Project Leader and Principal UC
Investigators
D.M. Brandon
L.A. Post
David R. Woodruff
J. Quick
Kenneth Nueller
J.F. Williams
W. Michael Canevari
C.M. Wick
G.J. St.Andre
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This project, led by scientists in the UCD Department of Agronomy and Range
Science, has the following aims:
- To determine the fertilizer requirements and crop management practices
that will lead to full expression of the yield capacity and quality of
improved rice genotypes.
- To evaluate the effect of plant type, plant population, and fertilizer
interrelations on plant growth characteristics and yield performance.
- To determine the physiological response of the plant to various nutrient
elements, organic acids, and gases produced in a flooded soil environment.
- To determine whether the critical nutrient values established for
traditional California varieties are applicable to improved types.
- To investigate improved fertilization in connection with the
changing technology of cultural management.
- To identify and ameliorate the factors in flooded soils which limit
growth, development, yield, and quality.
SUMMARY OF CURRENT YEAR'S RESULTS:
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þ Fertilizer 15N banded or broadcast and incorporated by discing before
flooding gave significantly higher yields than did split applications
applied pre-flood and topdressed. High yields were not necessarily correlated with
nitrogen use efficiency (see page 29 for details).
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þ Established and potential new varieties differ in growth and yield
responses to temperature and nitrogen. Regional evaluation will be
especially important for varieties containing indica germplasm.
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þ Rice straw incorporated just before flooding may cause nitrogen immobilization, with consequent nitrogen deficiency in seedlings. Organic acid and
toxic gases can be problems if straw is incorporated into soil just before
flooding. They are usually avoided by incorporating straw 2-4 weeks
before flooding.
- An Orange G colorimetric method of nitrogen plant analysis now being
adopted by commercial laboratories speeds tissue testing and lowers the
cost. Progress has been made in adapting the test for field use.
- Adding 2 lb actual zinc (2 .77 lb of ZnO) to 100 pounds of seed (applied
with the seed fungicide or a proper sticker) assures that the maintenance
zinc requirement will be met in rice grown on most zinc-deficient soils.
- Lime and high-pH-induced iron chlorosis can be corrected by fall applications
and incorporation of from 1000 to 2000 pounds of sulfur per acre. Adjusting
the soil surface to pH 7.0 will correct iron deficiency in most soils.
Sulfuric acid applied directly on the soil surface just before flooding will
give a similar response.
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