Typic Hapludalf Research Articles

Fractions of copper in soil and their contribution to copper availability and uptake in maize–wheat cropping system under Typic hapludalfs

Long-term effects of integrated application of organics and chemical fertilizers on transformation of copper (Cu) into various chemical pools and their availability under maize–wheat cropping system were investigated in the ongoing long-term fertilizer experiment initiated in 1972 at the research farm of Chaudhary Sarwan Kumar Himachal Pradesh Agricultural University on an acidic soil in the Western Himalayas of India. The continuous use of chemical fertilizers alone for 36 years brought about marked depletion in all forms of copper except organically bound Cu (Cu-III) compared to buffer plots. Integrated use of organics and chemical fertilizers gave higher content of Cu forms over chemically treated plots except Cu occluded by free oxides (Cu-IV). Residual Cu was the most dominant form of copper contributing about 62% of the total Cu. Organically bound Cu (Cu-III) was the most important fraction of copper contributing toward DTPA (diethylene triamine pentaacetic acid) extractable Cu. Content of DTPA-extractable Cu increased over control when chemical fertilizers were applied in conjunction with different organics, whereas DTPA-Cu content declined over control with application of chemical fertilizers alone for the last 36 years.

Phosphorus forms leached in a sandy Typic Hapludalf soil under no-tillage with successive pig slurry applications

Successive pig slurry (PS) applications can substantially increase phosphorus (P) movement due to leaching, mainly in sandy soils found in areas presenting high rainfall rates. The aim of the current study was to assess the transference of different P forms through leachate in a soil managed under no-tillage system, in a crop rotation system subjected to successive PS applications. The study was carried out from 2005 to 2007; the studied site presents Typic Hapludalf soil and its mean annual rainfall reaches 1,769 mm. The study adopted PS doses 0, 20, 40 and 80 m3 ha-1, which were applied to soil surface before each crop-sowing process. Leachate samples were collected 0.60 m down in the ground at each rainfall event (n = 24) that resulted in solution leaching during the experimental period. Available-P, soluble-P, particulate-P and total-P concentration in the leachate were determined. Successive PS applications increased leachate and P transfers in the leached solution. Phosphorus was transferred via leaching mainly in the particulate form, but soluble-P concentration increase was also observed. The highest P concentrations were observed in the treatment with the highest PS dose, whereas the highest P amounts were transferred in the treatment 40 m3 ha-1 of PS. The total amount of transferred P was very small – 0.2 kg ha-1 year-1 –, but it evidenced the likelihood of groundwater contamination, mainly due to increase in the available-P proportion. In addition, P concentrations in the leachate indicate that high and frequent PS doses should be avoided in sandy soils.

Effect of long-term application of inorganic fertilizers, farm yard manure and lime on wheat (Triticum aestivum L.) productivity, quality and nutrient content in an acid alfisol

The effect of long-term addition of fertilizers and amendments on productivity, quality and nutrient content of wheat (Triticum aestivum L.) in an acid Alfisol was evaluated in field experiment at the research farm of the Department of Soil Science, Chaudhary Sarwan Kumar Himachal Pradesh Krishi Vishvavidyalaya (CSKHPKV) Palampur, Himachal Pradesh (India). The Long-Term Fertilizer Experiment was initiated during 1972 in randomized block design (RBD) with 11 treatments which were replicated three times. The soil of the experimental area was silt loam and classified taxonomically as “Typic Hapludalf”. The highest productivity of wheat (2822 kg ha−1) was recorded in the treatment comprising the recommended dose of fertilizer along with farmyard manure (FYM) @ 10t ha−1 and was statistically comparable with 100% NPK + lime (2589 kg ha−1). Continuous application of nitrogen (N) alone through urea (100%) in an acid alfisol has resulted in zero yield of wheat. Application of FYM and lime along with recommended doses of fertilizers improved all the crop quality parameters viz. crude protein, gluten, ash, fat, fiber and carbohydrate as compared to control and imbalanced fertilization for the last 45 years led to decline in crop quality parameters. Nutrient content in wheat grain i.e., phosphorus (P), magnesium (Mg) and iron (Fe) content was also the highest in FYM amended treatment and lowest in control. Whereas, calcium (Ca) content was the highest in lime amended plot and the lowest in control.

