Terrace Soil Research Articles

Effect of integrated nutrient management on nutrient uptake and sustainable grain yield in transplanted aman rice

A field experiment was carried out at Sher-e-Bangla Agricultural University (SAU) Farm during July to November 2011 to evaluate the effect of integrated nutrient management (INM) on T. Aman rice (cv. BRRI dhan40). The field belongs to Red Brown Terrace soil under Tejgoan series having silt loam texture and 6.0 pH. Application of 70 % NPKS fertilizers + 4 t ha-1 dhaincha (Sesbania rostrata) (T1) produced the highest grain yield (5.90 t ha-1), the second highest yield (5.85 t ha-1) was obtained from 80% NPKS + 2 t ha-1 dhaincha (T2) treatment. The grain yield increased by 31.2 to 86.3% over control depending on the treatments. Treatments T1 and T2 resulted in higher N, P, K and S uptake by rice. The N, P, K and S concentrations of rice grain was higher for the treatments where Sesbania and cow dung were together applied in combination with NPKS fertilizers. The combined application of chemical fertilizers and organic manure increased organic carbon (OC), total N, available P, K and S contents in post-harvest soil. The overall results indicate that the integrated use of chemical fertilizer and organic manure can help increase grain yield of rice without deteriorating soil fertility.SAARC J. Agri., 15(1): 43-53 (2017)

Stability and instability on Maya Lowlands tropical hillslope soils

Substantial lake core and other evidence shows accelerated soil erosion occurred in the Maya Lowlands of Central America over ancient Maya history from 3000 to 1000years ago. But we have little evidence of the wider network of the sources and sinks of that eroded sediment cascade. This study begins to solve the mystery of missing soil with new research and a synthesis of existing studies of tropical forest soils along slopes in NW Belize. The research aim is to understand soil formation, long-term human impacts on slopes, and slope stability over time, and explore ecological implications. We studied soils on seven slopes in tropical forest areas that have experienced intensive ancient human impacts and those with little ancient impacts. All of our soil catenas, except for one deforested from old growth two years before, contain evidence for about 1000years of stable, tropical forest cover since Maya abandonment. We characterized the physical, chemical, and taxonomic characteristics of soils at crest-shoulder, backslopes, footslopes, and depression locations, analyzing typical soil parameters, chemical elements, and carbon isotopes (δ13C) in dated and undated sequences. Four footslopes or depressions in areas of high ancient occupation preserved evidence of buried, clay-textured soils covered by coarser sediment dating from the Maya Classic period. Three footslopes from areas with scant evidence of ancient occupation had little discernable deposition. These findings add to a growing corpus of soil toposequences with similar facies changes in footslopes and depressions that date to the Maya period. Using major elemental concentrations across a range of catenas, we derived a measure (Ca+Mg)/(Al+Fe+Mn) of the relative contributions of autochthonous and allochthonous materials and the relative age of soil catenas. We found very low ratios in clearly older, buried soils in footslopes and depressions and on slopes that had not undergone ancient Maya erosion. We found high (Ca+Mg)/(Al+Fe+Mn) values on slopes with several lines of evidence that suggest relative youth, soils possibly formed since Maya abandonment. Carbon isotopes (δ13C) also provide some evidence of past vegetation change on slopes. We found strong evidence for maize or other alien C4 species in an ancient terrace soil and additional evidence in buried footslopes but only evidence for C3 species (like tropical trees) on the backslopes and other crest-shoulders. The fact that steep slopes preserved no evidence of C4 species inputs may mean that the ancient Maya maintained forests here. Alternatively, ancient Maya land uses eroded slopes, with the δ13C signatures detected today being the result of more recent soil development under forest over the last millennium. Additional evidence that these soils are recent in age includes elevated (Ca+Mg)/(Al+Fe+Mn) values, skeletal soil profiles, and low soil magnetic susceptibility. Besides the evidence for truncating backslopes and aggrading footslopes, the ancient Maya built agricultural terraces that accumulated soils and altered drainage. All these ancient Maya slope alterations would have influenced modern tree distributions, because many tree species in the modern forest show strong preferences for different soil types and topographic situations that the ancient Maya changed.

