Liming is often applied to alleviate soil acidification and increase crop yield on acidic soils,but its effect on soil phosphorus(P)availability is unclear,particularly in rice paddies.The objective of this study was ...Liming is often applied to alleviate soil acidification and increase crop yield on acidic soils,but its effect on soil phosphorus(P)availability is unclear,particularly in rice paddies.The objective of this study was to examine the effect of liming on rice production,yield and P uptake in a three-year field experiment in a double rice cropping system in subtropical China.We also conducted an incubation experiment to investigate the direct effect of liming on soil available P and phosphatase activities on paddy soils in the absence of plants.In the incubation experiment,liming reduced soil P availability(measured as Olsenextractable P)by 14–17%and inhibited the activity of soil acid phosphatase.Nonetheless,lime application increased grain yield,biomass,and P uptake in the field.Liming increased grain yield and P uptake more strongly for late rice(26 and 21%,respectively)than for early rice(15 and 8%,respectively).Liming reduced the concentration of soil available P in the field as well,reflecting the increase in rice P uptake and the direct negative effect of liming on soil P availability.Taken together,these results suggest that by stimulating rice growth,liming can overcome direct negative effects on soil P availability and increase plant P uptake in this acidic paddy soil where P is not the limiting factor.展开更多
目的了解四川省绵阳市男男性行为者(men who have sex with men,MSM)预期人类免疫缺陷病毒(human immunodeficiency virus,HIV)阳性状况主动告诉性伴情况(以下简称阳性状况主动告知),分析相关因素。方法用滚雪球抽样法进行MSM预期阳性...目的了解四川省绵阳市男男性行为者(men who have sex with men,MSM)预期人类免疫缺陷病毒(human immunodeficiency virus,HIV)阳性状况主动告诉性伴情况(以下简称阳性状况主动告知),分析相关因素。方法用滚雪球抽样法进行MSM预期阳性状况主动告知和性行为等问卷调查,采用χ^(2)检验、logistics回归模型分析预期阳性状况主动告知的相关因素。结果有效问卷1086份,预期阳性状况39.6%会主动告知。不会主动告知的主要原因中,46.1%怕泄密、31.5%怕受歧视、12.0%因内心抵触。多因素分析结果,大专及以上文化、高水平自我隐瞒、近6个月性角色插入方及均可者预期阳性状况主动告知的可能性更大,县级城市居住、性取向双性恋/异性恋/不确定、社区网络较大、近1年接受过同伴教育、传统方式寻找性伴、近6个月多性伴者预期主动告知的可能性更小。结论MSM预期阳性状况会主动告知的比例较小,隐私泄漏、歧视是主要制约原因。预期阳性状况主动告知与多种因素相关,有高危行为的MSM预期更趋于不主动告知,HIV传播的潜在风险较大。展开更多
基金This work was supported by the National Key Research and Development Program of China(2018YFD0301102)the National Natural Science Foundation of China(31701383).
文摘Liming is often applied to alleviate soil acidification and increase crop yield on acidic soils,but its effect on soil phosphorus(P)availability is unclear,particularly in rice paddies.The objective of this study was to examine the effect of liming on rice production,yield and P uptake in a three-year field experiment in a double rice cropping system in subtropical China.We also conducted an incubation experiment to investigate the direct effect of liming on soil available P and phosphatase activities on paddy soils in the absence of plants.In the incubation experiment,liming reduced soil P availability(measured as Olsenextractable P)by 14–17%and inhibited the activity of soil acid phosphatase.Nonetheless,lime application increased grain yield,biomass,and P uptake in the field.Liming increased grain yield and P uptake more strongly for late rice(26 and 21%,respectively)than for early rice(15 and 8%,respectively).Liming reduced the concentration of soil available P in the field as well,reflecting the increase in rice P uptake and the direct negative effect of liming on soil P availability.Taken together,these results suggest that by stimulating rice growth,liming can overcome direct negative effects on soil P availability and increase plant P uptake in this acidic paddy soil where P is not the limiting factor.
文摘目的了解四川省绵阳市男男性行为者(men who have sex with men,MSM)预期人类免疫缺陷病毒(human immunodeficiency virus,HIV)阳性状况主动告诉性伴情况(以下简称阳性状况主动告知),分析相关因素。方法用滚雪球抽样法进行MSM预期阳性状况主动告知和性行为等问卷调查,采用χ^(2)检验、logistics回归模型分析预期阳性状况主动告知的相关因素。结果有效问卷1086份,预期阳性状况39.6%会主动告知。不会主动告知的主要原因中,46.1%怕泄密、31.5%怕受歧视、12.0%因内心抵触。多因素分析结果,大专及以上文化、高水平自我隐瞒、近6个月性角色插入方及均可者预期阳性状况主动告知的可能性更大,县级城市居住、性取向双性恋/异性恋/不确定、社区网络较大、近1年接受过同伴教育、传统方式寻找性伴、近6个月多性伴者预期主动告知的可能性更小。结论MSM预期阳性状况会主动告知的比例较小,隐私泄漏、歧视是主要制约原因。预期阳性状况主动告知与多种因素相关,有高危行为的MSM预期更趋于不主动告知,HIV传播的潜在风险较大。
