Typic Hapludands Research Articles

ANALISIS ERODIBILITAS TANAH DAN HUBUNGANNYA DENGAN PRODUKTIVITAS TANAMAN KOPI DI KECAMATAN WAJAK, KABUPATEN MALANG

Coffee plants (Coffea sp.) are among the most popular plantation crops for farmers in Wajak District. However, the soil condition in Wajak District is dominated by sandy soil, which can trigger soil sensitivity to high erosion potential. A mitigation effort for the declining of coffee production in the Wajak District can be made through the estimation of the soil erodibility index. This study aimed to suspect the soil erodibility index and obtain the relationship of soil erodibility index to coffee production on smallholder coffee plantations in Wajak District, Malang Regency. The methods of determining land boundaries with land map units (SPL) were land use, soil type, and slope. The parameters used were soil texture (M), organic matter (a), structure (b), and permeability (c) to determine erodibility, as well as coffee beans for coffee production analysis. Statistical analysis of data was in the form of correlation tests and data regression tests. The results of the data analysis showed that the highest wet weight of coffee fruit was found in SPL 8 with plantation land use, Typic Hapludands soil type and land slope of 8-15%. The wet weight value of coffee fruit at SPL 8 is 2.18 t ha-1 with an erodibility value of 0.37. While the lowest wet weight of coffee beans was found in SPL 2 with moor land use, Andic Eutrudepts soil type and land slope of 8-15%. The average wet weight value of coffee beans at SPL 2 was 0.12 t ha-1 with an erodibility value of 0.26.

Using a fuzzy logic approach to reveal soil-landscape relationships produced by digital soil maps in the humid tropical region of East Java, Indonesia

Digital soil mapping (DSM) has been developed and applied as a cost-effective alternative to conventional mapping. Most DSM studies in predicting soil classes evaluate the accuracy of the digital maps based on the percentage of correctly classified observations over an area or other global statistical measures. There is a lack of local accuracy assessment and spatial comparison of the actual soil-landscape relationships produced by the digital maps. This study aims to address this limitation by examining the use of digital elevation models and their derivatives in predicting the spatial diversity of soil types in the Jember Regency, East Java Province, Indonesia. We evaluated the accuracy of the map using a fuzzy set-map comparison, and in addition, we assessed the soil-landscape relationship of the digital maps. The study used 783 training data in the form of map polygons combined with a suite of covariates representing topography, organisms, and soil moisture. The prediction was carried out using three machine learning techniques: K-nearest neighbors, random forest, and Decision Tree. The soil maps were evaluated using the fuzzy logic metric to determine the global and local agreement between the DSM product and a conventional soil map. The results showed that the global fuzzy matching comparison between the predicted map and the reference map ranged from poor to good (0.30–0.39). However, examining the results locally, very good local fuzzy inference values of 0.69–0.84, were found in the lowland landscapes in the south and highlands in the north. Three digital maps generated by the random forest model combining three covariates showed that the dominant soil in the lowlands near the estuary and the coast was predicted as Typic Endoaquepts, then shifted to Typic Epiaquepts upstream, both of which were Inceptisols. At the top and bottom of the mountain, the predicted soils were Typic Hapludands and Andic Dystudepts, indicating Andisols at the top and a transition from Andisols to Inceptisols at the bottom. This pattern shows that DSM could detect the relationship between soils type formed in local environmental conditions. Evaluating the soil-landscape relationships of digital soil maps can reconcile pedology and digital soil mapping.

Differences in Andisols properties as affected by horticulture land use and pine forest in Lembang Sub District, West Java

Andisols have different characteristics depending on the use and management of the soil. This study aimed to determine the different characteristics of Andisols at horticulture land use and pine forest. Three soil profiles in Lembang, West Java, have been identified to represent land use differences and 23 soil samples were selected for analysis of the soil chemical and physical properties. The results showed that the three profiles have very thick solum (≥150 cm), bulk density of 0.40 to 0.68 g cm−3, pH NaF >10, very high P retention (>90%) with acid to slightly acid soil reaction. organic C was very high in the surface horizon and decreased irregularly with soil depth. The upper layer of soil planted with vegetables has a higher content of total K and available P compared to the soil under pine forests. The soil was classified as Typic Hapludands or Umbric Andosols. High P retention and low pH are some of the limiting factors in agricultural business, requiring soil cultivation and application of organic matter to increase soil pH and reduce P retention.