Searching for benchmark soils in the steppe zone of the Trans-Ural Plateau to compile the Red Book of Soils

A large amount of soil works on the steppe zone of the Trans-Ural Plateau has been analyzed for the purpose of finding benchmark soils to compile the Red Book of Soils. In light of the theory of basic, local, rare, and complex benchmark soils (Kliment’ev et al., 1996), the upland site on virgin soil in the center of the Stepnoe site of the Il’men State Reserve in the Ural Branch of the Russian Academy of Sciences (UB RAS), should be referred to the basic benchmark soils as the most valuable soil object in the area. The upland site is a representative example of the steppe zone of the Trans-Ural Plateau. Brown earth soils and paleourbanozems soils marked by anthropogenic impact should be considered rare soils in the region. Other rare soils include natural fossil soils—the vertical chronological series of buried soils of terraces above the flood plain and soils buried under mounds and under the ramparts of the ancient settlement of Arkaim. The entire Stepnoe site, where different soils of the region are found, is considered a complex benchmark soil site.

Response of hydrolytic enzyme activities and nitrogen mineralization to fertilizer and organic matter application in subtropical paddy soils

Drivers of nitrogen (N) mineralization in paddy soils, especially under anaerobic soil conditions, are elusive. The influences of exogenous organic matter (OM) and fertilizer application on the activities of five relevant enzymes (β-glucosaminidase, β-glucosidase, l-glutaminase, urease and arylamidase) were measured in two long-term field experiments. Of the two field experiments, the 18-year field experiment was established in a weathered terrace soil with rice-wheat crop rotation at the Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU) farm with five OM treatments and two levels of mineral N fertilizer. The 30-year experiment was established in a young floodplain soil with rice-rice crop rotation at the Bangladesh Agricultural University (BAU) farm with five mineral fertilizer treatments including one with farm yard manure. At BSMRAU, N fertilizer and OM amendments significantly increased all enzyme activities, suggesting the availability of primarily substrate for microbial activity. Whereas at BAU, non-responsiveness of β-glucosidase activity, suggesting that fertilizer and OM amendments had little effect on overall soil microbial activity. Nevertheless the microbial demand for N, β-glucosaminidase and l-glutaminase activities differed among the treatments (P < 0.05) and showed opposite trends with soil N mineralization. Hence enzymatic pathways to acquire N differed with the treatment at BAU site, indicates differences in soil N quality and bio-availability. l-glutaminase activity was the sole investigated variable that positively correlated to both the aerobic and anaerobic N mineralization rates in both field experiments. Combined with a negative correlation between β-glucosaminidase activity and N mineralization rate, it appears that terminal amino acid NH2 hydrolysis was a rate-limiting step for soil N mineralization at the BAU site. Future investigations with joint quantification of polyphenol accumulation and binding of N alongside an array of extracellular enzymes, including oxidases for phenols and hydrolases for N-compounds, would enable verification of the hypothesized binding and stabilization of N with accumulating polyphenols at BAU site under SOM storing management.

Response of capsicum to boron and zinc application in terrace soils of Gazipur, Bangladesh

A field experiment was conducted at vegetables research field of Horticulture Research Centre, Gazipur in terrace soils under Madhupur Tract (AEZ 28) during rabi seasons of 2009-10, 2010-11and 2011-12 to determine the optimum dose of boron and zinc for yield maximization of capsicum. There were sixteen treatment combinations comprising four levels each of B (0, 1, 2 and 3 kg ha-1) and Zn (0, 2, 3 and 4 kg ha-1) along with blanket dose of N150P65K120S20 kg ha-1 including cow dung 10 t ha-1 were used. The experiment was laid out in RCBD factorial with three replications. Results revealed that maximum mean number of fruits per plant (11.1), the highest fruit length (9.29 cm) and diameter (7.34 cm), maximum individual weight of fruits (122 g) were recorded from the combination treatment of B2.0Zn3.0 and the highest mean yield (31.8 t ha-1) was also recorded from the same treatment. The 84.8% yield increase over control (B0Zn0) due to combined application of B2.0Zn3.0 kg ha-1. The combined application of zinc and boron were observed superior to their single application. Therefore, the combination of B2.0Zn3.0 treatment may be considered as suitable dose for capsicum cultivation in terrace soils of Bangladesh.Bangladesh J. Agril. Res. 42(1): 43-52, March 2017

Effect of Urea Super Granule and Prilled Urea on Yield and Yield Attributes of Broccoli (&lt;i&gt;Brassica oleracea&lt;/i&gt; var. &lt;i&gt;italica&lt;/i&gt; L.)

