TRENDS IN FERTILIZER USAGE IN DIRECT SEEDING

by J. T. Harapiak

Introduction
On the Canadian prairies,, the selected method of fertilizer applications is influenced by soil and climatic conditions, fertilizer application rates, type of seeding equipment utilized as well as personal preferences. There has also been a dramatic increase in the interest and adoption of direct seeding methods in recent years which has significantly influenced attitudes towards managing fertilizer.

Westco researchers have been watching these developments with a great deal of interest, and have conducted a series of surveys of farmers practices and preferences to help establish research priorities. Most of the information presented in this paper was extracted from these surveys.

Seeding Equipment Used by Prairie Farmers

Options available for handling fertilizer are often limited by the type of seeding equipment that is available to a farmer. A non-exclusive Westco survey in which over 4,700 prairie farmers participated during the winters of 1992/93 and 1993/94 indicates that the type of

seeding equipment used by prairie farmers varies considerably depending on the farm size and the soil zone in which the farm is located. Perhaps the most significant trend is the fact that as farm size increase, the use of air seeders and air drills increase while the use of more conventional seeding equipment declines. Air seeders and air drills are well equipped to enable prairie farmers to reduce tillage operations.

It should be noted that the data for the Brown soil zone in somewhat skewed due to the influence of irrigation farmers who participated in the surveys. Irrigation farmers tended to inflate the values for use of the double disc and hoe drills above that which would be typical for this relatively arid soil zone.

Farm Size Influences N Management Practices

The survey data summarized in the upper portion of Table 2 indicates an increasing preference for band application of N and decreasing preference for broadcasting as farm size increases. In the lower portion of Table 2, the growing preference for fall application of N fertilizer at the expense of spring as farm size increases is clearly evident. These trends are probably most strongly influenced by farmers who use the highest rates of fertilizer (i.e., higher rainfall areas), and therefore prefer to separate fertilizer application from the seeding operation. There is also a tendency for application of N at the time seeding to increase with farm size.

The survey results summarized in the upper part of Table 3 indicates that the seed row option is used most frequently in the driest regions (i.e., Brown and Dark Brown soil zones) where rates of fertilizer applications are lowest. Band application is the most popular placement option in all regions except for the Brown soil zone. Applying N fertilizer in the fall of the year is most popular in the region of highest N rates (i.e., Black soil zone).

Volume of Fertilizer Handled Impacts Preferred N Management

During the last three decades, the Canadian Prairies have experienced a very significant growth in fertilizer usage and the balance between N and P2O5 has shifted from a ratio of 0.5 to one exceeding 2.5. This shift has been strongly influenced by a reduction in the amount of summerfallow and a growing realization of the important role that N fertilization plays in the success or failure of stubble cropping.

As illustrated in data summarized in Table 4, the amount of fertilizer purchased also strongly influences preferred N management options. Farmers who used the most

fertilizer exhibited the strongest preference for banding and fall application of N fertilizer.

When fertilizer application rates were lower, most of the fertilizer was simply applied in the seed row (i.e., drill-in or seed placed). As rates of usage increased, other placement options were developed. Initially, higher rates of fertilizer N were simply broadcast and incorporated into the soil prior to seeding. However, as farmers became more concerned about the economic benefits of using N more efficiently, broadcasting gave way to pre-plant band applications. The growing emphasis on reduced tillage (i.e., single-pass direct seeding), farmers have increasingly become interested in applying fertilizer at the time of seeding (i.e., sidebanding, mid-row banding or seed Row applications).

Preferred Tillage Practices Influence N Management Practices

In the survey conducted during the winter of 1993/94, participants were asked to categorize themselves according to their tillage practices. The options available included; conventional (39% of the respondents selected this category), reduced (41%), conservation (12%), direct seeding (15%), no-till (5%) and other (1%). Based on the similarity in responses, the reduced tillage and conservation tillage options were combined for purposes of summarizing the results. The farmers selection the conservation tillage option tended to be slightly more concentrated in the Brown and Dark Brown soil zones while those selecting the reduced tillage option tended to be slightly more concentrated in the Black and Gray soil zones.

The highest preference for banding in the group of farmers designating themselves in the reduced/conservation tillage category (i.e., 72%) followed by conventional (59%). In terms of preferred time of N application, at seeding rated highest for no till (74%) followed by direct seeding (54%). In terms of seeding equipment, in the conventional tillage category, the double disc press drill was most popular (42%). The air seeder was the most popular type of seeding equipment in the next two categories and the air drill was the most popular seeding equipment in the no-till category.

Summary

We have witnessed rapid and dramatic changes in the farming practices used by prairie farmers during the past decade. The introduction of improved fertilizer placement technology and the desire to reduce tillage operators helped encourage these developments. We expect that farming practices will continue to evolve into the future. The following are some of trends and concerns related to direct seeding crop production practices that become evident:

1. As farmers become more aware of the significant interaction that exists between disturbing the seedbed and weed establishment, we expect a growing interest in applying fertilizer at the time of seeding to develop. This development will be most difficult to implement in the areas of highest fertilizer use and on the largest farms.
2. In order to minimize soil disturbance, direct seeding farmers are becoming more interested in using wider spaced (i.e., 9 - 12 inch), knife openers. This objective is in direct conflict with the desire to spread the seed and fertilizer over a wider proportion of the seed bed in order to minimize the risk of fertilizer induced germination damage. The commercial development of cost-effective, slow-release fertilizers is necessary to help farmers achieve this goal. At the present time these farmers are limited to using a combination of a limited amount seed row starter N fertilizer followed up with a top-dress application for the bulk of the required N fertilizer.
3. Seed openers that effectively side band fertilizer below and the side of the seed row will become increasingly popular, particularly among farmers growing specialty crops such as peas, lentils and flax.
4. A separate fall N banding operation will continue to be popular in the Black soil zone where the highest rates of fertilizer are normally applied. These are also the areas that have to contend with the highest levels of crop residue. Under these conditions, a small degree of fall disturbance such as can be accomplished with a fertilizer banding operation can be desirable if it speeds warming of the seedbed.
5. In regions that are dominated by a fallow-crop rotation we expect that application of N fertilizer for wheat crops grown on fallow will become more routine to help counteract the lower levels of soil nitrogen being mineralized during the fallow period. This practice will be increasingly adopted by farmers attempting to produce wheat for the premium high protein markets.
   

References

Harapiak, J.T., 1993. Westco Farm Survey, Unpublished Data

Harapiak, J.T., 1994. Westco Farm Survey, Unpublished Data

Harapiak, J.T., 1994. Westco Direct Seeding Farmer Profile, Unpublished Data