生育约束型直播水稻生育特征与稳产关键技术

随着农村优质劳力减少和劳动力成本攀升以及农业规模化经营的发展,直播水稻作为一种轻简化的种植技术应用面积不断扩大。因此,促进直播水稻稳产与增产对保证中国粮食安全具有重要意义。根据我国南方多熟制地区直播水稻生产特点,笔者提出了生育约束型直播水稻的概念,即受前茬作物的影响,直播水稻较移栽水稻播种晚,全生育期缩短,温光资源利用减少,加上前茬秸秆全量还田和短农耗期内粗放或半粗放化整地播种,造成种子和苗期都处于多种逆境下,显著制约了水稻的正常出苗与生育,使水稻产量不高不稳。这种生育约束型直播水稻在生产上应用已较为广泛,制约了大面积平衡增产。为此,有针对性地探究了生育约束型直播水稻稳产栽培途径,选用江苏代表性的穗粒兼顾型粳稻品种,在大面积有代表性的简化耕作播种条件下,通过设置基本苗量120万/hm ²、240万/hm ²和360万/hm ²处理,分别代表分蘖为主成穗型、主茎分蘖成穗并重型、主茎成穗型3种栽培途径,系统比较研究各类型水稻群体光合物质生产特征、产量与品质特征,初步认为“适当增加基本苗,增加主茎成穗比例,以主茎成穗为主,通过足量主茎穗数产出较高群体颖花量,在生育中后期积累更多的干物质量”是利于生育约束型直播水稻稳产增效的有效栽培途径。本文中还介绍了生育约束型直播水稻稳产栽培关键技术,并对合理发展直播水稻提出了建议。

Growth Characteristics and Key Techniques for Stable Yield of Growth Constrained Direct Seeding Rice

With the decrease of high-quality labor in rural areas, the rising of labor cost and the development of large-scale production, direct seeding as a simplified rice planting technology was widely used continuously. Therefore, the promotion of its stable or increased yielding was of great significance in ensuring food security in this country. According to the growth characteristics of direct seeding rice in multiple cropping area of South China, a concept of growth constrained direct seeding rice was put forward. In other words, the rice emergence and seedling growth under direct seeding were significantly imitated and affected by multiple adversities, which were caused by 100% returning the previous crop straw to the field and lower quality of ploughing and sowing in short crop rotation time. And the rice later sowing date under direct seeding method than transplanting rice shortened the plant growth duration, reduced the utilization of temperature and light resources, and imitated the rice growth, as affected by the previous crop. Thus the yield of direct seeding rice was not high and instable. For now, this kind of growth constrained direct seeding rice was widely used in production and restricted the balanced production increase in large area. Therefore, the stable yield cultivation methods of growth constrained direct seeding rice were explored in this paper. The comparison experiments were carried out with a representative japonica rice variety in consideration of more panicles and more grains in Jiangsu, and the treatments of 1.2 million, 2.4 million and 3.6 million basic seedlings per hectare, under representative simplified cultivation and sowing methods on a large scale. With the basic seedlings treatments, three cultivation ways of growth constrained direct seeding rice were formed respectively, including panicles formed with more tillers, panicles formed with both stems and tillers, and panicles formed with more stems in the experiment. The characteristics of photosynthetic matter production, yield and quality of different types of rice were systematically analyzed. “The basic seedlings of rice should be increased appropriately to increase the ratio of main stem to panicle and produce more spikelets with sufficient main stem, and then the dry matter in middle and late growth duration would be produced and accumulated more and more” was tentatively believed as an effective cultivation way for stable yield, high quality and efficiency of growth constrained direct seeding rice. The key techniques of stable yield cultivation and reasonable development suggestions of growth constrained direct seeding rice were also introduced in this paper.