A field experiment was conducted at Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur during 2010-2011 to determine the effects and economic performance of urea super granule (USG) and prilled urea (PU) in terms of growth and yield of broccoli and to find out the optimum and economic doses of USG and PU for broccoli in Shallow Red-Brown Terrace Soil under Madhupur Tract. The experiment was laid out in a randomized complete block design with three replications having 17 treatment combinations constituted with different levels of urea super granule (USG) and prilled urea (PU). Result showed that yield of broccoli increased significantly with increasing rate of USG and PU. The treatments containing 160 kg N from USG and 180 kg N from PU exhibited the best performance on yield and yield contributing characters of broccoli having the head yield of 12.9 and 10.6 ton ha-1, respectively. All the yield contributing characters and the economic profitability were favorably correlated with these high yield performing treatments. The performance of USG in terms of growth, yield and yield attributes, head quality (compactness coefficient) and economic profitability was found significantly higher as compared to that of PU. Therefore, USG @ 160 kg N ha-1 and PU @ 180 kg N ha-1 alongwith other recommended fertilizerscould be suggested for broccoli production in terms of yield and economics. From quadratic equation USG @ 163 and 160 kg N ha-1 and PU @ 169 and 160 kg N ha-1 alongwith other recommended fertilizerscould be suggested as optimum and economic doses for broccoli production in Silty Clay Loam Soil of Madhupur Tract.The Agriculturists 2016; 14(2) 95-112

PEDOLOGICAL STUDIES ON SOME SOILS WEST IDFU ASWAN EGYPT BY USING REMOTE SENSING DATA

The study aims at using satellite images and GeographicalInformation System (GIS) for physiographic digital soil mapping andcapability assessment of the area western side of Idfu district, AswanGovernorate, Western Desert .The area lies between longitude 32°29¯45= and 32°47¯1332= E and latitudes 24° 22- 38= and 25°8¯36=N andoccupies total area about 139000 feddans. To fulfill this objectiveLandsat ETM+ image and digital elevation model (DEM) of the studiedarea were used to define the physiographic units of the studied area. Thephysiographic units of the area under consideration could be grouped anddescribed as young terraces, old terraces, Wadi, Outwash plain .Thedifferent landforms were represented by 9 soil profiles, the morphologicaldescription was carried out and 26 disturbed soil samples were collectedfor physical and chemical analysis . The obtained results revealed that thesoils of the studied area are classified as follow:A)-Soils of Old Terraces: Typic Torriorthents, sandy, mixed,hyperthermic.(Profile8).Gypsic Haplosalids coarse loamy, mixed hyperthermic.(profile9) B)-Soils of the Young terraces: a) Typic Torripsamments siliceaus,hyperthermic (profil,1)-b) Gypsic Haplosalides coarse loamy, mixed,hyperthermic(profile,2)–c). Typic Haplosalides, coarse loamy ,mixed,hyperthermic. profiles 2 and3. C)-Soils of Wadis: Typic Torriorthents, sandy,mixed, hyperthermic (profiles 4 and 5 ) D)-Soils of Outwash Plains:.TypicTorriorthents, sandy ,mixed ,hyperthermic (profile,6) Typic Calcigypsids,coarse loamy,mixed,hyperthermic (profile,7).Land capability classes was performed using Sys & Verheye (1978)System, The studied soils could be categorized into two suitability classes(S3) marginally suitable and (N) not suitable which are suffering from soiltexture, soil profile depth, salinity and alkalinity and CaCOз content assoil limitations. To correct the severity of these limitations further landimprovement should be executed and in turn potential suitability surveyedas moderately suitable (S2), marginally suitable (S3) and not suitable (N)were recognized in the studied area. The severity can be corrected byapplication of organic and inorganic soil amendments and salt leaching

