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Reactive (RP) and organic phosphorus (OP) losses from grazed paddocks were determined on a volcanic soil during 2004 and 2005. Paddocks were grazed by Holstein Friesian steers (3.5 steers ha?1) and received N (67.5 kg ha?1) and P fertilizer (30 kg P ha?1). Total losses ranged between 4 and 15 g P ha?1 year?1 and were greatly affected by incidental P losses associated with spring P fertilizer application. Reactive P constituted 90% of the total losses on average. Due to the high water infiltration capacity of the soil, run‐off was <1% of total drainage, therefore, phosphorus losses in run‐off were small. 相似文献
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不同水分含量对潮土和火山灰土硝化动态的影响 总被引：1，自引：0，他引：1
在试验室条件下研究了不同水分含量对取自中国的潮土和日本的火山灰土硝化动态的影响。潮土在土壤硝化过程中的土壤水分含量以田间持水量的60%～90%较为适宜,低于田间持水量的60%引起土壤硝化力降低。火山灰土在土壤硝化中的土壤水分含量以田间持水量的75%～90%较为适宜,低于田间持水量的75%引起土壤硝化力降低。潮土在硝化培养中有亚硝酸盐出现,火山灰土没有亚硝酸盐被检出。土壤亚硝酸盐含量在低水分含量下峰值低,持续时间较长,在高水分含量下峰值高,持续时间较短。 相似文献
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We characterized humic acids (HAs) and glycerol-extractable organic fractions (GEOFs) extracted from four Andisols, taken from comparable soil-climate conditions on the east side of Mount Etna. The soils were formed on old lava (about 9 000 years ago), old tephra (about 8 700 years ago), recent lava (about 2 600 years ago) and recent tephra (about 3 600 years ago). A part of the organic matter of the soils, deprived of HAs and fulvic acids (FAs), was isolated by glycerol extraction. The GEOF can not be extracted with alkaline solutions, probably because it is closely bound to the mineral component of the soil. The characterization of the extracted organic fraction was carried out using elementary and functional group analysis and Fourier transform infrared (FT-IR) spectroscopy. About 20 extractions were necessary to extract the HA and FA from the older soils and about 10 extractions to extract them from the younger soils. Data showed that the GEOFs had a greater ash content and a smaller N content, as well as a greater presence of aliphatic compounds and carboxylic groups as compared to the HA extracted from the same soil. The GEOFs extracted from younger soils also had a lower yield, ash and COOH-group content, and were more aliphatic than the GEOF extracted from older soils. Finally, the GEOFs were more closely bound to the amorphous component of the soil (‘short-range’ minerals) and consequently less subject to biodegradation. 相似文献
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Jeannette S. Bayuelo-Jiménez Takashi Muraoka Eulogio de la Cruz-Torres Esperanza Quintero-Ponce Lydia C. Paredes-Gutiérrez Mohammad Zaman 《Soil Use and Management》2020,36(2):240-249
Land-use change from forest to agriculture in the volcanic ash-derived soils of Mexico has increased over recent decades. It is likely that land uses and management practices, particularly fertilizer use have affected phosphorus (P) distribution and availability. The objective of this study was to evaluate the effects of land-use types (native forest and maize mono-cropping), and the related P addition, on the forms and distribution of soil P and their isotopic exchangeability. An Andisol, sampled from a cropping site, along with the contiguous area under native forest was treated with 32P-labelled potassium phosphate (KH232PO4). The soil samples were extracted after incubation times of 7, 21, 35 and 49 days. Phosphorus content and 32P recovery in fractions sequentially extracted were assessed for each incubation time. Total soil P was dominated by inorganic fractions (79 to 86%) in both land-use types. Resin-Pi, bicarbonate extractable inorganic P (Bic-Pi) and sodium hydroxide extractable inorganic P (NaOH0.1-Pi) were all raised with P addition. However, the proportion of organic P fraction was reduced under cropped soil. The recovery of 32P in soils with P addition indicates that resin-Pi, Bic-Pi and NaOH0.1-Pi comprised nearly all the exchangeable P. In native soils with no P addition, more than 19% of the 32P was recovered in Bic-Po and NaOH0.1-Po forms. This finding indicates that organic P cycling is crucial when soil Pi reserves are presented in an inadequate amount. Ecologically based management has to be designed for replenishment and succeeding maintenance of soil organic P compounds to increase sustainable agricultural production. 相似文献
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Kei Nakagawa Shin-Ichiro Wada Ryoma Kitamura Ronny Berndtsson 《Communications in Soil Science and Plant Analysis》2017,48(21):2594-2600
