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Residue Management in Double‐Crop Conservation Tillage Systems 1
Author(s) -
Langdale G. W.,
Hargrove W. L.,
Giddens Joel
Publication year - 1984
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1984.00021962007600040041x
Subject(s) - tillage , agronomy , sorghum , stover , crop residue , mulch till , fertilizer , minimum tillage , conventional tillage , crop , loam , no till farming , strip till , crop yield , soil fertility , mathematics , environmental science , agroforestry , biology , agriculture , soil water , ecology , soil science
Abstract Crop residues have become an increasingly important renewable natural resource. They can serve to maintain optimum crop production on the nation's severely eroding 45.3 million ha of cropland as well as decrease the increasing cost of synthetic N fertilizer. Conservation tillage technologies have been recently identified as a high priority research need for sustaining agronomic productivity in the humid USA. Three double‐crop tillage systems—spring and fall disking, fall disking, and no‐tillage—were evaluated for 4 years on a Southern Piedmont Ultisol (Cecil sandy loam—a clayey, kaolinitic, thermic Typic Hapludults). These tillage systems were considered conventional (CT), minimum (MT), and continuous no‐till (NT), respectively. Wheat ( Triticum aestivum L.) and grain sorghum [ Sorghum bicolor (L.) Moench] were used in the double‐crop systems as high stover producing as well as medium N fertilizer requiring crops. Six orthogonal N fertilizer rates ranging from 0 to 250 kg ha −1 were imposed on each tillage system. Both conservation tillage systems (MT and NT) were manageable in the short term (1 or 2 years) and produced significantly more sorghum grain than the conventional system. Grain yields (4 years) and favorable soil fertility status suggest the MT system was the best double‐crop management system in the long range (>2 years). The sum of wheat and sorghum grain yield increased significantly (5.0 to 7.4 Mg ha −1 year −1 ) in a linear manner with stover up to 11.5 Mg ha −1 year −1 . This suggests some crop use of the 62 kg N ha −1 year −1 returned to the land in stovers when N fertilizers were applied at the recommended rate (100 kg N ha −1 year −1 ). It appears that N fertilizer rates may be reduced progressively in small quantities for optimum double‐crop yields in longterm conservation tillage systems on Southern Piedmont lands.