Collaborating Producer: John & Jean Milne, Fairview Alberta
Research Coordinator: Dr. Akim Omokanye
Sod seeding is a no-till method that when compared to intensive tillage, offers a variety of benefits. These include increased moisture availability at seeding time, reduced risk from wind and water erosion and reduced soil carbon losses that are associated with intensive tillage practices. Direct seeding into sod further improves economics by decreasing labour and equipment requirements. Following termination of a pasture, hay or grass seed stand, an annual crop is sometimes grown for one or more years before perennial forages are then re-established.
With sod seeding, farmers are able to implement a number of fuel-saving measures that will not only reduce fuel consumption, but also prolong the life of the tractor. By decreasing the amount of fuel used, farmers can lower energy costs, boost the efficiency of farm operations and decrease the amount of harmful emissions released into the environment. The objectives of this study were (i) to evaluate the forage yield and nutritive value potential of annual crop combinations in a strip-intercrop system using sod-seeding and (ii) to examine fuel savings of removing perennial forage from rotation and growing annual replacement crops without tillage (sod seeding).
Methods
The project was located at John & Jean Milne’s Ranch (NW 27 T80 R3 W6), in Fairview. The designated area for the trial was 10 acres. We had the soil fertility analyzed for the intended crops and fertilized accordingly. Before the trial commenced in 2010, the site had been sown to mixtures of alfalfa & meadow brome 10 years before but was later dominated mainly by quackgrass and some fescue & timothy. It was used strictly for pasture and had declined in productivity over the years.
The treatments were randomized and replicated twice. Four annual crops consisting of 2 cereals, 1 legume and an oil seed crop were seeded in the following 5 treatments combinations (Figure 1): (1) Barley – Peas - Oats, (2) Barley – Peas – Canola, (3)Barley – Canola – Oats, (4) Barley – Canola and (5) Oats – Canola.
The crops within each treatment were strip-intercropped (sequential seeding). Each crop strip was 20-ft wide and 700-ft long in size. Plot sizes were 60ft x 700ft (for treatments 1-3) and 40ft x 700ft (for treatments 4-5). The crops were seeded at 102 lb/acre (Cowboy barley), 108 lb/acre (Mustang oats), 204 lb/acre (Eclipse peas) and 5.6 lb/acre (Invigor canola). CDC Cowboy, a 2 row forage barley, is an excellent dual purpose barley that is well adapted to a low input management system, lighter soils or drought conditions. Seeding and fertilizer application were carried out on May 24, 2011 with a 10-ft Agrowdrill (AD 100 Series) drawn by a 108 HP John Deere tractor. Fertilizer blend (28:26:0) was applied at 100lb/ac to all crops. Granular inoculants at 7lb/ac were used for peas at seeding.
At harvest, for forage yield determination, a crop plot combine harvester, which was 49 inches wide, was used to cut the crop across the width of the different crop treatment combinations (see Figure 1 above). All cut materials within a particular crop treatment combination were raked, weighed fresh and sub-sampled, whereby the sub-sampled materials were dried for dry matter yield estimation. Harvest was done for all crop treatment combinations on August 18, 2011. This corresponded to the soft dough stage for the Cowboy barley, late milk/early dough for the Mustang oats and mid-pod for both Invigor canola and Eclipse peas. Each of the four crops was hand-cut individually from two inner rows, 20 ft long, for individual forage DM yield estimation. Samples of each crop, as well as those of the crop treatment combination, were analyzed for forage nutritive value. After forage sampling, the site was swathed and baled for greenfeed by the collaborating producer. Other observations/measurements included notes taken on the level of soil disturbance before and after seeding, seedling emergence/plant counts, weed counts and assessment of crop health (data not shown).
Results & Discussion
Fuel Savings
Understanding and improving fuel efficiency in sod management will have a significant impact on fuel use on producers farms. No detailed fuel usage data is available from the present study, but a report on data collected across Alberta on the Energy Conservation and Energy Efficiency Project (ECEE) by ARECA shows that fuel savings on the sod seeded fields is dramatic. The traditional plow down required 15.76L/acre compared to only 2.51 L/acre when the farmer seeded the crop directly into sod. That’s a fuel savings of 84%. Another economic benefit is the difference in machine labor requirements. In Alberta, studies by Reduced Tillage Linkages have shown that direct seeding into sod may save as many as 80 hours of labour compared to plowing, discing, cultivating and harrowing a quarter section in preparation for conventional seeding.