Lime Protection for Young Vines Exposed to Copper Toxicity

While foliar application of copper (Cu) containing fungicides can protect vines from fungal infections such as downy mildew (Plasmopara viticola), it can increase soil Cu content which increases disease susceptibility, especially in acidic soils. In this study, we hypothesized that lime (CaCO3 + MgCO3) addition may minimize Cu toxicity in vines by increasing pH and reducing Cu bioavailability. We applied two Cu (no Cu added, 50 mg Cu kg−1) and three lime (no lime added, 1.5, 3.0 Mg ha−1) quantities on a Typic Hapludalf soil. After 60 days, root, plant performance, and biochemistry were measured. As expected, high Cu content negatively affected growth, nutrient status, and metabolism of young vines. However, addition of 3.0 Mg ha−1 lime raised the soil pH from 4.5 to 6.1, decreasing Cu toxicity effects in young vines. Thus, lime addition is an effective strategy in protecting young vines in soils with high levels of Cu.

Dynamics of Soil Organic Carbon Storage and Erosion due to Land Use Change (Illinois, USA)

Many factors including land use, management history, soil series, climate, and soil landscape processes affect the dynamics of soil organic carbon (SOC). The primary objective of this research was to determine the impact of land use change from timberland to cropland on erosion and the SOC storage on sloping landscapes of northwestern Illinois, USA. Typic Hapludalfs and Aquic Udifluvents were studied. The cropland area was previously cultivated from 1860 to 1929, between 1930 and 1979 the area was used for pastureland and was returned to cropland from 1980 to 2009. Since 1980, corn and soybean were grown on a yearly rotation system using a no-tillage system. The timberland area was never cleared and cultivated but was subjected to periodic grazing from 1860 to 2009. The SOC concentration of various soil layers, to a depth of 0.5 m, was measured and expressed on a volumetric basis. For both land uses, the subsurface layers had similar SOC levels. Results suggested that after 150 years the cropland landscape maintained or retained 69.4% of the total SOC of timberland on a volumetric basis. The other 30.6% of the SOC was either deposited in the water or released to atmosphere. This study only included SOC and did not attempt to address or include the amount of C stored in above ground timberland trees or cropland plants or in their root systems. Results suggest that if northwestern Illinois forest soils are cleared and used for cropland during the next 50 years, SOC will be retained in the sediment on lower landscape segments, released to atmosphere as CO2 or released to stream (water) in solution or attached to sediment. The initial timberland SOC levels will not be maintained when converted to cropland use even with a crop rotation which includes small grains and forages and no-till management systems for corn and soybean production. This land use conversion from timberland to cropland would result in greater SOC loss than if the area remained as forestland.

