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1.
利用高效液相色谱-串联质谱(HPLC-MS/MS)分析方法,探讨了广州市某绿色蔬菜基地和有机蔬菜基地土壤中4种喹诺酮类抗生素的含量与分布特征。结果表明,土壤中各化合物的检出率除洛美沙星为85%以外,其余均为100%,平均含量为0.80~24.95μg.kg-1,以诺氟沙星(24.95μg.kg-1)为主,其次为环丙沙星(15.40μg.kg-1)和恩诺沙星(7.68μg.kg-1)。4种喹诺酮类化合物总含量在7.15~122.25μg.kg-1之间,主要分布在50~100μg.kg-1之间,平均为48.85μg.kg-1。有机蔬菜基地土壤中4种喹诺酮类化合物的含量均高于绿色蔬菜基地土壤。同一基地不同蔬菜土壤中喹诺酮类抗生素的含量有一定差异,但化合物组成特征差异不大。研究区土壤中喹诺酮类抗生素的含量低于兽药国际协调委员会(VICH)筹划指导委员会的抗生素生态毒性效应触发值(100μg.kg-1),表明生态风险较小。  相似文献   

2.
畜禽废物中的抗生素可造成土壤及水体的抗生素污染,利用高效液相色谱及高效液相色谱-串联质谱分析了广州市代表性养殖场畜禽废物、施用畜禽粪土壤和鱼塘水中尼卡巴嗪、喹乙醇、四环素类、磺胺类、喹诺酮类、氯霉素类抗生素的含量。结果发现:猪粪、鸡粪中抗生素含量最高的均为四环素类,分别为123.76、14.59 mg.kg-1;含量最低的均为氯霉素类,分别为2.35μg.kg-1、0.08 mg.kg-1;小猪猪粪中抗生素的含量明显高于大猪。鱼塘水中抗生素含量较高的是四环素(5.16μg.L-1)与磺胺对甲氧嘧啶(4.78μg.L-1),土霉素在所有样点中均未被检出。施用禽畜粪土壤中四环素类、喹诺酮类含量较高,分别为70.40、49.77μg.kg-1;磺胺甲基嘧啶、磺胺对甲氧嘧啶、磺胺甲噁唑、甲砜霉素、氯霉素、喹乙醇均未被检出。粪样中的抗生素可导致土壤和水体的抗生素污染,TCs、QNs和NCZ可能对生态环境和人类健康安全的威胁更大。  相似文献   

3.
This study was designed to develop a sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the simultaneous detection and quantification of 25 mycotoxins in cassava flour, peanut cake and maize samples with particular focus on the optimization of the sample preparation protocol and method validation. All 25 mycotoxins were extracted in a single step with a mixture of methanol/ethyl acetate/water (70:20:10, v/v/v). The method limits of quantification (LOQ) varied from 0.3 μg/kg to 106 μg/kg. Good precision and linearity were observed for most of the mycotoxins. The method was applied for the analysis of naturally contaminated peanut cake, cassava flour and maize samples from the Republic of Benin. All samples analyzed (fifteen peanut cakes, four maize flour and four cassava flour samples) tested positive for one or more mycotoxins. Aflatoxins (total aflatoxins; 10-346 μg/kg) and ochratoxin A (相似文献   

4.
土壤中磺胺类抗生素的检测方法优化及残留、降解研究   总被引:3,自引:0,他引:3  
优化了磺胺甲基嘧啶(SM1)、磺胺二甲嘧啶(SM2)、磺胺对甲氧嘧啶(SMT)、磺胺甲噁唑(SMZ)4种磺胺类抗生素的高效液相色谱(H PLC)检测方法,分析了广州市养殖场周边土壤中磺胺类抗生素的残留特征,并进行了2种磺胺类抗生素的土壤降解试验。结果表明,4种磺胺类抗生素分别在0.10~10μg ml-1范围内线性良好,相关系数R>0.99。确定了最佳提取液为甲醇:含EDTA的Mcllvain缓冲液=1∶1(V/V),4种磺胺类药物的检测限与回收率分别为2.9~4.7μg kg-1、83.6%~90.1%。广州市18个规模化养殖场周边土壤中磺胺类抗生素污染以SM2为主,含量为1.75μgkg-1,其它3种均未被检出。土壤中磺胺类抗生素的含量总体呈随培养时间而不断下降的趋势,SMZ的降解速率大于SM2。  相似文献   

5.
Fusarium toxins, Alternaria toxins, and ergot alkaloids represent common groups of mycotoxins that can be found in cereals grown under temperate climatic conditions. Because most of them are chemically and thermally stable, these toxic fungal secondary metabolites might be transferred from grains into the final products. To get information on the commensurate contamination of various cereal-based products collected from the Czech retail market in 2010, the occurrence of "traditional" mycotoxins such as groups of A and B trichothecenes and zearalenone, less routinely determined Alternaria toxins (alternariol, alternariol monomethyl ether and altenuene), ergot alkaloids (ergosine, ergocryptine, ergocristine, and ergocornine) and "emerging" mycotoxins (enniatins A, A1, B, and B1 and beauvericin) were monitored. In a total 116 samples derived from white flour and mixed flour, breakfast cereals, snacks, and flour, only trichothecenes A and B and enniatins were found. Deoxynivalenol was detected in 75% of samples with concentrations ranging from 13 to 594 μg/kg, but its masked form, deoxynivalenol-3-β-d-glucoside, has an even higher incidence of 80% of samples, and concentrations ranging between 5 and 72 μg/kg were detected. Nivalenol was found only in three samples at levels of 30 μg/kg. For enniatins, all of the samples investigated were contaminated with at least one of four target enniatins. Enniatin A was detected in 97% of samples (concentration range of 20-2532 μg/kg) followed by enniatin B with an incidence in 91% of the samples (concentration range of 13-941 μg/kg) and enniatin B1 with an incidence of 80% in the samples tested (concentration range of 8-785 μg/kg). Enniatin A1 was found only in 44% of samples at levels ranging between 8 and 851 μg/kg.  相似文献   

6.
太湖水网地区不同种植类型农田磷素渗漏流失研究   总被引:3,自引:0,他引:3  
采用田间原位小型土壤渗漏计法研究了太湖流域水网地区不同种植类型农田土壤中的速效磷累积量与渗漏水中磷素含量之间的关系。结果表明:研究区菜地、果园高的年均磷肥施用量分别为946.8 kg/hm2和832.6 kg/hm2,显著高于水田的年均磷肥施用量(83.6 kg/hm2),约为水田的10~12倍。施入农田中的磷肥主要累积在土壤表层,0—5 cm土层中的Olsen-P含量最高,菜地、果园和水田的平均含量分别高达161.75 mg/kg、143.88 mg/kg和23.77 mg/kg,菜地和果园显著高于水田,约为水田的6~8倍。随着土层深度的增加,土壤中Olsen-P的含量显著降低。农田浅层渗漏水中的可溶态磷在总磷中所占的比例远高于颗粒态磷所占的比例。本研究结果显示,农田浅层渗漏水中溶解性正磷酸盐(DRP)含量与土壤中速效磷(Olsen-P)含量之间具有极显著的指数相关关系,表明伴随着农田施肥量的增加和土壤中速效磷含量的增加,浅层渗漏水中的溶解性正磷酸盐含量会显著增加,大大提高了农田磷素的渗漏淋失风险,造成对农业面源污染的巨大潜在压力。  相似文献   

7.
研究了安徽省合肥、芜湖和亳州市周边蔬菜地土壤和蔬菜中PAHs的含量及其污染特征。结果表明:安徽省典型蔬菜地土壤中15种PAHs(除萘外)的残留总量在58.2~437.8μg·kg-1之间,三环和四环PAHs占PAHs残留总量的70%以上。胡萝卜、菠菜和茄子体内15种PAHs的含量在23.4~209.1μg·kg-1之间,均值为120.7μg·kg-1,三环和四环PAHs占蔬菜中PAHs富集总量的92.8%~94.4%。不同蔬菜体内8种可疑性致癌PAHs的含量在11.5~17.4μg·kg-1之间,分别占蔬菜中PAHs残留总量的9.80%~13.8%,其中BaP含量在1.69~2.03μg·kg-1之间,低于国家对食品中污染物(BaP)的限量标准(5μg·kg-1)。不同类型PAHs在蔬菜体内的富集系数在0.10~9.20之间,极差达10倍以上,低分子量PAHs在蔬菜体内的富集系数要大于高分子量PAHs。不同PAHs在蔬菜体内的富集系数表现为胡萝卜〉菠菜〉茄子,其中芴在蔬菜体内的富集系数最高。  相似文献   

