Showing papers in "Communications in Soil Science and Plant Analysis in 2007"
TL;DR: In this article, the effects of N and K fertilization on some fruit quality attributes of the Fuji apple were evaluated in three orchards in Brazil during 2004 and 2005 using a factorial design.
Abstract: Nitrogen (N) and potassium (K) are usually found in higher concentrations than other macronutrients in apple (Malus x domestica Borkh) fruits and are most frequently associated with changes in fruit quality. The aim of this article was to evaluate the effects of N and K fertilization on some fruit quality attributes of Fuji apple. The experiment was conducted at Sao Joaquim, State of Santa Catarina, Brazil, during 2004 and 2005. A factorial design was used with N and K annual fertilizer rates (0, 50, 100, and 200 kg ha−1 of N and K2O) replicated in three orchards. Fifteen days prior to harvest, three fruit samples were collected from each treatment and site. One sample was used for total soluble solid content (TSS), titratable acidity, pulp firmness, and fruit color parameter analyses, and the other samples were refrigerated in a conventional atmosphere for 3 and 6 months for subsequent determination of fruit quality. Nitrogen fertilization negatively affected fruit color, flesh firmness, and TSS...
97 citations
TL;DR: In this paper, the authors evaluated three different dry combustion methods for assessing organic compound (OC) content in soil organic carbon (SOC) stock changes in a Belgian agricultural soil, including the Walkey and Black method, the Springer and Klee method and the Shimadzu TOC analyzer.
Abstract: Renewed interest in temporal soil organic carbon (SOC) stock changes has stressed the importance of reliable methods for quantitative assessment of organic compound (OC) content. Particularly with the establishment of modern dry‐combustion analyzers, which are replacing the traditional wet‐oxidation methods, the need for correct relationships between both is of crucial importance for comparison of past and current SOC data in long‐term SOC stock change studies. Dry combustion with a Variomax CNS‐analyzer was the standard to evaluate three other methods for Belgian agricultural soils. Excellent linear relationships were found with the Walkey and Black method and the Springer and Klee method, whereas a Shimadzu TOC‐analyzer slightly underestimated the OC content. Precision of the investigated methods was comparable and tended to be dependent on the sample size used for measurement. The OC oxidation efficiency of the most widely applied method of Walkey and Black for the soils in this study was very...
80 citations
TL;DR: The results suggest that foliar P could be used as an efficient P‐management tool in corn when applied at the appropriate growth stage and rate.
Abstract: Foliar applications of fertilizer phosphorus (P) could improve use efficiency by minimizing soil applications. Nine experiments were conducted in 2002 and 2003 to determine foliar P rates and appropriate growth stages for application. Treatments comprised of 10 factorial combinations of three foliar P application timings and four rates of foliar P. Foliar application times were V4 (collar of fourth leaf visible), V8 (collar of eighth leaf visible), and VT (last branch of the tassel completely visible but silks not yet emerged) corn growth stages. Foliar P rates were 0, 2, 4, and 8 kg ha−1. Foliar P applied at the VT growth stage improved grain and forage P concentration, which was reflected in increased grain yield in some of the experiments. A foliar P rate of 8 kg ha−1 improved yield to some extent and forage and grain P concentration more than the smaller rates. The results suggest that foliar P could be used as an efficient P‐management tool in corn when applied at the appropriate growth stag...
75 citations
TL;DR: In this article, a soil incubation study was undertaken to establish relative potential rates of mineralization of three organic manures to estimate the value of manure as N fertilizer, and the results indicated that soil had substantial potential for mineralization.
Abstract: The rate and timing of manure application when used as nitrogen (N) fertilizer depend on N‐releasing capacity (mineralization) of manures. A soil incubation study was undertaken to establish relative potential rates of mineralization of three organic manures to estimate the value of manure as N fertilizer. Surface soil samples of 0–15 cm were collected and amended with cattle manure (CM), sheep manure (SM), and poultry manure (PM) at a rate equivalent to 200 mg N kg−1 soil. Soil without any amendment was used as a check (control). Nitrogen‐release potential of organic manures was determined by measuring changes in total mineral N [ammonium‐N+nitrate‐N (NH4 +–N+NO3 −–N)], NH4 +–N, and accumulation of NO3 −–N periodically over 120 days. Results indicated that the control soil (without any amendment) released a maximum of 33 mg N kg−1soil at day 90, a fourfold increase (significant) over initial concentration, indicating that soil had substantial potential for mineralization. Soil with CM, SM, and P...
