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21.
G. W. Yeates T. W. Speir M. D. Taylor L. Clucas A. P. Schaik 《Biology and Fertility of Soils》2006,42(6):550-555
The impact of biosolids on soil processes in five soils under pasture was assessed. Five biosolid treatments (control, dried pellets, compost, biosolids at 200 kg N/ha, and biosolids at 800 kg N/ha) were mixed in 0- to 10-cm-deep soil in lysimeters each year. Nematodes were sampled after 2 years. Many of the nematode populations and indices showed significant soil effects. Nematode responses to the range of biosolid amendments were similar across the five soils. Few populations showed an interaction between the type of amendment and the soil. The most marked response to amendment was that of bacterial-feeding Rhabditidae, in which populations were affected by the weight of the biosolid amendment. Nematode contribution to the soil processes in these soils was not adversely affected by the application of biosolids. 相似文献
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David Badia 《Arid Land Research and Management》2013,27(2):193-203
The impact of straw incorporation (6 Mg ha -1 year -1 ) into agricultural soils compared with straw removal on organic matter mineralization and salinity was studied. The mineralization coefficient (CO 2 -C evolved/organic C ratio) was obtained to evaluate organic matter mineralization. Soil salinity was measured as means of electrolytic conductivity of saturation paste extract. Both parameters were measured seasonally during two years in two salt-affected soils of the semiarid Central Ebro Valley (northeast Spain), a saline soil and a saline-sodic soil. The electrolytic conductivity (ranging from 2.5 dS m -1 to 24.3 dS m -1 ) and the mineralization coefficient (ranging from 5.9 10 -4 day -1 to 37.9 10 -4 day -1 ) varied widely during seasonal samplings of both soils. The lowest electrolytic conductivity values, coincided with the highest mineralization coefficient values. Straw mulching and burying decreased significantly the average seasonal electrolytic conductivity of both soils: 2.5 times in the saline soil, and 1.9 times in the saline-sodic soil. The EC reduction only increased significantly (P < 0.05) the mineralization coefficient on saline soil (1.6 times). Straw amendment, followed by rainy periods, allowed the soluble salts leaching but did not modify significantly sodium content. A logarithmic regression was found between mineralization coefficient and electrolytic conductivity (r 2 = 0.41), considering both soils. Infiltration, water aggregate stability, and qCO 2 were improved with the straw amendment, but only in saline soil. Soil differences showed the existence of a double effect: an osmotic and a specific ion effect. 相似文献
