While many laboratory studies have focused on the short term effects of biochar addition to soil), there have been comparatively few tracing its longer term effects in the field. This study investigated the multiyear impact of biochar on crop performance and soil quality with specific emphasis on carbon (C) and nitrogen (N) cycling over a 3 y period. Biochar was added to an agricultural field at 0, 25 and 50 t ha(-1) and planted with maize (year 1) and grass (years 2 and 3). Biochar addition affected plant performance in the grass crop with significant increases in foliar N (year 2) and above-ground biomass (year 3). Below-ground, biochar increased soil respiration, fungal and bacterial growth rate and turnover in year 2. This change coincided with a shift toward a bacterial dominated decomposer community, suggesting a decrease in the potential for microbially mediated C sequestration. Biochar did not affect dissolved organic C (DOC) and N (DON), NO3- or NH4+ pool sizes. Similarly, biochar addition had limited effects on the turnover of C-14-labelled SOC (plant litter), DOC (sugars and organic acids) and DON (amino acids) and no long term effect on N mineralization, NH3 volatilization, denitrification and NH4+ sorption. After 3 years in the field, the alkalinity associated with the biochar had been fully neutralized and biochar lost most of its cations (K, Na, Ca) but had built up an associated microbial community. We conclude that biochar addition to soil causes small and potentially transient changes in a temperate agroecosystem functioning. Importantly, many of the short-term effects of biochar on plant growth and soil behavior reported from laboratory studies were not observed in the field emphasizing the need for long term field trials to help inform agronomic management decisions involving biochar. (C) 2011 Elsevier Ltd. All rights reserved. (Less)

Biochar-mediated changes in soil quality and plant growth in a three year field trial

The abundance and composition of soil ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) communities under different long-term (17 years) fertilization practices were investigated using real-time polymerase chain reaction and denaturing gradient gel electrophoresis (DGGE) A sandy loam with pH (H(2)O) ranging from 83 to 87 was sampled in years 2006 and 2007, including seven fertilization treatments of control without fertilizers (CK), those with combinations of fertilizer nitrogen (N), phosphorus (P) and potassium (K): NP, NK, PK and NPK, half chemical fertilizers NPK plus half organic manure (1/2OMN) and organic manure (OM) The highest bacterial amoA gene copy numbers were found in those treatments receiving N fertilizer The archaeal amoA gene copy numbers ranging from 154 x 10(7) to 425 x 10(7) per gram of dry soil were significantly higher than those of bacterial amoA genes, ranging from 124 x 10(5) to 279 x 10(6) per gram of dry soil, which indicated a potential role of AOA in nitrification Ammonia-oxidizing bacteria abundance had significant correlations with soil pH and potential nitrification rates Denaturing gradient gel electrophoresis patterns revealed that the fertilization resulted in an obvious change of the AOB community, while no significant change of the AOA community was observed among different treatments Phylogenetic analysis showed a dominance of Nitrosospira-like sequences, while three bands were affiliated with the Nitrosomonas genus All AOA sequences fell within cluster S (soil origin) and cluster M (marine and sediment origin) These results suggest that long-term fertilization had a significant impact on AOB abundance and composition, while minimal on AOA in the alkaline soil

Abundance and composition of ammonia‐oxidizing bacteria and ammonia‐oxidizing archaea communities of an alkaline sandy loam

Physiological perspectives of changes over time in maize yield dependency on nitrogen uptake and associated nitrogen efficiencies: A review

A review of the mechanical effects of plant roots on concentrated flow erosion rates

Plant Root Systems: Their Function and Interaction with the Soil.