Changes in Soil Organic Carbon Fractions Across a Loess Toposequence

Soil organic carbon fractions may vary with soil development and soil genesis controls its vertical distribution. The objectives of this study were to determine organic carbon fractions in soil derived from loess parent material and the role of relief in its vertical distribution. Five soil pedons, i.e., Typic Ustorthents (Rajar), Typic Calciustepts (Missa), Udic Calciustepts (Basal), Udic Haplustalfs (Guliana), and Typic Hapludalfs (Mansehra), were selected along a loess toposequence and sampled at genetic horizon level. Soils were characterized for texture, pH, calcium carbonate (CaCO3), and organic carbon fractions including total organic carbon (TOC), dissolved organic carbon (DOC), particulate organic carbon (POC), HCl-insoluble organic carbon, and density fractions, i.e., heavy fraction (HF) and light fraction (LF). Total organic carbon content ranged from 0.03 to 0.98% in these soils and significantly differed with soil depth within each soil and soil type. Mansehra and Guliana had 0.04 and 0.031% POC, respectively, which was greater compared to remaining soils. Dissolved organic carbon was greater in the Basal followed by Mansehra, Rajar, Missa, and Guliana soil profiles, and distribution remains uniform throughout the profile’s depth. Insoluble C fraction was 0.214% in Mansehra profiles followed by 0.156% in Rajar, 0.078% in Basal, 0.063% in Guliana, and 0.091% in Missa soil profiles. The Mansehra soil profiles had the highest (0.008 and 0.30%) content of both light and heavy fractions. Total organic carbon had little correlation with clay. Particulate organic carbon, DOC, and HCl-insoluble organic carbon had a significant correlation with TOC. The HF had the strongest correlation with TOC, while LF had a negative correlation. The soil organic fractions significantly differed with soil type and soil genesis. The soils at gentle slopes are dominant in most of the organic carbon fractions due to higher development stage.

Dynamics of zinc under long‐term application of chemical fertilizers and amendments by maize–wheat cropping sequence in Typic Hapludalfs

AbstractThis present investigation took place on a continuing long‐term fertilizer experiment, initiated in 1972 at the experimental farm of the College of Agriculture CSK HPKV, Palampur, aimed at studying nutrient dynamics of micronutrients, especially Zn, after continuous use of chemical fertilizers and amendments over the previous 36 years in an acid Alfisol under a maize–wheat system. Treatments investigated were as follows: T1: Control; 100% N; 100% NP; 100% NPK (optimal application ‐ 120:26:33(maize)/25(wheat)); 100% NPK + FYM (10 t ha−1 to the maize crop); T6: 100% NPK + lime (900 kg ha−1); T7: 100% NPK + Zn (25 kg ha−1 as ZnSO4); T8: 100% NPK + Hand weeding; T9: 100% NPK (‐S); T10: 150% NPK (super‐optimal application); and T11: 50% NPK (sub‐optimal application). Different forms of zinc in soil were determined through a sequential extraction method. Results revealed that previous applications of high‐analysis fertilizers and amendments caused a marked depletion in the pools of Zn as compared to buffer plots. All pools of Zn as well as crop productivity and Zn uptake were noticeably greater in farmyard manure (FYM)‐amended plots compared with plots not receiving fertilizer. The residual fraction was the dominant form but organically bound and exchangeable forms were found to play major role in nutrient supply, crop productivity and nutrient uptake. Correlation and regression analysis studies showed that organic forms constituted the most important pool contributing towards variation in yield and uptake by maize and wheat crops. Exchangeable and organically bound forms contributed significantly towards the availability of DTPA‐extractable Zn in soil.

Conservation soybean production systems in the mid‐southern USA: II. Replacing subsoiling with cover crops

AbstractThe adoption of cover crop production systems is lagging in the mid‐southern United States due to concerns over yield stability and on‐farm profitability. This research was conducted to determine if the inclusion of a cover crop in conservation tillage systems improves yield, profitability, and water use efficiency. The effects of replacing subsoiling with a cereal rye (Secale cereale L.) or tillage radish (Raphanus sativus L. var. longipinnatus) cover crop on soybean [Glycine max (L.) Merr.] grain yield, net returns above specified costs, and water use efficiency were evaluated in a conservation tillage system, that is, surface residue ≥30% at planting, on a Dubbs silt loam (Fine‐silty, mixed, active, thermic Typic Hapludalfs) from 2016 to 2018 near Stoneville, MS. Relative to the conservation tillage system with subsoiling, the replacement of subsoiling with a tillage radish cover crop reduced soybean grain yield, net returns above specified costs, and water use efficiency by up to 41% (P ≤ 0.0266). Conversely, the replacement of subsoiling with a cereal rye cover crop had no effect on soybean grain yield or water use efficiency but reduced net returns above specified costs by 28% (P ≤ .0266). In the mid‐southern United States, a cereal rye cover crop can maintain soybean grain yield and water use efficiency relative to the regional standard, but widespread adoption of this production system is unlikely due to reduced profitability associated with additional seed and planting costs.