Application of GIS in General Soil Mapping of Bangladesh

Bangladesh is a densely populated country where food crisis is one of the major issues where proper soil mapping is lacking till now. The purpose of this study is to prepare soil mapping of Bangladesh including different soil factors like pH, salinity, nutrients, texture, porosity, toxicity etc., along with general soil types and land availability through application of Geographical Information System (GIS). Q-GIS software and secondary data are used in this study. In present study, it was found that 12 types of soil texture were present in all around of Bangladesh and the maximum percentage of soil porosity values varied from 20% to 70%. A medium range of soil organic matter and strongly acidic soil was found all around the Bangladesh. It was found that the southern part of Bangladesh had slightly saline to highly saline soil. The major part of Bangladesh had medium high land which is very much preferable to agriculture. In Bangladesh, three categories of land such as highland, medium highland and low land cover 29%, 35% and 21% of total land, respectively. Agriculture land covers 9.5 million hectares in Bangladesh. The shifting rate based on agricultural use had been reported to be about 1% per year. At present, the amount of forest land covers 9.84% of total land of our country but 1976 it was 12.11%. Mangrove is now at 4.07% of total land mass of our country. In generally, 20 types of soils were found all around the country. Mapping of soil types described these 20 general soil types under 5 main categories and these are calcareous soil, non-calcareous soil, terrace soil, gray soil, peat and hill soils. This study will be helpful for the cultivator to cultivate appropriate crops in appropriate places after exploration at a glance.

System Yields, Nutrient Uptake and Balance of Mustard-Mungbean-T. Aman Rice Cropping Systems in Terrace Soils of Bangladesh

Conducted experiments on mustard-mungbean-T. aman rice cropping system to measure the system yield, nutrient uptake and apparent balance in terrace soils of Gazipur. Four fertilizer treatments were considered viz. absolute nutrient control (T1); farmer’s practice (T2); AEZ basis fertilizer application (T3) and soil test basis fertlizer application (T4). The treatments were compared in a randomized completely block design with three replications over two consecutive years. The average yields of mustard, mungbean and T. aman rice ranged from 798 to 1543 kg ha-1, 995 to 1489 kg ha-1 and 3270 to 4521 kg ha-1, respectively showing T4 as the best treatment. Soil test basis fertilizer application (T4) exhibited the highest nutrients uptake by all tested crops. The apparent balance of N and K was negative; however it was less negative for T4 treatment. The apparent P balance was positive in T2, T3 and T4 but negative in T1. Positive S balance observed in T4 but negative in T1, T2 and T3. Zinc and B balance in the system was positive in case of T3 and T4. Highest yield, gross margin and soil fertility have been recommended that the soil test basis fertilizer application is profitable for mustard-mungbean-T. aman rice cropping system in terrace soils. The study indicate clearly an opportunity for the re-adjustment of the N, P, K, S and miconutrients (Zn & B) fertilizer doses for the different rice-based cropping systems in Bangladesh.

Biological activity of anthropogenic mountain soils of medieval agricultural terraces of mountainous Dagestan

The study of agricultural terraces in mountainous Dagestan that date to the Middle Ages revealed the polygenetic character of anthropogenic soils, which reflects the main stages of their evolution. In light of their long-term burial, the soil layers of the preanthropogenic stage of evolution were characterized by fairly high values of biological activity, with the exception of the biomass of fungal mycelium, a small amount of which remained. At the early agrogenic stage, soil plowing without irrigation did not significantly change their microbiological properties; however, the increase in urease activity in some studied profiles may indicate that cattle fertilizers were applied in some areas of the terraces. During the Little Ice Age (the 16–18th centuries A.D.) the terraces were abandoned, which led to the accumulation of organic carbon in the soils as a result of the fallow process, as well as an increase in their enzymatic activity. The second agrogenic stage with irrigation was characterized by a noticeable growth in the active microbial biomass, the soil phosphatase activity, and, in particular, the urease activity, which may indicate that farming was intensive and organic fertilizers were applied. In the last 20 years, the development of terraces under natural conditions led to a noticeable growth in the biological activity of upper fallow horizons. However, the urease activity significantly decreased in nonirrigated areas, whereas the indicators of microbial biomass remained at the same level.

Optically-stimulated luminescence profiling and dating of historic agricultural terraces in Catalonia (Spain)

Dating agricultural terraces is a notoriously difficult problem for archaeologists. The frequent occurrence of residual material in terrace soils and the potential for post-depositional disturbance mean that conventional artefactual and lab-based dating methods often provide unreliable dates. In this paper we present a new technique using luminescence field profiling coupled with OSL dating to produce complete (relative) sequences of dates for sedimentary stratigraphies associated with agricultural terraces and earthworks. The method is demonstrated through a series of case-studies in western Catalonia, Spain, in which we reconstruct the formation sequence of earthwork features from the Middle Ages through to the present day. OSL profiling at the time of archaeological survey and excavation permitted spatially and temporally resolved sediment ‘chronologies’ to be generated, and provides the means to interpret the environmental and cultural archives contained in each. The case-studies presented here show that luminescence approaches are a valuable tool to reconstruct landscape histories.