70 citations
TL;DR: In this paper, heavy metal concentration in underground and surface water, soil, and crop plants growing in farmers' fields near the industrial city of Ludhiana, Punjab, India, that receive irrigation with water contaminated with sewer and untreated industrial effluents was studied.
Abstract: Heavy‐metal concentration in underground and surface water, soil, and crop plants growing in farmers' fields near the industrial city of Ludhiana, Punjab, India, that receive irrigation with water contaminated with sewer and untreated industrial effluents was studied. The concentrations of lead (Pb), chromium (Cr), cadmium (Cd), and nickel (Ni) in sewage‐contaminated water were 18, 80, 88, and 210 times higher than in shallow handpump water, and 21, 133, 700, and 2200 times higher than in deep tube‐well water, respectively. The concentrations of Cd and Ni in shallow handpump underground water were significantly higher than in deep tube‐well underground water. The concentrations of Pb, Cr, Cd, and Ni in deep tube‐well water were 0.017, 0.003, 0.0002, and 0.0002 mg L−1, respectively. Soils irrigated with sewage‐contaminated water had higher electrical conductivity, cation exchange capacity, organic carbon (C), and clay content but had lower pH and calcium carbonate content compared to soils irrigat...
64 citations
TL;DR: In this article, the feasibility of using a natural clinoptilolite to enhance rice grain yield, nitrogen (N) recovery and N use efficiency was investigated in a coarse-textured rice field in the Guilan province of Iran.
Abstract: The unique cation exchange, adsorption, hydration–dehydration, and catalytic properties of natural zeolites and their abundance have promoted their use in a wide variety of agricultural processes as soil amendments, slow‐release fertilizers, and other materials. To investigate the feasibility of using a natural clinoptilolite to enhance rice grain yield, nitrogen (N) recovery and N use efficiency, an experiment was conducted in a coarse‐textured rice field in the Guilan province of Iran. Three levels of 8, 16, or 24 tons of zeolite ha−1 were incorporated into the soil with and without 60 kg N ha−1 as urea, and their effects on the grain and straw yields, available K, apparent N recovery, N use efficiency, and some soil properties were determined. Results indicated a significant positive effect of treatments on the grain yield, straw, and tiller numbers of rice. All levels of zeolite with N showed a significant increase in grain yield compared with 60 kg N ha−1 and control treatment. Zeolite appli...
64 citations
TL;DR: Chlorophyll content of butterhead lettuce leaves was estimated by correlations between the Minolta SPAD•502 and Minoltas chroma meter CR 300 as discussed by the authors. Butterhead lettuce is grown in soilless culture, leaves were selected and SPAD‐502 and chroma meters readings were made.
Abstract: Chlorophyll content of butterhead lettuce leaves was estimated by correlations between the Minolta SPAD‐502 and Minolta chroma meter CR 300. The SPAD‐502 readings and extractable chlorophyll (Chl a, Chl b, and total Chlorophyll) contents were related. High linear correlations were obtained for chlorophyll a (R2=0.90), chlorophyll b (R2=0.85), and total chlorophyll (R2=0.92). After that, during the growth cycle of butterhead lettuce grown in soilless culture, leaves were selected and SPAD‐502 and chroma meter readings were made. Finally, correlations between SPAD‐502 readings and leaf color (L*, a*, b*, C*, and hue angle) determined by the chroma meter were calculated. Hue angle (H°; R2=0.75) and lightness index (L*; R2=0.68) were the parameters that better relate with SPAD‐502 readings, so these parameters can also be used for rapid and nondestructive estimates of leaf chlorophyll in situ.
63 citations
TL;DR: In this article, the precision of measurement and the sensitivity of the following indicators to crop sequence, tillage, and liming effects were compared: (i) mineral N production during a 24-day incubation under aerobic conditions, (ii) ammonium (NH4)‐N production under waterlogged conditions, and (iii and iv) hot potassium chloride (KCl)extractable and hydrolyzable NH4‐N (the latter obtained by subtracting initial NH4•N from extracted NH4−N), and (v) protease activity.
