Unravelling upbuilding pedogenesis in tephra and loess sequences in New Zealand using tephrochronology

The genesis of soils developed in either tephra or loess on stable sites differs markedly from that of soils developed on rock because classical topdown processes operate in conjuction with geological processes whereby material is added to the land surface so that the soils form by upbuilding pedogenesis. Understanding the genesis of such soils (typically Andisols and Alfisols, respectively) often requires a stratigraphic approach combined with an appreciation of buried soil horizons and polygenesis. In New Zealand, calendrically-dated tephras provide an advantage for assessing rates of upbuilding through chronostratigraphy. Many Andisol profiles form by upbuilding pedogenesis as younger tephra materials are deposited on top of older ones. The resultant profile character reflects interplay between the rate at which tephras are added to the land surface and topdown processes that produce andic materials and horizons. In loess terrains, upbuilding pedogenesis since c. 25,000 years ago is associated with maximum rates of loess accumulation c. 3 10 mm per century, sufficiently slow for soil-forming processes to continue to operate as the land surface gradually rises. Thus, Alfisol subsoil features are only weakly developed and Bw or B(x) horizons typically are formed. In contrast, topdown pedogenesis is associated with minimal or zero loess accumulation, the land surface elevation remains essentially constant, and subsoil features become more strongly developed and Bg, Bt, or Bx horizons typically are formed

Carbon storage and DNA absorption in allophanic soils and paleosols

Andisols and andic paleosols dominated by the nanocrystalline mineral allophane sequester large amounts of carbon (C), attributable mainly to its chemical bonding with charged hydroxyl groups on the surface of allophane together with its physical protection in nanopores within and between allophane nanoaggregates. C near-edge X-ray absorption fine structure (NEXAFS) spectra for a New Zealand Andisol (Tirau series) showed that the organic matter (OM) mainly comprises quinonic, aromatic, aliphatic, and carboxylic C. In different buried horizons from several other Andisols, C contents varied but the C species were similar, attributable to pedogenic processes operating during developmental upbuilding, downward leaching, or both. The presence of OM in natural allophanic soils weakened the adsorption of DNA on clay; an adsorption isotherm experiment involving humic acid (HA) showed that HA-free synthetic allophane adsorbed seven times more DNA than HA-rich synthetic allophane. Phosphorus X-ray absorption near-edge structure (XANES) spectra for salmonsperm DNA and DNA-clay complexes indicated that DNA was bound to the allophane clay through the phosphate group, but it is not clear if DNA was chemically bound to the surface of the allophane or to OM, or both. We plan more experiments to investigate interactions among DNA, allophane (natural and synthetic), and OM. Because DNA shows a high affinity to allophane, we are studying the potential to reconstruct late Quaternary palaeoenvironments by attempting to extract and characterise ancient DNA from allophanic paleosol

Efisiensi Pemupukan P Terhadap Pertumbuhan Dan Produksi Tanaman Jagung (Zea Mays L.) Pada Tanah Andisol Dan Ultisol

An experimental research was done to measure the nutrient use efficiency (NUE) of Phosphorus (P)in Andisols and Ultisols. The research was conducted in Screenhouse and Research and TechnologyLaboratory, Faculty of Agriculture, University of North Sumatera from September 2012 until July2013. It was arranged in Non-factorial Randomized Block Design with 6 dosages of PhosphorusFertilizer (SP-36) in Andisols and Ultisols (0; 0,4; 0,8; 1,2; 1,6; and 2,0 grams of SP-36/plant). The intertreatments effects were analyzed using DMRT.The results showed thatRecovery Efficiency (RE) and Agronomic Efficiency (AE) in Ultisols are higher than in Andisols,meanwhile Physiological Efficiency (PE) in Andisols is higher. RE and AE were decreased as aresult of increasing dosage of SP-36 meanwhile PE was increased. The best treatment in Andisolsand Ultisols is 0,8 grams SP-36/plant. In Andisols, productivity of maize at that treatment is 109,23grams/plant (7,28 tons/Ha); RE (11,55%); PE (576,67 grams dry weight cob of maize /g P2O5);and AE (66,68 grams dry weight cob of maize /g P2O5). In Ultisols, productivity of maize at thattreatment is 67,30 grams/plant (4,48 tons/Ha); RE (15,16%); PE (589,29 grams dry weight cob ofmaize /g P2O5); and AE (88,94 grams dry weight cob of maize /g P2O5

Penentuan Jenis Mineral Liat Alofan Tanah Andisol Di Desa Dolat Rakyat Kecamatan Tiga Panah Kabupaten Karo