Trace metals in soils of the main geomorphological units in the southwestern part of Western Siberia

Total concentrations of Ti, Cr, Mn, Ni, Cu, Zn, Rb, Sr, and Pb as well as soil granulometric texture were studied for three plot sites representing different geomorphologic units of the southwestern part of Western Siberia: periphery of the upland Tobolsky Mainland, Ishim plain, Turinskaya plain. Interregional difference in the relationship by and among the content of trace elements and particle size distribution of soil horizons is established. Thus, for the soils of Turinskaya plain such interrelations are not observed. For the soils of Ishim Plain moderate negative correlation between Pb concentrations and medium silt, as well as average positive correlations between Zn and fine sand, coarse sand and Pb are found. For the soils of the high terraces of the Irtish and periphery of Tobolsky Mainland interface zone moderate positive correlations between contents of Ti, Zn, Sr and fine sand, weak positive ones between Rb and medium sand, moderate negative ones between Zn and clay, Ti, Ni, Cu, Zn, Rb, Sr, and fine dust, Ti, Cu, Zn, Rb, Sr and medium silt are observed. Consequently, properties and genesis of local parent rocks are significant factors for distribution and accumulation of trace elements in the soils of the southern taiga; at the same time, the processes of bioaccumulation in thick humus horizons of dark gray soils and chernozems apparently play an important part in accumulation and migration of trace elements in forest-steppe soils of Ishim and Turinskaya plains.

LAND SUITABILITY FOR IRRIGATED AGRICULTURE IN KOMOMBO WESTERN PLAIN ,ASWAN-EGYPT.

Kom –Ombo western plain is located in upper Egypt betweenlongitudes of 32° 38- and 32° 55- 30= East and latitude of 24° 20- 30= and24°40-40=North covering about(215151.9 feddans).Twelve representativesoil profiles of the studied area were chosen on basis of differentiation inthe physiographic units,i.e., river terraces, alluvial fans and wadi bottom.The studied soil profiles were classified to eight soil familiesblonging Aridisols and Entisols orders and four subgroups i.e., TypicHaplogypsids,Typic Haplocalcids, Typic Torriopsamments and TypicTorriorthents.Concerning land suitablity, the studied soils are affected mainly bytopography, soil texture and salinity/alkalinity as soil lemitation in variableintensity degrees with moderately and marginally suitable classes. Byexciting the suitable soil improvement practices, the potential capabilityclasses assessed were highly and moderately suitable.Land suitability levels were assessed for cultivating group ofproposed crops including annual crops (barley, maize, wheat, sesame,soya,alfalfa, sorghum, beans, cabbage and carrots) and perennial ones (citrus,mango and olives). The current suitability was negatively affected by somesoil limitations, which require.a major improvement concerning soil, salinity, sodicity and fertilityto improve the land suitability to be more profitable potential landsuitability as: (1) Soils of river terraces were moderately suitable (S2) forsesame, alfalfa, cabbage, olives and marginally suitable (S3) for barley,wheat, carrots, citrus and mango. (2) Soils of alluvial fans were highlysuitable (S1) for Cabbage; moderately suitable (S2) for maize, sesame,alfalfa, olives and marginally suitable (S3) for sorghum and mango. (3)Soils of wadi bottom were highly suitable (S1) for sesame moderatelysuitable (S2) for maize, alfalfa, sorghum; cabbage and marginally suitable(S3) for barley and wheat.

Почвы области сопряжения высоких террас реки Иртыш с краевой частью возвышенности Тобольский Материк

Почвы области сопряжения высоких террас реки Иртыш с краевой частью возвышенности Тобольский Материк

New evidence of a lithic assemblage containing in situ Late Pleistocene bifaces from the Houfang site in the Hanshui River Valley, Central China

As few lithic assemblages containing in situ bifaces in China have been dated to over 600ka and few industries with the association of in situ bifaces and reliable Late Pleistocene dates have been formally reported, the nature and evolution of Chinese industries with bifaces remained unclear for a long time. The Houfang site, deposited in the Aeolian soils of the second terrace of the Hanshui River, Central China, yielded 162 stone artifacts including 2 typical bifaces in stratigraphic context. TT-OSL dating indicated that the sediments containing bifaces were deposited between 110 and 90kaB.P. Preliminary technological analysis suggested that the percentage of bifaces in this assemblage is much lower (<3%) than in the Acheulean complex and that the operative schemes for producing typical bifaces are totally different from those of Acheulean implements. So, on the one hand, it provides new evidence for questioning the validity of the “Movius Line” sensu stricto and, on the other hand, it serves as an important marker for investigating the technological evolution and possible cultural affiliation within East Asia and casts new light on the technological specificity and continuity in East Asia and on the main cultural differences between this area and the Old World Acheulean Complex.

