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No‐Tillage Soybean Response to Banded and Broadcast and Direct and Residual Fertilizer Phosphorus and Potassium Applications
Author(s) -
Buah Samuel S.J.,
Polito Thomas A.,
Killorn Randy
Publication year - 2000
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/agronj2000.924657x
Subject(s) - fertilizer , tillage , agronomy , phosphorus , human fertilization , mathematics , potassium , grain yield , potash , zoology , environmental science , chemistry , biology , organic chemistry
Improved P and K management systems for no‐tillage soybean [ Glycine max (L.) Merr.] may be needed to increase yield and profits. This study evaluated the response of soybean to fertilizer P or K rates and placement as well as residual and direct fertilization from 1995 through 1996. Two K and two P experiments were established on farmers’ fields with 10‐yr histories of no tillage. An additional P experiment was conducted on one of Iowa State University's research farms. Treatments on farmers’ fields included two rates of P (0 and 19.5 kg P ha −1 ) or K (0 and 51 kg K ha −1 ), placement of fertilizer (surface broadcast or a subsurface band 5 cm beside and 5 cm below the seed) and time of fertilizer application. Treatments on the research farm were similar, except the P fertilizer rates applied were 0, 19, 39, and 78 kg ha −1 . Leaf P and K concentrations and grain yields were measured. Soil test P and K levels at the 0‐ to 15‐cm depths ranged from low to very high across sites at the beginning of the experiment. Placement effects were variable for leaf P or K concentrations. Grain yields for broadcast P and K were as good as or better than the banded applications. However, there may be an advantage to applying P directly to the soybean crop, at least when soil test levels are optimum or lower.