Abstract: Soil nitrogen (N) mineralization indicators are useful only if they are sensitive to management practices. The precision of measurement and the sensitivity of the following indicators to crop sequence, tillage, and liming effects were compared: (i) mineral N production during a 24‐day incubation under aerobic conditions, (ii) ammonium (NH4)‐N production under waterlogged conditions, (iii and iv) hot potassium chloride (KCl)–extractable and hydrolyzable NH4‐N (the latter obtained by subtracting initial NH4‐N from extracted NH4‐N), and (v) protease activity. The coefficients of variation decreased in this order: protease activity>KCl‐hydrolyzable NH4‐N>aerobic incubation>KCl‐extractable NH4‐N=anaerobic incubation. Most of the test results obtained using the indicators were correlated with each other. Mineralizable N measured by aerobic and anaerobic incubation was sensitive to tillage, liming, and crop sequences, especially when using soil 5‐cm deep. Hot KCl‐extractable NH4‐N was influenced by till...
62 citations
TL;DR: In this article, the impact of agricultural practices on the spatial distribution of trace elements (TEs) in the surface horizon of Albeluvisols was studied by comparing three types of situation with an increasing anthropogenic gradient: a forest soil, considered as a reference, and cultivated soils with and without spreading of sewage sludge.
Abstract: The impact of agricultural practices on the spatial distribution of trace elements (TEs) in the surface horizon of Albeluvisols was studied by comparing three types of situation with an increasing anthropogenic gradient: a forest soil, considered as a reference, and cultivated soils with and without spreading of sewage sludge. Total cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) were determined in soil surface horizons. The quantity of particles finer than 2 µm, organic carbon (OC), iron (Fe), manganese (Mn), and calcium (Ca) contents were also measured and used as tracers of soil components that may have contained TEs. Governing factors of the spatial variability of TEs were searched for through comparison of the descriptive statistics (mean and coefficient of variation) and the determination of the best multivariate model predicting TE contents. Nickel and Cr distributions seem to be mainly linked to variability of the parent material composition, w...
61 citations
TL;DR: In this article, the authors compared anaerobic and aerobic laboratory methods and an in situ field method for the 0-to 15-cm depth of a silt loam soil under irrigated corn.
Abstract: Nitrogen (N) mineralization makes a considerable contribution to crop- available N and is difficult to estimate. Reliable methods for measuring N mineraliz- ation are needed to produce data sets for developing N-mineralization models, as a component in fertilizer recommendation algorithms, and to assess the effect of manage- ment practices on N mineralization. Numerous methods are available for estimating N mineralization. Laboratory methods are relatively easy but may not reflect conditions in the field, and field methods are usually labor-intensive. A study was conducted to compare N-mineralization estimates using anaerobic and aerobic laboratory methods and an in situ field method for the 0- to 15-cm depth of a silt loam soil under irrigated corn (Zea mays L.). Mineralization estimates were also compared to N min- eralization based on crop N content. Estimates of N mineralization were 101 kg ha 21 for the anaerobic laboratory method, 284 kg ha 21 for the aerobic laboratory method, and 134 kg ha 21 for the in situ field method. The in situ field method provided a reason- able estimate of N mineralization (0 to 15 cm) when compared to the estimate of miner- alized N (root zone) based on crop N content (215 kg ha 21 ). The in situ field method can be used to measure N mineralization during the growing season and for comparing N mineralization among management practices.
60 citations
TL;DR: Arsenic (As) is a deadly poison at high concentrations and people are exposed to it most of the time through drinking groundwater, fortunately at much lower concentrations than the deadly levels, and usually without knowing it.
Abstract: Arsenic (As) is a deadly poison at high concentrations. It is mysterious in the sense that people are exposed to it most of the time through drinking groundwater, fortunately at much lower concentrations than the deadly levels, and usually without knowing it. Arsenic content in alluvial aquifers of Punjab varied from 3.5 to 688 µg L−1. Arsenic status of groundwater is classified into low ( 50 µg L−1). In zone I, the concentration of As in groundwater varied from 3.5 to 42 µg L−1 with a mean value of 23.4 µg L−1. On the basis of these limits, only 8% of samples were low, whereas 51 and 41% of the total samples collected from this region fall in the moderate and high As categories. The concentration of As in groundwater of zone II varied from 9.8 to 42.5 µg L−1 with a mean value of 24.1 µg L−1. Arsenic concentration in the alluvial aquifers of the central plain of zone II is 2 and 52% in the low and moderate limits....