8.
利用固相萃取-高效液相色谱-串联质谱联用技术(SPE-HPLC-MS/MS)分析了天津近郊养殖水体的表层水及沉积物中喹诺酮类、四环素类及磺胺类3类共18种抗生素的残留,同时考察3类抗生素在不同季节的变化分布特征。结果表明,在淡水养殖水体的表层水中环丙沙星、恩诺沙星和土霉素等检出率较高,浓度范围在10.5~26.8μg·L-1之间;相对地,在养殖水体的沉积物中磺胺甲基异噁唑、磺胺甲噻二唑、磺胺二甲氧嘧啶、诺氟沙星的检出率较高,浓度范围在1.5~30.1μg·kg-1之间。研究同时发现,冬季3类抗生素在表层水和沉积物中的检出率和检出浓度普遍高于夏季。说明在我国部分淡水养殖地区的养殖水体中已经有一定量的磺胺类和喹诺酮类抗生素的残留,并可能威胁到水生生物的安全,进一步对人体健康产生危害,因此应加强对淡水养殖环境中抗生素残留的监测与管理。  相似文献   

9.
Metal Enrichment in Zlatna, a Romanian Copper Smelting Town   总被引:1,自引:0,他引:1  
A preliminary survey of metal concentrations in soil and vegetable samples was undertaken in the town of Zlatna, in western Romania that is dominated by a large copper smelter. One data set (town survey) consisted of soil samples taken from sites both in the centre of the town (near smelter and school grounds) and the outskirts and included those from roadside verges and wooded areas. The second data set consisted of soil samples taken from vegetable garden plots together with an associated sample of spring onion (Allium fistulosum). The aim of this study was to measure levels of the elements Cu, Zn, Pb, Cd and As in soil samples from Zlatna in general, and to assess their uptake into home grown vegetables and thus into the food chain. Concentrations of the elements of interest in soils and vegetables peaked southwest of the smelter and also in soils near the school in the town centre. Concentrations of elements in soils from the town, including those near the school, had the following ranges: Cu, 41–12,000, geometric mean 863 μg/g; Zn, 89–15,600, geometric mean 920 μg/g; Pb, 32–7860, geometric mean 740 μg/g; Cd, BDL–329.5, geometric mean 3.35 μg/g; As, 15–1440 geometric mean 223 μg/g; Thus, the residents of Zlatna are potentially exposed to levels of these elements that are higher than the recommended guideline values. Mean concentrations of the toxic elements in spring onions were: Cu, 10.2; Zn, 95; Pb, 11; Cd, 0.8; As 2.6 μg/g dry weight.  相似文献   

10.
金昌市土壤养分现状与施肥建议   总被引:1,自引:0,他引:1       下载免费PDF全文
杨炳成 《土壤》2006,38(2):228-231
通过2002年秋后对甘肃省金昌市1县1区12个乡镇10万hm2耕地的601个土样化验分析,结果表明:土壤有机质含量平均15.1g/kg,大面积处于较缺和中等状况,而且较缺面积在扩大,中等面积在减少。土壤碱解N含量平均38mg/kg,以缺和较缺占据了绝大部分面积,而且缺的面积在扩大,较缺面积在减少。土壤有效P含量平均20.9mg/kg,明显增加,已处于中等和较丰富状况,也有一定面积处于较缺状况。土壤速效K含量平均158mg/kg,明显下降,大面积处于较丰富和中等状况,中等面积大幅度增加。  相似文献   

11.
亚热带小流域土壤氮磷分布及其环境效应   总被引:3,自引:0,他引:3  
土壤氮磷积累是引起农业面源污染的主要原因。为探讨土壤氮磷含量的分布状况及其对环境的影响,选取位于长沙县金井镇的小流域为研究区域,以表层土壤(0-20cm)为采样对象,按不同的土地利用方式共采集样品1 118个。以土地利用类型为分析单元,分析说明了土壤全氮、全磷的分布特征及其环境效应。结果表明:土壤全氮和全磷含量的平均值分别为1.66,0.54g/kg,变异系数分别为34.9%和46.3%,均属于中等变异。菜地土壤全氮含量主要分布在1.8~2.4g/kg区间,旱地和水田为1.2~1.8g/kg,林地和茶园为0.6~1.2g/kg;菜地土壤全磷含量主要分布在大于1.0g/kg区间,旱地为0.6~0.8g/kg,水田为0.4~0.6g/kg,林地和茶园为0.2~0.4g/kg。结合地下水氮磷含量分析表明,土壤氮素含量与地下水铵态氮含量增加有关,对地下水水质产生影响,其中水田的影响尤为突出;土壤磷素的淋失可能具有季节性差异,还有待进一步验证。  相似文献   