Forage Yield
Figure 2 shows forage DM yields from the strip-intercrop crop combinations (treatments 1-5), as well as those of the individual annual crops used for the trial. The treatments with three annual crop combinations (treatments 1-3) all produced >6000 lb/acre forage DM. Forage DM yield was highest with 6943 lb/acre for the barley-peas-canola combination (treatment 2) and lowest for the barley-canola strip-intercrop crop combination (treatments 4), which had 5702 lb/acre. Forage DM yields for the
individual annual crops were in the order of peas > canola > oats > barley. Higher forage DM yields recorded for treatments 1 and 2 than those of treatments 3-5 resulted from the inclusion of peas in the crop combinations. Based on the individual crop forage DM yield (Figure 2), we estimated that peas contributed to about 40% of the total forage DM yield in both treatments 1 and 2. Across the strip-intercrop crop combinations and the individual crops, mean forage DM yields were similar (6237 vs 6344 lb/acre).
Forage Quality
Forage nutritive value can be expected to vary, depending on crop variety, agronomic practices, environmental conditions during growth and the proportion of legume in the intercrop mixtures. In the present study, all crop combinations gave more than 10% crude protein content, but the highest was obtained for the barleycanola-oat strip-intercrop with 12.53% CP (Figure 3). Considering the protein requirements for beef cows from the second trimester through to the third trimester, to post calving, all strip-intercrop treatment combinations were well above the 7 -9% CP requirement of pregnant beef cows, and within the 10-11% CP recommended after calving.
For the individual crops, both oats and barley had lower than 9% CP, while peas and
canola had 14% and 16 % CP, respectively. Had the individual crops been swathed and baled for hay or utilized as swath grazing, both the barley and oat crops would require some form of protein supplement to be fed to the cows post calving.
Protein is a building block and energy facilitates the use of these building blocks for growth and other productive purposes. For the strip-intercrop crop combinations, the barley-canola combination had the most total digestible nutrients (TDN) (Figure 4). As it has been established, for a mature beef cow to maintain her body condition score (BCS) through the winter, the ration must have a TDN energy level of 55% in mid pregnancy, 60% in late pregnancy and 65% after calving. Based on the 55.7% to 59.6% TDN obtained in the strip-intercrop crop combinations, some form of energy supplementation would be necessary, depending on the state of the cows. This also applies to all individual crops. Energy can be monitored in the beef cow by watching BCS; low energy rations result in a loss of BCS.
Forage mineral and detergent fiber contents are shown in Table 2. Inclusion of canola in some of the stripintercrop crop combinations (treatments 2-4) seemed to have some positive effects on the forage calcium (Ca) content, compared to when canola was not included (treatment 1). Peas on its own had the highest Ca content of all the individual crops, but did not have any significant effect when it was present in the crop combinations (treatments 1-2). Forage phosphorus (P) content, on the other hand, seemed to be slightly favored by the inclusion of oats in the crop combinations of treatments 1, 3 & 5. It is important to note that strip-intercrop crop combinations improved the forage P content and in all cases the levels were sufficient for the requirements of mature beef cows regardless of their physiological state. For the individual crops, barley and peas were short of meeting the P requirement of mature beef cows. The Ca:P ratio for a mature beef cow should be within the range of 2:1 and 7:1, assuming actual required grams of each are adequate. But in the present study, Ca:P was generally low (1.23:1 to 1.96:1) for all strip-intercrop crop combinations. For the individual crops, peas and canPeace Country Beef & Forage Association 2011 Annual Report Page 26 ola, respectively, they had 6.0:1 and 4.08:1 Ca:P. Acid detergent fiber (ADF) is the fraction of indigestible plant material present in a forage and it is a useful predictor of the energy and digestibility of a forage. The neutral detergent fiber (NDF) of a forage is inversely related to the amount that a cow or calf is able to consume. Therefore, forages with a low NDF will have higher intakes than those with a high NDF content. Looking at the forage ADF and NDF contents in the present study (Table 2), barley-canola strip-intercrop (treatment 4) had lower forage ADF and NDF contents than other strip-intercrop crop combinations. For the individual crops, peas had lower ADF and NDF contents than the other three crops.
Conclusion
When strip-intercrop crop combinations were compared with individual crop (monoculture) systems, there were no apparent forage yield advantages of the strips. However, the resulting forage quality indicates, that in every respect, nutritive value was significantly improved by the strip-intercropping systems compared to the individual or monoculture system. The best crop combination tested in this trial was the barley-peascanola combination. Strip-intercropping with common annual crops is feasible and is likely to produce quality feed for a greenfeed system. Producers are required to make sure that the strips are of equal width to accommodate this rotation scheme and use a strip width compatible with their equipment. Different varieties of the component crops and other agronomic practices, such as changing varying fertility and seeding rates in a strip-intercropping system, could be tested to see if these factors have the ability to improve forage yield, when compared to a monoculture system.