Effects of Integrated Rice-Cum-Fish Culture and Water Regime on Weed Growth and Development in Irrigated Lowland Rice Fields of Northeast Thailand

The presence of the fish species Cyprinus carpio L., Tilapia nilotica L. and Puntius gonionotus Bleeker in irrigated paddy fields resulted in a reduction of the numbers of sedges and broadleaved weeds at low water levels around 5 cm. On the contrary, weed growth was enhanced at higher water levels. Similar results were obtained for the percentage area covered and the species Marsilea crenata . At low water levels the number of uprooted weeds in rice-fish fields was markedly increased if compared to control fields. This indicates that fish prefer shallow areas of rice fields with more abundant food supplies as a feeding place. In rice-fish fields the water was turbid on 77.8 % of the test plots (1 m²) compared to only 47.4 % on the control fields. The findings are explained by the combined action of a 'fertilizing effect' and a 'feeding effect', both of which are due to fish.     

菜草净等防除茄果类蔬菜田杂草试验

48 %菜草净EC 15 0 0、180 0ml/hm2 可有效防除茄果类蔬菜田杂草 ,除草效果可达 90 %以上 ;同时菜草净具有明显的壮苗效果 ,可有效提高蔬菜的株高、茎粗及鲜重等秧苗素质指标。综合考虑节本安全 ,建议菜草净的用量以 15 0 0ml/hm2 为宜。     

阔锄防除花生田杂草效果

田间小区试验表明 ,阔锄对花生田反枝苋、铁苋菜、苍耳、龙葵等一年生阔叶杂草的防除效果明显 ,但对黎、苘麻的防除效果较差。和威霸混用 ,可增加对马唐、稗草等禾本科杂草的防效。适宜施药时期为花生 3～ 5叶期 ,适宜用药量为单用 375～ 4 75ml/hm2 ,与威霸混用的适宜剂量为阔锄 375ml/hm2 ,混加威霸 6 0 0～ 90 0ml/hm2 。在上述推荐剂量范围内 ,对花生安全 ,且除草效果好 ,防治成本低 ,可作为克阔乐等除草剂的替代品种     

Recovery of Pantoea ananatis, causal agent of center rot of onion, from weeds and crops in Georgia, USA

Center rot of onion, caused by Pantoea ananatis, has been a problem of sweet onions in Georgia since 1997. A polymerase chain reaction (PCR) protocol was developed to screen for populations of P. ananatis on plant surfaces. Plant samples producing a positive PCR reaction were targeted for further processing to culture the bacterium. In a survey of the Vidalia onion-growing region of Georgia, we detected and cultured P. ananatis from 25 asymptomatic weed species, which included commonly occurring weeds such as crabgrass (Digitaria sanguinalis), Florida beggarweed (Desmodium tortuosum), Florida pusley (Richardia scabra), sicklepod (Cassia obtusifolia), Texas Millet (Panicum texanum), tall verbena (Verbena bonariensis) and yellow nutsedge (Cyperus esculentus). In addition, the bacterium was recovered from crop plants such as Bermuda grass (Cynodon dactylon), cowpea (Vigna unguiculata) and soybean (Glycine max). Based on the field survey and tests with strains held in storage in the Coastal Plain Experiment Station culture collection, we concluded that P. ananatis was in Georgia prior to 1997, and was distributed widely on weeds and crops throughout southern Georgia.     

特种蔬菜——荠菜的开发利用

农田杂草在我国分布十分广泛。农田杂草中可以食用的野菜称为特种蔬菜,河南省可食用的野菜有200多种。由于野菜食用鲜嫩可口,营养价值高,是真正的无公害绿色产品。本文对荠菜的形态特征、生物学特性、营养与药用价值、食用方法进行了详细的阐述,对人们综合开发利用野菜具有普遍的指导意义。     

草甘膦铵盐可溶性粒剂防治非耕地杂草药效试验

对草甘膦铵盐可溶性粒剂防治非耕地杂草的效果进行了试验研究,结果表明,74．7％草甘膦铵盐可溶性粒剂可有效防除反枝苋、地肤、旱稗、小藜、狗尾草等杂草。74．7％草甘膦胺盐可溶性粒剂是一种苗后茎叶喷雾除草剂,适用于非耕地防除多种杂草,施药时期为杂草出苗后,适宜剂量为2060．0g a．i．／hm^2,药液量750．0L／hm^2。     

胡麻田间杂草防除药剂筛选研究

[目的]筛选对胡麻田间杂草具有较好防除效果的药剂。[方法]测定了不同剂量的40%立清乳油、56%2甲4氯钠可湿性粉剂、8.8%精喹禾灵乳油3种除草剂对胡麻田间杂草的防除效果。[结果]用40%立清600～900 ml/hm2,对水675 kg/hm2,在胡麻苗高约10cm时喷雾,对阔叶杂草防除效果达90%以上,保产效果在70%以上。[结论]为宁南山区胡麻田杂草的有效控制提供了参考。     

除草剂土壤处理对旱直播稻田杂草的防除效果

[目的]筛选对旱直播稻田杂草具有较好防除效果的土壤封闭除草荆。[方法]研究了4种除草剂土壤封闭处理对旱直播稻田阔叶草、禾本科杂草、莎草的防除效果。[结果]除360g／L异嗯草松CS（广灭灵）对秧苗前期生长有点影响外,50％二·苄·异WP、35％丙·苄WP、42％丁·恶EC对水稻安全性较好。4种药剂对旱直播稻田杂草有较好的防效,药后45d,50％二·苄·异WP1500、1800g／hm^2 2个处理对禾本科杂草的株防效为92．31％～94．51％,对阔叶草的株防效为93．48％^-97．19％,对莎草的株崎效为97．44％～97．68％;35％丙·苄WP1200g／hm。对莎草的株防效为97．4‘4％;42％丁·恶Ec1650ml／hm^2对禾本科杂草的株防效为97．80％;360g／L异嗯草松CS750ml／hm^2对禾本科杂草的株防效为98．90％,但对阔叶草和莎草只有抑制作用。[结论]为旱直播稻田杂草的有效防除提供了理论依据。     

Weed flora of water rice in the Red River Delta,Vietnam

The occurrence of weeds in water rice was surveyed in the Red River Delta, Vietnam during spring and summer rice-growing seasons in 1995 and 1996. Sixty different weeds from 19 plant families were recorded. The most important plant families as weeds of rice were Poaceae and Cyperaceae. The most important weed however was Rotala indica (Willd.) Koehne (Lythraceae) followed by Echinochloa crus-galli (L.) Beauv. and Cyperus difformis L. A brief comparison of this rice weed flora and those of Australia and California was made.     

越冬之星苜蓿苗期除草剂筛选及杂草防除

[目的]筛选出对越冬之星苜蓿苗期生长安全的除草剂,并确定其防除效果,为苜蓿田杂草的防治提供依据。[方法]选用9种除草剂对苗期越冬之星苜蓿田进行除草剂筛选及杂草防除试验。[结果]不同除草剂对其生长发育、防除效果及增产效果都有一定影响,影响程度因除草剂种类与剂量不同存在差异,金普施特的综合表现最佳,能够同时防除大部分阔叶杂草和单子叶杂草。[结论]金普施特可在越冬之星苜蓿田大面积生产中推广应用。