Conservation production systems in the mid‐southern USA: III. Zone tillage for furrow‐irrigated soybean

AbstractMid‐southern U.S. soybean [Glycine max (L.) Merr.] producers are frequently encouraged to adopt no‐tillage systems to capture the associated environmental benefits; however, adoption is minimal due to the need for raised seedbeds for irrigation and drainage purposes. This research was conducted to determine if zone tillage systems, with and without a tillage radish (Raphanus sativus L. var. longipinnatus) cover crop, can maintain yield, profitability, and water use efficiency relative to that of a conservation tillage system with subsoiling. The effects of conservation systems on soybean grain yield, net returns above specified costs, and water use efficiency were investigated near Stoneville, MS on a Dubbs silt loam (Fine‐silty, mixed, active, thermic Typic Hapludalfs). Relative to a conservation tillage system with subsoiling, switching to a zone tillage system with or without a cover crop had no effect on soybean grain yield (P = .4986), net returns above specified costs (P = .3724), or water use efficiency (P = .5652). Our data indicate that mid‐southern U.S. soybean productivity and profitability are maintained in zone‐tillage systems.

Conservation soybean production systems in the mid‐southern USA: I. Transitioning from conventional to conservation tillage

AbstractThe adoption of production systems that leave greater than 30% residue coverage on the soil surface, that is, conservation tillage, is limited in the mid‐southern United States due to the development of a hardpan and subsequent yield reductions. This research was conducted to determine if the inclusion of subsoiling in conservation tillage systems can maintain yield and profitability relative to that of conventional tillage. The effects of surface and subsurface tillage on soybean [Glycine max (L.) Merr.] grain yield, net returns above specified costs, and water use efficiency (WUE) were investigated near Stoneville, MS on a Dubbs silt loam (Fine‐silty, mixed, active, thermic Typic Hapludalfs). Conservation tillage with subsoiling maintained or improved soybean grain yield, net returns above specified costs, and WUE up to 68% in three of four years. Conversely, conservation tillage alone either had no effect or decreased soybean grain yield up to 14%, decreased net returns above specified costs up to 20%, and decreased WUE up to 14%. Our data indicate that inclusion of subsoiling minimizes yield and net return declines commonly associated with conservation tillage systems and should be a component of the early soybean production system on medium‐ to coarse‐textured soils.

Copper and zinc distribution and toxicity in ‘Jade’ / ‘Genovesa’ young peach tree

The frequent application of fungicides containing copper (Cu) and zinc (Zn) in orchards can lead to accumulation of these metals in soil at toxic levels. The aim of this study was to evaluate Cu and Zn distribution and toxicity in young peach trees grown in Cu and Zn supplemented soil. For this purpose, a pot experiment was carried out in a greenhouse using a Typic Hapludalf soil under natural conditions. The two-factor experiment investigated the combination of Cu (0, 30 and 60 mg kg−1) and Zn (0, 15, 30, 60, 120, and 180 mg kg−1) rates in four replicates per treatment. ‛Jade’ young peach trees [Prunus persica (L.) Batsch] grafted on ‛Genovesa’ (P. salicina) propagated by herbaceous cuttings were then cultivated for 78 days with one plant per pot. Height increase, dry matter production, Cu and Zn concentration in plant organs, photosynthetic pigments and antioxidant activity were evaluated. Soil available Cu and Zn content increased with the rate. Consequently, plants presented Zn, and mainly Cu, accumulation mechanisms in root system, reduced transport of both elements to leaves, where toxic effects of heavy metals was observed. However, combining high content of soil available Cu and Zn, especially at higher doses, resulted in decreased production of dry matter production. Biochemical parameters were also affected. The SOD activity was smaller in peach leaves grown in the soil supplemented with Cu, while the chlorophyll a and b content decreased according to the increase of Zn rate, compromising the antioxidant response and the photosynthetic activity. Thus, increasing soil available Cu and Zn contents in sandy soil with low organic matter soils may maximize toxic effects to young peach trees.