12.
黄河三角洲土地利用对土壤氮素及其转化的影响   总被引:1,自引:0,他引:1  
以黄河三角洲垦利县轻度盐渍化土壤为研究对象,选取菜地、果园、粮田和新淤未利用地共4种土地利用类型,通过实地采样分析,探讨了土地利用对土壤氮素及其转化的影响。结果表明,全氮含量在0—20 cm土壤中以粮田最高,平均含量为1.42 g/kg,其次是果园、菜地和新淤未利用地土壤,其平均含量分别为1.17,0.97和0.57 g/kg,而20—40 cm土壤中,菜地全氮平均含量为0.86 g/kg,明显高于其它3种用地土壤;硝态氮在菜地0—20 cm土壤中的平均含量为27.25 mg/kg,远高于果园、粮田和新淤未利用地土壤,铵态氮在4种用地类型土壤中含量范围为2.65~4.09 mg/kg,不同用地类型间差异不大,二者在20—40cm土壤中的变化规律与0—20 cm基本相同;通过铵态氮、硝态氮与全氮的相关分析,表明菜地土壤中有效氮含量主要与外源氮素的补充有关,果园和粮田土壤中的有效氮与土壤全氮关系密切而受环境变化情况较小,新淤未利用地土壤氮素反映了研究区土壤氮素及其转化的初始状况。  相似文献   

13.
利用GC-ECD对环鄱阳湖区11个县市蔬菜地土壤中有机氯农药测定的数据,研究蔬菜地土壤中有机氯农药残留状况,并进行生态风险评价。结果显示,蔬菜地土壤中HCHs、DDTs、氯丹和六氯苯均有检出,且DDTs、HCHs的残留量较高,总有机氯农药含量范围为2.39~47.28μg·kg-1。从整体上分析,处于工业分布区域的土壤中有机氯农药含量高于其他区域。有机氯农药组成特征研究表明,该地区土壤中除个别采样点有机氯农药主要来自于早期残留外,大部分地区有新的污染源输入。与国内其他地区蔬菜地土壤相比,环鄱阳湖区蔬菜地土壤中有机氯农药含量较低。生态风险分析显示,环鄱阳湖区蔬菜地土壤中HCHs残留对于土壤生物的风险较低,而DDTs可能对鸟类和土壤生物具有一定的生态风险。  相似文献   

14.
采用气相色谱串联质谱测定了金华城区20份土壤样品中的7种指示性PCBs(PCB28,PCB52,PCB101,PCB118,PCB138,PCB153,PCB180),并分析了其分布特征和来源。结果显示金华城区PCBs残留总量在0.111~2.688μg.kg-(1干重)之间,相比国内外其他城市污染程度较轻。和我国其他地区相类似,PCBs的构成中主要以低氯代的三氯联苯和四氯联苯为主,即可能的污染源是我国历史上生产和使用较多的1号PCB,但个别点也显示2号PCB或进口PCBs污染的存在。PCBs污染程度为工业园区〉农田〉公园,说明城市中PCBs的污染源仍是工业园区,其他区域的污染可能来自于大气传播。农田土壤在作物采收后直接暴露在空气污染中,可能是导致其PCBs含量高于公园土壤的主要原因。  相似文献   

15.
张小真    宋媛  胡亚鲜     《水土保持研究》2023,30(2):74-80
东北黑土坡耕地侵蚀沉积分异明显,且冻融交替频繁,但各坡位土层结构以及通气孔隙度随含水率和温度的季节性变化对有机碳矿化和CO2扩散效率的影响机理尚不清楚。以典型黑土坡耕地为研究对象,采集未侵蚀区表土风干、筛分后,选取粗(0.5~1 mm)、细(<0.125 mm)两种粒级,分层回填,全粗、全细、上粗下细、上细下粗4种土柱模拟典型坡位土层结构,对比分析冻融与非冻融不同温度梯度下,各土层结构CO2释放速率变化特征。结果表明:非冻融变温(5~30℃)条件下,各土层结构CO2释放速率存在显著差异,其中上粗下细土层CO2释放速率均值为14.45μg/(kg·h),显著高于其他土层,增幅达20%~59%,说明不同土层间土壤颗粒大小和上下堆叠关系对CO2传输效率有重要调控作用。经两次冻融作用后,0~15℃变温培养中,各土层间无显著差异,上粗下细土层CO2释放速率均值为4.17μg/(kg·h),略高于其他土层,说明冻涨融缩效应削弱了不同土层结构之间孔隙结构和联通性差...  相似文献   

