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用衍生气相色谱法测定了溴甲烷熏蒸大棚土壤后土壤及作物(黄瓜)中残留的Br^-,用顶空法测定土壤吸附的溴甲烷。在0.4-40mg/kg的添加范围内,Br^-的平均回收率为83.7%-94.8%,相对标准偏差为±2.5% ̄14.7%。Br^-在土壤和黄瓜中的半衰期为15.0和14.2d(北京)、24.7和10.3d(沈阳)。土壤吸附的溴甲烷量较少,其半衰期和Br^-的相近。低于75.0g/m^2的施用 相似文献
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土壤C管理对于含C量低的东南沿海平原(SCP)壤砂土极为重要。1979年开始的一项长期调查旨在确定实行玉米、棉花、大豆和小麦水保轮作制能否提高诺福克壤砂土的含C量。小区长60m, 宽23m, 5次重复。在采用现代水保耕作措施以前,垄作,特别是棉花-大豆轮作时,人们认为提高含C量几乎是不可能的。试验初期含C量无显著差异,在第9—14年间,实施水保耕作的小区0~5 cm土层平均含C量为12.0g/kg,实施常规耕作的小区为7.2g/kg,前者几乎是后者的2倍(P≤0.05)。14年间,实施水保耕作小区的0~5cm土层含C量随时间变化的速率为0.61g/kg·a,相关系数为r=0.66;变化率为0的概率小于0. 001,在5~10cm土层,C的变化速率增加较小,为0.17g/kg·a。不同处理中,15cm以下土层含C量差异性不一致。改善设备、管理、土壤质量使实施水保耕作的小区在 9~ 14年间产量提高。在SCP壤砂土上,对垄作作物进行长期保护耕作,甚至在轮作中包括大豆和棉花的情况下,也是提高含C量的一种可行方法。 相似文献
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不同农作措施对稻田甲烷排放通量的影响 总被引:7,自引:1,他引:7
通过网室小区试验,观测得到单施尿素处理的甲烷排放通量为0.64mg/m^2·h;农家肥+尿素处理、农家肥+硝铵处理、农家肥+硫铵处理的甲烷排放通量分别为57.1,42.1,30.7mg/m^2·h;农家肥+硫铵+间歇灌溉处理和农家肥+尿素+间歇灌溉处理的甲烷排放通量分别为22.0和14.7mg/m^2·h。结果表明,以农家肥为基肥的5个处理的甲烷排放通量大大高于单施尿素处理的甲烷排放通量,表明高量 相似文献
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施用2种有机肥(羊粪、猪粪),并配施少量化肥,进行雨养梯田种植玉米的田间试验,结果表明,施有机肥后土壤总孔隙度、毛管孔隙度分别提高5.2%~13.1%和3.6%~10.0%,土壤容重降低1.8%~7.9%;雨后土壤含水量提高9.8%~15.3%;玉米平均株高、平均茎粗分别增加0.1~6.5cm和0.1~0.5cm,玉米产量提高33.5%~77.2%。玉米产量与有机肥施用量呈3次方关系,并由此确定了 相似文献
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本文探讨了铝与铬天青S的最佳显色反应条件。当pH为6.5,在溴化十六烷基三甲铵(CTMAB)和乙醇的存在下,铝与铬天青S形成绿色配合物,最大吸收峰位于635um,表观摩尔吸光系数为1.65×105L/mol·cm,铝含量在0~0.24μg/mL范围内符合比耳定律。在本实验条件下,该方法具有良好的选择性,应用于植物和土壤水中铝的测定,结果满意。 相似文献
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采用东方红-75链轨拖拉机牵引由犁架、犁刀、犁锋和穿洞空心弹头组成的鼠道犁,在低这地和缓坡耕地上作业试验,结果表明,鼠道耕法可使深0.6m、顶宽0.9~1.0m的土体膨松,土壤容重较对照减少0.29~0.39g/cm3,并在底部形成直径11cm的鼠道,从而提高了土壤渗蓄水能力,减免了水土流失;在坡度小于1.5°的坡耕地顺坡耕作的鼠道,其排水量可达0.5~1.6L/s,使融雪季及雨季地表凹处积水现象基本消除;旱时蓄存在鼠道中的水分可供作物生育需要。试验区甜菜增产15.5%,大豆增产13.3%。按作业间距5m计,一套机具每台班可耕6.7~8.0hm2,费省效宏。 相似文献
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用丙酮提取,经水-二氯甲烷液-液分配净化,气相色谱FPD检测器的P滤光片测定嘧啶氧磷的水稻土壤,水中的残留量,其回收率为:糙米95.0-97.0%,稻杆86.4-96.7%,稻壳83.2-91.7%,土壤89.5-96.5%,水80.0-80.7%。土壤中半衰期为6.23-7.93天,稻田水中0.85-3.93天。测得终点残留量糙米≤0.08mg/kg,稻壳≤0.5mg/kg,稻杆≤0.24mg/ 相似文献
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反相高效液相色谱法检测水,土壤中的除草醚 总被引:3,自引:0,他引:3
介绍了应用反相高效液相色谱检测水,土壤中除草醚的方法。该方法对除草醚在水和土壤中的回收率分别为99.0%和92.5%,最小检出浓度分别为1.1×10^-2mg/L和0.11mg/kg。 相似文献
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马光庭 《广西农业生物科学》1994,(3)
本文介绍从德国哥廷根污水处理厂腐化塔污泥中分离出的两株甲烷细菌,其中一株为甲酸甲烷杆菌(Methanobacteriumformicicum),其细胞杆状,可利用甲酸或H2/CO2作为碳源和能源,另一株为甲烷八叠球菌属(Methanosarcina),其细胞球状,成堆排列,可利用甲醇或H2/CO2作为碳源和能源。 相似文献
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C. M. MUNDIE 《European Journal of Soil Science》1976,27(3):331-336
Two methods have been used for the identification and determination of uronic acids in soils and soil fractions. The uronic acids were released by hydrolysis with sulphuric acid. After partial purification by ion-exchange chromatography they were separated either by further ion-exchange or by gas-liquid chromatography of derivatives. The latter method is preferable for determination of the specific activities of uronic acids in soil tracer work. Both galacturonic and glucuronic acids were detected in the four Scottish soils examined, the galacturonic acid being present in slightly greater amounts in each soil. Mannuronic acid was not detected. The total amount of uronic acids found ranged from about 4 mg to 6 mg/g soil. 相似文献
