Studies On The Technique Of Chemical Weed Control In Narrow Row Solid-Seeding Soybean Field

The narrow row solid-seeding is planting technique of a high yield soybean with widely prospect, which needs combine with a complete set of techniques including improving cultivars, weed control, improving machinery and so on. Chemical weed control is a key technique for narrow row solid-seeded soybean, which is also a major factor about confining its development and extension. The best herbicides combination was screened out and the technique of chemical weed control was established in the solid-seeding soybean field through investigation of the weed community, occurrence and harm rule in this paper.The results of investigation through the method of curvilinear "W" showed that the weed communities were various in solid-seeded soybean field of different Shenyang military farms. Wherein, the Suiling farm of Jilin military was the predominant weed community of Avena fatua L. + Commelina communis L. + Eriochloa villosa (Thunb.) Kunth, the Longzhen farm of Shenyang military was the predominant weed community of Echinochloa crusgalli (L.) Beauv.+ Avena fatua L.+Glycine soja, the Dedu farm of Heilongjiang military was the predominant weed community of Echinochloa crusgalli (L.) Beauv. + Xanthium strumarium L.. In these areas, soybean weed occurrence period was 33 days or so, the pinnacle was 10 days or so, which showed the characteristic was fulminant, high density and in-phase of pinnacle of soybeans and weeds. The yield of soybeans was influenced by the density of predominant weeds and the period of intergrowth between weeds and soybeans. According to the concept of economic threshold, the curve between occurrence density (x) of weeds of Avena fatua L. and the soybeans income (y) after chemical weed control was established, which was y = 2267.2Ln(x) - 4934.2. Hence, the academic threshold of control Avena fatua L. was 10.75 plant/m2. The longer the period of Avena fatua L. was, the lower the yield of soybeans was. The 61.1% yield of soybean was reduced, when their whole growth duration was intergrowth.According to the occurrence rule of weed in narrow row solid-seeding soybean field, we ascertained the best scheme of chemical weed control was the technique two times using herbicides, those were preemergence soil treatment and postemergence folia treatment respectively.Through field trial, the herbicides (combination) groups fitted for different periods wereoptimized.(1) The herbicides (combination) groups applied in preemergence soil treatment w ere Flumioxazinl80g/hm2+ Acetochlor2200ml/hm2, Flumetsulam70g/hm2+ Acetochlo r2200ml/hm2.(2) The herbicides (combination) groups applied in postemergence foliar treatment were Fluazifop-P-buty 1000ml/hm2+ Fomesafen 1500ml/hm2.(3) The herbicides (combination) groups applied in two times treatment of preemergence and postemergence were preemergence (Imazethapyr 1750ml/hm2) + preemergence( Fluazifop-P-buty 1000ml/hm2 + Fomesafen 1500ml/hm2 ) , preemergence (Imazethapyr 1750ml/hm2) + postemergence (Fluazifop-P-buty 750ml/hm2+ Fomesafen 1000ml/hm2) , preemergence (2,4-D 2000ml/hm2) + postemergence (Fluazifop-P-buty 1000ml/hm2 + Fomesafen 1500ml/hm2) .This study made clear that the character of compose, occurrence and harm of the weed community in narrow row solid-seeding soybean field. Those established the base for applying herbicides on the basis of weeds and provided the academic basis for father research about the technique of chemical weed control in narrow row solid-seeding soybean field. The best scheme of chemical weed control and the herbicides (combination) groups in our studies settled the question of weed in narrow row solid-seeding soybean field, provided the technical ensure for bringing planting technology of narrow row solid-seeding into effect, and accelerated to generalize and apply the technology of narrow row solid-seeding, and played an important role in increasing soybean yield, enhancing income of farmer and driving agricultural economic development.Candidate: Gao Tongbin Specia...