16.
A novel multiresidue analysis method is developed for the determination of twenty phthalate esters at the μg/kg level in edible vegetable oils by microwave-assisted extraction-gel permeation chromatography-solid phase extraction-high resolution gas chromatography-tandem mass spectrometry (MAE-GPC-SPE-HRGC-MS/MS). The samples were extracted with methanol under microwave incubation. Cleanup was carried out with GPC followed by a further C18 SPE column and then separated by the HP-5MS capillary column under a temperature program. The eluents were qualitatively and quantitatively determined by tandem mass analyzer with selected reaction monitoring (SRM) type and positive ion mode. The calibration curves showed good linearity in the range 5 μg/kg to 2.50 mg/kg with correlation coefficients larger than 0.999. Low detection limits (LODs) of 0.218-1.367 μg/kg and quantification limits (LOQ) of 0.72-4.51 μg/kg were achieved. The mean recoveries were in the range from 93.04% to 104.6% at 5, 15, and 40 μg/kg spiked levels, and the relative standard deviations (RSDs) were in the range of 1.01% and 5.26% (n = 7). This method could potentially overcome the interference from large amounts of lipids and pigment. The real sample test showed this method can be used for sensitive and accurate determination and confirmation of phthalate ester residues in high-fat and complex samples.  相似文献   

17.
天然富硒土壤上三种蔬菜对硒的吸收与转化差异   总被引:1,自引:1,他引:0  
【目的】研究对硒 (Se) 不同敏感性蔬菜对天然富硒土 (Se ≥ 0.4 mg/kg) 中硒的吸收和转化差异,为富硒土壤生产富硒蔬菜提供理论与技术指导。【方法】以大蒜、芥菜和菠菜三种蔬菜为试验材料,在全硒含量为0.29、0.58、0.98、2.07 mg/kg的四种土壤上进行了盆栽试验 (依次标记为Se0.29、Se0.58、Se0.98、Se2.07),并测定四种土壤中不同形态硒的含量。芥菜和菠菜于生长40 d、53 d、68 d和82 d后取样,测定蔬菜可食部分硒含量;于生长97 d后收获,分为根部和地上部。大蒜于生长42 d、68 d、82 d、120 d后取样,测定地上部硒含量;于生长165 d后收获,分为根部、鳞茎和叶。测定供试蔬菜总硒含量、有机硒含量,计算不同硒含量土壤上蔬菜对硒的吸收和转化系数。【结果】三种蔬菜中芥菜的生长对土壤硒最为敏感,芥菜可食部位生物量鲜重以Se0.29处理最高,菠菜和大蒜均以Se0.58处理最高,与Se2.07处理均达显著差异。三种蔬菜地上部硒含量在整个生育期总体呈现增加的趋势,不同生育期均表现为大蒜 > 芥菜 > 菠菜。收获期三种蔬菜各部位的硒含量随着土壤硒含量 (0.29~2.07 mg/kg) 的增加而增加,表现为Se2.07 > Se0.98 > Se0.58 > Se0.29,Se2.07处理的菠菜地上部和地下部硒含量分别是其Se0.29处理的8.63倍和7.10倍,芥菜是12.25倍和23.29倍,Se2.07处理大蒜鳞茎和叶部硒含量是Se0.29处理的39.92倍和4.90倍;可食部位硒含量为大蒜 (7.25~289 μg/kg) > 芥菜 (1.22~14.9 μg/kg) > 菠菜 (0.73~6.30 μg/kg),均表现为地下部 > 地上部,Se2.07处理菠菜根部硒含量是茎叶的4.80倍,芥菜是12.06倍,大蒜是8.22倍。在富硒土壤Se0.98和Se2.07处理条件下,大蒜和芥菜能从土壤中富集硒,吸收系数是菠菜的3.06~8.47倍和1.58~5.8倍,均达到了富硒蔬菜标准 (≥ 0.01 mg/kg)。三种蔬菜可食部位有机硒含量占总硒比例为73.5%~84.7%,并随土壤硒含量的增加而增加,其中Se2.07与Se0.29处理差异显著;蔬菜硒含量不但与土壤总硒含量相关,而且与有效态硒含量呈显著正相关。【结论】蔬菜种类和土壤硒含量均影响蔬菜硒的吸收、转化和富集。三种蔬菜对土壤硒的敏感性以芥菜最强。蔬菜硒含量和可食用部位有机硒的转化率均随着土壤硒含量的增加而增加,与土壤总硒含量和有效态硒含量呈显著正相关。富硒能力为大蒜 > 芥菜 > 菠菜,在天然富硒土壤上生长的大蒜和芥菜硒含量易达到富硒蔬菜标准,而菠菜未显示出富硒能力。因此,虽然土壤硒含量高影响了大蒜和芥菜的生长,但大蒜和芥菜具有较强的将硒转移到可食部位的能力,可作为富硒蔬菜生产。  相似文献   