The aim of the research was to determinate type of Allophane minerals by means of Thermogram and to know type of Allophane minerals with Allophane–Organic Matter relations. The research was done in Dolat Rakyat villages, District of Tiga Panah Karo Regency, In Soil Fertility Laboratory University of North Sumatera, and College of Chemical Industry (PTKI), Medan in June - October 2014. Soil type is Andisol. The result of the research in Dolat Rakyat Village Tiga Panah District, Regency of Karo Thermogram interpretation showed that type of Allophane minerals Andisol that is Allophane B. Allophane-Organic Matter relations showed that type of Allophane minerals is Allophane B with positive relations between Allophane-Humic Acid; negative relations between Allophane-Fulvic Acid, and Allophane-Humic Acid+Fulvic Acid

Sifat-sifat Kimia dan Mineralogi Tanah Serta Kaitannya dengan Kebutuhan Pupuk untuk Padi (Oryza Sativa), Jagung (Zea Mays), dan Kedelai (Glycine Max)

Laboratory experiment was conducted to identify soil chemical and mineralogical characteristics from topsoil (0-20 cm) of Inceptisols, Oxisols, Vertisols, and Andisols, as well as its relationship with the requirement of NPK, lime, and organic matter fertilizers for rice, maize, and soybean at laboratory of Indonesian Soil Research Institute and Soil Science Department of Bogor Agricultural University. The result showed that Inceptisols was dominated by kaolinite (1:1), Oxisols by kaolinite and goethite (hydroxide), and Vertisols by smectite (2:1). Andisols had kaolinite and crystobalite (oxide) minerals in it, while amorphous materials could not be detected through X-ray Diffraction (XRD) method. The soil reaction of Inceptisols, Oxisols, and Andisols was acid; exchangeable (exch) Ca and Mg, the contents of K and P, as well as base saturation (BS) of the soils were low. On the contrary, the soil reaction of Vertisols was neutral; exch. Al and H were very low, whereas exch. Ca and Mg, the contents of K and P, as well as base saturation (BS) of the soil were high. Both Vertisols and Andisols had high cation exchange capacity (CEC) which was from permanent charge in Vertisols and from variable charge (organic matter) in Andisols. Fertilizer requirement for crops in the soil was affected by land use system, plant species, soil nutrient content and its behavior in the soil system

Penentuan Jenis Mineral Liat Alofan Tanah Andisol Di Desa Dolat Rakyat Kecamatan Tiga Panah Kabupaten Karo

The aim of the research was to determinate type of Allophane minerals by means of Thermogram and to know type of Allophane minerals with Allophane–Organic Matter relations. The research was done in Dolat Rakyat villages, District of Tiga Panah Karo Regency, In Soil Fertility Laboratory University of North Sumatera, and College of Chemical Industry (PTKI), Medan in June - October 2014. Soil type is Andisol. The result of the research in Dolat Rakyat Village Tiga Panah District, Regency of Karo Thermogram interpretation showed that type of Allophane minerals Andisol that is Allophane B. Allophane-Organic Matter relations showed that type of Allophane minerals is Allophane B with positive relations between Allophane-Humic Acid; negative relations between Allophane-Fulvic Acid, and Allophane-Humic Acid+Fulvic Acid

A comparative Digital Soil Mapping (DSM) study using a non-supervised clustering analysis and an expert knowledge based model - A case study from Ahuachapán, El Salvador

DSM is the inference of spatial and temporal soil property variations using mathematical models based on quantitative relationships between environmental information and soil measurements. The quality of DSM information depends on the method and environmental covariates used for its estimations. We compared two DSM methods to predict soil properties such as Organic Matter “MO” (%), Sand (%), Clay (%), pH (H2O), Phosphorus (mg/kg), Effective Cationic Exchange Capacity “CICE” (cmol/L), Potassium (cmol/L) and Water Holding Capacity (mm/m) for the department of Ahuachapán in El Salvador to support the activities of the Agriculture Landscape Restoration Initiative (ALRI) in the countr

Nutrient deficiencies in export tree and food crops: literature review and field observations

This paper reviews nutrient deficiencies in agricultural crops of PNG using the literature of agronomic trials and field observations made throughout the country. Nutrient deficiencies have been investigated systematically since the mid-1950s, but research has mainly focused on export tree crops and relatively little information is available on food crops. Literature analysis and field observations showed consistent trends, with deficiencies of boron and phosphorus in large parts of the PNG highlands. The review has been useful in delineating areas where nutrient deficiencies occur and these findings could be used for planning nutrient management research and extension activities in food crop