A5031876873- Soil Carbon and Nitrogen Dynamics
- Soil and Water Nutrient Dynamics
- Isotope Analysis in Ecology
- Rice Cultivation and Yield Improvement
- Clay minerals and soil interactions
- Agriculture, Soil, Plant Science
- Plant Growth Enhancement Techniques
- Phosphorus and nutrient management
- Crop Yield and Soil Fertility
- Metabolomics and Mass Spectrometry Studies
- Cassava research and cyanide
- Heavy metals in environment
- Geology and Paleoclimatology Research
- Agronomic Practices and Intercropping Systems
- Peatlands and Wetlands Ecology
- Soil Geostatistics and Mapping
- Soil and Unsaturated Flow
- Agricultural Systems and Practices
- Pesticide and Herbicide Environmental Studies
- Marine and coastal plant biology
- Plant nutrient uptake and metabolism
- Soil Management and Crop Yield
- Marine and coastal ecosystems
- Composting and Vermicomposting Techniques
- Water Quality Monitoring and Analysis
National Laboratory for Agriculture and the Environment
2016-2025
Agricultural Research Service
2009-2024
United States Department of Agriculture
2015-2021
Soil Science Society of America
2013
Rice University
2006
Can Tho University
2004
Iowa State University
2004
International Rice Research Institute
1995-2002
Queen Mary University of London
2000
Makati Medical Center
2000
Labile, 'high-quality', plant litters are hypothesized to promote soil organic matter (SOM) stabilization in mineral fractions that physicochemically protected from rapid mineralization. However, the effect of litter quality on SOM is inconsistent. High-quality litters, characterized by high N concentrations, low C/N ratios, and phenol/lignin not consistently stabilized with greater efficiency than 'low-quality' concentrations. Here, we attempt resolve these inconsistent results developing a...
Large-scale soil application of biochar may enhance fertility, increasing crop production for the growing human population, while also sequestering atmospheric carbon. But reaching these beneficial outcomes requires an understanding relationships among biochar's structure, stability, and contribution to fertility. Using quantitative (13)C nuclear magnetic resonance (NMR) spectroscopy, we show that Terra Preta soils (fertile anthropogenic dark earths in Amazonia were enriched with char >800...
Summary Rice systems in Asia have intensified rapidly the past 30 years, and significant areas of irrigated lowland rice are now supporting two or three crops per year. Our objective was to compare chemical composition soil organic matter (SOM) from four fields with different histories cropping intensity submergence: (i) a single‐crop rainfed, dryland system without submergence, (ii) an soybean rotation, (iii) double‐ (iv) triple‐crop which remains submerged during much In all soils,...
Nitrogen fertilization is critical to optimize short-term crop yield, but its long-term effect on soil organic C (SOC) uncertain. Here, we clarify the impact of N SOC in typical maize-based (Zea mays L.) Midwest U.S. cropping systems by accounting for site-to-site variability maize yield response fertilization. Within continuous and maize-soybean [Glycine max (L.) Merr.] at four Iowa locations, evaluated changes surface over 14 16 years across a range fertilizer rates empirically determined...
The possibility that N fertilizer increases soil organic matter (SOM) mineralization and, as a result, reduces SOM stocks has led to great debate about the long-term sustainability of maize-based agroecosystems well best method estimate use efficiency (FNUE). Much this is because synthetic can positively or negatively affect via several direct and indirect pathways. Here, we test series hypotheses determine direction, magnitude, mechanism effect on discuss implications for methods FNUE. We...
Abstract Increased use of humic substances in agriculture has generated intense interest among producers, consumers, and regulators for an accurate reliable method to quantify acid (HA) fulvic (FA) raw ores products. Here we present a thoroughly validated method, the new standardized determination HA FA contents humate solid liquid products produced from them. The methods used preparation were adapted according guidelines International Humic Substances Society involving alkaline extraction...
J. Environ. Qual. 48(2):217–232 In Table 2 of this article, the phrases “2004 humic acid” and fulvic were inadvertently switched in far-left column. Reversing their order then provides proper data matrix. We provide corrected table here.
Previous research has shown that long-term intensive cropping of irrigated lowland rice led to significant grain-yield declines in field trials. The yield decline was attributed decreased availability soil nitrogen, which is held mostly the organic matter. By advanced solid-state NMR spectroscopy, we have detected amounts amide nitrogen directly bonded aromatic rings a humic acid fraction extracted from continually submerged, triple-cropped soil. Because aromatics not readily...
Extraction of soil organic matter (SOM) fractions has been a long‐standing approach to elucidating the pivotal roles SOM in processes. Several types extraction procedures are commonly used, and all provide partial information on function. This report accompanying papers summarize regarding functions real‐world issues that gained through physical or chemical fractionations. Each procedure its strengths weaknesses; each is capable some degree distinguishing labile from nonlabile for studying...
Phosphorus has long been known to be present in soil humic fractions, but little is about specific P forms fractions or their lability. We extracted the mobile acid (MHA) and recalcitrant calcium humate (CaHA) from a Nebraska Hord silt loam (a fine-silty, mixed, superactive, mesic Cumulic Haplustoll) under continuous corn (Zea mays L.) receiving either inorganic fertilizer animal manure. Solution 31P nuclear magnetic resonance spectroscopy demonstrated that both MHA CaHA was predominantly...
Natural organic matter (NOM) plays key environmental roles in both aquatic and soil systems. A long‐standing approach for evaluating NOM composition activity is to extract soils with alkali solutions obtain humic substances, namely acids (HA), fulvic (FA), or briefly expose isolated fractions of dissolved alkali. Critics have claimed these methods create laboratory artifacts are thus unsuitable studying behavior field conditions. In response, we describe case studies which were analyzed...
The objective of this work was to evaluate the suitability carbohydrates and amino compounds in soil organic matter (SOM) fractions depict management‐induced changes over short‐term course. Soil samples were collected from two experimental fields managed according farming regulations a sequential fractionation procedure applied separate light fraction (LF), particulate (POM), mobile humic acid (MHA). Contents determined correspondent SOM fractions. Over 2‐year course, carbohydrate contents...
The North Central Education and Research Activity Committee (NCERA-59) was formed in 1952 to address how soil organic matter formation management practices affect structure productivity. It is this capacity that we comment on the science supporting quality associated health assessment for agricultural lands with goal of hastening progress important field. Even though suite indicators being applied by U.S. efforts closely mirrors 'minimum data set' developed recommended mid-1990s, question...