As usual it all depends and it depends on several if not numerous things based on the limnology of the pond, water shed and water chemistry. Many fertilization scenarios are possible each in different water bodies depending on water chemistry conditions of each water body. What works in one may not work well in another. Sometimes systems are N limiting, sometimes P limiting, and sometimes macro or micro-nutrient limiting. Sometimes existing plant growth will limit phytoplankton development despite adequate fertilization and proper water chemistry. Ever see a pond that did not develop a bloom after fertilizing? In those cases usually something "chemical wise" was not correct in the additives and/or the dissolved solids in the water body. The referenced studies of Culver were conducted in limestone rich soils and nutrient organic sediment rich ponds which can lead to biased opinions based on others areas of the country where watersheds and soils are different. Often a "shotgun approach" (adding ample amounts of each) is used hoping to get a bloom which very often works well. Degree of alkalinity of the receiving water body can play a big role in developing a bloom and amount of N and/or P needed.
Sometimes when filamentous algae has gotten a good start in the pond, it is sometimes beneficial to kill it or somehow suppress it first, then fertilize so there is not so much FA biomass present to consume the majority of the added fertilizer and stiffle the desired development of a bloom.
Last edited by Bill Cody; 03/15/10 10:17 PM.
