【目的】旨在明确生物源和新烟碱类杀虫剂对棉叶蝉Amrasca biguttula若虫的毒力水平和田间药效,为棉叶蝉科学防治提供依据。【方法】以浸叶法在室内测定了3种生物源杀虫剂(藜芦胺、阿维菌素、苦参碱)和5种新烟碱类杀虫剂(烯啶虫胺、氯...【目的】旨在明确生物源和新烟碱类杀虫剂对棉叶蝉Amrasca biguttula若虫的毒力水平和田间药效,为棉叶蝉科学防治提供依据。【方法】以浸叶法在室内测定了3种生物源杀虫剂(藜芦胺、阿维菌素、苦参碱)和5种新烟碱类杀虫剂(烯啶虫胺、氯噻啉、呋虫胺、噻虫嗪和啶虫脒)处理24 h时对湘北棉区棉叶蝉3龄若虫的致死中浓度(median lethal concentration,LC_(50))值。基于各杀虫剂推荐使用剂量,以人工喷雾法在棉叶蝉发生盛期于2021年8月湖南桃源县棉田对0.5%藜芦胺可溶液剂(soluble concentrate,SL)(5.625 g a.i./hm^(2))、5%阿维菌素乳油(emulsifiable concentrate,EC)(10.5 g a.i./hm^(2))、2%苦参碱水剂(aqueous solution,AS)(10.5 g a.i./hm^(2))、10%烯啶虫胺AS(30 g a.i./hm^(2))、40%氯噻啉水分散粒剂(water dispersible granule,WG)(30 g a.i./hm^(2))、20%呋虫胺悬浮剂(suspension concentrate,SC)(75 g a.i./hm^(2))、30%噻虫嗪SC(33.75 g a.i./hm^(2))和5%啶虫脒EC(18 g a.i./hm^(2))进行棉叶蝉田间防效评价。【结果】室内毒力测定结果表明:处理后24 h时,8种杀虫剂对棉叶蝉3龄若虫的毒力从大到小依次为0.5%藜芦胺SL>5%阿维菌素EC>10%烯啶虫胺AS>40%氯噻啉WG>20%呋虫胺SC>2%苦参碱AS>30%噻虫嗪SC>5%啶虫脒EC,且生物源杀虫剂0.5%藜芦胺AS与5%阿维菌素EC对棉叶蝉3龄若虫的LC_(50)值分别为1.79和4.00 mg/L,其毒力均高于供试的5种新烟碱类杀虫剂。田间药效试验结果表明,0.5%藜芦胺SL对棉叶蝉的田间防效最佳,施药1 d后校正防效为91.36%,显著高于其他杀虫剂;药后7和14 d时的校正防效分别为86.14%和80.09%,仅次于20%呋虫胺SC的92.02%和86.99%,与10%烯啶虫胺AS和40%氯噻啉WG的无显著差异,但显著高于其他杀虫剂的。【结论】本研究结果表明藜芦胺和烯啶虫胺对湘北棉区棉叶蝉种群兼具较好的室内杀虫活性与田间防效。为了减少杀虫剂的不合理使用,促进化学农药与生物源农药的协同应用,建议在棉田交替使用藜芦胺与烯啶虫胺防治棉叶蝉。展开更多
昊星铅锌矿床位于黔西北威宁县境内的云炉河坝地区,毗邻川滇黔接壤铅锌矿集区内第二大的毛坪铅锌矿床。该矿床赋存于泥盆系碳酸盐岩中,矿体呈似层状、透镜状及脉状产出,与赋矿地层产状基本一致,受NE向构造控矿明显。硫化物矿石的Pb品位...昊星铅锌矿床位于黔西北威宁县境内的云炉河坝地区,毗邻川滇黔接壤铅锌矿集区内第二大的毛坪铅锌矿床。该矿床赋存于泥盆系碳酸盐岩中,矿体呈似层状、透镜状及脉状产出,与赋矿地层产状基本一致,受NE向构造控矿明显。硫化物矿石的Pb品位为1.5%42.80%,平均2.89%,Zn品位为1.5%35.92%,平均9.86%。可见,昊星铅锌矿床的成矿特征与会泽、毛坪和天桥等川滇黔铅锌矿集区内的其他典型矿床较相似。昊星铅锌矿床硫化物(黄铁矿、闪锌矿和方铅矿)的δ34 S CDT值介于-57.21‰+3.93‰,则明显不同于会泽、毛坪和天桥等矿床(5‰%25‰),暗示昊星铅锌矿床的还原硫可能具有不同的来源或形成机制。通过分析认为,该矿床的硫很可能是海相硫酸盐生物还原过程(BSR)的产物,而黄铁矿异常低的δ34 S可能是非封闭体系BSR批式分离的结果,即BSR过程形成的还原硫分批随着流体迁移至异地参与成矿。方铅矿的Pb同位素组成显示,昊星铅锌矿床的成矿金属主要由基底岩石提供。因此,本文认为昊星铅锌矿床是流体混合的产物,起源或流经基底岩石的成矿流体与BSR过程形成的还原性流体在异地发生混合,伴生部分TSR和水/岩相互作用过程,赋矿沉积岩中的蒸发岩和金属元素参与到了成矿之中,最终形成昊星铅锌矿床。展开更多
The increasing demand for fresh sweet maize （Zea mays L. saccharata） in southern China has prioritized the need to find solutions to the environmental pollution caused by its continuous production and high inputs of...The increasing demand for fresh sweet maize （Zea mays L. saccharata） in southern China has prioritized the need to find solutions to the environmental pollution caused by its continuous production and high inputs of chemical nitrogen fertilizers. A promising method for improving crop production and environmental conditions is to intercrop sweet maize with legumes. Here, a three-year field experiment was conducted