Soil Classification in Nagari Sungai Kamuyang, Luak District, Limapuluh Kota Regency

This study was aimed to examine the classification of soil in Nagari Sungai Kamuyang, Luak District, Limapuluh Kota Regency by the USDA Soil Taxonomy up to the level of family and synchronized with the National Soil Classification. This study was conducted in Nagari Sungai Kamuyang. Soil analysis conducted at the Laboratory Soil Department Faculty of Agriculture Andalas University, Soil Chemistry Laboratory and the Mineralogy Laboratory of Soil Research Institute in Bogor. This study used a survey method with purposive sampling random sampling based on unit land. This study consisted of preparation, pre-survey, the main survey, laboratory analysis, and data processing. Based on the results of research on the study of the soil classification in Nagari Sungai Kamuyang, Luak District, Limapuluh Kota Regency, showed soil classification based on Soil Taxonomy on the profile 1 was classified as the Ordo: Inceptisols, Sub Ordo: Udepts, Great Group: Dystrudepts, Sub Group: Andic Dystrudepts, Family: Fine Dust, Kaolinite, Isohypertermik, Andic Dystrudepsts. The profile 2 was classified as an Ordo: Andisols, Sub Ordo: Udands, Great Group: Hapludands, Sub Group: Typic Hapludands, Family: Medial, Amorfik, Isohypertermik, Typic Hapludands. Based on the National Soil Classification, profile 1 was classified as Type: Latosol, Various: Latosol Umbrik. Profile 2 was classified as Type: Andosol, Various: Andosol District.

The impact of ridge direction and latex on the yield of potato (Solanum tuberosum l.) in typic hapludands, Pengalengan, West Java

The objective of this experiment was to find out the effect of ridge direction and latex soil conditioner on potatoes yields on Typic Hapludands from Pangalengan. The experiment was conducted in Pangalengan, with elevation 1,600 meters above sea level and 30% of slope steepness. The experiment used a split plot design with 12 treatments and three replications. The main plot ridge direction consists of: in line with slope direction, in line with contour, and diagonal. The sub plot was latex concentration level as follow: 0%, 0.6%, 1.2% and 1.8%. The result of the experiment showed that there was no interaction effect between ridge direction and latex soil conditioner. The independent effect of latex just influenced potatoes yields. Potatoes yield of latex 0%, 0.6%,1.2% and 1.8% was 72.97 kg was 74.47 kg, 75.14 kg and 76.48 kg, respectively.

Characteristics and Classification of Soil Formed from Banda Recent Volcanic Ash on Various Topographic Positions

The Banda Islands consist of three main islands namely Banda Besar Island, Banda Naire Island, and Banda Api Island. Banda Api Mountain is an active volcano and based on history has erupted 20 times over the past 400 years. The eruption of volcanic ash has covered most of Banda Naire Island in the east and Banda Big Island in the east and south of Banda Api Mountain. This study aims to determine the characteristics and classification types of soil formed from parent material deposited in recent volcanic ash in different topographic positions. The method used was free survey method through toposequence approach by determining the profile point based on a straight line (transect) while soil classification refers to the Soil Taxonomy System. The results of the study showed that the profile of the soil at the position of the foothills on the island of Banda Naire and the Banda Besar morphologically had Andisols properties (Typic Hapludands), but in generally the physical and chemical characteristics of each soil profile did not match with the Andisols requirements so that they were classified into the Inceptisols (Vitrandic Eutrudepts and Vitrandic Dystrudepts) (in the slope and foothills), while at the top of the hill were classified as Entisols (Typic Udipsamments).