Soil conservation management with cover crops: effects on critical energy levels, release and dispersion of aggregates

ABSTRACT The normalized dispersion index (NDI) and the b/a index are commonly used to express the stability of aggregates measured by ultrasound. However, few studies have used the critical energy (CE) extracted from modeling to explain the effects of soil use and management on soil aggregation. The objective of this study was to evaluate the influence of soil cover on the CE level required for dispersion of aggregates of a Typic Hapludalf. Soil samples collected from the 0.0-0.05 m depth were evaluated in five different managements with cover plants: perennial soybean (PS), peanuts (P), spontaneous vegetation (SV), black oat/forage turnip (BOFT), and black oat/hairy vetch (BOHV). Aggregates ? 2 mm of the treatments were exposed to ultrasonic irradiation during 0, 30, 60, 120 and 180 s. The specific applied energies were calculated based on sonification time and potency: 0, 745, 1490, 2980, and 4470 J·g–1. After each sonification, sand (2000-53 ?m), silt (53-2 ?m) and clay (< 2 ?m) were quantified. The mass of aggregates of each size class was modeled as a function of the ultrasonic energy. The CE, the NDI and the b/a indexes were coefficients extracted from these models. Cover crops influenced the critical energy levels required for dispersion of aggregates of the Typic Hapludalf. However, our methodology did not prove management systems with intercrops of the cover crops, as black oats and vetch, contribute more effectively to the increase of soil aggregation.

Effect of regular application of fertilizers, manure and lime on soil health and productivity of wheat in an acid Alfisol

The present study on the long-term effect of fertilizers, farmyard manure and lime on changes in soil properties and wheat productivity was carried out at Himchal Pradesh Agricultural University, Palampur (India). The soil was acidic in reaction and classified taxonomically as Typic Hapludalf. Soil samples, collected from two depths viz., 0–0.15 m and 0.15–0.30 m after the harvesting of wheat (2015–2016) were analyzed for different soil properties. Regular use of optimal dose of chemical fertilizers and farmyard manure influenced bulk density, porosity, water holding capacity, saturated hydraulic conductivity, mean weight diameter, pH, organic carbon, cation exchange capacity, available nitrogen, phosphorus, potassium, sulfur, DTPA extractable iron, zinc, copper and manganese, microbial biomass carbon, microbial biomass nitrogen and dehydrogenase activity of soil significantly. Highest grain yield of wheat (30.34 q ha−1) was recorded at 100% NPK + FYM which was at par with 100% NPK + lime (27.89 q ha−1). However, imbalanced use of nutrients affected different soil properties and productivity adversely.

Copper and Zinc in Rhizosphere Soil and Toxicity Potential in White Oats (Avena sativa) Grown in Soil with Long-Term Pig Manure Application

Successive applications of pig manure increase Cu and Zn contents in soils and may cause toxicity to plants. However, plants may have defense strategies that reduce Cu and Zn availability in rhizosphere soil. The study aimed to evaluate growth of white oats (Avena sativa) and Cu and Zn availability in rhizosphere soil subjected to long-term applications of pig slurry (PS) and pig deep litter (PL). The study was carried out with samples of a Typic Hapludalf soil from an 11-year experiment with annual fertilization of 180 kg N ha−1 as pig slurry (PS180) and pig deep litter (PL180) and a control (C) treatment. White oats were grown in pots with soil collected at 0.0–0.10 m depth. Thirty-five and 70 days after emergence (DAE), rhizosphere (RS) and bulk soil (BS) were analyzed to determine Cu and Zn availability. Plant growth, tissue Cu and Zn concentration, and content (concentration X dry weight) were measured. The application of pig manure for 11 years increased available soil Cu and Zn, as well as tissue concentration and content. Dry matter yield and plant height in PL180 were similar to those found in plants grown in the control treatment, while plants grown in PS180 had higher dry matter than in C. We found few differences in soil chemical characteristics and Cu and Zn contents between RS and BS. The high Cu concentrations in roots, especially in soil treated with PL180, show that Cu retention in the roots prevents excess Cu transport to white oat shoots.

