稻茬高度对谷林套播油菜生长发育及产量形成的影响

摘要

[Objective] Under the pattern of interplanting rapeseed in late rice, standing stubble height affected soil water storage and preservation, interplanting rapeseed emergence rate, growth and development. This study aimed at finding out a proper standing stubble height to promote emergence rate, growth and development, and finally to improve yield of interplanting rapeseed. These results provide practical references for reaching efficiency and organic combination of agronomy with agricultural machinery.[Method] Fengyou 730, a elite rapeseed cultivar, was employed in a field experiment with four stubble height treatments during the 2014-2016 growing seasons at Jiangxi Institute of Red Soil, Jiangxi province. Four stubble height treatments were compared: 20, 30, 40 and 50 cm. The seedling rate, mature plant rate, agronomic traits at two growth stages (wintering stage and full bloom stage), chlorophyll content of leaves, root activity, yield were measured in this study.[Result]In the range of 20-50 cm, an increased stubble height could thoroughly promote the seedling density, the seedling rate and mature plant rate were increased at the initial stage but deteriorated under a further increased stubble height, the optimal seedling rate and mature plant rate were the treatment with stubble height of 40 cm, the mature density was relatively larger. The seedling rate and mature plant rate of 40 cm stubble height were 13.73%, 7.09% and 13.18%, 7.23% higher than that of 20 cm and 30 cm, respectively, but the differences were not significant between 40 cm and 50 cm. Stubble height significantly affected growth and development of interplanted rapeseed. The number of total leaves, number of green leaves, width of maximum leaf, crown diameter, the dry weight of individual plants and the chlorophyll content of the top 3 leaves, root activity were gradually fell, the length of maximum leaf was gradually increased, the leaf area index and dry matter of population plants were primitively increased and then subsequently fell with increasing of the stubble height. The yield per plant of interplanted rapeseed in rice was diminished, whereas the yield per area was heightened initially and diminished later with increasing of the stubble height, and the optimal rapeseed yield could be approached with stubble height of 40 cm. Compared with the stubble height of 20 cm, the yield increasing rate of the stubble height of 40 cm was 18.92%, the yield increased obviously. Stubble height was highly related to yield components of interplanted rapeseed in rice including primary branches, siliques per plant, siliques on main inflorescence, 1000-grain weight, dry matter weight per plant, and yield per plant with a substantial negative correlation or significant negative correlation.[Conclusion] A lower seedling rate, mature plant rate and mature density, but strong individuals under a lower stubble height as well as a higher mature density and weak individuals under a higher stubble height could result in yield reduction. Results of the study indicated that late rice stubble height of 40 cm was helpful to population growth and strongly improved the yield of interplanted rapeseed.%[目的]在晚稻-油菜套种模式下,稻茬高度对套种油菜田土壤蓄水保墒、套种油菜出苗及生长发育均具有重要影响.本研究旨在探求适宜套播油菜出苗、生长发育及高产的晚稻机收留茬高度,为实现农艺、农机高效有机结合提供参考.[方法]试验于2014—2016年在江西省南昌市进贤县江西省红壤研究所进行,以丰油730为试验材料,在大田条件下设4个稻茬高度(20、30、40、50 cm).通过测定套播油菜成苗率、成株率、越冬期和盛花期农艺性状、叶片叶绿素含量、根系活力、产量及构成因素,比较分析晚稻不同留茬高度对套播油菜生长发育、产量的影响.[结果](1)在20—50 cm范围内,留茬高度增加有利于提高套播油菜出苗期密度,且成苗率和成株率随着留茬高度增加先增加后下降,以留茬40 cm处理最大,成熟期密度也相对较大.与留茬20 cm、30 cm处理相比,留茬40 cm处理成苗率和成株率分别提高了13.73%、7.09%和13.18%、7.23%,与留茬50 cm处理差异不大;(2)留茬高度显著影响套播油菜生长发育.油菜总叶数、绿叶数、最大叶宽、根颈粗、单株干重等个体指标及顶部3片全展叶叶绿素含量和根系活力随留茬高度增加而下降,最大叶长随留茬高度增加而增加,叶面积指数和群体干重等群体指标随着留茬高度增加先增加后下降;(3)套播油菜单株产量随着留茬高度增加而下降,单位面积产量随着留茬高度增加先增加后下降,以留茬高度40 cm产量最高;相比产量最低的留茬20 cm处理,增产18.92%,增产效果显著.留茬高度与套播油菜成熟期的一次分枝数、单株角果数、主序角果数、千粒重、单株干重、单株产量等产量相关性状关系密切,均达到极显著或显著负相关.[结论]留茬过低,成苗率和成株率低,尽管个体生长发育较好,但成熟期密度不足不利于高产群体构建;留茬过高,成苗率和成株率显著提高,但个体生长发育偏弱,不能发挥群体生长优势,最终影响产量形成.在4个稻茬高度下,留茬高度以40 cm为宜,套播油菜群体生长和产量表现优势明显.