双草醚悬浮剂对直播稻田杂草防效及水稻产量的影响

为探讨10%双草醚悬浮剂（农美利）在南方直播水稻田中的安全性及其对杂草的防效,特进行了直播早稻田和中稻田杂草的田间药效试验。结果表明,农美利与对照药剂稻杰一样,对水稻直播田稗草、鸭舌草、陌上菜、节节菜、异型莎草等杂草有较好的防除效果,对直播水稻安全无药害;建议在水稻直播田除杂草时,农美利的有效成分用量为22.5-30.0 g/hm2,在水稻播后3叶期以上、杂草2-4叶期时,对茎叶喷雾防效最佳。     

广东省杂草稻发生与分布情况调查

为明确广东省杂草稻的发生与分布情况以及生物学特征,为广东省杂草稻的防治提供基本信息,通过采用目测法和样方法点面结合,调查广东省栽培稻田杂草稻的发生与危害情况,对调查的杂草稻生物学特征与其发生率、发生密度、综合危害指数综合进行分析,结果显示,广东省杂草稻的发生率为0.00%~33.11%,发生密度最低的县（市）约0,最高约18株/m2,综合危害指数都在20%以上。以雷州、惠东尧封开和恩平最为严重,杂草稻密度依次为18.10、2.52、1.60、0.96株/m2,综合危害指数依次为56.00%、45.00%、29.20%和15.80%。杂草稻植株较高、分蘖较强、叶色偏淡、成熟早、易落粒、种皮红色、籽粒偏籼型,得出广东省不同稻作区杂草稻发生与分布情况依次为粤西南稻作区>粤中南稻作区>粤中北稻作区>粤北稻作区,且杂草稻发生率为直播田>抛秧田>移栽田。     

17%苄·二甲戊WP防除水稻移栽田杂草的效果

采用田间小区试验方法,研究了17%苄.二甲戊WP对水稻移栽田主要杂草的防除效果,同时测定了其对水稻产量以及杂草氮、磷、钾和水分含量的影响。结果表明,有效成分用量为89.25～255.00 g/hm2的17%苄.二甲戊WP施药后50 d,稗草的密度防效和鲜重防效分别为88.45%～99.44%、91.63%～98.56%,鸭舌草的密度防效和鲜重防效分别为97.64%～100.00%、95.91%～100.00%,异型莎草的密度防效和鲜重防效分别为85.76%～99.03%、86.89%～99.38%;显著优于对照药剂33%二甲戊灵EC和10%苄嘧磺隆WP。施用17%苄.二甲戊WP能降低杂草对田间养分和水分的吸收,从而提高水稻产量。     

34%丙炔氟草胺·二甲戊灵乳油对棉田阔叶杂草的防除效果

【目的】研究丙炔氟草胺与二甲戊灵混配剂的除草作用及对棉花的安全性,为新疆棉田杂草防除系统提供新方案。【方法】以二甲戊灵为参比对照,通过田间药效试验方法测定丙炔氟草胺单剂、丙炔氟草胺·二甲戊灵混配剂对棉田杂草的控制作用,评价药剂对棉花的安全性。【结果】34%丙炔氟草胺·二甲戊灵乳油在剂量175~200 mL/667 m²下对3种杂草的效果均较好,与对照药剂42%丙炔氟草胺悬浮剂相比,无显著差异,与对照药剂33%二甲戊灵乳油相比,优于该药剂。【结论】丙炔氟草胺·二甲戊灵混配剂的阔叶杂草的防除效果优于二甲戊灵,对棉花安全,可在新疆地区进行推广使用。     

Management of rice straw with relay cropping of Chinese milk vetch improved double-rice cropping system production in southern China