TL;DR: In this article, the authors found that nitrogen mineralization in soil depends on carbon (C) input of plant materials, site environmental conditions, and soil texture, and empirically correlates of N mineralization can be difficult to int...
Abstract: Nitrogen (N) mineralization in soil depends on carbon (C) input of plant materials, site environmental conditions, and soil texture. Empirical correlates of N mineralization can be difficult to int...
TL;DR: A field experiment was conducted over three consecutive years to assess response of common bean (Phaseolus vulgaris L.) to lime and iron (Fe) applications on an Oxisol in a no-tillage system as mentioned in this paper.
Abstract: Soil acidity is the principal limiting factor in crop production in Oxisols, and deficiency of micronutrients has increased in recent years because of intensive cropping. A field experiment was conducted over three consecutive years to assess response of common bean (Phaseolus vulgaris L.) to lime and iron (Fe) applications on an Oxisol in a no-tillage system. Changes in selected soil chemical properties in the soil profile (0- to 10- and 10- to 20-cm depths) with liming were also determined. Lime rates used were 0, 12, and 24 Mg ha–1, and Fe application rates were 0, 50, 100, 150 200, and 400 kg ha–1. Both lime and Fe were applied as broadcast and incorporated in the soil. Grain yields of common bean were significantly increased with the application of lime. Iron application, however, did not influence bean yield. There were significant changes in soil profile (0- to 10-cm and 10- to 20-cm depths) in pH, calcium (Ca2+), magnesium (Mg2+), hydrogen + aluminum (H+ + Al3+), base saturation, acidity saturatio...
TL;DR: A field experiment was conducted during two consecutive years to determine dry-matter and grain yield, nutrient uptake, and P•use efficiency of lowland rice (Oryza sativa L) grown on an acidic Inceptisol Phosphorus rates used in the experiment were 0, 131, 262, 393, 524, and 655 kilogram P−1 applied as broadcast through termophosphate yoorin this article.
Abstract: Phosphorus (P) deficiency is one of the most yield‐limiting factors in lowland acid soils of Brazil A field experiment was conducted during two consecutive years to determine dry‐matter and grain yield, nutrient uptake, and P‐use efficiency of lowland rice (Oryza sativa L) grown on an acidic Inceptisol Phosphorus rates used in the experiment were 0, 131, 262, 393, 524, and 655 kg P ha−1 applied as broadcast through termophosphate yoorin Dry‐matter yield of shoot and grain yield were significantly (P<001) and quadratically increased with P fertilization Concentrations (content per unit dry‐weight leaves) of nitrogen (N), P, and magnesium (Mg) were significantly increased in a quadratic fashion with the increasing P rates However, concentrations of potassium (K), calcium (Ca), zinc (Zn), copper (Cu), and iron (Fe) were not influenced significantly with P fertilization, and Mn concentration was significantly decreased with increasing P rates Phosphorus use efficiencies (agronomic, physiologi
TL;DR: In this paper, seven controlled-release fertilizers, Nutricote Total 13−13−13, NN Total 18−6−8, Osmocote Plus 15−9−12, Polyon 14−14−14, and Plantacote 14−8−15, were placed in leaching columns containing acid-washed sand.
Abstract: Samples of seven controlled‐release fertilizers, Nutricote Total 13–13–13, Nutricote Total 18–6–8, Osmocote Plus 15–9–12, Osmocote 13–13–13, Polyon 18–6–12, Polyon 14–14–14, and Plantacote 14–8–15, were placed in leaching columns containing acid‐washed sand. Samples of all leachates were analyzed weekly to determine release rates of ammonium‐nitrogen (N), nitrate‐N, phosphorus (P), potassium (K), magnesium (Mg), manganese (Mn), and iron (Fe). Release rates for P from all products were slower than those for NH4‐N, NO3‐N, and K. Release of Mg, Mn, and Fe was very poor, with less than 50% of the total amount of each of these elements ever being released from the prills for some products. Nutricote products released Fe and Mn more effectively than did Osmocote or Plantacote.
