Manure Timing Matters: How To Reduce Phosphorus Loss

Jan 20, 2026

By Ehsan Ghane and Sarah Zeiler

Important takeaways

Applying manure in December and January causes much higher phosphorus loss than in October and November.
Applying manure soon after harvest in early fall reduces phosphorus loss.
Winter flows dodge dormant vegetation, and even manure applied on unfrozen ground can freeze under snow and later wash out during thaw, as snowmelt and rain flush phosphorus into tile drains.
If injection is not available, incorporate manure after surface broadcasting.
Avoid spreading on frozen ground or before heavy rain.
Plan storage early to prevent winter spreading.

Manure is an excellent source of crop nutrients but applying it at the wrong time, especially during winter when tile drainage is more active, can greatly increase phosphorus loss. This poses risks to water quality.

Winter applications increase risk

In a six-year Michigan study from 2019–2024, manure applied in December–January lost 1.1 pounds per acre (lbs/ac) of total phosphorus, compared to only 0.13 lb/ac when applied in October–November. Dissolved phosphorus losses were 0.71 lb/ac in winter versus 0.12 lb/ac in fall.

These losses represent phosphorus from recent manure applications only and do not include legacy phosphorus already present in the soil. This distinction shows the direct impact of winter manure spreading.

Source : msu.edu

Video: Seeing the Whole Season: How Continuous Crop Modeling Is Changing Breeding

Plant breeding has long been shaped by snapshots. A walk through a plot. A single set of notes. A yield check at the end of the season. But crops do not grow in moments. They change every day.

In this conversation, Gary Nijak of AerialPLOT explains how continuous crop modeling is changing the way breeders see, measure, and select plants by capturing growth, stress, and recovery across the entire season, not just at isolated points in time.

Nijak breaks down why point-in-time observations can miss critical performance signals, how repeated, season-long data collection removes the human bottleneck in breeding, and what becomes possible when every plot is treated as a living data set. He also explores how continuous modeling allows breeding programs to move beyond vague descriptors and toward measurable, repeatable insights that connect directly to on-farm outcomes.

This conversation explores:

• What continuous crop modeling is and how it works

• Why traditional field observations fall short over a full growing season

• How scale and repeated measurement change breeding decisions

• What “digital twins” of plots mean for selection and performance

• Why data, not hardware, is driving the next shift in breeding innovation As data-driven breeding moves from research into real-world programs, this discussion offers a clear look at how seeing the whole season is reshaping value for breeders, seed companies, and farmers, and why this may be only the beginning.