Improved utilization of rice(Oryza sativa L.) straw and Chinese milk vetch(Astragalus sinicus L., vetch) has positive effects on rice production. So far, few studies have investigated the productivity of vetch under different residue management practices in double-rice cropping system. The effects of rice straw on the growth and nutrient accumulation of vetch across seven years(2011–2017) and the subsequent effects of rice straw and vetch on two succeeding rice crops in a vetch–rice–rice cropping system, with the vetch established by relay cropping, were examined. The seven-year double-rice experiment consisted of the following treatments:(1) 100% chemical fertilizer(F-F100);(2) only vetch without chemical fertilizer(M-Con);(3) 80% chemical fertilizer plus vetch plus a low-cutting height(low-retained stubble) with the removal of straw(M-F80);(4) 80% chemical fertilizer plus vetch plus a low-cutting height with the retention of straw(M-F80-LR);(5) 80% chemical fertilizer plus vetch plus a high-cutting height(high-retained stubble) with the retention of straw(M-F80-HR); and(6) no fertilizer(F-Con). The yields of the two rice crops after vetch were not affected by either the cutting height of stubble with retention of straw or by the management of straw(retention vs. removal) with low-cutting height of stubble. The yields of the two rice crops after vetch were significantly higher for M-F80-HR than for M-F80-LR, but the relative contributions of the high-cutting height and straw retention to the higher rice yield could not be determined in this study. The yield stability of the double-rice grain in M-F80-HR was also increased, as determined by a sustainable yield index. Significant increases in vetch biomass and nutrient uptake were observed in the fertilized treatments during the rice season compared with the unfertilized treatments. In M-F80-HR plots, improvements in the growing environment of the vetch by conserving soil water content were associated with the highest vetch biomass, nutrient uptake, and yield stability of vetch biomass. These increased nutrient inputs partially replaced the demand for chemical fertilizer and stimulated the rice yields. It can be concluded that retaining higher-cutting stubble residues with straw retention could be the best straw management practice for increasing the vetch biomass and nutrient use efficiency, thereby allowing utilization of high-cutting height with retention of straw and vetch to improve the stability of rice productivity in a double-rice cropping system.     

不同密度杂草稻对栽培稻光合特性及灌浆进程的影响

以杂草稻JS-Y1和栽培稻南粳44为材料,通过田间小区试验研究了不同密度(1 m20株、1 m22株、1m24株、1 m26株、1 m28株)的杂草稻对栽培稻光合特性及灌浆进程的影响。结果表明,随着杂草稻密度的增大,栽培稻分蘖期和灌浆期的净光合速率及灌浆期的穗增重速率和净同化率均降低。不同密度杂草稻处理下的栽培稻产量分别比对照(1 m20株)处理降低了24.94%、31.40%、33.69%、60.14%。表明,杂草稻密度越大,栽培稻灌浆期的净光合速率越低,产量越小。     

氯嘧磺隆降解菌降解效果研究

近年来除草剂在土壤中持续积累,对后茬敏感作物造成严重药害,导致作物减产甚至绝产,氯嘧磺隆就是其中一种广谱、超高效和残留期较长的磺酰脲类除草剂。该试验通过氯嘧磺隆降解菌的筛选并作用于受氯嘧磺隆药害的萌芽水稻种子,利用测定筛选出的氯嘧磺隆降解菌对氯嘧碘隆的降解作用来研究其对氯嘧磺隆的降解作用效果。结果表明:所筛选的氯嘧磺隆降解菌对氯嘧磺隆有一定的降解作用。在同一菌不同浓度下,氯嘧磺隆5μg.kg-1时降解效果最好。在同一氯嘧磺隆水平下,降解菌稀释倍数为100倍时降解效果最佳。     

江苏沿江地区杂草稻的生物学特性及危害调查

【目的】明确江苏沿江地区杂草稻的发生现状、危害和生物学特性,掌握其鉴别方法。【方法】采用目测法和样方法点面结合,调查江苏沿江地区6个市的28个县（市、区）的直播稻田杂草稻的发生率、发生密度、综合危害指数,定点研究6个地点的杂草稻生物学特性及其危害性。【结果】杂草稻在各县（市）的发生率从78%-100%不等,发生密度最低的县（市）约2株/m2,平均最高约9株/m2,综合危害指数都在20%以上,导致栽培稻减产8.3%-82.3%;泰州、扬州和常州的危害相对更重。综合6个地点的调查结果显示杂草稻与栽培稻主要区别为：杂草稻的叶环和叶耳呈紫红色,植株基部褐色;苗期生长旺盛,分蘖力强、分蘖角大于栽培稻20°以上,株高高出8-10 cm;株型松散;单株结实量高于栽培稻3倍以上,繁育系数显著高于栽培稻,但结实率较低,为78%-86%,千粒重仅为18.93-20.10 g;成熟期早1月左右并显早枯。【结论】江苏沿江地区的杂草稻发生量大且危害严重;杂草稻与栽培稻有形态学差异;杂草稻的分蘖初期、扬花期是人工拔除的适宜时期。     

