Search Results - "Olk, D.C."

Chemical stabilization of soil organic nitrogen by phenolic lignin residues in anaerobic agroecosystems by Olk, D.C., Cassman, K.G., Schmidt-Rohr, K., Anders, M.M., Mao, J.-D., Deenik, J.L.

“…This review summarizes independent reports of yield decreases in several agricultural systems that are associated with repeated cropping under wet or submerged…”
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Phenol Accumulation in a Young Humic Fraction following Anaerobic Decomposition of Rice Crop Residues by Olk, D.C, Jimenez, R.R, Moscoso, E, Gapas, P

“…Soil phenols have been implicated as inhibitors of soil N cycling within many agroecosystems, including irrigated lowland rice (Oryza sativa L.). To quantify…”
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Crop Nitrogen Uptake and Soil Phenols Accumulation under Continuous Rice Cropping in Arkansas by Olk, D.C., Anders, M.M., Filley, T.R., Isbell, C.

“…Soil C stocks in the Grand Prairie region of eastern Arkansas have declined under the prevalent 2‐yr rotation of rice (Orzya sativa L.)–soybean [Glycine max…”
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Using Anion Chromatography-Pulsed Amperometry to Measure Amino Compounds in Dairy Manure-Amended Soils by Olk, D.C, Fortuna, A, Honeycutt, C.W

“…Amino acids and amino sugars comprise the bulk of soil N, so information on their chemical forms and cycling patterns should enable better understanding of…”
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Multinuclear magnetic resonance analysis of two humic acid fractions from lowland rice soils by MAHIEU, N, OLK, D. C, RANDALL, E. W

“…To determine the effects of intensive cropping of tropical lowland rice (Oryza sativa L.) and the associated long-term soil submergence on chemical properties…”
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On-farm soil N supply and N nutrition in the rice–wheat system of Nepal and Bangladesh by Adhikari, C, Bronson, K.F, Panuallah, G.M, Regmi, A.P, Saha, P.K, Dobermann, A, Olk, D.C, Hobbs, P.R, Pasuquin, E

“…On-farm research to evaluate the productivity and nitrogen (N) nutrition of a rice ( Oryza sativa L.)–wheat ( Triticum aestivum L.) cropping system was…”
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Soil organic matter and the indigenous nitrogen supply of intensive irrigated rice systems in the tropics by Cassman, K.G., Dobermann, A., Sta Cruz, P.C., Gines, G.C., Samson, M.I., Descalsota, J.P., Alcantara, J.M., Dizon, M.A., Olk, D.C.

“…Soil organic matter (SOM) has been proposed as an index of N supply in paddy soils although field validations are few. We evaluated the relationship between…”
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Chemical Fractionation for Structure-Function Relations of Soil Organic Matter in Nutrient Cycling by Olk, D.C

“…Chemical extractions of soil organic matter (SOM) have not been widely used to elucidate the dynamics of SOM in field settings, especially to address issues of…”
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Nitrogen-bonded aromatics in soil organic matter and their implications for a yield decline in intensive rice cropping by Schmidt-Rohr, K, Mao, J.D, Olk, D.C

“…Previous research has shown that long-term intensive cropping of irrigated lowland rice has led to significant grain-yield declines in field trials. The yield…”
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Opportunities for increased nitrogen-use efficiency from improved resource management in irrigated rice systems by Cassman, K.G., Peng, S., Olk, D.C., Ladha, J.K., Reichardt, W., Dobermann, A., Singh, U.

“…Research and extension work to improve nitrogen (N) management of irrigated rice has received considerable investment because yield levels presently achieved…”
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Crop rotation and residue management effects on carbon sequestration, nitrogen cycling and productivity of irrigated rice systems by Witt, C., Cassman, K.G., Olk, D.C., Biker, U., Liboon, S.P., Samson, M.I., Ottow, J.C.G.

“…The effects of soil aeration, N fertilizer, and crop residue management on crop performance, soil N supply, organic carbon (C) and nitrogen (N) content were…”
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Multinuclear Magnetic Resonance Analysis of Two Humic Acid Fractions from Lowland Rice Soils by Mahieu, N., Olk, D.C., Randall, E.W.

“…ABSTRACT To determine the effects of intensive cropping of tropical lowland rice (Oryza sativa L.) and the associated long‐term soil submergence on chemical…”
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Internal nutrient efficiencies of irrigated lowland rice in tropical and subtropical Asia by Witt, C, Dobermann, A, Abdulrachman, S, Gines, H.C, Guanghuo, Wang, Nagarajan, R, Satawatananont, S, Thuc Son, Tran, Sy Tan, Pham, Van Tiem, Le, Simbahan, G.C, Olk, D.C

“…This study estimates the nitrogen (N), phosphorus (P) and potassium (K) requirements of irrigated rice (Oryza sativa L.) in South- and Southeast Asia. Grain…”
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Inhibition of nitrogen mineralization in young humic fractions by anaerobic decomposition of rice crop residues by Olk, D.C, Samson, M.I, Gapas, P

“…Field observations indicate a long-term decrease in crop uptake of N derived from soil organic matter under continuous production of irrigated lowland rice…”
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Triggering of methane production in rice soils by root exudates: effects of soil properties and crop management by Mitra, S, Aulakh, M.S, Wassmann, R, Olk, D.C

“…Elevated CH4 production in flooded soils during the reproductive growth stages of lowland rice (Oryza sativa L.) is believed to result from decomposition of…”
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Characterization of humic acid fractions improves estimates of nitrogen mineralization kinetics for lowland rice soils by Nguyen Bao Ve, Olk, D.C, Cassman, K.G

“…Nitrogen mineralization in irrigated lowland rice (Oryza sativa L.) soils is poorly predicted by total soil C and N. To improve its prediction, two humic acid…”
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Nitrogen mineralization from humic acid fractions in rice soils depends on degree of humification by Nguyen Bao Ve, Olk, D.C, Cassman, K.G

“…Although the chemical nature of soil organic matter (SOM) is thought to affect the mineralization rate of N bound in SOM, little direct evidence exists for…”
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Organic matter in double-cropped lowland rice soils: chemical and spectroscopic properties by Olk, D.C, Brunetti, G, Senesi, N

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Interpreting fertilizer-use efficiency in relation to soil nutrient-supplying capacity, factor productivity, and agronomic efficiency by Olk, D.C. (International Rice Research Inst., Manila (Philippines).), Cassman, K.G, Simbahan, G, Cruz, P.C.S, Abdulrachman, S, Nagarajan, R, Tan, P.S, Satawathananont, S

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Quantitative solid-state 13C NMR spectroscopy of organic matter fractions in lowland rice soils by Smernik, R.J, Olk, D.C, Mahieu, N

“…Summary Spin counting on solid‐state 13C cross‐polarization (CP) nuclear magnetic resonance (NMR) spectra of two humic fractions isolated from tropical lowland…”
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