planting

Don’t Be Too Eager to Work That Soil!

By: Penn State Extension

soilWorking soil that is too wet results in soil compaction. Learn how to test your soil to see whether it is too wet to till or plant.

As I write this, we’ve had some substantial rain lately, with more forecast in the near future.  This time of year, everyone is ready to put winter behind them, and turn the page to another growing season.  One of the first activities in the spring is tilling the soil for spring planting.  However, damage can be done rather quickly by getting into the fields when soil is too wet, causing soil compaction.

Soil compaction occurs when soil aggregates and particles are compressed into a smaller volume.  As soil is compacted, the amount of open pore, or void space, decreases and the density, or weight of the soil increases considerably.  Excessively compacted soil can result in problems such as poor root penetration, reduced internal soil drainage, reduced rainfall infiltration, and lack of soil aeration from larger macropores.  Most soil compaction occurs from machinery being driven over a field when conditions are too wet, and may lead to reduced yields of 10-20%.

To determine whether your soil is dry enough to work, a simple test can be performed.  Using a trowel or a spade, dig a small amount of soil and squeeze it in your hand.  Does the soil stick together in a ball or crumble apart?  Soil that crumbles through your fingers when squeezed is ready to till.  If, however, the soil forms a muddy ball and will not fall apart, give the soil another few days to dry, and sample again later.

If you suspect you may have soil compaction, a tool called a penetrometer may be able to help you determine your depth of soil compaction.  Based on the depth and severity of compaction, you will be able to identify corrective measures.  Some of these measures include deep tillage, and more recently, the use of cover crops.

For more information on soil compaction, see http://extension.psu.edu/agronomy-guide

When to Turn Under Spring Cover Crops?

spring maple buds

I heard the peepers last night for the first time this year. There have already been a couple of sunny, almost warm, spring-like weeks in my neighborhood. Recently the overwintered rye has switched its dull reddish-green color scheme to bright green.

I remember reading a couple of years ago that stands of overwintered rye, if killed early, will provide the most nitrogen value.  Incorporating the young plants when they are just beginning to grow, will give as much as a 30-50 lb N credit. Providing soils are dry enough to drive onto, the best time to kill winter rye is when plants are no more than 6-8 inches tall and shortly after they have greened up.

Usually a light harrowing can kill winter rye when root crowns are small and the young stalks are not yet fibrous.  Allowing rye to continue to grow will put on biomass, however, the early spring nitrogen credit will be lost.  Nitrogen scavenged the previous fall and held in its roots throughout the winter will be utilized to put on rapid spring growth. Additional nitrogen will be required to mineralize it, when incorporated into the soil later in the spring.

If significant biomass is one’s goal, as well as field grown nitrogen, it’s better to seed a legume into one’s fall planted winter rye. Let the green manure cover crops grow to full maturity late into May or early June. Then turn them under and allow them to slowly break down to feed later summer cash crops.

Meanwhile, utilize the extensive root growth of an overwintered cover crop and benefit from the value of its winter carry over of “free” nitrogen. Many overwintering cover crops give the most value if you turn them under quite early.

— Eero Ruuttila,

Sustainable Agriculture Specialist – Scaling Up Program

UConn Extension – Tolland County

Information on early killing of spring cover crops came from the March 2011 Cornell VegEdge newsletter, authored by Thomas Bjorkman