Authors:
Craig S.Hankins
, Michael S. Cox
, William L. Kingery
, Shankar G.Shanmugam
,
Patrick Gerard
, Rocky Lemus |
Abstract:
Soil biochar application effects on warm- and cool-season crops are not well understood. Corn
(Zea mays L.), soybean (Glycine max L.), wheat (Triticum aestivum L.), cereal rye (Secale cereal
L.), and alfalfa (Medicago sativa L.) were grown in a Marietta fine sandy loam (fine-loamy,
siliceous, active, thermic Fluvaaquentic Eutrudept) and a Houston silty clay (very fine, smectitic,
thermic Oxyaquic Haplaudert) amended with 0, 45, 90, and 180 Mg ha-1
of pine biochar and
allowed to equilibrate for 56-d. To investigate a possible nitrogen effect, three nitrogen rates (0,
0.5 and 1.0X of the recommended rate for each crop) were added to non-legume species at
planting. Legume crops were inoculated with Brady Rhizobia upon planting. All species were
pre-germinated for 14-d in sand trays. After 21-d growth in the treatments, plants were harvested
and shoots were analyzed for shoot dry weight, nutrient uptake and concentration, and forage
quality. Decreases in uptake of nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg),
and calcium (Ca) were found for corn, soybean and alfalfa in both soils at higher rates of biochar
(90 and 180 Mg ha-1
). Changes in forage quality were specific to soil, crop and parameter and
clear trends were not apparent. This study found biochar amendment decreased plant nutrient
uptake, and affected forage quality. Thus, the appropriateness of biochar incorporation depends
on the nature of the cropping system in which it is to be used.
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