TL;DR: In this article, the degree of antimony and arsenic pollution and their bioavailability in mining-affected grassland soils were determined, indicating a high degree of pollution of the soils.
Abstract: The degree of antimony (Sb) and arsenic (As) pollution and their bioavailability in mining‐affected grassland soils were determined. Antimony and As concentrations in aboveground parts of plants, collected in three consecutive years, were measured to investigate their uptake capacity, food chain contamination, and ecological risks. Total Sb and As contents in soils ranged from 60 to 230 mg/kg and from 42 to 4530 mg/kg, respectively, indicating a high degree of pollution of soils. The mobile fractions of Sb (0.02–0.27% of the total Sb content) and As (0.02–0.70% of the total As content) in soils, which reflect the plant‐available portion, are extremely low compared to total Sb and As contents in soils. The Sb and As contents in plants were also very low in both study areas. This lower accumulation of Sb and As in the plants is attributed to the low bioavailability of Sb and As in mine soils. Antimony and As contents in some plants were lower than the controls, and the concentrations in some plants...
TL;DR: In this paper, the aliphatic components of tomato, pepper, and apple fruit cuticles, and the leaf cuticles of mature olive trees, were characterized using elemental analysis, 13carbon (C) nuclear magnetic resonance (NMR), and Fourier transform infrared spectroscopy (FTIR).
Abstract: Aliphatic components of tomato, pepper, and apple fruit cuticles, and the leaf cuticles of mature olive trees, were characterized using elemental analysis, 13carbon (C) nuclear magnetic resonance (NMR), and Fourier transform infrared spectroscopy (FTIR). Cuticular fractions isolated for analyses included bulk, dewaxed, nonsaponifiable, and nonhydrolyzable cuticles. Results from 13C NMR and FTIR spectra indicate that the cuticles of all the plant materials studied are comprised of extractable lipids, polysaccharides, and cutin, whereas the cuticles extracted from the olive leaf, pepper fruit, and apple fruit also contained nonsaponifiable, nonhydrolyzable residues, likely to be cutan. Hydrogen (H)/C and [oxygen (O)+nitrogen(N)]/C atomic ratios for the olive leaf, pepper fruit, and apple fruit cuticle fractions indicate that their bulk cuticle, dewaxed cuticle, and lipid fractions are more aliphatic than but have a similar polarity to their respective cutan‐like fraction. These results provide evid...
Abstract: A glasshouse investigation was undertaken to evaluate the natural potential of fenugreek (Trigonella foenumgraecum L.), spinach (Spinacia oleracea L.), and raya (Brassica campestris L.) for cleanup of chromium (Cr)–contaminated silty loam and sandy soils. Four kilograms of soil per treatment in earthen pots was treated with five levels of chromium [0, 1.25, 2.5, 5.0, and 10.0 mg Cr kg−1 soil through dipotassium chromate (K2Cr2O7], equilibrated for 21 days at field-capacity moisture content, and then fenugreek, spinach, and raya were grown for 60 days after seeding. The concentration of diethylene triamine pentaacetic acid (DTPA)‐extractable Cr increased significantly with increasing rate of Cr application in both soils, but the increase was higher in sandy soil than in silty loam soil. The DTPA‐extractable Cr in both soils decreased after harvesting of crops compared to its concentration in soil before sowing of the crops. The decrease in DTPA‐extractable Cr concentration was highest in soil grow...
TL;DR: In this article, a commercially available software was utilized to analyze digital images of a cotton (Gossypium hirsutum L.) canopy in an effort to quantify canopy coverage.
Abstract: Sampling plant canopies for their ability to intercept sunlight has traditionally been done with destructive or time‐consuming methods. Although nondestructive methods are available, they are either time consuming or subject to large variation. A commercially available software was utilized to analyze digital images of a cotton (Gossypium hirsutum L.) canopy in an effort to quantify canopy coverage. Digital images were obtained from a vertical perspective using a stationary camera stand. Images were analyzed using Adobe Photoshop 4.0 (Adobe Systems, Inc., Seattle, WA) software. Using functions within the software, plant material in the image was separated from the soil and converted to black. The soil surface was converted to white. The resulting black and white image was analyzed with Javascript software developed at North Carolina State University that counts the black and white pixels in each image. The resulting percentage of black pixels in the image was termed percent ground cover for the c...