to assess the influence of four different cropping systems （sole sweet maize （SS）, sole soybean （SB）, two rows sweet maize-three rows soybean （S2B3） intercropping, and two rows sweet maize-four rows soybean （S2B4） intercropping）, together with two rates of N fertilizer application （300 and 360 kg N ha-1） on grain yield, residual soil mineral N, and soil N2O emissions in southern China. Results showed that in most case, inter- cropping achieved yield advantages （total land equivalent ratio （TLER=0.87-1.25） was above one）. Moreover, intercropping resulted in 39.8% less soil mineral N than SS at the time of crop harvest, averaged over six seasons （spring and autumn in each of the three years of the field experiment）. Generally, intercropping and reduced-N application （300 kg N ha-1） produced lower cumulative soil N20 and yield-scaled soil N20 emissions than SS and conventionaI-N application （360 kg N ha-l）, respectively. $2B4 intercropping with reduced-N rate （300 kg N ha-~） showed the lowest cumulative soil N20 （mean value=0.61 kg ha-1） and yield-scaled soil N20 （mean value=0.04 kg t-1） emissions. Overall, intercropping with reduced-N rate maintained sweet maize production, while also reducing environmental impacts. The system of S2B4 intercropping with reduced-N rate may be the most sustainable and environmentally friendly cropping system.展开更多
文摘【目的】旨在明确生物源和新烟碱类杀虫剂对棉叶蝉Amrasca biguttula若虫的毒力水平和田间药效,为棉叶蝉科学防治提供依据。【方法】以浸叶法在室内测定了3种生物源杀虫剂(藜芦胺、阿维菌素、苦参碱)和5种新烟碱类杀虫剂(烯啶虫胺、氯噻啉、呋虫胺、噻虫嗪和啶虫脒)处理24 h时对湘北棉区棉叶蝉3龄若虫的致死中浓度(median lethal concentration,LC_(50))值。基于各杀虫剂推荐使用剂量,以人工喷雾法在棉叶蝉发生盛期于2021年8月湖南桃源县棉田对0.5%藜芦胺可溶液剂(soluble concentrate,SL)(5.625 g a.i./hm^(2))、5%阿维菌素乳油(emulsifiable concentrate,EC)(10.5 g a.i./hm^(2))、2%苦参碱水剂(aqueous solution,AS)(10.5 g a.i./hm^(2))、10%烯啶虫胺AS(30 g a.i./hm^(2))、40%氯噻啉水分散粒剂(water dispersible granule,WG)(30 g a.i./hm^(2))、20%呋虫胺悬浮剂(suspension concentrate,SC)(75 g a.i./hm^(2))、30%噻虫嗪SC(33.75 g a.i./hm^(2))和5%啶虫脒EC(18 g a.i./hm^(2))进行棉叶蝉田间防效评价。【结果】室内毒力测定结果表明:处理后24 h时,8种杀虫剂对棉叶蝉3龄若虫的毒力从大到小依次为0.5%藜芦胺SL>5%阿维菌素EC>10%烯啶虫胺AS>40%氯噻啉WG>20%呋虫胺SC>2%苦参碱AS>30%噻虫嗪SC>5%啶虫脒EC,且生物源杀虫剂0.5%藜芦胺AS与5%阿维菌素EC对棉叶蝉3龄若虫的LC_(50)值分别为1.79和4.00 mg/L,其毒力均高于供试的5种新烟碱类杀虫剂。田间药效试验结果表明,0.5%藜芦胺SL对棉叶蝉的田间防效最佳,施药1 d后校正防效为91.36%,显著高于其他杀虫剂;药后7和14 d时的校正防效分别为86.14%和80.09%,仅次于20%呋虫胺SC的92.02%和86.99%,与10%烯啶虫胺AS和40%氯噻啉WG的无显著差异,但显著高于其他杀虫剂的。【结论】本研究结果表明藜芦胺和烯啶虫胺对湘北棉区棉叶蝉种群兼具较好的室内杀虫活性与田间防效。为了减少杀虫剂的不合理使用,促进化学农药与生物源农药的协同应用,建议在棉田交替使用藜芦胺与烯啶虫胺防治棉叶蝉。