Determination of the water regulation capacity of a typic hapludands by means of humidity retention curves and the modeling of its hydrophysical properties

In the watershed Centella , located in the upper river basin of the Dagua - Valle del Cauca, in nine farms with association coffee - banana, coffee - guamo, cane panelera and pastures, the water regulation capacity of the soil was studied by means of humidity retention curves obtained in the laboratory and by modeling its hydrophysical properties in Hydrus 2D. Properties such as texture, bulk density, porosity, organic matter, hydraulic conductivity, infiltration and humidity were determined. Subsequently, moistureretention curves were simulated using the hydraulic models of Van Genuchten, Brooks and Corey, Van Genuchten modified and Kosugi, evaluating the average errors and the dispersion of the data. Agreed to the results it is possible to point out that the soil under study has a high capacity for moisture retention ( > 18%), consequence of the high content of clays ( > 41%) and organic matter ( > 5%), characteristics of the Andisols of the Valle del Cauca. Finally, the best fitting model was compared statistically with the data of the curves obtained in the laboratory, finding that Van Genuchten and Van Genuchten models modified, are the most appropriate for obtaining the retention curves from the hydrophysical properties since they presented a lower mean error (ME) with a value not higher than -0.11 cm3 / cm3 and a value of the square root of the mean square error (RMSE) less than 0.11 cm3 / cm3.

Using Soil Stratigraphy and Tephrochronology to Understand the Origin, Age, and Classification of a Unique Late Quaternary Tephra-Derived Ultisol in Aotearoa New Zealand

In this article, I show how an Ultisol, representative of a globally-important group of soils with clay-rich subsoils, low base saturation, and low fertility, in the central Waikato region in northern North Island, can be evaluated using soil stratigraphy and tephrochronology to answer challenging questions about its genesis, age and classification. The Kainui soil, a Typic Kandiudult (Soil Taxonomy) and Buried-granular Yellow Ultic Soil (New Zealand Soil Classification), occurs on low rolling hills of Mid-Quaternary age mainly in the Hamilton lowlands in, and north and northeast of, Hamilton city. It is a composite, multi-layered tephra-derived soil consisting of two distinct parts, upper and lower. The upper part is a coverbed typically c. 0.4–0.7 m in thickness (c. 0.6 m on average) comprising numerous late Quaternary rhyolitic and andesitic tephras that have been accumulating incrementally since c. 50 ka (the age of Rotoehu Ash at the coverbed’s base) whilst simultaneously being pedogenically altered (i.e., forming soil horizons) via developmental upbuilding pedogenesis during Marine Oxygen Isotope Stages (MOIS) 3-1. Any original depositional (fall) bedding has been almost entirely masked by pedogenic alteration. Sediments in lakes aged c. 20 ka adjacent to the low hills have preserved around 40 separate, thin, macroscopic tephra-fall beds mainly rhyolitic in composition, and equivalent subaerial deposits together form the upper c. 30 cm of the coverbed. Okareka (c. 21.8 ka), Okaia (c. 28.6 ka), Tāhuna (c. 39.3 ka) and (especially) Rotoehu tephras make up the bulk of the lower c. 30 cm of the coverbed. Tephra admixing has occurred throughout the coverbed because of soil upbuilding processes. Moderately well drained, this upper profile is dominated by halloysite (not allophane) in the clay fraction because of limited desilication. In contrast, Otorohanga soils, on rolling hills to the south of Hamilton, are formed in equivalent but thicker (>c. 0.8 m) late Quaternary tephras ≤c. 50 ka that are somewhat more andesitic although predominantly rhyolitic overall. These deeper soils are well drained with strong desilication and thus are allophanic, generating Typic Hapludands. Ubiquitous redox features, together with short-lived contemporary reduction observed in the lower coverbed of a Kainui soil profile, indicate that the Kainui soil in general is likely to be saturated by perching for several days, or near saturation for several months, each year. The perching occurs because the coverbed overlies a slowly-permeable, buried, clay-rich paleosol on upper Hamilton Ash beds, >c. 50 ka in age, which makes up the lower part of the two-storeyed Kainui soil. The coverbed-paleosol boundary is a lithologic discontinuity (unconformity). Irregular in shape, it represents a tree-overturn paleosurface that may be c. 74 ka in age (MOIS 5/4 boundary). The buried paleosol is markedly altered and halloysitic with relict clay skins (forming paleo-argillic and/or paleo-kandic horizons) and redoximorphic features. It is inferred to have formed via developmental upbuilding pedogenesis during the Last Interglacial (MOIS 5e). The entire Hamilton Ash sequence, c. 3 m in thickness and overlain unconformably by Rotoehu Ash and underlain by c. 340-ka Rangitawa Tephra at the base, represents a thick composite (accretionary) set of clayey, welded paleosols developed by upbuilding pedogenesis from MOIS 10 to 5.