TL;DR: The application of CD and dhaincha GM along with chemical fertilizers not only increased organic C, total N, available P, and available S in soil but also increased exchangeable K, available Zn, available iron (Fe), and available manganese (Mn) in soil.
Abstract: A 7‐year‐long field trial was conducted on integrated nutrient management for a dry season rice (Boro)–green manure (GM)–wet season rice (T. Aman) cropping system at the Bangladesh Rice Research Institute Farm, Gazipur during 1993–1999. Five packages of inorganic fertilizers, cow dung (CD), and GM dhaincha (Sesbania aculeata) were evaluated for immediate and residual effect on crop productivity, nutrient uptake, soil‐nutrient balance sheet, and soil‐fertility status. Plant height, active tiller production, and grain and straw yields were significantly increased as a result of the application of inorganic fertilizer and organic manure. Usually, the soil‐test‐based (STB) fertilizer doses for a high‐yield goal produced the highest grain yield of 6.39 t ha−1 (average of 7 years) in Boro rice. Application of CD at the rate of 5 t ha−1 (oven‐dry basis) once a year at the time of Boro transplanting supplemented 50% of the fertilizer nutrients other than nitrogen (N) in the subsequent crop of the croppin...
TL;DR: In this paper, the authors investigated the corresponding uptake and assimilation of nitrate (NO3 −) in leafy radish and effects on soil chemical properties by foliar application of amino acid fertilizer (AAF).
Abstract: The objective of the present work was to investigate the corresponding uptake and assimilation of nitrate (NO3 −) in leafy radish and effects on soil chemical properties by foliar application of amino acid fertilizer (AAF). The activity of the enzymes related to the process of NO3 − reduction (NR: nitrate reductase; NiR: nitrite reductase; GS: glutamine synthetase) and the content of NO3 −, total N, and the end products of this process (amino acids and proteins) were analyzed. The soils were sampled twice, and some chemical properties were analyzed. The results of this study showed that application of AAF increased biomass production, and nitrogen (N) utilization in the treatment of a low rate of AAF increased 55% over the control. In addition, the activities of the enzymes were affected differently depending on applied rate of AAF. Furthermore, the NO3 − content was reduced 4–24%, and total N content was increased 14–32% by AAF treatments. Finally, application of AAF improved uptake efficiency o...
TL;DR: The results showed that the percentage of germination and the number of normal seedlings at different salt treatment at 15°C were higher than at 25 or 35°C, and the mean time to 50% germination was least at this temperature for both genotypes.
Abstract: Milk thistle [Silybum marianum (L.) Gaertn] is an annual plant belonging to the Asteraceae family whose ripe seeds contain flavonoid substances, which are important in the modern pharmaceutical industry. Seed germination is a major factor limiting the establishment of plants under saline conditions. The effect of salinity and temperatures on germination and seedling establishment was studied in two genotypes of milk thistle, an Iranian wild type and German (Royston) type in the laboratory and in the field. Experiments were done with seven salt concentrations [0.1 (control), 1, 3, 6, 9, 12, and 15 dS/m] and three temperatures (15, 25, and 35°C). There were three replications for each treatment, and the experiment was run three times. The results showed that the percentage of germination and the number of normal seedlings at different salt treatment at 15°C were higher than at 25 or 35°C. The mean time to 50% germination was least at this temperature for both genotypes. Results suggested all germin...
TL;DR: In this paper, the impact of conservation tillage, crop rotation, and cover cropping on soil quality indicators was evaluated in a long-term experiment for cotton, showing that the microbial biomass is a more sensitive indicator (compared to SOC) of management impacts.