Responses of garlic to zinc, copper, boron and molybdenum Application in grey terrace soil of amnura soil series

A field experiment was conducted at the Spices Research Centre, Shibgonj, Bogra, Bangladesh during rabi (winter) seasons of 2008-09 and 2009-10 to determine the requirement of Zn, Cu, B and Mo of garlic (BARI Garlic 2) along with a blanket dose of cowdung 5 t, 100 kg N, 40 kg P, 100 kg K and 30 kg S/ha for achieving satisfactory bulb yield of this crop. Different levels of zinc (0, 1.0, 1.5, 3.0 and 4.5 kg/ha), copper (0, 0.5, 1.0 and 1.5 kg/ha), boron (0, 1.0, 2.0 and 3.0 kg/ha) and molybdenum (0, 0.5 and 1.0 kg/ha) were distributed in the plot. The experiment was tested in randomized complete block design with three replications. The positive impact of application of those nutrients plant height, number of leaves per plant, cloves per bulb, diameter and weight of bulb and yield of garlic up to a moderate level of Zn3.0Cu1.0B3.0Mo1.0 kg/ha. The highest bulb yield (4.87 t/ha in 2008-09 and 6.6 t/ha in 2009-10) was obtained from Zn3.0Cu1.0B3.0Mo1.0 kg/ha and yield was declined with higher dose of these elements except Mo. The fertilizer treatment Zn3.0Cu1.0B3.0Mo1.0 kg/ha was observed to be the best suitable dose for garlic production on Grey Terrace Soil of Amnura Soil Series under AEZ-25 (Level Barind Tract) of Bangladesh.Bangladesh J. Agril. Res. 41(1): 85-90, March 2016

Assessing the effect of a major storm on 10BE concentrations and inferred basin-averaged denudation rates

Abstract 10Be concentrations in stream sediments are commonly employed to calculate basin-averaged denudation rates. Such calculations assume that denudation is steady in time and that quartz is uniformly distributed in the watershed. The 10Be concentrations in stream sediments are assumed to represent a spatially and temporally averaged concentration, and therefore should not be affected by a discrete erosion event. The effect of such events on 10Be concentrations has been modeled, but has not been previously field-tested following a large precipitation event. In this study, we resampled stream sediments that had been previously analyzed to deduce basin averaged erosion rates in small, tributary basins in the Colorado Front Range following an extreme precipitation event in 2013. Most of our sample sites show no significant change between pre- and post-flood concentrations, and hence no change in the denudation rates inferred from them. The sample locations include a partially burned site, a debris flow site, and sites with very small drainage areas. A notable exception exists at lower Gordon Gulch, within the Boulder Creek Critical Zone Observatory; here, local 10Be data indicate that a large portion of flood-deposited sediment is likely derived from deep soils in fans, terraces, and fills, that are predominantly located on the north-facing toe slope. Overall, the reproducibility of denudation rates deduced from pre- and post-storm samples indicates that the uncertainty associated with 10Be-derived denudation rates is likely less than 15% in this setting.

Testing soil fertility of Prehispanic terraces at Viejo Sangayaico in the upper Ica catchment of south-central highland Peru

