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United States Department of Agriculture

Agricultural Research Service

Title: Soil nitrogen storage and fractions as influenced by tillage, cropping system, and nitrogen source)

Author
item Sainju, Upendra
item Senwo, Zachary
item Nyakatawa, Ermson
item Tazisong, Irenus
item Reddy, Chandra

Submitted to: Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2008
Publication Date: N/A
Citation:

Interpretive Summary:

Technical Abstract: Management practices are needed to increase soil N storage and reduce N fertilization rate and N leaching by replacing inorganic N fertilizer by organic manure, such as poultry litter. We evaluated the 10-yr effects of tillage [No-till (NT), mulch till (MT), and conventional till (CT)], cropping systems [rye/cotton-rye/cotton-corn (R/C-R/C-CN) and cotton-cotton-corn (C-C-CN)], and N sources and rates [0 and 100 kg N ha-1 from NH4NO3 and 100 and 200 kg N ha-1 from poultry litter] on soil N fractions and N balance in northern Alabama. Nitrogen fractions were soil total N (STN), particulate organic N (PON), microbial biomass N (MBN), potential N mineralization (PNM), NH4-N, and NO3-N. Crop residue N returned to the soil varied with treatments and years and total residue N from 1997 to 2005 was greater in R/C-R/C-CN than in C-C-CN and greater with NH4NO3 than with poultry litter. Concentrations of soil N fractions at 10- to 20-cm depth were not influenced by treatments. The STN and PON contents at 0- to 20-cm were greater in NT with poultry litter than in NT and CT with NH4NO3 and in MT with poultry litter. As a result, poultry litter stored N at 38 kg N ha-1 yr-1 compared with -4 kg N ha-1 yr-1 with NH4NO3. Similarly, poultry litter increased MBN, PNM, and NO3-N contents compared with NH4NO3. Cropping increased STN, MBN, and PNM contents compared with fallow in NT. Estimated N loss after 10 yr was greater in NT with C-C-CN and 100 kg N ha-1 from NH4NO3 than in other treatments, except in NT with R/C-R/C-CN and 100 kg N ha-1 from NH4NO3 and poultry litter. Long-term poultry litter application increased soil N storage and N fractions and reduced N loss probably by N leaching compared with inorganic N fertilization.

Last Modified: 8/24/2016
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