Abstract: The impact of conservation tillage, crop rotation, and cover cropping on soil‐quality indicators was evaluated in a long‐term experiment for cotton. Compared to conventional‐tillage cotton, other treatments had 3.4 to 7.7 Mg ha−1 more carbon (C) over all soil depths. The particulate organic matter C (POMc) accounts for 29 to 48 and 16 to 22% of soil organic C (SOC) for the 0‐ to 3‐and 3‐ to 6‐cm depths, respectively. Tillage had a strongth influence on POMc within the 0‐ to 3‐cm depth, but cropping intensity and cover crop did not affect POMc. A large stratification for microbial biomass was observed varing from 221 to 434 and 63 to 110 mg kg−1 within depth of 0–3 and 12–24 cm respectively. The microbial biomass is a more sensitive indicator (compared to SOC) of management impacts, showing clear effect of tillage, rotation, and cropping intensity. The no‐tillage cotton double‐cropped wheat/soybean system that combined high cropping intensity and crop rotation provided the best soil quality.
TL;DR: In this article, the impact of different soil management practices on soil organic carbon (SOC) pools and aggregate stability in black soils, SOC in whole soil, various size aggregates, and density-separated fractions from three long-term experiments (20 years) was examined.
Abstract: Soil cultivation influences organic carbon storage and soil structures. To evaluate the impact of different soil‐management practices on soil organic carbon (SOC) pools and aggregate stability in black soils, SOC in whole soil, various size aggregates, and density‐separated fractions from three long‐term experiments (20 years) was examined. The three soil‐management systems were grassland (GL), bare land (BL), and croplands. The croplands had two treatments: nitrogen and phosphorus fertilizer application (NP) and NP together with organic manure (NPM). The SOC in the 0‐ to 10‐cm layer decreased in the order NPM>GL>NP>BL and also declined with the soil depth. The SOC of GL increased by 9.7% as compared to NP after 20 years of natural vegetation restoration. The SOC of NPM increased by 11% over NP after 13 years of organic manure application. The percentages of water‐stable aggregate (>0.25 mm) (WSA>0.25mm) decreased in the order GL>BL>NPM>NP in the top 0‐ to 20‐cm horizon. WSA>2mm, the most importa...
TL;DR: In this article, the authors compared several quick analytical procedures with the amount of ammonium (NH4)•N mineralized after a 14-d anaerobic incubation, and the analytical methods of interest were applying a mild acid oxidation to the soil using acidified permanganate.
Abstract: A routine soil test that accurately predicts soil nitrogen (N) mineralization has long eluded researchers. Soil incubations, which are not practical for routine soil testing, are the only methods that have proven successful. Although several quick analytical methods have been proposed, no one method has correlated consistently enough to be implemented into a soil‐testing program. The objective of this study was to compare proposed quick analytical procedures with the amount of ammonium (NH4)‐N mineralized after a 14‐d anaerobic incubation. The analytical methods of interest were applying a mild acid oxidation to the soil using acidified permanganate; analyzing a 1 M potassium chloride (KCl) soil extract in the ultraviolet (UV) spectrophotometric range before and after nitrate (NO3) removal with Devarda's alloy; and quantifying soil amino sugar‐N content using the Illinois soil N test (ISNT) diffusion method. Fifty agricultural soils with different physical and chemical properties were utilized in...
TL;DR: A greenhouse study was conducted to determine the effects of low-rate commercial humic acid (HA) on phosphorus (P), iron (Fe), and zinc (Zn) availability and spring wheat yields.
Abstract: A greenhouse study was conducted to determine the effects of low‐rate commercial humic acid (HA) on phosphorus (P), iron (Fe), and zinc (Zn) availability and spring wheat yields, in both a calcareous soil and a noncalcareous soil. In Phase I, soluble P concentrations were monitored at 1.9, 3.8, and 5.7 cm from a monoammonium phosphate (MAP) fertilizer band that had either been coated with one of two HA products at the equivalent of 1.7 kg HA ha−1, a label rate, or left uncoated. Sampling occurred periodically up to 48 d after fertilizer application. In Phase II, uptake of P, Fe, and Zn and grain yield were measured in soils that had been fertilized with 7.5 or 25 kg P ha−1, either coated with HA or left uncoated. In Phase I, only three significant differences (P=0.05) out of 66 comparisons were found in soluble P concentrations between HA and control treatments at time points ranging from 4 to 48 d after fertilization. In addition, no significant differences were found in nutrient uptake, shoot b...
TL;DR: In this article, the authors investigate the Nmineralization rates of different soil types in Coastal Plain soils and compare them to a soil from Illinois, with and without dairy composted manure addition were subjected to different wetting/drying cycles [constant moisture at 60% waterfilled pore space (WFPS) and cycling moisture from 60 to 30% WFPS] under laboratory conditions at three different temperatures (11°C, 18°C and 25°C).