文摘昊星铅锌矿床位于黔西北威宁县境内的云炉河坝地区,毗邻川滇黔接壤铅锌矿集区内第二大的毛坪铅锌矿床。该矿床赋存于泥盆系碳酸盐岩中,矿体呈似层状、透镜状及脉状产出,与赋矿地层产状基本一致,受NE向构造控矿明显。硫化物矿石的Pb品位为1.5%42.80%,平均2.89%,Zn品位为1.5%35.92%,平均9.86%。可见,昊星铅锌矿床的成矿特征与会泽、毛坪和天桥等川滇黔铅锌矿集区内的其他典型矿床较相似。昊星铅锌矿床硫化物(黄铁矿、闪锌矿和方铅矿)的δ34 S CDT值介于-57.21‰+3.93‰,则明显不同于会泽、毛坪和天桥等矿床(5‰%25‰),暗示昊星铅锌矿床的还原硫可能具有不同的来源或形成机制。通过分析认为,该矿床的硫很可能是海相硫酸盐生物还原过程(BSR)的产物,而黄铁矿异常低的δ34 S可能是非封闭体系BSR批式分离的结果,即BSR过程形成的还原硫分批随着流体迁移至异地参与成矿。方铅矿的Pb同位素组成显示,昊星铅锌矿床的成矿金属主要由基底岩石提供。因此,本文认为昊星铅锌矿床是流体混合的产物,起源或流经基底岩石的成矿流体与BSR过程形成的还原性流体在异地发生混合,伴生部分TSR和水/岩相互作用过程,赋矿沉积岩中的蒸发岩和金属元素参与到了成矿之中,最终形成昊星铅锌矿床。
基金supported by the Key Technologies R&D Program of China during the 12th Five-year Plan period(2012BAD14B16-04)the Science and Technology Development Program of Guangdong,China(2012A020100003 and 2015B090903077)
文摘The increasing demand for fresh sweet maize （Zea mays L. saccharata） in southern China has prioritized the need to find solutions to the environmental pollution caused by its continuous production and high inputs of chemical nitrogen fertilizers. A promising method for improving crop production and environmental conditions is to intercrop sweet maize with legumes. Here, a three-year field experiment was conducted to assess the influence of four different cropping systems （sole sweet maize （SS）, sole soybean （SB）, two rows sweet maize-three rows soybean （S2B3） intercropping, and two rows sweet maize-four rows soybean （S2B4） intercropping）, together with two rates of N fertilizer application （300 and 360 kg N ha-1） on grain yield, residual soil mineral N, and soil N2O emissions in southern China. Results showed that in most case, inter- cropping achieved yield advantages （total land equivalent ratio （TLER=0.87-1.25） was above one）. Moreover, intercropping resulted in 39.8% less soil mineral N than SS at the time of crop harvest, averaged over six seasons （spring and autumn in each of the three years of the field experiment）. Generally, intercropping and reduced-N application （300 kg N ha-1） produced lower cumulative soil N20 and yield-scaled soil N20 emissions than SS and conventionaI-N application （360 kg N ha-l）, respectively. $2B4 intercropping with reduced-N rate （300 kg N ha-~） showed the lowest cumulative soil N20 （mean value=0.61 kg ha-1） and yield-scaled soil N20 （mean value=0.04 kg t-1） emissions. Overall, intercropping with reduced-N rate maintained sweet maize production, while also reducing environmental impacts. The system of S2B4 intercropping with reduced-N rate may be the most sustainable and environmentally friendly cropping system.
