Fertilization - 70
 

 

 

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FASTER WORD ON NITROGEN NEEDS COMES FROM NEW TEST

A UC Davis colorimetric plant-analysis test for nitrogen replaces the slower (and more expensive) Kjeldahl method for determining rice needs. Commercial laboratories can now give you faster nitrogen tissue analysis. Tissue-test information should ultimately cost less too. (Simple field tests for grower use are still sought.)

NITROGEN USE IS GREATLY AFFECTED BY METHODS

In 1970 as before, very best results came from applying all nitrogen right off, preplant. Sometimes there are reasons not to (because of special problems in a particular district). Then, preplant 2/3, and 70 to 80 days later (at panicle development stage) apply 1/3 as a top dressing. Nitrogen placement depth in preplant should be 2 to 4 inches.

ZINC DEFICIENCY IS READILY CORRECTED BY BROADCAST APPLICATION

Seedling chlorosis and stand failure (most frequent on soils of a high pH and where land has recently been leveled) may be caused by either zinc or iron deficiencies. Iron materials have corrected this problem, but sometimes zinc in commercial-grade iron really did the job. If zinc is the problem, it is cheaper to mix zinc compounds with dry commercial nitrogen fertilizers like urea or ammonium sulfate and apply with preplant nitrogen. Where iron deficiency is the problem, use ferric sulfate. A preplant soil analysis will guide you. See your Farm Advisor for details about these matters.

MICRONUTRIENT DEFICIENCIES CORRECTED BY SEED TREATMENT?

In greenhouse tests, zinc deficiency has been corrected by seed treatment with zinc oxide. Technique not yet proved in the field.

CUSTOM-DESIGNED FERTILIZATION PROGRAMS NEARING

Preplant laboratory analysis of soils and growing-season tissue analysis makes it possible to custom-design your rice fertilization for time of year, variety, and the individual field. Progress continues toward faster diagnosis. May be only a couple of years away if research continues successful toward tissue tests that can be made right in the field.

FERTILIZER DISTRIBUTION BY AIR IS IMPROVED

Better distribution is needed for the heavy fertilizer loads California rice uses. And now it is here -- in a new aerial fertilizer distributor tested here in 1969 and 1970. Results are better than with the ram-air distributor used for so long. One new rig tested was developed at the University of Auckland (New Zealand). The other was invented for forest-land use in the Pacific Northwest.

 

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