Soil chemical and microbiological properties in hay production systems: residual effects of contrasting N fertilization of swine lagoon effluent versus ammonium nitrate |
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Authors: | Kannan Iyyemperumal Jr" target="_blank">James GreenJr Daniel W Israel Noah N Ranells Wei Shi |
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Institution: | (1) Soil Science, North Carolina State University, Raleigh, NC 27695, USA;(2) Crop Science, North Carolina State University, Raleigh, NC 27695, USA |
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Abstract: | This study characterized soil chemical and microbiological properties in hay production systems that received from 0 to 600 kg
plant-available N (PAN) ha−1 year−1 from either swine lagoon effluent (SLE) or ammonium nitrate (AN) from 1999 to 2001. The forage systems contained plots planted
with bermudagrass (Cynodon dactylon L.) or endophyte-free tall fescue (Festuca arundinaceae Schreb.). In March 2004, the plots were sampled for measurements of a suite of soil chemical and microbiological properties.
Nitrogen fertilization rates were significantly correlated with soil pH and K2SO4-extractable soil C but not with total soil C, soil C/N ratio, electrical conductivity, or Mehlich-3-extractable nutrients.
Soil supplied with SLE had significantly lower Mehlich-3-extractable nutrients than the soil supplied with AN. Two indicators
of soil N-supplying capacity (potentially mineralizable N and amino sugar N) varied with plant species and the type of N fertilizer.
However, they generally peaked at an application rate of 200 or 400 kg PAN ha−1 year−1. Soil microbial biomass C also peaked at an application rate of 200 or 400 kg PAN ha−1 year−1. Nitrification potential was significantly higher in soil supplied with AN than in the unfertilized control but was similar
between SLE-fertilized and unfertilized soils. Our results indicated that an application rate as high as 600 kg PAN ha−1 year−1 did not benefit soil microbial biomass, microbial activity, and N transformation processes in these forage systems. |
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Keywords: | Microbial biomass C and N mineralization Amino sugar N Forage Swine lagoon effluent |
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