Synergy and/or Antagonism in a Cover Crop Sequence: Rotational Effects on Rye in the Midwest

Cover cropping reduces soil erosion mainly by providing cover when the soil is left barren after a short season crop. It also improves nutrient cycling and prevents the loss of NO3-N by leaching especially during late fall and early spring season. When CCs are grown in a sequence, they are able to harvest both the benefits mentioned above and provide ecological services. However, there may be synergistic or antagonistic effects in action between CCs just as is the case of CC allelopathy in weed control. Field experiments were conducted over two cropping seasons (2016-16 and 2016-17) at Michael Fields Agricultural Institute, Wisconsin on a forest derived Fox silt loam (Fine-loamy, mixed, mesic Typic Hapludalfs) under organic certification to determine the effect of sequential planting of CCs on Above Ground Biomass (AGB) yield, N and C addition and to determine the synergistic or antagonistic effect of the species grown in a sequence on each other. Ten different species of CCs were planted immediately after crop harvest in early August followed by winter rye in a sequence, after roll-crimping of the first cover. The cropping sequences significantly affected the cover crop yield and related parameters. Radish &amp;ndash; winter rye sequence was the best performing one in both years of study with regard to the AGB yield (13.96 and 14.87 Mg ha-1 respectively), and large amounts of N and C added to the soil. Phacelia &amp;ndash; winter rye followed close, with the sequence recording on par yields in 2015-16 (13.28 Mg ha-1). Winter rye performed better following a dicot compared to monocot; non-legume compared to a legume. The CC sequences also exhibited synergism and antagonism. The yield of winter rye was boosted when the biomass yield of the forage radish it followed increased, which we consider as synergy: while the yield of winter rye reduced whenever the yield of oat, barley or beseem clover it followed increased, which we consider as an antagonistic effect. The other CCs performed moderately and were greatly a reflection of the prevailing weather conditions. More research along this line is recommended to generate research based information on synergy and antagonism in CC sequence.

Indeks Produktivitas Tanah Berbasis Soil Taxonomy dan Korelasinya Dengan Produktivitas Kopi pada Beberapa Ordo Tanah

Penilaian indeks produktivitas (IP) berbasis taksonomi tanah merupakan salah satu model yang sederhana dan bersifat relatif tetap, sehingga model ini sangat menjanjikan untuk kepentingan praktis dalam skala regional, namun sampai saat ini pengujian-pengujian lapangan menyangkut keakuratan model tersebut untuk tanaman tahunan masih belum pernah dilakukan. Penelitian ini bertujuan untuk mengevaluasi keakuratan aplikasi model IP berbasis taksonomi tanah untuk tanaman kopi, yang dimanifestasikan dalam bentuk tingkat keeratan hubungan antara IP dengan produktivitas kopi robusta. Penelitian dilaksanakan di enam lokasi perkebunan kopi yang berada di wilayah Kabupaten Jember dan Banyuwangi, yaitu kebun kopi Sidomulyo (kebun rakyat), Rayap-1 dan Rayap-2, Tretes, Kampung Tengah, dan kebun Gumitir (kebun PTPN XII). Di setiap lokasi dibuat satu profil tanah pewakil berukuran 1 x 1,5 m dengan kedalaman 1 m untuk keperluan pencanderaan morfologi tanah dan analisis sifat-sifat fisika dan kimia setiap lapisan tanah. Analisis sifat-sifat tanah meliputi tekstur tanah, pH (H2O) dan pH (KCl), C-Organik tanah, kapasitas tukar kation (KTK), dan kejenuhan basa. Berdasarkan hasil pencanderaan dan sifat-sifat fisika kimia di enam lokasi penelitian tersebut, diperoleh empat jenis tanah tingkat subgrup, yaitu Typic Udorthents untuk kebun Sidomulyo (IP = 6); Typic Dystrudepts untuk kebun Rayap-2 (IP = 7); Typic Hapludalfs untuk kebun Rayap-1, Kampung Tengah dan Tretes (IP = 10);; serta Typic Eutrudepts untuk kebun Gumitir (IP = 11). Hasil penelitian ini menunjukkan bahwa IP mempunyai hubungan positif sangat kuat dengan produktivitas kopi robusta (r = 0,84) dalam bentuk model linier sederhana, semakin tinggi IP produktivitas kopi robusta semakin meningkat.