Abstract: Interest in manure management and its effects on nitrogen (N) mineralization has increased in recent years. The focus of this research was to investigate the N‐mineralization rates of different soil types in Coastal Plain soils and compare them to a soil from Illinois. Soils with and without dairy composted manure addition were subjected to different wetting/drying cycles [constant moisture at 60% water‐filled pore space (WFPS) and cycling moisture from 60 to 30% WFPS] under laboratory conditions at three different temperatures (11°C, 18°C, and 25°C). Samples were collected from three different soil types: Catlin (Mollisols), Bama (Ultisols), and Goldsboro (Utilsols). Soil chemical and physical properties were determined to help assess variations in N-mineralization rates. Addition of composted manure greatly impacted the amount of N mineralized. The amount of manure‐derived organic N mineralized to inorganic forms was mainly attributed to the soil series, with the Catlin (silt loam) producing th...
TL;DR: In this paper, the volatilization of ammonia derived from nitrogen (N) fertilizers and its possible reabsorption by crops depend on specific soil, climate and atmospheric conditions, as well as the method of fertilizer application and plant architecture.
Abstract: Volatilization of ammonia derived from nitrogen (N) fertilizers and its possible reabsorption by crops depend on specific soil, climate, and atmospheric conditions, as well as the method of fertilizer application and plant architecture. In an experiment carried out in Piracicaba, State of Sao Paulo, Brazil, the volatilization of ammonia derived from urea, ammonium sulfate, and natural soil were quantified using static semi‐open N‐ammonia (NH3) collectors. Fertilizers were top‐dressed under the plant canopy on top of dead leaf mulch. In another experiment, the reabsorption of the volatilized ammonia by plants was quantified using 15N‐labeled urea. Results showed, as expected, that volatilization derived from urea was seven times more intense in relation to ammonium sulfate, whose volatilization was very low, and slightly more than the natural volatilization from soil at pH 5.3. The loss of ammonia from the ammonium sulfate was very low, little more than twice of that of the natural soil. Through i...
TL;DR: In this article, the effects of freeze, air (22°C), and oven (65°C) drying on sequentially fractioned poultry manure P were examined and it was shown that higher drying temperatures resulted in lower percentage of dry matter.
Abstract: Laboratory drying may alter manure phosphorus (P) distribution. The effects of freeze, air (22°C), and oven (65°C) drying on sequentially fractioned poultry manure P were examined. Higher drying temperatures resulted in lower percentage of dry matter. Increased H2O‐ and decreased sodium bicarbonate (NaHCO3)‐extractable P with drying provided evidence that drying increases poultry manure P solubility. Labile fractions were predominantly inorganic P (Pi), whereas sodium hydroxide (NaOH) and hydrochloric acid (HCl) fractions had significant amounts of organic P (Po). Drying altered H2O‐ and NaHCO3‐extractable Pi but had no consistent effect on Po in these fractions. This work suggests that variations due to drying should be taken into consideration when evaluating manures for P availability or when comparing data in which different drying methods have been utilized.
TL;DR: Calcium additions to the culture medium significantly improved germination percentage and seedling survival, which markedly decreased after addition of K and B under saline conditions, and iron addition counteracted the effects of salinity on seed germination and seedlings survival.
Abstract: The effects of three levels of salinity [0, 50, and 100 mM of sodium chloride (NaCl)] and the addition of potassium, calcium, nitrogen, phosphorus, iron, manganese, and boron (K, Ca, N, P, Fe, Mn, and B) on seed germination and survival of Helianthus annuus L. plants grown in an inert medium were studied. Increasing levels of salinity significantly decreased germination percentage. The presence of NaCl affected seedling survival rather than germination. Nitrogen addition damaged seedling growth, especially in high saline conditions. Addition of some nutrients may alleviate the effects induced by NaCl. Calcium additions to the culture medium significantly improved germination percentage and seedling survival, which markedly decreased after addition of K and B under saline conditions. Iron addition, especially in the ferrous form, counteracted the effects of salinity on seed germination and seedling survival. Phosphorus addition showed detrimental effects on germination and especially in seedling s...