Soil morphogenesis diversity at the southern flank of Merapi Volcano, Indonesia five years post-eruption

This study aims to find out the soil morphology diversity at the southern flank of Mt.Merapi Yogyakarta, Indonesia. The field research was conducted using purposive sampling method where each site of geomorphological unit as representing of the cone, upper, middle and lower slopes of Mt.Merapi. Poligenesis of the soil morphology was observed at pedon P1 with composition of the upper and buried soil was Typic Hapludands-Typic Hapludands, P3 (Andic Eutrudepts-Vitrandic Udorthents), P4 (Vitrandic Udorthents -Typic Hapludands), and P5 (Andic Eutrudepts-Andic Eutrudepts). Whereas the monogenesis of the soil morphology was observed at pedon P2, P6, P7 and P8 with subgroups of Typic hapludands, Andic Eutrudepts, Andic Dystrodepts and Typic Udorthents, respectively. Soil morphogenesis diversity (polygenesis) shown by the presence of a pedon having more than one soil profile was not a limiting factor for crop roots growth, so the agro-ecosystem recovery process was relatively fast.

Tropical Volcanic Soils From Flores Island, Indonesia

Tropical Volcanic Soils from Flores Island, Indonesia (Hikmatullah and K Nugroho): Soils that are developed in tropical region with volcanic parent materials have many unique properties, and high potential for agricultural use. The purpose of this study is to characterize the soils developed on volcanic materials from Flores Island, Indonesia, and to examine if the soils meet the requirements for andic soil properties. Selected five soils profiles developed from andesitic volcanic materials from Flores Island were studied to determine their properties. They were compared in their physical, chemical and mineralogical characteristics according to their parent material, and climatic characteristic different. The soils were developed under humid tropical climate with ustic to udic soil moisture regimes with different annual rainfall. The soils developed from volcanic ash parent materials in Flores Island showed different properties compared to the soils derived from volcanic tuff, even though they were developed from th e same intermediary volcanic materials. The silica contents, clay mineralogy and sand fractions, were shown as the differences. The different in climatic conditions developed similar properties such as deep solum, dark color, medium texture, and very friable soil consistency. The soils have high organic materials, slightly acid to acid, low to medium cation exchange capacity (CEC). The soils in western region have higher clay content and showing more developed than of the eastern region. All the profiles meet the requirements for andic soil properties, and classified as Andisols order. The composition of sand mineral was dominated by hornblende, augite, and hypersthenes with high weatherable mineral reserves, while the clay fraction was dominated by disordered kaolinite, and hydrated halloysite. The soils were classified into subgroup as Thaptic Hapludands, Typic Hapludands, and Dystric Haplustands.

