CONSERVATION
TILLAGE PRODUCTIVITY CENTRE. |
1996 Report
David Rourke and Andrew Hargrave
Ag-Quest. Inc.
The Conservation Tillage Productivity Centre is in its final year of activity and has completed its seventh year of the Rotation X Tillage study at Minto, Manitoba. This paper will illustrate the significance of some of the findings.
Other related projects carried out by Ag-Quest, Inc during the 1996 growing season included:
-Gigantic Seeding Demonstration (July 3);
-Conservation Tillage Project on heavy clay soils (LaSalle, Manitoba),
-Zero Tillage Row Spacing (Ducks Unlimited);
-Conservation Tillage Pulse Crop Project (Manitoba Pulse Growers Assoc.);
-Special Weeds in Zero Tillage (night flowering catchfly and absinthe); and
-participation in writing the Zerotill-Advancing the Art
-chapters on economics and rotations.
INGREDIENTS FOR SUCCESSFUL ZERO TILLAGE
The success of a farming operation can be looked upon using the barrel stave example of limiting factors. For most of the prairies, crop available water is often the most limiting factor (Figure 1).
Zero tillage offers the cheapest and surest way to increase available water in most of the prairie region. Data collected in 92-93 from tillage studies illustrate the advantage zero tillage can provide in increasing available water (Figure 2).
One pass zero tillage can provided up to 3.5" of extra moisture over conventional tillage In terms of wheat production; 3.5" of extra moisture can easily translate into 14 bushels more grain (4 bulextra inch of water). In some high yielding varieties this can stretch to 6 bu/inch of water or 3.5 x 6 = 2 1 bu/acre more yield. Considering reduced evaporation in fall and spring plus reduced runoff of heavy rainfall the extra moisture available under zero tillage cropping conditions can be substantial.
From practical experience on our own farm at Minto, we believe zero tillage offers a true yield advantage in approximately 7 out of 10 years when compared to conventional tillage due to this moisture advantage. In 1 or 2 years out of 10 there will probably be no difference in yield due to ideal moisture conditions and in the other 1 or 2 years out of 10, zero tillage may have a slight disadvantage due to excessive moisture.
On the wetter, heavy clay soils, zero tillage probably is only an advantage in 6 out of 10 years. A 2 pass zero tillage system with fall banding is often very important in these wet soils to help reduce the chance of delayed seeding, particularly in the wettest years.
Zero tillage can also be especially helpftrl in keeping moisture more uniform across a field. Figures 3 and 4 illustrate the advantage zero tillage can have over conventional tillage for keeping moisture on the tops of hills and even on the side slopes.
The extra moisture can then be converted into yield as illustrated in Figure 5.
Substantial difference exist betvveen zero tillage and conventional tillage at all field positions however the difference between low areas and hill top is less for zero tillage than for conventional tillage when expressed as a difference of maximums. The hill top yield on zero tillage was 85.5% of the low position yield but only 75% for the conventional tillage This is perhaps an extreme finding but zero tillage, overall field positions, average 84 bu/acre compared to 48 bulacre for conventional tillage
Obtaining higher yields from the extra moisture associated with zero tillage can not be taken for granted. Again the barrel stave model suggests other factors may become limiting once available water is improved.Extensive trials at Minto and elsewhere have often shown that good crop rotations play an important role to utilize the extra yield potential of zero tillage and as well provide an opportunity to influence the price receiv~ed by selecting crops which hopefirlly are overall more profitable than our usual mainstay - wheat. Figure 6a-b illustrate the importance of rotations to farm profitability.
Figure 6a. Effect of tillage system and rotation on yields (Minto 1991-1996)
Average returns to labour and management ran from a low of$12 for continuous conventional tilled wheat to a high of$105/ac for 4 year rotation of wheat/canola/wheat/flax using zero tillage In each example of the trial from 1991-96, zero tillage crop out yielded conventional tillage Higher yields compared with cost savings of approximately $6/ac give substantially higher net profit to zero tillage crop production compared to conventional tillage which in these cases was 2 fall deep tillage and 1 spring cultivation just ahead of the seeder, plus harrowing and packing as necessary. Zero tillage is one pass seed and fertilizer. Garth Butcher in 1990 reported zero till costs as being $5.68/acre higher than conventional till, largely due to the price of Roundup. Since 1993, studies have shown zero till production costs to be lower than conventional till costs. Rourke and Hargrave (1993), Lafond et al (1993) and Josephson (1993) reported zero till production costs to be $6.10, $7-il and $5.61/acre (respectively) lower than convnetional till costs.
Further improvements to the profitability
of zero tillage can sometimes be achieved by adding either a seed treatment or
a foliar firngicide or both. Figures 7 and 8 illustrate the effect rotation and
ftrn2icide can have on zero till yields.
