Optimal timing for foliar nutrition in soybean

Pod initiation was found to be most appropriate stage for application of Multi-K

Crop/cultivar	Soybeans / A-4100 ; A-4501 ; Dorado 4.8. ; Dekalb 458
Country / location	North cent. Argentina / Junin ; Murphy ; Arequito ; Va. Dafonte
Objectives	Increase yields
Haifa product tested	Multi-K
Application method	Foliar nutition
Tested treatment	1x 3% or 1x 6% or 3x 6% Multi-K at 200 lit./ha, combined with insecticides (against a caterpillar eating the stem base) at three different physiological stages: flower initiation, pod initiation & beginning of bean filling
Locations: Control treatment results Kg/ha	Junin 2328	Murphy 4438	Arequito 4517	Va. Dafonte 2160
Best treatment results Kg/ha	2735	5030	5030	2579
Characteristics of best treatment	Best timing in all locations was spraying the Multi-K at pod initiation. In ¾ of the cases 6% produced best results. In one location 3% Multi-K was even better. The result obtained in Murphy is statistically very significant (P0.01), and the mean of all locations is significant (P0.05). Mean yield increase: 0.4 MT/ha Grower’s revenue from yield: 155.- US$/MT Cost of treatment (material only ): 6 $/Ha
Net benefit of best treatment	0.4 x 155 –6 = $ 56
Benefit/Cost ratio	62 / 6 = 10.3
Conclusions	This experiment is additional to several previous positive results showing considerable beneficial value for the soybean grower. Therefore, the results of this experiment can be implemented for all tractor- spraying at volumes of 100-200 L/ha. This experiment should be followed by an experiment with 20-40 L/ha (rates used in aerial sprays), and 9-12% Multi-K.
Reference	G. Farbman and R. Melgar / Almidar & Haifa Chemicals Argentina, and National Institute for Agriculture