No-Till, Conventional Till Small Grain Forage Yields Equal

by Jim Johnson

Some have questioned if tillage systems influence small grain forage production and if banding phosphorus (P) fertilizer near the seed provides any additional advantage in early forage production. During the 2003 to 2006 growing seasons, the Noble Foundation conducted research at the Pasture Demonstration Farm northwest of Ardmore, Okla., to determine the effects of no-till and conventional management on small grain forage yields. Treatments consisted of hard red winter wheat (2174), soft red winter wheat (Coker 9663), rye (Maton) and oats (Harrison) under no-till and conventional tillage systems. The effect of in-furrow banded and broadcast P fertilizer was also evaluated on each of these crops under both tillage systems. Each small grain/tillage combination included three P treatments; check, broadcast and banded with the seed. P was supplied by liquid ammonium polyphosphate (APP) 10-34-0 at a rate of 60 pounds P2O5 per acre. Nitrogen (N) was applied at a rate of 150 pounds per acre actual N, and soil tests indicated pH, P and potassium (K) were adequate.

A field planted using no-till system (top image) is contrasted with a conventionally tilled field. A three-year Noble Foundation small grains study showed no statistical forage yield difference between the two tillage systems.

We found that for fall/winter (November-March) and total forage production, there was no statistically significant yield difference between no-till and conventional tillage. We also found no statistically significant yield difference between the three P treatments. There was no interaction between tillage and P treatment, tillage and crop, crop and P treatment, and tillage, crop and P treatment. Let me state again that the soil test showed adequate P.

So what is the take-home message? When P and other nutrients are not limiting, there is no fall/winter or total forage yield difference between conventional and no-till, regardless of the combination of forage and P treatments. Also, there is no fall/winter or total forage yield advantage to adding additional P fertilizer, either broadcast or in furrow, regardless of the combination of forage and tillage practice.

Two lessons that can be learned from this are:

1. The lack of yield depression with no-till indicates that it is a viable alternative to conventional tillage for small grain forage production.

2. If soil test levels of pH, P and K are adequate, there is no yield advantage to applying additional P fertilizer.

Table 2.