Abstract:

The combination of machine transplanting and returning of total wheat straw has become main recommended technology of rice production in Jiangsu province. However, there exist some problems in machine-transplanted rice production, such as weak seedling quality, long revival time and late tillering. The traditional soil preparation of paddy field was water harrow. Frequently soil plowing, soaking and poor soil permeability were not conducive to early rooting and tillering. It is helpful to alleviate these problems by adopting dry harrow. There were few studies on the effects of dry harrow in paddy field on the tiller dynamics, grain yield, root system and soil characteristics under the combination of machine transplanting and total wheat straw returning. Therefore, some experiments were conducted using Zhendao 99 as material. The results showed that, there were some differences in the tiller dynamics of dry harrow in different years; the peak seedling of dry harrow was similar with that of water harrow, while the panicle rate was higher than that of wet harrow; compared with water harrow, the yield of dry harrow was increased by 8.36%, the effective panicles per unit area were higher and the spikelet number per panicle was lower, while the seed setting rate was higher; the dry harrow had higher leaf area index at heading and middle grain-filling stage, and higher spikelets per unit area, the photosynthetic area of middle and late stage was increased obviously. The dry matter weight at heading and mature stage, and economic coefficient of dry harrow were higher than those of water harrow. Compared with water harrow, the decline percentage of dry matter weight of stems and leaves at grain-filling stage of dry harrow was lower. Dry harrow had more adventitious roots and higher dry weight of roots per hill, which were beneficial to the occurrence of early tillers and delay leaf senescence in late stage and improve photosynthetic function. Compared with water harrow, the soil redox potential of dry harrow was improved effectively, soil water content was decreased and soil permeability was improved.

Key words: dry harrow in paddy field, machine transplanted rice, grain yield, root system, soil redox potential

摘要：

机插秧与麦秸秆全量还田相结合已成为江苏省水稻生产的主推技术。但机插秧秧苗素质弱，生产上普遍存在缓苗期长、分蘖发生迟等问题。传统的稻田整田方式主要为水耕水耙，翻耕、泡田过于频繁，土壤通透性差，不利于幼苗早发根、早分蘖。采用旱耕旱耙方式有利于减轻这一问题。关于旱整方式对秸秆全量还田条件下机插水稻茎蘖动态、产量形成、根系及土壤有关性状影响的研究极少。为此，笔者在上海农场、江苏五图河农场，研究了麦秸秆全量还田条件下不同整田方式对机插水稻镇稻99上述性状的影响。结果表明，旱整田茎蘖动态年度间有一定差异，高峰苗与水整田相近，但成穗率高于水整田；旱整田产量高于水整田，平均增产8.36%。旱整田单位面积有效穗数多，每穗粒数少，结实率较高；旱整田抽穗期、灌浆结实中期的叶面积系数高于水整田，中、后期光合面积明显增加，单位面积颖花量高于水整田；旱整田抽穗期、成熟期干物质生产量、经济系数均大于水整田，结实期茎鞘叶干物质比重降幅小于水整田；旱整田有利于水稻根系生长，主要生育时期水稻单丛不定根数多、单丛根干质量大，有利于前期分蘖的发生，也有利于延缓后期叶片衰老，提高光合功能；旱整田有效提高了土壤氧化还原电位，降低了土壤含水率，改善了土壤的通透性。

关键词: 水田旱整, 机插水稻, 产量, 根系, 土壤氧化还原电位