Nitrogen is the most limiting plant nutrient in Vertisols in Kenya. Soil properties, climatic conditions and management factors as well as fertilizer characteristics can influence fertilizer nitrogen (N) use efficiency by crops. Vertisols, characterized by low-basic water infiltration rate, are prone to waterlogging under sub-humid and humid conditions. We determined effects of drainage, N source and time of application on yields, nutrient uptake and utilization efficiencies by maize grown on Vertisols in sub-humid environments. Treatments comprised two furrows (40 cm and 60 cm deep) and a check (i.e., no furrow), calcium nitrate to furnish NO3-N, ammonium sulphate to supply NH4-N at 100 kg N ha−1, a control (i.e., no fertilizer N), and fertilizer N application at sowing, 40 days after sowing, and split (i.e., half the rate at sowing and half 40 days after sowing). A split-plot design was used in which drainage formed the main plots and N source × time of N application formed the sub-plots. Higher grain and total dry matter yields, harvest index, leaf N content, uptake of N, P and K, as well as N agronomic (NAE) and recovery (NRE) efficiencies were obtained from drained compared to undrained plots. The increase ingrain yields as a result of drainage varied from 31 to 45% for control, 35 to 43% for NO3-N, and 16 to 21% for NH4-N treatments. Drainage resulted in total N uptake increases from 50 to 80 kg N ha−1 in control plots, 80 to 130 kg N ha−1 in NO3-N treated plots, and 90 to 130kg N ha−1 in NH4-N treated plots. Ammonium-N source was superior to NO3-N source in terms of higher yields, NAE, and NRE in undrained plots, but the two N sources behaved similarly in drained plots. Delayed or split NO3-N application gave higher yields, NAE and NRE than when all N was applied at sowing in undrained plots. There was no difference between 40 cm and 60 cm deep furrows in terms of crop yields and nutrient use efficiencies. Thus, draining excess water with furrows at least 40 cm deep is essential for successful crop production in these Vertisols under sub-humid conditions.

Effects of improved drainage and nitrogen source on yields, nutrient uptake and utilization efficiencies by maize (Zea mays L.) on Vertisols in sub-humid environments

Land Evaluation for Soybean (Glycine max L. Merrill) Production Based on Kriging Soil and Climate Parameters for the Kakamega District, Kenya

Denitrification is of particular concern to agronomists with respect to fertilizer nitrogen (N) recovery by crops grown on soils of poor drainage. The objectives of this study were to determine the effects of (i) soil moisture content, (ii) available carbon, (iii) nitrogen rate, and (iv) nitrogen source on denitrification in a Vertisol (heavy clay) and a Phaoezem (loam). Three experiments were undertaken to examine the influences of soil moisture content and available carbon (Experiment 1), the effects of nitrogen rate (Experiment 2), and the effects of nitrogen source (Experiment 3) on denitrification. The critical moisture level for denitrification to commence in the studied soils was 60% WHC. Available C was an important limiting factor for denitrification, more so in Vertisol than in Phaoezem. The highest denitrification N losses were obtained at 140% WHC with additional available C, and were 29 and 55 mg N kg− 1 soil for Vertisol and Phaoezem, respectively. Denitrification rates at 100 and 400 mg NO3...

Denitrification risks in relation to fertilizer nitrogen losses from vertisols and phaoezems

Denitrification plays important roles in nitrogen cycling and management affecting both the environment and agricultural systems. Potential denitrification has a role in comparison of denitrification magnitudes in different soils. This paper discusses the concept of potential denitrification in relation to denitrification rate and conditions under which it is determined. The terminologies such as denitrification activity, intensity, capacity and potential are variously applied to describe denitrification rates, but the use of these terms is not consistent. Similarly, the concept of potential denitrification is variously espoused. Many researchers measure potential denitrification under entirely different conditions, and express the values in divergent units making meaningful comparisons between soils unfeasible. It is proposed that the concept of potential denitrification embraces the principle of maximum attainable denitrification rate under optimal conditions within the limitations of natural setting. T...

Potential Denitrification: Concept and Conditions of Its Measurement

In order to monitor spatial inorganic N concentrations in soils over time, collected soil samples are composited and thoroughly mixed. The sticky characteristic of Vertisol when wet makes it difficult to thoroughly mix wet samples. There is the need for appropriate drying of Vertisol samples to facilitate thorough mixing and storage to retain mineral N content reflective of field status. We determined the effects of drying method, storage period and C:N ratio on inorganic N contents of tropical Vertisols. The treatments comprised of three soils with different C:N ratios, five drying methods inclusive of a check (method 1), and five storage periods including a check (period 1). Storage temperature was -10°C. In method 1, field-fresh soil samples were kept at -10°C and later used for mineral N extraction using 0.5 M K2SO4. Period 1 involved storing soil samples for two days from sampling date before mineral N extraction. Ammonium-N and NO3 -N were determined using colorimetric method. Method 1 x period 1, for each soil, resulted in NH4+-N and NO3--N contents significantly different from other treatments indicating that extraction for mineral N should be done on field moist soil not later than two days after sampling. Key words : Drying method, mineral nitrogen, storage period, soil preparation, Vertisols.

/pdf/effects-of-drying-method-storage-period-and-carbon-nitrogen-90n0m02sqq.pdf

Effects of drying method, storage period and carbon: nitrogen ratio on inorganic nitrogen contents of Vertisols

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

D.O. Sigunga

Author Tools

Chat about Author