东北稻区杂草稻种子的越冬特性

东北稻区杂草稻经历了蔓延、大发生过程之后,近期进入衰弱态势,分布区域由过去大发生的东部稻区转移到降水量少的西部稻区。在东北稻区,稻田落粒的杂草稻种子只能以"干态"安全越冬,"湿态"种子不能安全越冬的主要原因在于其无休眠性;杂草稻种子安全越冬能力介于杂草类种子与栽培稻种子之间,其安全越冬能力强于栽培稻种子的原因在于种皮厚、吸水速率低、低温水中生存能力强、萌发后的种子耐旱性强,而脂肪酸、蛋白质含量差异不大。分析认为,杂草稻种子低温发芽能力强,秋季遇水易发芽而冬季冻死现象与其种子萌发期淀粉酶低温活性高于栽培稻种子相关。     

超高茬麦田套稻田间杂草防除效果研究

[目的]采用超高茬麦田套稻技术田间杂草危害严重,是其大面积推广应用的主要障碍之一,通过不同药剂的防效试验筛选最佳除草剂。[方法]选用35.5%丁.恶乳油等除草剂在水稻套播后和小麦收割后,用毒土法先后2次处理麦田套播水稻田,调查防效。[结果]除草效果以35.5%丁.恶乳油2 250 ml/hm2最佳,其后依次为30%丁.苄1 500 ml/hm2、50%杀草丹3 000 ml/hm2＋10%苄磺隆225 ml/hm2、50%苯噻草胺750 ml/hm2＋10%苄磺隆225 ml/hm2,而36%二氯.苄750 ml/hm2效果最差;用药时间越早,对禾本科杂草防效越好,供试药剂持效期均为45 d左右;中、后期可根据田间杂草发生情况辅以茎叶处理,效果更佳。[结论]以稗草和阔叶杂草为主的田块,5种药剂均可使用;以千金子和阔叶杂草为主的田块,除36%二氯.苄750 ml/hm2外,其他4种药剂均可使用;以莎草科和阔叶杂草为主的田块,可用含有苄磺隆的复配除草剂,或单用10%苄磺隆225～300 ml/hm2进行防除。供试药剂均对水稻安全。     

杂草稻生物学特性、发生与防控研究进展

杂草稻Oryza sativa f.spontanea是一种伴生性的稻田恶性杂草,和栽培稻Oryza sativa同属禾本科Poaceae稻属Oryza,具有生长势强、易脱粒、休眠性强、耐逆等特性;其起源主要是由栽培稻品种去驯化而成。杂草稻的发生严重影响栽培稻产量,降低稻米品质,影响稻种纯度,且难以防除。中国杂草稻发生分布不均,在广东、辽宁、宁夏、江苏、江西、黑龙江、安徽、山东、浙江等地均有发生,且发生程度不同。其发生原因主要有农机跨区作业、栽培技术改变、选择性除草剂缺乏等。目前常采用人工拔除,调整栽培方式（套播、直播转变为移栽、机插）,实施水旱轮作,施用丙草胺类除草剂等方式防除,但尚未有非常有效的防控措施。此外,由于杂草稻的变异类型丰富,其遗传背景又与栽培稻相似,因此可作为栽培稻改良的重要种质资源。     