Characteristics and Stocks of Soil Nutrient under Various Land Use Types in a Super Wet Tropical Rain Forest Padang, West Sumatra

Tropical Volcanic Soils from Flores Island, Indonesia (Hikmatullah and K Nugroho): Soils that are developed in tropical region with volcanic parent materials have many unique properties, and high potential for agricultural use. The purpose of this study is to characterize the soils developed on volcanic materials from Flores Island, Indonesia, and to examine if the soils meet the requirements for andic soil properties. Selected five soils profiles developed from andesitic volcanic materials from Flores Island were studied to determine their properties. They were compared in their physical, chemical and mineralogical characteristics according to their parent material, and climatic characteristic different. The soils were developed under humid tropical climate with ustic to udic soil moisture regimes with different annual rainfall. The soils developed from volcanic ash parent materials in Flores Island showed different properties compared to the soils derived from volcanic tuff, even though they were developed from th e same intermediary volcanic materials. The silica contents, clay mineralogy and sand fractions, were shown as the differences. The different in climatic conditions developed similar properties such as deep solum, dark color, medium texture, and very friable soil consistency. The soils have high organic materials, slightly acid to acid, low to medium cation exchange capacity (CEC). The soils in western region have higher clay content and showing more developed than of the eastern region. All the profiles meet the requirements for andic soil properties, and classified as Andisols order. The composition of sand mineral was dominated by hornblende, augite, and hypersthenes with high weatherable mineral reserves, while the clay fraction was dominated by disordered kaolinite, and hydrated halloysite. The soils were classified into subgroup as Thaptic Hapludands, Typic Hapludands, and Dystric Haplustands.

SOIL PROPERTIES OF THE EASTERN TOPOSEQUENCE OF MOUNT KELIMUTU, FLORES ISLAND, EAST NUSA TENGGARA AND THEIR POTENTIAL FOR AGRICULTURAL USE

Kelimutu stratovolcano is one of the young volcanoes extensively found in Flores island. Studies on volcanic soil properties and their suitability for agricultural development in the whole island are lacking. The research was conducted to evaluate the relationship of elevation and soil properties, and suitability for agricultural development. Five representative pedons at elevation of 550, 1,000, 1,200, 1,400, and 1,600 m above sea level (asl), respectively, were studied in the field, and 22 soil samples were analyzed in the laboratory. The results indicated that elevation significantly affected soil properties and degree of soil weathering. With decreasing elevation, sand content, amorphous material content, and phosphate retention decreased. Concomitantly, clay content, H2O-pH, exchangeable Ca and Mg, base saturation, and soil-CEC increased. A highly positive correlation was shown between P retention and NaFpH, Al, and (Al+0.5 Fe) contents extracted by acid ammonium oxalate. Soil-CEC also showed significant positive correlation with clay and silt contents, organic carbon, and exchangeable Ca and Mg. Degree of weathering increased with decreasing elevation as reflected by decreasing silt/clay ratio. Soils developed from Entisols (Lithic Udorthents) at 1,600 m asl, to Andisols (Typic Hapludands) at 1,000-1,400 m asl, and Mollisols (Typic Hapludolls) at lower elevation down to 550 m asl. Soils at 1,400-1,600 m asl are unsuitable for agriculture. Soils at 1,000-1,200 m are moderately suitable for food crops, horticulture, and estate crops. Dominant limiting factors are steep slopes and P retention. Soils at 550 m asl are suitable for food and estate crops, and also lowland horticulture.

SOIL PROPERTIES OF THE EASTERN TOPOSEQUENCE OF MOUNT KELIMUTU, FLORES ISLAND, EAST NUSA TENGGARA AND THEIR POTENTIAL FOR AGRICULTURAL USE

Kelimutu stratovolcano is one of the young volcanoes extensively found in Flores island. Studies on volcanic soil properties and their suitability for agricultural development in the whole island are lacking. The research was conducted to evaluate the relationship of elevation and soil properties, and suitability for agricultural development. Five representative pedons at elevation of 550, 1,000, 1,200, 1,400, and 1,600 m above sea level (asl), respectively, were studied in the field, and 22 soil samples were analyzed in the laboratory. The results indicated that elevation significantly affected soil properties and degree of soil weathering. With decreasing elevation, sand content, amorphous material content, and phosphate retention decreased. Concomitantly, clay content, H2O-pH, exchangeable Ca and Mg, base saturation, and soil-CEC increased. A highly positive correlation was shown between P retention and NaFpH, Al, and (Al+0.5 Fe) contents extracted by acid ammonium oxalate. Soil-CEC also showed significant positive correlation with clay and silt contents, organic carbon, and exchangeable Ca and Mg. Degree of weathering increased with decreasing elevation as reflected by decreasing silt/clay ratio. Soils developed from Entisols (Lithic Udorthents) at 1,600 m asl, to Andisols (Typic Hapludands) at 1,000-1,400 m asl, and Mollisols (Typic Hapludolls) at lower elevation down to 550 m asl. Soils at 1,400-1,600 m asl are unsuitable for agriculture. Soils at 1,000-1,200 m are moderately suitable for food crops, horticulture, and estate crops. Dominant limiting factors are steep slopes and P retention. Soils at 550 m asl are suitable for food and estate crops, and also lowland horticulture.