Figure 7. Effect of rotations and fungicides on wkeat yield (minto, 1994-96) (UTC=Untreated control; T= Tilt; V=Vitaflow 280; T + V = Tilt and Vitaflow 280)
Figure 8. Yearly variability of fungicide applications in a 50% cereal based zero till rotation on wiieat yields (Minto, 1994-t996) (UTC~Untreated check T=TiIt; V--Vitaflow 280; TV = Tilt and Vitaflow 280)
Wheat yields as shown in Figure 7 are substantially higher when cereals make up only 50% of the rotation vs 100%. The seed treatment on average had a more positive affect over the 3 years, than the foliar fiangicide, particularly in the 50% rotation. The data presented in Figure 8 show that foliar fingicide can indeed contribute to higher yields. In 1994, TiltÆ and VitaflowÆ increased yields 22 bulacre over the untreated control. In 1995, however, TiltÆ reduced yields, even though yields were quite high; low disease pressure and particularly hot dry stress conditions interacted negatively with TiltÆ to ftrrther stress the crop. TiltÆ should only be applied when disease reach a critical level and the crop is not expected to be under stress. In 1996, the yield response to TiltÆ may have reasonably been expected to be larger, however, damage from wheat midge and flisarium head blight may have prevented the firll yield potential from being realized.
Additional insight into the role rotations can play can be seen in pulse based rotations shovvn in Table ]. Net returns range from - $12.00/acre to $124. 70/acre depending on the rotation and also the price of the various crop at the time of analysis. Under certain prices (Price 1) the more profitable rotation appears to be wheat/canola/peas using both seed treatments and foliar fin(~icide on all crops. Following second is the wheat/peas/canola rotation using only seed treatment. Neither of these rotations are recommended due to the susceptibility of both peas and canola to sclerotinia. These studies are in their third year of a 4 year project and more detailed analysis will be available after the 1997 season. The most profitable rotation, in the Price 2 scenario was the vvheat/lentils/peas. This rotation also is not normally recommended due to potential disease problems. In the short rotation of vvheat/lentils, the lentil yields were as low as 1441 lbs/acre even after 2 applications of foliar firngicide, whereas in the better rotations lentil yields were 2000 lbs/acre or more. In other words. ftrngicides cannot replace a good rotation for keeping disease in check. Net returns for all of the rotations in Table 1 are approximatelv $20/acre lower than comparable nets for earlier cereal based examples, with main differences being the inclusion of labour in Table I figures.
| TABLE 1. EFFECT OF ROTATIONS AND FUNGICIDE ON ZERO TILL YIELDS & PROFITS (MINTO, 1995-96) | ||||
| Rotations | Net incomes Price 1 | Net incomes Price 2 | ||
| ST,NF | ST,F | ST,NF | ST,F | |
| 1.) Wheat(48/52) Wheat(35/36); Wheat(44/48).Pcas(40/45) | 14.50 | 13.00 | 14.50 | 13.00 |
| 2.) WTicat(50/51) Canola(32/33); Wileat (41/43), Peas (40/38) | 46.00 | 25.80 | 46.00 | 25.80 |
| 3.) Wheat(45/49). Lentils( 1557/1 670) Wheat(46/50).Peas(39/44) | 23.50 | 20.50 | 65.50 | 66.50 |
| 4.) Wheat(45/48) Wheat 46/46). Wheat (42/54). Lentils (791L~060) | 23.00 | 23.50 | 72.00 | 80.50 |
| 5.) ~cat(53/47). \~eat(44/46). Peas(45/53) | 46.00 | 37.70 | 46.00 | 37.70 |
| 6.) Wheat(46/45). ~~cat(42/49), Lentils(1528/2054) | 7.30 | 20.00 | 63.00 | 96.00 |
| 7.) \~eat(45/50). Canola(36/44); Pcas(43/5 1) | 72.00 | 96.70 | 72.00 | 96.70 |
| 8.) wheat(48/55), Lentils(169612195), Peas(41/40) | 38.00 | 44.70 | 100.00 | 124.70 |
| 9.) Wheat(46/53) Peas(42.5/47) | 43.00 | 50.00 | 43.00 | 50.00 |
| 10.) Wbeat(44/56), Lentils(1200/1441) | -12.00 | 6.00 | 55.00 | 86.00 |
| 11.)Wheat (54/50) Peas(39/42) Canola(41/42) | 90.00 | 71.70 | 90.00 | 71.70 |
Yield bu/acre except lentils lbs/acre. (ST,NF/ST,F)
ST=Seed Treatment; F=Foliar Fungicide; NF=No Fungicide
Total costs except labour & management
| ST,NF | ST,F | |
| Wheat | $168 | $184 |
| Lentils | $188 | $214 |
| Canola | $194 | $217 |
| Peas | $186 | $212 |
While these examples of economics of rotation are far from answering all your questiopns, the one ftrndamental point is that zero till has limited profitability under continuous cereals. Root and foliar diseases become the yield limit factors in a 100% cereals based rotation.
Deciding on a profitable rotation can be difficult. The decision will depend on many factors including:
1. Choosing adaptable crops. Corn, soybean and dry beans will not be suitable in short season zones.;
2. Choosing marketable, economic crops.
There is no sense in growing a crop for which there is little of no economic demand.
3. Choose crops or varieties with different optimum seeding dates This can be important in trying to keep weeds off balance (e.g. winter wheat or buckwheat).;
4. Use of forage crops in rotation. Provides weed control and soil improvement solutions where the proper economics and markets can be achiev'ed.;
5. Preventing the accumulation of yield limiting diseases. This appears to be one of our largest problems, especially for crops susceptible to sclerotinia. Fungicide can help but are often not sufficient to control infection cycles or all diseases.; and
6. Weed problems, soil conditions, distance to market, equipment, or knowledge limitations or even just risk may also affect the crops which will be included on the farm.
Choosing a proper rotation is one of the key steps to utilizing the extra water and yield potential available from using zero tillage crop production techniques.
