气力式水稻穴播机播种精度与田间成苗率关系的试验研究

气力式水稻精量穴直播技术是一种播种精度高、伤种率低的播种技术。为进一步研究气力式水稻穴播机播超级杂交稻品种时田间成苗率与播种精度的关系,该文选取3种超级杂交稻"Y-2优"、"超优1000"、"五丰优615"为研究对象,进行了实验室内发芽率试验与田间播种精度试验,建立了稻种发芽率与播种精度对田间成苗率的关系公式,采用10行气力式水稻精量穴播机进行田间试验。3种超级杂交稻的室内发芽率分别为94%、91%、92%;播种合格率(1~3粒/穴率)分别为94.98%、95.07%、95.21%,空穴率分别为1.78%、2.03%、1.95%,利用本文建立的关系公式计算出理论成苗率为96.85%、95.79%、96.07%,田间实际成苗率分别为94.22%、93.94%、93.76%(均低于理论计算成苗率结果)。分析了影响田间成苗率的主要因素,为提高田间成苗率,一是应进一步提高播种精度,减小空穴率与1粒/穴率,提高2粒/穴率,二是进一步提高稻种发芽率。该文的研究结果可为气力式排种技术在超级杂交稻精量直播中的应用提供参考。

Experimental study on relationship of seeding precision and germination rate in field of pneumatic rice hill-drop drilling planter

Abstract: Rice is the staple food for more than half of the global population, and the rice production, especially planting, needs a lot of labor force, material and financial resources. At present, the rice mechanized planting level is low in China. According to statistics, the mechanization level of rice planting in China was only 44.45% in 2015. The main ways of planting are artificial seeding and transplanting. The mechanization of rice direct seeding technology mainly includes mechanical seeding, mechanical drilling, and hill-direct-seeding. Compared to mechanical transplanting, mechanical direct seeding can avoid the process of raising rice seedlings, reduce the input of prophase cost, and does not affect yield. It is expected to be the developing trend in mechanized rice planting in the future. Normally, it is difficult to control the precision of mechanical sowing and mechanical drilling. This leads to uneven seedling distribution and affects the growth and field management of rice. In recent years, due to the increase of labor cost, the cost of rice planting has also increased. It is imperative to develop the mechanized planting of rice. The mechanization of rice direct seeding can eliminate rice seedlings process and save the labor and material consumption. Super hybrid rice has stronger tillering ability than ordinary hybrid rice. By using direct seeding technology, the high yield population structure can be formed with only 1-3 seeds per hill. The pneumatic rice precision direct seeding technique is a combination of machinery and air flow. This technique has the advantages of high seeding precision, low seed damage rate, and strong adaptability and can satisfy the seeding demands of many kinds of seeds. However, existing pneumatic seed metering devices are mainly for soybean, corn, wheat, rape and other crops. Seed metering devices have been widely used in actual production, and theoretical research is also relatively mature. In this study, the relationship between emergence rate in the field and seeding precision are studied with the pneumatic rice direct seeder seeding super hybrid rice. The relation formula between the germination rate of rice seed and the precision of seeding was established. The field experiments were conducted using pneumatic rice seeder with 10 seed metering devices. 3 kinds of super hybrid rice, which named "Y-2 You", "Chao you 1000" and "Wu feng you 615" respectively, were selected as the research objects. The tests of germination rate in the laboratory and the precision of seeding in the field were carried out. The germination rate was 94%, 91% and 92%, respectively. The seeding qualified rate (the probabilities of 1-3 seeds per hill) was 94.98%, 95.07% and 95.21%, respectively. The probability of empty hill was 1.78%, 2.03% and 1.95%, respectively. The relation formula established in this study was used to calculate theoretical seedling survival rate. The theoretical seedling survival rate were 96.85%, 95.79% and 96.07%, respectively. The actual seedling survival rate in the field were 94.22%, 93.94% and 93.76%, respectively, which were lower than those calculated by theoretical calculation. The main factors that affect the seedling survival rate in the field were analysed. In order to improve the seedling survival rate in the field, 1) the precision of seeder should be further improved, the probability of empty hill and the probabilities of 1 seed per hill should be reduced, and the probabilities of 2 seeds per hill in the agricultural machinery should be increased, 2) the germination rate of rice should be further improved in the agronomy. The results of this study provided a basis for the application of the pneumatic seed metering technology to the precision direct seeding of super hybrid rice.