18.
邢喆  黄标  董成森  孙维侠  胡文友  田康 《土壤》2013,45(3):405-411
在2011年土壤采样的基础上,参照1981年沭阳县二次土壤普查资料,对该县土壤有机质和全氮30年来的时空演变进行了分析,并进一步讨论了时空演变的自然和人为因素.结果表明:30年来,沭阳县农田耕层(0~20cm)土壤有机质和全氮均明显增加,2011年土壤有机质和全氮的平均含量分别为23.12 g/kg和1.36 g/kg,分别比1981年增加了12.15 g/kg和0.61 g/kg,平均增加速率达0.41 g/(kg·a)和0.02 g/(kg.a).2011年土壤有机质和全氮的整体空间分布格局与1981年相似,均呈现北部黏性土壤高而南部砂性土壤低、东部水田高西部旱地低的空间分布格局.土壤质地是造成这种时空变异最主要的结构性因素,而秸秆还田量的增加、土地利用方式的转化是30年来影响土壤有机质和全氮时空演变的主要人为随机性因素.  相似文献   

19.
An on-line solid-phase extraction (SPE) following a liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method was established for the simultaneous analysis of bisphenol A (BPA), nonylphenol (NP), and octylphenol (OP) in cereals (including rice, maize, and wheat). The target compounds were extracted by acetonitrile, purified by an automated on-line SPE cartridge, and analyzed by LC-MS/MS under the negative-ion mode. Mean recoveries fortified at three concentration levels ranged from 81.6 to 115.7%, and the coefficient of variation ranged from 4.6 to 19.9% (n = 6). The limits of quantification (LOQs) of the method were 0.5, 0.5, and 0.25 μg/kg for BPA, NP, and OP, respectively, in both rice and maize, while the LOQs in wheat were 0.5, 1.25, and 0.5 μg/kg for BPA, NP, and OP, respectively. This method was applied in the analysis of rice, maize, and wheat from a local market. As a result, NP occurred in all cereal samples at the concentration range of 9.4-1683.6 μg/kg and BPA was detected in a few samples.  相似文献   

20.
山西省主要农田施肥状况及典型县域农田养分平衡研究   总被引:14,自引:1,他引:14  
根据山西省农业统计资料,结合实地调查和土壤测定数据,采用典型农户问卷调查的方式,研究了全省和3个典型县域农田施肥状况、养分平衡和土壤养分变化趋势。农户施肥状况调查结果表明,2000年山西省平均N肥用量为181.8Nkg/hm2,P肥用量为93.7P2O5kg/hm2,K肥用量为41.9K2Okg/hm2,N∶P∶K为1∶0.52∶0.23。从化肥的投向来看,水地的施用量明显高于旱地,蔬菜和果树的施用量高于粮食作物和其它经济作物。从3个典型县域农田养分平衡来看,1980年后随着N、P肥施用量的增加,农田N素和P素出现大量盈余,K素则处于亏缺状态。通过对第二次全国土壤普查和2000年土壤测定结果分析,了解了山西省近20年来土壤有效磷和速效钾的变化趋势,以及典型县域农田养分平衡状况对土壤养分变化的影响及特点。  相似文献   

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