Occurrence pattern and morphological polymorphism of Chinese weedy rice

Rice, the main food crop in China, has been sporadically reported to suffer from weedy rice infestation. However, the overall occurrence and distribution pattern of Chinese weedy rice remains unclear because a systematic survey has not been conducted. In order to reveal the infestation of Chinese weedy rice, a field survey was conducted in 999 sampling sites all over the rice-growing regions in China from 2009 to 2016 using seven-scale visual scoring of the level of weed infestation. Weedy rice was found 39% occurrence incidence in a total of 387 sites. The sampling sites with 50% or higher overall weedy rice infestation index mainly radiated from Jiangsu, Heilongjiang, Ningxia and Guangdong to the whole East China, Northeast China, Northwest China and South China. A total of 45 morphological characters from 287 populations (collected simultaneously with the field survey) out of those occurred sites were observed and analyzed using multivariate analysis in common gardens with the same cultivation conditions in 2017 and 2019. Canonical correlation analysis showed that 45 morphological characters were significantly related to the latitude, mean temperature, minimum temperature, precipitation and mean diurnal range factors. The 287 weedy rice populations were divided into three morphological groups with climate-dependent geographical differentiation: strong tiller type only in Jiangsu, large leaf type in South China and Central China and large grain type mainly in North China. Weedy rice seriously infested rice fields and had a geography, climate and cultivated rice type-dependent morphological and biotype differentiation in China. It is suggested to pay attention to the harmfulness of weedy rice and adopt comprehensive control strategies.     

抛栽水稻田间杂草生态防治阈期

通过多年多点试验 ,建立抛栽水稻大田立苗后有草天数或无草天数与水稻产量损失率之间的函数关系 ,以探明抛栽水稻田间杂草的生态防治阈期。结果表明 :抛栽水稻田间杂草的生态防治阈期 ,汕优 6 3为抛后 14～ 2 3d ;武运粳 8号为抛后 12～ 31d ,此时水稻处于 6叶期至 8叶期 ,此阈期的始期和终期为田间杂草密度及生物量的快速增长期。在此阈期内保持田间无草 ,既能使杂草造成的水稻减产率低于 3% ,又能充分发挥杂草在田间生态系统中所起的积极作用     

稻秆覆盖结合除草剂减量化使用对移栽豆角田杂草的控制效果

为了明确稻秆覆盖结合除草剂减量使用对移栽豆角田杂草的控制效果及对产量的影响,采用大田试验的方法,将乙草胺和二甲戊乐灵按常量（田间常规推荐剂量）,半量（1/2 常量）,1/4 量（1/4 常量）分别与稻秆覆盖相结合,调查不同处理对移栽豆角田杂草发生及豆角产量的影响。结果表明：从豆角移栽至收获,若仅用稻秆覆盖对豆角田杂草的株防效和鲜重防效分别为64.7%和61.9%;若将除草剂与稻秆相结合使用,从对总草的控制效果看,二甲戊乐灵各剂量与稻秆相结合均不同程度高于乙草胺相应剂量与稻秆相结合效果。二甲戊乐灵1/4 剂量与稻秆相结合对豆角田总草的株数和鲜重达到了较好的效果,分别为88.7%和83.9%,且具有一定的增产效果,增产率为320.0%。     

Co-application of compost or inorganic NPK fertilizer with biochar influences soil quality,grain yield and net income of rice

Most agricultural soils in sub-Saharan Africa are degraded, compromising the grain yield of rice and farmers return on investment. A 3-year field study was undertaken to explore the effect of the application of compost or inorganic NPK fertilizer applied alone or in combination with biochar on soil quality, grain yield of rice and net income. The five treatments were laid out using a randomized complete block design with four replications. The treatments were applied to supply approximately 75 kg N ha^–1. The best fertilizer input was compost+biochar which resulted in the greatest improvement in soil physico-chemical properties by reducing bulk density and increasing porosity and moisture retention, organic matter content, percent nitrogen, available phosphorus and cation exchange capacity. Apart from treatment with inorganic fertilizer alone, treated soils showed a decrease in pH. Bacterial and fungal counts and basal respiration decreased in soils in the following order: compost+biochar>compost only>inorganic NPK fertilizer+biochar>inorganic NPK fertilizer>control. The increase in pooled grain yield and net income in response to treatment followed the order: compost+biochar>NPK+biochar>NPK>compost>control. The findings suggest that the use of compost or NPK alone might improve soil quality and increase grain yield and net income, but it is greatly recommended to co-apply these fertilisers with biochar.     