This study presents a pilot geoarchaeological investigation of terraced agricultural systems near San Francisco de Sangayaico, in the upper Ica catchment of the Southern Peruvian Andes. It aims to assess the evidence for soil fertility associated with agricultural strategies practised throughout the Prehispanic, Spanish colonial and modern occupations in this region. A series of twenty-two test pits were hand excavated through two terraced field systems, and sampled to examine the changes in soil physical and chemical characteristics down-profile and downslope.This study provides the first geoarchaeological analyses of the agrarian soil system surrounding Viejo Sangayaico in the upper Ica catchment. Results demonstrate that the soil system was much modified prior to the creation of the terrace systems, probably about 900years ago. This system was characterised by a weakly acidic to slightly calcareous pH, a consistent but low electrical conductivity, reasonable-but-variable phosphorus content, and a loamy soil texture with a component of weathered volcanic tonalite parent material. The shallow terrace soil build-up on the slopes investigated indicates that slope modification was as minimal as possible. Moreover, the relatively low frequencies of organic material and phosphorus suggest that the terraces were not heavily fertilised in the past, making the stability and management of the nutrient-rich topsoil vital.The results of these excavations and soil fertility analyses are situated within the context of the wider Andean ethno-historic and the archaeological record to address questions regarding how the terraces were built and maintained over time. Agricultural terraces undoubtedly mitigated the effects of slope erosion associated with cultivation. But, the terrace soil features observed at Sangayaico do not appear to be the same as those documented in other geoarchaeological studies of Andean terrace systems. These contrasts may be accounted for by a combination of differing geological substrate and hydrological conditions, as well as variable trajectories in past soil development, erosion factors, manuring/field management practises and crop selection.

Optimizing crop geometry for processing-grade tuber yield, quality and economics of potato in Grey Terrace Soil

ABSTRACTCrop geometry has great influence on economically important characteristics such as total yield, processing-grade yield, tuber size distribution and tuber quality in Grey Terrace Soil. An experiment was conducted to develop a suitable crop geometry for the production of higher processing-grade yield and quality of potato tubers. The treatment consisted of three levels of inter-row spacing (60, 67.5 and 75 cm) and four levels of intra-row spacing (20, 25, 30 and 35 cm). Crop geometry significantly influenced growth, yield contributing characters, tuber size distribution and yield of potato. The highest chips, French fry grade tubers and total potato tuber yield were found in 67.5 cm × 25 cm crop geometry without affecting processing quality but all were in the highly acceptable range. Intra-row spacing of 25 cm produced the maximum processing quality tubers, closely followed by 30 cm. The highest gross and net returns with a benefit–cost ratio of 1.75 were recorded in 67.5 cm × 25 cm crop geometry. Therefore, the 67.5 cm × 25 cm crop geometry can be recommended for higher potato tuber yield and processing-grade tubers as well as higher economic return.

Landscape development and soils around the Bronze Age settlement Kamennyi Ambar, southern Trans-Urals, Russia

Landscape and soils around the prehistoric Bronze Age site of Kamennyi Ambar, southern Trans-Urals, have been studied. The topography of the Trans-Ural peneplain was formed by denudation during Mesozoic and Tertiary. The resulting gently undulating plain was subsequently dissected during Pleistocene under periglacial climatic conditions, and wide valleys with gentle slopes were formed. The saprolized pre-quaternary rocks are covered by thin layers of quaternary sediments, which are sometimes loess-containing. Deposits of in-situ loess are almost absent. Most probably, deluviation under periglacial conditions played the dominant role and prevented the formation of loess deposits. Thin loess deposits are preserved only in some flat watershed positions. The Quaternary layers sometimes contain strongly weathered coarse bedrock components indicating a solifluidal genesis of the cover beds on the slopes. The degree of weathering of the autochthonous components increases towards the water divide where the cover beds consist almost completely of pre-Quaternary saprolite. The slopes of the Karagaily Ajat valley are structured by numerous smaller tributary valleys which usually have a yellow-brown loam fill and show in their lower parts gully-like linear erosion features. Decalcified Haplic Chernozems are prevalent soils in the fills of the tributary valleys, at the lower slopes of the Karagaily Ajat-valley, and in the loams of the Lower Terrace. When clay cutans and coatings were observed in the subsoil the soils were identified as Luvic Chernozems. On the gentle slopes, Mollic Leptosols or Leptic Regosols (Mollic) are developed in thin cover beds. Up the slope, the depth of the humus horizons decreases. When examining the layer succession of the near surface underground and the associated soils along transects across the tributary valleys, it was found that the thickness of the cover beds on the slopes increases towards the valley floor. In the soils of the Lower Terrace varying salt contents can be found. Mollic Solonetz were identified therein. Within the excavation area in Kamennyi Ambar, Anthrosols and Solonetz were found in the compacted layers of the older Sintashta culture, while Haplic Chernozems (colluvic) with similar features like the virgin soils have developed in the fillings of younger pit houses.