Potential of vermicompost and limestone in reducing copper toxicity in young grapevines grown in Cu-contaminated vineyard soil

Foliar fungicide application in grapevines increases the content of heavy metals such as copper (Cu) in vineyard soils, which may reach phytotoxic levels. The application of soil amendments such as limestone and vermicompost may reduce Cu availability and phytotoxicity. The study aimed to assess growth, physiological status and changes in root morphology in young grapevines grown for 12 months in Cu-contaminated soil with and without the application of soil amendments. Samples of a Typic Hapludalf soil were collected in a vineyard with more than 30 years of cultivation. The following treatments were used: 1) control (without amendment), 2) application of organic vermicompost (86.7 g kg−1) and 3) application of limestone (3 Mg ha−1). Grapevines (Paulsen 1103 rootstock) were transplanted and grown for 12 months in PVC soil columns. We assessed parameters of growth, photosynthesis and root morphology. Grapevines grown in soil treated with limestone showed increased growth, dry matter yield and photosynthetic efficiency. The highest Cu concentrations in root tissue were found in grapevines grown in control soil. The application of vermicompost in this study did not alleviate Cu toxicity. Grapevines grown in soil treated with vermicompost showed high manganese (Mn) concentration in shoots before the winter pruning, reflecting the high Mn concentrations in soil solution that caused Mn phytotoxicity, resulting in plant death after the winter pruning. The vermicompost used in this study is not suitable for agronomic use. The use of limestone was an effective strategy to reduce Cu availability and phytotoxicity.

Planting Date and Biculture Affect Sunn Hemp Productivity in the Midwest

Sunn hemp (Crotalaria juncea L.) is recommended as a warm season cover crop in the Midwest due to its ability to produce high levels of biomass and fix atmospheric nitrogen. It can also be grown in biculture with other cover crops to enhance overall ecosystem services. Two field experiments were conducted over four growing seasons (2014 &amp;ndash; 2017) in Wisconsin on a forest derived Fox silt loam (Fine-loamy, mixed, mesic Typic Hapludalfs) under organic certification to determine the effect of planting date on sunn hemp dry matter yield, N and C addition and to determine the effect of species ratio in a biculture with sorghum-sudan [Sorghum bicolor (L.) Moench] on the same output variables as well as seed cost and the related per unit cost of production. Planting dates significantly affected all biomass yield variables, which declined linearly from the initial date and appear related to growing degree accumulation. Regression analysis revealed a biomass yield decline of 1.3% per day (8.9% week-1) in relative yield, and 0.90 Mg day-1 (0.61 Mg week-1) in actual yield. In biculture, sunn hemp grown in a planting ratio of 50:50 with sorghum-sudan maximized N addition through nitrogen fixation and added N from dry matter, without a significant difference in the dry matter recorded. Analysis of seed cost data revealed that as the ratio of sunn hemp in the planting mixture decreased, the cost per hectare decreased. The cost of production per unit of DM, N, C and CO2 equivalent at this planting ratio were 7.08 $ Mg-1, 0.57 $ kg-1, 17.51 $ t-1 and 4.78 $ t-1 respectively. In pure culture, early planting dates (June 15th to July 15th) are recommended for sunn hemp, and in biculture, a planting ratio of 50:50 with sorghum-sudan could serve Midwestern producers well by reducing per unit cost of biomass production.