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黄土与古土壤中重金属的存在形态及风化成土作用对其影响 总被引:1,自引:0,他引:1
本文采用了七步连续萃取方法,研究了洛川黄土剖面黄土与古土壤中Fe,Cu,Zn,Co和Ni五种重金属的存在形态。结果表明:黄土与古土壤中上述元素主要存在于残余态和晶形,无定形氧化铁的结合态中,而且线性回归分析表明Cu,Zn,Ni与晶形氧化铁之间存在关;cU,cO,Ni与无定形氧化铁之间存在相关;黄土风化为古土壤后,碳酸盐结合态的重金属含量增加是古土壤相对于黄土重金属增加的主要原因。 相似文献
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Asha Yahya 《Journal of plant nutrition》2013,36(5):670-683
Net uptake and partitioning of sodium (Na+) and potassium (K+) in plants of two sesame cultivars (Sesamum indicum cv. ‘PB-1’ and cv. ‘UCR’) exposed to 20 mM sodium chloride (NaCl) were studied over a period of 28 days. Both cultivars showed a marked discrimination between K+ and Na+ during uptake. The reduction of K+ in the plants caused by the NaCl treatment was of similar magnitude in the two cvs. The cv. ‘UCR’ showed lower Na+ concentrations in the shoot tissues than ‘PB-1’ and K+/Na+ selectivity ratios were higher in cv. ‘UCR’ than in cv. ‘PB-1’. At the last sampling on day 28 there was a marked decrease of shoot growth in cv. ‘PB-1’ in comparison to the cv. ‘UCR’. Leaves of cv. ‘PB-1’ showed clear toxic symptoms, while those of cv. ‘UCR’ did not. It is concluded that Na+ exclusion from the shoot contributes to salt tolerance of sesame, cv. ‘UCR’. 相似文献
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The ability of clay to move ahead of an ice-liquid interface depends on the rate of freezing, the particle size, the release of dissolved air from the water through its probable effect on local freezing rates, and on the electrolyte and its concentration through their effects on interparticle forces and particle mobility. A freezing-rate of 1 cm per hour did not move flocculated clay in most cases, but moved dispersed clay up to 0.7 cm before being trapped in the ice with released air. Aggregates of clay (0.1 to 1 mm) were produced by freezing. After thawing they swelled and dispersed depending on the electrolyte and its concentration in a similar manner to aggregates formed by drying. 相似文献
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Hongen Liu Chengxiao Hu Xiaoming Hu Zhaojun Nie Xuecheng Sun Qiling Tan 《Journal of plant nutrition》2013,36(12):1751-1760
A hydroponic trial was conducted to assess interaction of molybdenum (Mo) and phosphorus (P) on uptake and translocation of P and Mo by Brassica napus. Molybdenum was applied at four rates (0, 0.01, 0.1 and 1 mg L?1) and P at three rates (1, 30, and 90 mg L?1) in nutrient solution. The results indicated that P increased shoot growth and 0.01 mg L?1 Mo improved the growth of shoots and roots. Molybdenum increased shoot P uptake and root P concentration and uptake when higher P was provided, and had a stimulating effect on P translocation from shoots to roots. P increased shoot Mo concentration and uptake, decreased those in roots, and enhanced Mo transport from roots to shoots. These results implied that both Mo and P had beneficial effects on Mo and P absorption and translocation and co-application of them were necessary to promote growth and utilization of Mo and P for Brassica napus. 相似文献