Groundwater pollution by nitrate from agricultural fields is a worldwide problem. To improve the understanding of nitrate transport processes through volcanic ash soils overlying groundwater aquifers, salt sorption experiments were performed. Salt sorption is the process that involves the simultaneous use of cation and anion adsorption mechanisms without changing the pH. Prepared six different concentrations of potassium chloride (KCl) solutions were mixed with soil samples. Anion and cation contents of the liquid and solid phases were determined. Experiments were performed in triplicate of six kinds of KCl solutions for three types of soils. Thus, total 54 of samples were analyzed. Relationships between ionic strength and sorption capacity increments of cations and anions were determined. The results show that if ionic strength of the infiltrating solution to the volcanic ash soil is known, the ECEC (effective cation exchange capacity) and EAEC (effective anion exchange capacity) can be reliably estimated. The resulting prediction equations can be included to improve reactive transport simulation models. Consequently, it will be possible to better understand solute transport with changing sorption capacity for the solid soil phase. 相似文献
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《Communications in Soil Science and Plant Analysis》2012,43(17-18):2743-2755
A long‐term (61 years) experimental field was used to examine the effect of acidification on the chemical composition of an allophanic Andisol in northeastern Japan. The pH values of the 1:10 water extract of the plow layer soils were 4.1, 4.7, and 6.2 for three fertilizer application treatments: chemical fertilizers only (CF), CF and compost (CFC), and CFC with liming, respectively. Three batch dissolution analyses were conducted to determine water‐soluble and exchangeable (D1), D1 plus, inorganically bound elements to noncrystalline clays and organically bound elements (D2), and total concentration of elements (TCE, 45 elements). The D1 fraction of 20 elements increased, and that of eight decreased with acidification. The D2 fraction of lithium increased, and that of eight elements decreased with acidification. Because the D2 fraction of many other elements and TCE were not strongly altered, present acidification of this soil can be restored with liming and other necessary amendments. 相似文献
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Spatial and temporal variability of physical properties of Aquands under different land uses in southern Chile 
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下载免费PDF全文 José Dörner Dorota Dec Oscar Thiers Leandro Paulino Felipe Zúñiga Susana Valle Oscar Martínez Rainer Horn 《Soil Use and Management》2016,32(3):411-421
The aquands found in southern Chile are derived from volcanic ash and contain high levels of organic matter. Due to the presence of an impermeable stratum, they have shallow soil profiles, which induce waterlogging for several months each year. These fragile soils, locally known as ‘Ñadi’, cover an area of 475 000 hectares and have undergone intensive land use changes, which have affected the soil physical properties. These are still not well understood but are relevant for the design of efficient drainage systems. The aim of this research was to analyse the impact of the land use change in Ñadi soils on the spatial and temporal variability of their soil physical properties. For the land use change from secondary native forest (sNF) to naturalized grassland (NG), the effective soil depth was measured at defined points. Time‐ and space‐dependent changes of water‐table depth and penetration resistance were recorded. Volumetric water content and soil temperature were measured with sensors installed at three depths and the water retention curve and air permeability at these depths were also determined. The changes in land use over time have induced a reduction in soil depth. Soils under NG showed a smaller soil water storage capacity, air capacity and permeability compared with soils under sNF, as well as waterlogging during winter and greater mechanical strength and soil profile temperatures during summer. Therefore, the land use change affected the spatial and temporal variability of soil physical functions across the field. 相似文献
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长白山及五大连池火山灰土电荷零点的初步研究 总被引：1，自引：0，他引：1
本文采用电位滴定法测定了长白山、五大连池火山灰土的电荷零点(ZPC),分析了影响电位滴定曲线形状、ZPC高低及其位移的因素。研究结果表明,两地火山灰土的ZPC均以C层最高,B层次之,A层最低;长白山剖面A、Bw、C三层的ZPC分别为2.65,4.20,4.35;五大连池削面A、Bw、C三层的ZPC分别为3.20,3.25,3.40;两地火山灰土的ZPC都有不同程度的位移,即ZPC均落在滴定零点(ZPT)的酸侧,说明两地火山灰土均为恒表面电位型胶体和恒表面电荷型胶体的复合体系,两地土壤不同层次中ZPC位移量大小顺序均为:A层>Bw层>C层。 相似文献
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Munehide Ishiguro 《Soil Science and Plant Nutrition》2005,51(5):637-640
Allophanic Andisols have a significant pH-dependent charge. The positive charge increases and the negative charge decreases as pH decreases; therefore, anion movement becomes slower and cation movement becomes faster as pH decreases in the soil. At low pH, soil dispersion occurs easily due to electric repulsive force. The permeability of the soil then decreases because of structural changes that occur when dilute HCl or HNO3 is percolated in the soil. However, soil permeability does not decrease when dilute H2 SO4 is percolated in the soil. This is because SO4 2- strongly adsorbs on the soil surface at low pH and the soil remains flocculated. 相似文献