Acetylcholinesterase activity in the terrestrial snail Xeropicta derbentina transplanted in apple orchards with different pesticide management strategies

Apple orchards are highly manipulated crops in which large amounts of pesticides are used. Some of these pesticides lack target specificity and can cause adverse effects in non-target organisms. In order to evaluate the environmental risk of these products, the use of transplanted sentinel organisms avoids side-effects from past events and facilitate comparison of multiple sites in a short time. We released specimens of the terrestrial snail Xeropicta derbentina in each 5 of two kinds of apple orchards with either conventional or organic management strategies plus in a single abandoned orchard. After one month, individuals were retrieved in order to measure acetylcholinesterase (AChE) activity. Mean values of AChE activity were significantly reduced in all conventional apple orchards compared to the others. Results show that the measurement of biomarkers such as AChE inhibition in transplated X. derbentina could be useful in the environmental risk assessment of post-authorized pesticides.     

应用土壤肥力系统研究法诊断芒果国土壤的矿质营养

广东省赤红壤垦种芒果后，土壤的矿质营养状况基本上改善不大，地力产量仍然很低。应用土壤肥力系统研究法诊断土壤营养元素的结果表明，其缺素效应排序为：Ｎ＞Ｐ、Ｃａ＞Ｋ＞Ｍｇ；土壤Ｆｅ和Ｃｕ无缺素反应，而Ｓ、Ｂ、Ｍｎ、Ｍｏ和Ｚｎ有个别土样显示缺素效应，对这些元素丰缺的确切结论，有待进一步研究。     

Effects of five insecticides used in apple orchards on Hyaliodes vitripennis (say) (Hemiptera: Miridae)

Abstract

Azinphos‐methyl, carbaryl, dimethoate, phosmet and phosalone were used in apple orchards to manage apple aphid, apple maggot, woolly apple aphid and leaf eating caterpillars. Among the five insecticides evaluated, dimethoate, carbaryl and azinphosmethyl were the most toxic to the nymphs and adults of Hyaliodes vitripennis (Say) from two regions. Phosalone was the least toxic. Nymphs were more resistant than the adults. While the LC₅₀ for dimethoate was 130 ppm for nymphs, it was 3 ppm for adults from St. Jean‐Baptiste‐de‐Rouville. There were also significant differences in the level of resistance between the two regions where the H. vitripennis were collected. At St. Alexandre the LC₅₀ for phosalone on nymphs was 19, 250 ppm whereas, at St. Jean‐Baptiste‐de‐Rouville it was 160, 000 ppm.     

太湖流域肥料施用策略调整对典型作物系统氮磷流失的影响

太湖流域种植业肥料施用强度普遍较高，且以化学肥料为主要形态.因肥料投入不适宜，种植业氮、磷流失问题显著.2015年以来，各地区积极对种植业肥料施用策略进行调整，但当前工作主要基于粮食作物系统且仍停留在化肥施用总量削减和有机肥施用面积提升层面上，缺少菜地、果园、茶园作物系统的相关数据以及对农业环境问题的响应.对此，以苏州市吴中区为太湖流域典型农区代表，研究2019～2021年稻田、菜地、果园和茶园这4类作物系统肥料策略调整对氮、磷流失的影响.结果表明，肥料源养分投入强度的调控是决定氮、磷流失的关键；适宜的有机肥替代比例有助于降低氮、磷流失风险，但有机肥施用需考虑时机并尽可能搭配农用机械.肥料效率是兼顾农业生产过程环境友好、生产主体经济效益的核心，也是后期肥料施用策略调整的导向.稻田系统的肥料施用策略调整应重视养分中不同元素配比，菜地系统应以种植结构调整为抓手，茶园、果园系统可从复合系统视角制定同时满足茶、果生长的施肥策略，助力构建满足农业绿色发展需求的作物系统.