Effect of Topography on Characteristics, Fertility Status and Classification of the Soils of Almora District in Uttarakhand

Topographic position is one of the most dominant factors that govern soil development in the hilly areas. Ten soil profiles representing different landform units i.e. hill top, side slope, broad valley and narrow valley terraces were chosen to investigate the soil morphological, physical and chemical characteristics and their relationships with topography in Almora district of Uttarakhand. Soil properties varied remarkably among the studied profiles. The soils were moderately shallow to very deep in depth (32–160 cm), nonsaline (EC 0.03–0.45 dS m−1), acidic in nature (pH 5.1–6.6), low to high in organic carbon (OC) (0.03–2.91%) with low to moderate CEC [1.6–19.4 cmol(p+)kg−1]. Base saturation ranged from 45.9 to 75.1% in which calcium (Ca2+) and magnesium (Mg2+) were the dominant cations on exchangeable sites followed by potassium (K+) and sodium (Na+). The studied soils were dominated by silt fraction followed by clay, except in Dhamas (P4), Dhaili (P5) and Kosi (P10) which showed high sand content. Hill top profiles showed the highest OC. The upper soil layers of hill top and broad valley terrace profiles showed higher availability of soil macronutrients, whereas micronutrients were higher than agronomic critical limits in all profiles. Three soil profiles were classified as Entisols and keyed out as Typic Udifluvents (Kosi), Lithic Udorthents (Dhamas) and Typic Udorthents (Dhaili). Majkhali (P7) soils were placed under Inceptisol soil order and were classified as Dystric Eutrudepts. The remaining soils were placed under Alfisol soil order and keyed out as Hapludalf at great group level. Among the Alfisols, Someshwar (P9) was classified as Oxyaquick Hapludalfs, Sitlakhet (P1) was classified as Ultic Hapludalfs, Salla Routela (P2) and Chaubattia (P3) were classified as Mollic Hapludalfs, while Kausani (P6) and Hawalbagh (P8) soils were keyed out as Typic Hapludalfs. The soils in Almora district of Uttarakhand exhibited wide variations with topographic positions and proper soil management will help in maintaining sustainable production of this area.

Characterizing Minimally Disturbed Soils in a Highly Disturbed Urban Environment

Core Ideas Historical maps were used to identify two undisturbed soil pedons in the urban area. Strong correlation was found between dolomite and the very coarse and coarse sand fractions. The Y2O3/ZrO2 ratios of soil minerals can be used to identify disturbance boundaries. Urban soils are often highly disturbed by anthropogenic activity, and consequent impacts on soil function are not well understood. Minimizing the disturbance of highly modified soils, including those at The Ohio State University, will decrease local C footprints. The main objective of this study was to locate and characterize relatively undisturbed soils in the urban study area to use as a baseline for comparison with a wider range of sampled profiles. Historical campus maps were used to locate and sample three areas where building footprints indicated that minimally disturbed soils might be found. Pedon 1 was classified as a Celina silt loam (fine, mixed, active, mesic Aquic Hapludalfs) and Pedon 2 as an Eldean silt loam (fine, mixed, superactive, mesic Typic Hapludalfs). Pedon 3 exhibited evidence of significant disturbance due to the presence of foreign materials and disrupted horizonation. Pedon 3 had the highest percentage of total C of all three sites at 0‐ to 70‐cm depth due to the presence of asphalt. In Pedon 2, most of the total C from the BC horizon and below was inorganic C derived from calcareous glacial outwash parent material. Pedon 1 showed a mostly homogeneous parent material due to the consistent geochemical ratios throughout the soil profile. There were abrupt horizon discontinuities in Pedon's 2 and 3 ratios indicating heterogeneity of materials. Establishing baseline soil characteristics shows how urban soils have been modified over time and provides information for policymakers to understand the urbanization of soil environments and to enhance ecosystem services.