Variabilidad espacial de los atributos químicos del suelo en el rendimiento y calidad de café

La importancia ambiental y económica del uso racional de insumos para una agricultura competitiva y sostenible hace necesaria una mayor comprensión de las diferentes variables que intervienen en la producción agrícola. El objetivo del presente estudio fue establecer el comportamiento espacial de los atributos químicos del suelo y su relación con el rendimiento y la calidad del café en un Typic Hapludands. El muestreo se realizó de manera aleatoria en 64 puntos georreferenciados a una profundidad de -0,20 m. Los datos fueron analizados a través de estadística descriptiva, geoestadística, correlaciones lineales y los métodos multivariados clúster y componentes principales (ACP). La interpolación se realizó a través de kriging. El análisis descriptivo mostró alta variabilidad para los atributos químicos y los demás mostraron dependencia espacial excepto el contenido de B en el suelo. Se presentó una correlación de 35,88 % entre el contenido de carbono orgánico del suelo (CO) y el rendimiento, además de una correlación negativa de 40,98 % entre la merma en trilla y el contenido de Ca en el suelo. El análisis de componentes principales (ACP) y clúster mostraron poca relevancia para los atributos Na, P, B y rendimiento. A partir del análisis clúster y la distribución espacial, se propone un manejo para el cultivo de café.

Zoning Rural Area For The Development Of Annual Plants

One strategy to protect land from degradation is to use the land according to their capability. Zoning of commodities is an effort in that direction and determination of commodities is based on the suitability of land with agronomic needs of crops and farming feasibility analysis. The purpose of this study was to determine the development zone of annual crops, based on the analysis of agro-ecological characteristics and agricultural viability. Analysis of land suitability for the cultivation of coffee, vanilla, pepper, cocoa, banana, durian, mango, and melinjo, found that land can be recommended for the development of the annual crops is about 29,230 ha from an area of 54,764 ha. The land was divided into six agro-ecological zones i.e. two zones at area with land slope of 3- 8%, each covering an area of 2,737 ha at an altitude of 15-50 m above sea level (asl), and 12,008 ha at an altitude of 50-300 m asl, the two zone at area with land slope of 8-15%, each covering 6119 ha at an altitude of 25-250 m asl and 1,221 ha at an altitude of 15-50 m asl, and two zones at area with land slope of 16-40% , each covering an area of 1,101 ha at an altitude of 400-700 m asl, and 6,134 ha at an altitude of 400-500 m asl. The soil types found are Typic /Vitrandic Eutrudepts, Typic Hapludands, and Vitrandic Hapludalfs. This study recommends that the banana is a perennial plant with the most potential to be developed and has good economic prospects in almost all agro-ecological zones. Other commodities are also preferred, coffee and vanilla.

