with uniconazole, rice stem width was increased by 0.1-0.2 mm, rice plant height was significantly decreased, and SPAD values of rice leaves and root activities of rice seedlings were significantly increased compared with the control. The rice seeds soaked with uniconazole showed a better performance on rice mechanized transplanting qualities for longer age of rice seedlings, however, the performance on rice mechanized transplanting qualities was poorer for shorter age of rice seedlings (less than 18 d). The most suitable seedlings age for Jia 58 raised by nutrient soil was 18 d, while the most suitable seedlings age for Jia 58 raised by light soilless substrate was 18-24 d. When rice seedlings age was more than 24 d, the number of effective panicles and grains per panicle treated by nutrient soil could increase after rice seeds were soaked with uniconazole, rice grain yield treated by nutrient soil was also increased after rice seeds were soaked with uniconazole, and the modifying effects for rice seeds soaked with uniconazole were more favorable for longer age of rice seedlings. The performances of rice seeds soaked with uniconazole on rice grain yield treated with light soilless substrate were poorer compared with that treated with nutrient soil. Many kinds of raw material were widely used for light soilless substrate, the management procedures raising rice seedlings by light soilless substrate were simple, and the rice grain yield treated by light soilless substrate was also higher than nutrient soil treatment. Therefore, light soilless substrate is suitable for late rice transplanting with machine.