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Influence of Herbicide and Soil Amendments on Soil Nitrogen Dynamics, Microbial Biomass, and Crop Yield in Tropical Dryland Agroecosystems
Author(s) -
Singh Pratibha,
Singh R. P.,
Ghoshal Nandita
Publication year - 2012
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2011.0412
Subject(s) - agronomy , agroecosystem , crop yield , sesbania , green manure , manure , crop residue , mineralization (soil science) , biomass (ecology) , straw , soil fertility , chemistry , nitrogen , environmental science , soil water , biology , agriculture , ecology , soil science , organic chemistry
Nitrogen (N) dynamics is the key factor for designing management strategies to achieve sustained crop productivity. A 2‐yr field experiment was performed to examine the influence of herbicide (butachlor [2‐chloro 2′6′ diethyl‐n‐butoxy‐methylacetanilide]; HC) alone or in combination with soil amendments on N dynamics involving N mineralization rate (N min ), inorganic N pool, N uptake (N up ) by plants, soil microbial biomass N, and crop yield in tropical dryland agroecosystems. The N min rate showed distinct seasonal patterns which decreased from rice period to summer fallow except herbicide + animal manure (farmyard manure; HC + AM) and herbicide + crop residue (wheat [ Triticum aestivum L.] straw; HC + CR) treatments.The annual rate of N min , inorganic N pool, and crop yield were higher in HC + AM, herbicide + chemical fertilizer (NPK; HC + CF), herbicide + green manure {dhaincha [ Sesbania aculeata (Willd.) Pers.] shoots; HC + GM} while comparable in HC + CR and HC treatments relative to control (CO). Soil moisture content better predicted variation in N min rate compared to soil temperature. Plant N up and crop yield relative to CO was higher in HC + CF, HC + GM, and HC + AM, comparable in HC + CR while lower in the HC treatment. Annual N min rate explained a significant part of variations in annual soil microbial biomass N, inorganic N pool, plant N up , and crop yield. Results indicate that combined application of HC + AM result in relatively sustained availability of inorganic N and higher crop yield throughout the annual cycle.