Calibration of CO2FIX to native forest, pine plantation, and pasture on a volcanic soil of the Chilean Patagonia

Terrestrial stocks of soil carbon (C) are an important part of the global C budget, and are considered in the Kyoto Protocol. However, there have been few studies in forested regions over the influence of land-use changes on volcanic soils (Andisols) and its simulation through models. The objective of this study was to determine the influence of native forest, pine plantation, and pasture on the C content and organic matter quality in an Andisol of the Chilean Patagonia, and to simulate the effects using the CO2FIX model. The model was calibrated to each land-use area, and C content was determined in lenga (Nothofagus pumilio) and pine (Pinus ponderosa) trees using previously derived allometric equations, and in pasture by direct measurement. The C content was measured in soils (0–100-cm depth) (Typic Hapludands; Umbric Andosols), and the light (>212 µm), intermediate (212–53 µm), and heavy (<53 µm) fractions of organic matter (0–40-cm depth) which have progressively lower labilities. Total C (vegetation + soil) in the lenga forest was greater than in the pine plantation or pasture, but the C content in soil was greater in the pasture than in the other areas. Over all sites, there was more C in the light fraction than in the intermediate and heavy fractions at 0–5-cm depth, but C content was greater in the heavy fraction with increasing soil depths. However, the quality of soil organic matter was better in the lenga forest compared with the other sites, as indicated by higher ratios of light fraction C between 0–20- and 20–40-cm depths. CO2FIX adequately simulated the C contents in the vegetation, and recalibration for slower degradation rates of soluble organic compounds in Andisols provided better approximation of C content in soil, but overestimated the content of labile C.

The influence of land-use change on the organic carbon distribution and microbial respiration in a volcanic soil of the Chilean Patagonia

Land-use changes can modify soil carbon contents. Depending on the rate of soil organic matter (SOM) formation and decomposition, soil-vegetation systems can be a source or sink of CO 2. The objective of this study was to determine the influence of land-use change on SOM distribution, and microbial biomass and respiration in an Andisol of the Chilean Patagonia. Treatments consisted of degraded natural prairie (DNP), thinned and pruned Pinus ponderosa plantations (PPP), and unmanaged second-growth Nothofagus pumilio forest (NPF). The soil was classified as medial, amorphic, mesic Typic Hapludands. Soil microbial respiration and microbial biomass were determined in the laboratory from soil samples taken at 0–5, 5–10, 10–20 and 20–40 cm depths obtained from three pits excavated in each treatment. Physical fractionation of SOM was performed in soil of the upper 40 cm of each treatment to obtain the three following aggregate-size classes: macroaggregates (>212 μm), mesoaggregates (212–53 μm) and microaggregates (<53 μm). Plant C content was 68% higher in PPP than in DNP and 635% higher in NPF than in PPP. Total soil and vegetation C content in both DNP and PPP were less than half of that in NPF. Total SOC at 0–10 cm depth decreased in the order DNP (7.82%) > NPF (6.16%) > PPP (4.41%), showing that land-use practices affected significantly ( P < 0.01) SOC stocks. In all treatments, microbial biomass C and respiration were significantly higher ( P < 0.05) in the upper 5 cm. Soil microbial respiration was also correlated positively with microbial biomass C and SOC. The different land uses affect the formation of organic matter, SOC and microbial biomass C, which in turn will affect soil microbial respiration. Conversion of DNP to PPP resulted in a 44% decrease of SOC stocks in 0–10 cm mineral soil. The largest amount of SOC was stabilized within the mesoaggregate fraction of the less disturbed system, NPF, followed by PPP. In the long term, formation of stable mesoaggregates in soils protected from erosion can behave as C sinks.

P adsorption and desorption capacities of selected Andisols from the Azores, Portugal.

Phosphorous adsorption maxima (P-ads max) and the amounts of P desorbed (P-des) using Langmuir equation and eight successive extractions with 0.01M CaCl2, were determined on sixteen horizons of Andisols from the Azores, Portugal. Results showed that the values of P-ads max and the proportions of P desorbed (P-des) were highly influenced by allophane, Alo, Ald, and Fed contents, and by the values of Alo + ½ Feo and ferrihydrite + allophane. P-des were negatively correlated with these constituents, but not with allophane. Vitrandic Haplustepts and Typic Udivitrands, and Typic Hapludands containing low amounts of allophane, Alo, Ald, and Fed showed low values of P-ads max, but high P-des values. Phosphate ions applied as fertilizer on these soils are highly available for plant use, but maybe easily lost through surface runoff, subsurface drainage and soil erosion. They may require restricted amounts of P fertilizer, and P losses should be controlled to minimize eutrophication of nearby water bodies. Conversely, Typic Placudands containing large amounts of allophane, and Acrudoxic Hydrudands and Typic Hapludands containing large amounts of organic C showed high values of P-ads max, but low P-des, indicating unavailability of P when retained by these soils. Large amounts of slow P-releasing fertilizer may be required for better crop use.

