“Soluble organic nitrogen sources suitable for fertigation in organic vegetable production are much needed,” said lead author of the study, Charles Ogles. Ogles and colleagues at Auburn University studied the effects of three different nitrogen sources during a two-year crop sequence of yellow squash and collards. The scientists used hydrolyzed fish fertilizer, inorganic nitrogen (N) source with secondary and micronutrients, inorganic nitrogen without secondary or micronutrients and a zero nitrogen control for the study. Nitrogen was applied at recommended rates for both squash and collards, 80 percent of the recommended rates and 60 percent of the recommended rates. The study design included a zero nitrogen treatment used as the control.
“To eliminate the rotation order effect, the crops were switched each year: yellow squash-collard in year one and collard-yellow squash in year two” said Ogles. Continue Reading →