23 research outputs found
The Promise, Practice, and State of Planning Tools to Assess Site Vulnerability to Runoff Phosphorus Loss
Publication history: Accepted - 23 October 2017; Published online - 1 November 2017.Over the past 20 yr, there has been a proliferation of phosphorus
(P) site assessment tools for nutrient management planning,
particularly in the United States. The 19 papers that make up this
special section on P site assessment include decision support
tools ranging from the P Index to fate-and-transport models to
weather-forecast-based risk calculators. All require objective
evaluation to ensure that they are effective in achieving intended
benefits to protecting water quality. In the United States, efforts
have been underway to compare, evaluate, and advance an
array of P site assessment tools. Efforts to corroborate their
performance using water quality monitoring data confirms
previously documented discrepancies between different P
site assessment tools but also highlights a surprisingly strong
performance of many versions of the P Index as a predictor of
water quality. At the same time, fate-and-transport models, often
considered to be superior in their prediction of hydrology and
water quality due to their complexity, reveal limitations when
applied to site assessment. Indeed, one consistent theme from
recent experience is the need to calibrate highly parameterized
models. As P site assessment evolves, so too do routines
representing important aspects of P cycling and transport. New
classes of P site assessment tools are an opportunity to move P
site assessment from general, strategic goals to web-based tools
supporting daily, operational decision
The economics of fertilizer management
Growers who practice nutrient management apply the proper rate and type of nutrients, and they place these nutrients correctly and at the right time based on their crop needs. Correctly applied nutrients can protect the environment and save money. Part of nutrient management is selecting the correct fertilizer