9 research outputs found
Recommended from our members
Phosphorus characterization in Sri Lankan Alfisols : Soprition, fractions, plant availability and soil test suitablitiy
Twelve Sri Lankan Alfisols were characterized for P. Soils
were incubated for three weeks with sufficient P applied
(P2) to elevate soil solution P to 0.2 ug P/g solution as
determined by sorption curves, with 75 percent of P2 (P1),
and without P (P0). For PO treatments, (a) organic P,
(b) 0.5 M NaHCO₃ extractable "labile" inorganic P, (c) 0.1 M
NaOH extractable "moderately labile" inorganic P, and
(d) concentrated HC1 extractable residual P fractions
contained 44, 10, 13, and 22 % of total P respectively.
Fifty five percent of applied P (P1 and P2) was recovered in
the inorganic 0.5 M NaHCO₃ fraction and 25 percent in the
inorganic 0.1 M NaOH fraction. Significant amounts of
applied P were recovered in the organic fractions of some
soils. Factor analysis of PO treatment fractionation data
suggested that inorganic and organic fractions were separate
equilibrium systems. Both inorganic and organic systems,
however, contributed significantly to P uptake in a Neubauer
experiment. Moreover, applied fertilizer P appeared to
increase contributions of organic P to P uptake.
Correlation of Neubauer plant uptake data to Olsen, Bray 1,
Bray 2, CAL, and Double acid extractable soil P showed that
P uptake was most highly correlated to Double acid
extractable P. Regression analysis suggested that the
higher correlation was due to the Double acid extractant's
ability to measure the organic P contribution to P uptake.
Phosphorus sorption by the soils ranged from low to medium
and was described satisfactorily by either the Langmuir two
surface or the Freundlich equation but not by the Langmuir
one surface equation. Correlation analysis indicated that
oxalate extractable Fe was the soil component most active in
P sorption. Although organic matter and pH were correlated
to sorption capacity and may have been directly involved in
the P sorption mechanisms they could also have covaried with
other components responsible for sorption. Although
citrate-dithionite extractable Fe did not appear to be
involved in P sorption its high correlation with residual P
fractions suggests an involvement with "slow" sorption.
Phosphorous sorption had no apparent influence on P uptake
by foxtail millet from the 12 soils in a Neubauer
experiment
Recommended from our members
Columbia root-knot nematode control in potato : using crop rotations and cover crops
Traditionally, M. chitwoodi is controlled with
chemical nematicides, many of which risk
suspension for use on potatoes due to health and
environmental concerns. It is essential to develop
and refine alternative strategies for controlling
Columbia root-knot nematode now, so that
productive and profitable potato acreage will not
be lost if nematicide use is prohibited.Declared out of print April 2010. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo
Recommended from our members
Cover crop weed suppression in annual rotations
Weed suppression varies with cover crop type
and management, residue and tillage management,
and weed populations.Declared out of print April 2010. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo
Recommended from our members
Fava bean (Vicia faba L.)
Fava bean is used as a winter or
spring cover crop, green manure,
silage, forage, hay, and vegetable. It
is capable of producing large
amounts of dry matter and accumulating
large quantities of nitrogen (N),
part of which is available to subsequent
crops.Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo
Recommended from our members
Field pea (Pisum sativum L. or Pisum sativum L. ssp. arvense (L.) Poir.
Field pea can be used as a cover
crop, green manure, forage, hay, and
silage. Hay is good quality, but pea is
more succulent than vetches and
more difficult to cure. Regrowth after
mowing or grazing is poor.Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo
Recommended from our members
Red clover (Trifolium pratense)
Red clover is used successfully in
Oregon as a fall-planted cover crop
and green manure in rotations with
vegetable crops.Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo
Recommended from our members
Barley, oats, triticale, wheat (Hordeum vulgare, Avena sativa, Triticosecale X, Triticum aestivum)
Cereal grains are grasses and may have a prostrate, semierect, or erect physical stature. All have fibrous root systems.
Barley, oats, triticale, and wheat are each comprised of hundreds of varieties whose growth characteristics vary considerably.Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo
Recommended from our members
Cereal rye (Secale cereale L.)
Cereal rye is an erect annual grass
with greenish blue, flat blades and an
extensive fibrous root system. It
resembles wheat, but usually is taller
(3–5 ft) and tillers less. Flowering is
induced by 14 hours of light in
spring.Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo
Recommended from our members
Nitrogen scavenging : using cover crops to reduce nitrate leaching in western Oregon
Willamette Valley field trials have shown
that properly managed cover crops can
reduce the amount of nitrate (NO3-)Declared out of print April 2010. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo