A Demonstrative Study on Rice Culture Management based on Leaf Color of Rice Plant

一项为期三年的水稻稳产栽培项目已经完成，该项目通过制定栽培日历安排利用叶色计进行栽培管理。本实验使用的叶色仪为SPAD-501和SPAD-502。进行了田间试验。利用土壤箱进行了实验室试验。对DSSP和常规移栽方法进行了试验。最初，对叶片颜色的测量只针对耳叶。在实验过程中发现，在包括穗叶在内的上三片叶的叶片颜色值中，最大值与SPAD值吻合。这些SPAD值用于制定栽培日历。在相同的栽培条件下，品种间叶片颜色也存在较大差异。然而，由于品种差异造成的叶片颜色差异可以通过使用适当的转换因子来补偿。今后的任务应该是确定每一种水稻的换算系数。根据SPAD值制定的栽培日历与基于富士叶色标的栽培日历有很大不同。新开发的栽培日历的要点包括比传统的每山有更多的茎和最大限度地提高每穗的粒数。这就产生了新方法与基于V形理论的传统方法在叶片颜色管理上的差异。为验证新方法的有效性，在部分商品水稻生产田中进行了示范操作。人们一直预期会有高收益。对于未来的研究，以下管理有望发展。必须根据新制定的栽培日历制定减少追肥管理以控制叶片颜色。

A three-year project aming at stable-high-yielding cultivation of rice by developing a cultivation calendar which schedules the cultivation management using leaf color meters has been completed. The leaf color meters used for this experiment were SPAD-501 and SPAD-502. A field experiment was conducted. Lab tests using soil bins were conducted. The DSSP and the conventional transplanting method were tested.Initially, the measurement on the leaf color was taken only for the ear leaf. During the experiment it was found that the maximum value among the values of leaf color taken from the upper three leaves including the ear leaf substantiates the SPAD value. Those SPAD values were used to develop the cultivation calendar. It was also found that broad differences in leaf color between varieties were exist even under the same cultivation condition. However, the difference in leaf color due to the varietal difference can be compensated by using appropriate conversion factors. The future task should be the determination of those conversion factors for every variety of rice. The cultivation calendar developed based on SPAD values much differs from the ones based on the Fuji leaf color scale. The key points that the newly developed cultivation calendar includes are to have more number of stalkes per hill than conventional and to maximize the number of grains per head. This originates the difference in the leaf color management between the newly developed method and the conventional method based on the V shape theory. Some demonstrative operation to prove the effectiveness of the newly developed method were conducted using some commercial rice production fields. A high yield has been expected.For the future study the following management is expected to develop. A reduced-top-dressing-management to control the leaf color according to the newly developed cultivation calendar must be developed.