Sorption of lead, copper, zinc, and cadmium by soils: effect of nitriloacetic acid on metal retention

Laboratory experiments were carried out to evaluate lead (Pb), copper (Cu), zinc (Zn), and cadmium (Cd) sorption‐desorption by three soils of contrasting characteristics. Talamanca (silt loam, montmorillonite, Calcic Haploxeralfs), Mazowe (clay, kaolinite, Rhodic Kandiustalf), and Realejos (sandy silt loam, allophane, Typic Hapludands). A second objective was to study the effect of nitriloacetic acid (NTA) on the sorption process. The Talamanca soil, which had a native pH of 6.4 and presented the highest effective cation exchange capacity (ECEC), sorbed more of each of the metal tested than did the other two soils. When the other two soils were compared metal sorption was also related to pH and ECEC. The very low sorption capacity showed by Realejos may be attributed to the low net surface negative charge density of this soil, arising from its allophanic nature. A common feature of the three soils was the relative strong sorption of both Pb and Cu relative to Cd and Zn with Pb showing the highest sorption levels. The selectivity sequences of metals retention were Pb>Cu>Zn>Cd for Talamanca soil, Pb>Cu>Zn≈Cd for Mazowe, and Pb>Cu>Cd>Zn for Realejos. Metal desorption values were low. The order of metal desorption (Cd≈Zn>Cu>Pb) was the same for the three soils studied. Quantitative differences observed in the extractability of the sorbed metals between the soils (Realejos>Mazowe>Talamanca) indicated that soil properties which enhanced metal sorption contributed at the same time to slow down the backward reaction. The addition of NTA to the soil suspension significantly depressed metal sorption by the three soils investigated. Compared with the free ligand system Pb, Cu, Zn, and Cd sorption in the presence of NTA decreased roughly 50%.

Andisols of the Kitakami mountain range, Northeastern Japan: Their characterization and classification

Andisols of the Kitakami mountain range were derived from a mixture of tephras and long range eolian dust deposited during the Quaternary. Thus, the relative proportions of the components of the mixture determined the unique properties of the soils. Soils of the northern and central parts of the mountain range were derived mainly from tephras and had been classified, generally, as Typic Kuroboku soils by the Group of Japanese Pedologists. Soils of the southern part showed a strong influence of long range eolian dust and had been classified, generally, as Typic Para Kuroboku soils. We studied the Andic soil properties of 35 pedons covering the mountain range in order to classify them under the Andisols order. All the soils showed a bulk density (BD) < 0.90 Mg m-3 and Pretention >85% in the Andisol diagnostic horizon. The soils of the northern and central parts of the mountain range had a pH(H20) range of 5.1- 6.7 and acid oxalate-extractable Al plus half Fe (A1o+0.5Feo) level was >2%. They were therefore classified under criterion one of the Andic soils requirements. The soils of the southern part of the mountain range had a pH(H20) range of 4.3-5.7 and the majority of them contained <2.0% of Alo +0.5Feo. The pedons with Alo +0.5Feo level <2.0%, however, had a sufficient amount of volcanic glass in their sand fraction to satisfy the criterion two of the Andic soil requirements. The soils of the northern part contained moderate amounts of organic C and were mainly Typic Hapludands. The soils of the southern part contained large amounts of KCI-extractable Al and organic C and also showed a wider spectrum of Andisols. However, Alic and Typic Fulvudands, and Alic and Typic Melanudands tended to occur in higher frequencies. The classification of the pedons of the central part bridged that of the pedons of the northern and the southern parts.