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The US and EU markets are the main destinations of Chinese forest products.Through analyzing the similarities and differences between the US Lacey Act Amendment and the EU Timber Regulation,the paper focused on how to realize better compatibility and practicality of Chinese timber legality verification scheme in terms of verification standard setting,verification procedures,pilot work of timber legality verification scheme,capacity-building trainings and studies on key problems. 相似文献
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[目的]为滨海盐渍土改良找到新的有效途径。[方法]通过田间试验,研究了Encapsalt改良剂对黄河三角洲滨海盐渍土土壤盐分及作物的影响。[结果]Encapsalt改良剂的最佳施用量为9 000～12 000 ml/hm2,分2次施的效果较好。第1次施Encapsalt改良剂,可明显降低土壤的含盐量和pH,提高作物的出苗率。第2次施Encapsalt改良剂,可以维持土壤的含盐量不升高,使土壤不发生返盐现象,从而减少死苗现象,保证作物的正常生长,提高作物产量。[结论]Encapsalt改良剂值得进一步试验示范推广。 相似文献
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依据等断面积径级标准木法,在东北林业大学帽儿山实验林场老山人工林示范区设置的8块樟子松人工林不同年龄的样地中分别选伐5株树木,实测每株样木的每年实际高生长,并采用树干解析法预估了樟子松样木的树高生长。通过分析发现:采用传统的树干解析法预估樟子松的树高生长存在偏差,预估偏差范围一般在0~0.8m之间,樟子松幼年时相对偏差较大,最大可达200%以上;相对偏差随年龄的增大呈倒“J”字形曲线。为了克服传统的树干解析法预估树高每年生长的偏差,建立了相对偏差与年龄的关系函数,用以修正传统的树干解析法预估的树高每年生长。 相似文献
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高聚物对土壤结构改良的研究 Ⅲ.聚丙烯酰胺对赤红壤的改良研究 总被引：32，自引：0，他引：32
研究了不同离子类型 (中性、阴离子和两性 )聚丙烯酰胺对赤红壤的改良作用。实验结果显示 ,聚丙烯酰胺能够提高赤红壤 >0 .2 5mm水稳性团粒结构数量 ,降低土壤容重 ,增大土壤的毛管持水量和渗透系数 ,提高土壤的含水量 ;在施用量为 0 .0 0 5 %— 0 .2 0 0 %的范围内 ,改良剂对赤红壤的改良效果随其施用量的增大而增强 ;聚丙烯酰胺的离子类型和分子量及其施用方式和添加剂对土壤的改良效果有显著影响 相似文献
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苏南地区两种土壤钾素供应状况及其调节 总被引：3，自引：0，他引：3
苏南地区黄刚土和白土供钾潜力较低 ,加之复种指数较高、雨水过多 ,致使土壤钾素亏缺严重 ,而我国钾矿资源贫乏 ,钾肥生产量有限 ,因此如何充分利用有限的钾肥资源 ,就显得尤为迫切和重要 .本文主要从钾肥的供需现状、作物的需钾特征和土壤的供钾规律等方面探讨了钾肥的合理投向及其调节 ,以提高钾肥的利用效率和增产效益 相似文献
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改良剂对镉污染酸性水稻土的修复效应与机理研究 总被引：29，自引：0，他引：29
为探明田间条件下施用石灰、钙镁磷肥、海泡石和腐殖酸等改良剂对Cd污染酸性水稻土的修复效应和作用机理, 通过在Cd污染区建立田间小区试验, 研究了改良剂单施和与石灰配施对Cd污染酸性水稻土中Cd作物有效性的影响。结果表明, 施用改良剂有效地改变了土壤中Cd的存在形态, 除腐殖酸外, 其他改良剂均使土壤酸提取态Cd不同程度地转化为可还原态Cd和残渣态Cd; 施用改良剂可使0.1 mol·L-1 NaNO3和 0.01 mol·L-1CaCl2提取态Cd 降低26%~97%, 降低效果为石灰+海泡石>海泡石>石灰+钙镁磷肥>钙镁磷肥>石灰>石灰+腐殖酸>腐殖酸; 改良剂使水稻地上部分的Cd吸收量降低6%~49%。试验结果还显示, 施用改良剂提高土壤pH是引起土壤中Cd作物有效性降低的主要原因之一。根据田间试验的结果, 海泡石可推荐作为Cd污染酸性水稻土的改良剂, 而腐殖酸则不宜使用。 相似文献
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钝化剂-锌肥降低烟草镉含量长期效果研究 总被引：5，自引：0，他引：5
采用田间小区试验,通过外源添加1.5 mg kg-1镉(Cd)模拟轻度Cd污染土壤,研究赤泥、油菜秸秆、玉米秸秆及其组合并配施硫酸锌降低土壤Cd有效性和烟草各部位Cd含量的长期效果。结果表明,施用钝化剂后,烟叶产量增加了7.0%~32.1%,中上等烟叶比例提高了2.9%~20.2%,烟草经济效益提高了6.6%~31.3%。钝化剂处理土壤有效态Cd含量降低显著,2012年和2013年降幅分别为18.6%~47.4%、16.0%~27.0%。烟草各部位Cd含量排序为下部叶中部叶、上部叶茎秆,且均与土壤有效态Cd含量呈极显著正相关关系。2011—2013年钝化剂处理烟草叶片Cd平均含量较对照分别降低了28.3%、28.1%、15.2%,烟草各部位Cd含量年变化幅度下部叶最大,茎秆最小,叶位间Cd含量差异随钝化时间延长逐渐缩小。钝化剂降低土壤-烟草系统Cd生物有效性效果稳定持久,其中油菜秸秆优于玉米秸秆,有机无机复合钝化剂效果最好。配施锌肥后,2011—2013年烟草叶片Cd含量较对照分别降低了19.1%、23.3%、17.9%,且下部和中部叶片降低效果达到显著水平;中部和上部叶Cd、Zn含量呈显著负相关关系。因此,在轻度Cd污染土壤上,赤泥油菜秸秆复合钝化剂配施锌肥是降低烟叶镉含量兼顾高产的最佳生产措施。 相似文献