轮叶党参栽培地适宜化学除草剂筛选的研究

为解决轮叶党参栽培过程中的除草难题，进行了对轮叶党参适宜化学除草剂筛选的研究。试验结果表明：适宜苗前土壤处理剂为敌草胺和除芽通，两种除草剂混合处理可扩大杀草谱。轮叶党参实生苗地播后苗前适宜处理剂量为(1．0 0．7)kg a．i／hm^2。1年生以上秧苗移栽田苗前适宜处理剂量为(1．5 1．0)kg a．i／hm^2，对1年生杂草的防除效果可达到90％。该混剂药效发挥的适宜土壤湿度范围是70％左右，土壤湿度过高易造成药害，过低降低药效。适宜茎叶处理剂为拿捕净及芳氧苯氧基丙酸类除草剂；1年生以上的轮叶党参对克芜踪有一定的耐性。     

水直播稻田稗、水莎草的危害损失与复合防除指标

在稗、水莎草自然混生条件下对水直播稻产量损失测定的基础上，建立了水稻产量损失预测模型：Y＝368．8362－8．4888X1－0．3524X2，并进一步推导出5种不同除草措施的经济阈值，提出相应的复合防除指标，即水直播稻田杂草密度分别达到稗1株/m^2和水莎草30株／m^2时，需用“二氯喹啉酸＋吡嘧磺隆”等除草措施进行防除。     

温州农区早稻抛秧田的杂草发生特点与化学除草技术研究

温州农区早稻抛秧田杂草发生种类以稗草、矮慈菇、节节菜、异型莎草、牛毛毡为主,稗草为优势种群,杂草危害程度重于插秧田。抛秧后２ｄ杂草开始陆续出苗,抛后１０ｄ呈现出苗高峰,比插秧田早５ｄ,稗草的出苗高峰出现于抛秧后５～１０ｄ。经３年试验证明,禾大壮＋苄嘧磺隆,二氯苄和丁苄对禾本科、莎草及阔叶草均有良好防效,对水稻安全,增产幅度大。不同施药期试验表明,二氯苄和丁苄分别于抛秧后３～５ｄ和５～９ｄ使用,对水稻株高和分蘖有明显抑制作用,故安全有效用药期应为抛秧后７～１１ｄ和１１～１３ｄ。     

杂交水稻与稗草种间竞争的优势表现 Ⅱ.水稻与稗草在混播栽培中的种间竞争分析(英文)

试验结果表明,水稻在稗草的竞争干扰下,其产量损失可用Ｙ＝ａ＋ｂｅ－０．３３３ｘ２数学模型来预测．水稻减产主要与稗草密度增大引起水稻单位面积分蘖数减少（Ｙ＝ａ＋ｂｅ－０．３３３ｘ）有关．在作物—杂草系统竞争中,杂交水稻具有较高的竞争生长渐近线下限,因而是较好的竞争者．这是由于与常规稻相比,杂交水稻有分蘖力强、叶面积增长快、净光合作用强之特性。因此,认为杂交水稻在与农田杂草竞争中要比常规稻显示更强的竞争优势．     

超级稻中浙优1号蓄留再生稻高产栽培技术研究

[目的]为超级稻中浙优1号蓄留再生稻获得高产提供理论依据。[方法]以品种中浙优1号为研究材料,研究头季稻收割成熟度、收割后留桩时间和定桩高度3个因子对再生稻苗情、有效穗、结实粒数、千粒重和实际产量等的影响。[结果]头季稻在80%、85%成熟度时收割再生稻产量最高;头季稻收割后,留桩时间越短产量越高;定桩高度为10 cm时产量最高,其次是15、20、5 cm。[结论]中浙优1号蓄留再生稻时要掌握好头季稻收割成熟度、留桩时间和定桩高度,才能获得高产。