Swine Manure Carryover in a Cereal/Pulse Crop Rotation

By Bryan Nybo, PAg

Wheatland Conservation Area

The rapid increase in hog production has led to producer and public demand that swine manure be handled in an environmentally sustainable manner and that manure be applied to the soil with the least possible nutrient escape and odour. PAMI has worked to develop technology which addresses these concerns and, along with Wheatland Conservation Area, realized the need to further examine the agronomic benefits that exist with the use of swine manure as a fertilizer. As barns continue to grow so does the demand for locally grown, quality feed such as peas and barley. With surrounding land required for both production of feed and removal of manure, there is a need to know how one effects the other in a cropping rotation. Wheatland (WCA) would like to encourage the cooperation between farmer and hog producer to show them how a symbiotic relationship will benefit their long-term sustainability. WCA would also like to further prove the value of swine manure as a fertilizer and to show producers how it can be effectively used in a pulse crop rotation.

In the fall of 1998 swine manure was injected at three different rates (3000, 6000, 9000 gallons per acre (gpa)). Urea was also deep banded with a Flexi-coil 5000 air drill using a double shoot stealth opener. The Urea rates were 50, 100, 150 lbs/acre of actual N. An analysis of the manure showed the amount of actual N in the urea was very close to that of the manure. No additional fertilizer of any type has been applied to the soil since the fall of 1998.

The first year of the study dealt with the injection process and odour management. A producer tour was held in the fall of 1998 to demonstrate the equipment in action as the manure was injected. The tour group was impressed with the equipment and the absence of odour throughout the afternoon.

The next two years of testing looked at how durum responded to the various treatments. The third year of the study looked at how chickpeas, peas, and barley respond to possible nutrient carry over from 1998. From this data we determined which of these crops has the best fit in a rotation involving various rates of swine manure

Results from this study were impressive. Durum yields and proteins in 1999 were as good or better when fertilized with swine manure as compared to their urea counterparts (Figure 1). In 2000, there was enough carry over nutrient in the 6000 and 9000 gal/ac swine manure and the 150 lbs/ac urea treatments to significantly increase durum yield and protein (Figure 2).

Figure 1. 1999 Durum yield and protein.

Figure 2. 2000 Durum yield and protein

In 2001, there is enough nutrient carryover from the 9000 gpa treatment to positively affect yield in barley, and negatively affect yield in the pulses (Figures 3 and 4). Response in the peas and chickpeas were similar. Barley yields drop significantly on plots receiving 6000 and 3000 gpa of swine manure as well as all the urea treatments, yet remaining significantly higher than the check that received no manure or urea (Figure 3).

Figure 3. 2001 Barley yield .

Figure 4. 2001 Pulse yields.

Pulse yields increase significantly as manure application rates decrease (Figure 4). The same trend occurs with the urea treatments although the differences are not significant. This negative yield response appears to be the result of poor nodulation in the pulses due to additional nutrient carryover and a soil moisture deficit from previous crops. Plots receiving high rates of manure and fertilizer in 1998 produced high durum yields in 1999 and 2000 (Figures 1 and 2). These high yielding crops may have created a moisture deficit for the third year pulse crop in 2001, a year already plagued with drought.

This test shows that seeding a pulse within three years of applying swine manure, can be detrimental in a dry year. We also see the 9000 gal/ac rate has enough nutrient carry over to affect yields in barley. To achieve optimum yield in a third year cereal, however, would require supplemental nutrients, as would the remaining treatments.