Bare patch and poor emergence of cereals

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Journal of the Department of Agriculture, Journal of the Department of Agriculture, Western Australia, Series 4 Western Australia, Series 4

Volume 2

Number 4 April, 1961 Article 5

1-1-1961

Bare patch and poor emergence of cereals : factors under Bare patch and poor emergence of cereals : factors under investigation. 2. Depth of planting

investigation. 2. Depth of planting

S C. Chambers

Follow this and additional works at: https://library.dpird.wa.gov.au/journal_agriculture4 Part of the Agronomy and Crop Sciences Commons, and the Plant Pathology Commons

Recommended Citation Recommended Citation

Chambers, S C. (1961) "Bare patch and poor emergence of cereals : factors under investigation. 2. Depth of planting," Journal of the Department of Agriculture, Western Australia, Series 4: Vol. 2: No. 4, Article 5.

Available at: https://library.dpird.wa.gov.au/journal_agriculture4/vol2/iss4/5

This article is brought to you for free and open access by the Agriculture at Digital Library. It has been accepted for inclusion in Journal of the Department of Agriculture, Western Australia, Series 4 by an authorized administrator of Digital Library. For more information, please contact [email protected].

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Bare patch and poor emergence of cereals : factors under investigation. 2. Depth Bare patch and poor emergence of cereals : factors under investigation. 2. Depth of planting

of planting

Cover Page Footnote Cover Page Footnote

The author is indebted to Mr. L. Price for assistance with the field work and to Mr. M. Thornett for statistical analyses of results.

This article is available in Journal of the Department of Agriculture, Western Australia, Series 4:

https://library.dpird.wa.gov.au/journal_agriculture4/vol2/iss4/5

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FACTORS UNDER INVESTIGATION

2 . * - Depth of Planting

By S. C. CHAMBERS, M.Sc., Plant Pathologist

| \ E P T H of planting a p p e a r s t o h a v e a n i m p o r t a n t influence upon the emergence of a - • - ' cereal crop. I n c r e a s i n g t h e d e p t h by one i n c h within t h e range 1-5 inches, not only depressed t h e emergence counts of wheat seedlings, but also increased t h e n u m - ber which emerged abnormally.

During the past t h r e e years m a n y reports of poor emergence of cereals h a v e been i n - vestigated and it h a s become a p p a r e n t t h e condition is caused by several factors.

Many of t h e early observations pointed to deep sowing as a n i m p o r t a n t cause, because bare patches often occurred where t h e combine h a d sunk i n t o soft ground during seeding.

It was these observations which led to the following experimental work being undertaken, to e v a l u a t e t h e effects on emergence of sowing wheat a t various depths.

EXPERIMENTAL

Seed of the w h e a t variety Gabo, was planted by h a n d a t d e p t h s of 1, 2, 3, 4 a n d

* The first of the series, entitled " 1 . Seed Treatment and Moisture Content," was published In t h e March Issue of this Journal.

5 inches in small plots at South P e r t h on the 2nd and 3rd August, 1960. The soil in the experimental area was a coarse sand, which is typical of t h e Swan coastal plain.

T h e experimental design for t h e test plots was a simple randomized system, containing 10 replications of t h e five sowing depths. Each component plot contained 100 seeds, sown in 10 rows of 10, with a space interval of 2 in. between each seed.

Each seedling was examined as it emerged from the soil a n d rated as n o r m a l or a b n o r m a l in accordance with the following system:

Normal—coleoptile emerges from the soil before t h e appearance of t h e first leaf.

Abnormal—coleoptile fails to appear and t h e first leaf emerges from the soil.

331 Journal of Agriculture, Vol 2 No 4, 1961

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Emergence counts were taken five weeks after sowing (Table 1) and these were analysed using the transformation arcsin V% value (table 2).

TABLE 1

Percentage emergence of Gabo wheat seedlings in relation to depth of sowing.

Depth of Sowing (in inches)

-

1 2 3 4 5

Percentage

Emergence

Xormal Abnormal

92-7 76-1 31-6 4 - 9 0-5

2-8 15-3 52-5 45-9 32-5

Non- Emergence

4-5 8-6 15-9 49-2 67-0

TABLE 2

Analysis of emergence counts using transformation arcsin V % value.

the

Depth of Sowing (in inches)

1

1 ::

4 5

Diff. for Sig. P = 0 05 0 0 1

Transformed Values

Emergence

Normal Abnormal

7 4 1 9-6 6 0 1 2 3 0 3 4 1 46-1 12-8 42-3 4 0 34-7 5-2 5 1 7 0 6-8

Non- Emergence

12-2 1 7 0 23-5 44-2 54-7 3-7 5 0

DISCUSSION

During recent years, there has been an ever increasing tendency to sow very large acreages of cereals in the minimum of time by working shifts for 24 hours a day.

This "mass production" attitude has re- sulted in less care being taken during the actual seeding operation. In some in-

stances, the sowing depth is set on the combine at the commencement of seeding and remains unchanged for the whole of the operation. Consequently, the depth of sowing varies as the seeder goes over various types of ground, sinking in some places and riding high in others.

In normal emergence, the coleoptile functions chiefly as a protective tube for the young foliage, which grows up through it to the surface.

In abnormal emergence, the coleoptile fails to reach the surface and emergence is made difficult for the first leaves which grow by elongation of the basal portions.

The subsequent growth of such seedlings is influenced markedly by the soil barrier, through which the leaves must grow to reach the surface.

When the seedling is close to the surface, the basal growth of the leaf will push its tip through, often at an angle. At greater depths, the basal growth will cause the leaf to arch upwards, and these leaves often emerge in a bow-like manner with their tips still buried beneath the surface.

However, when a seedling cannot over- come the soil barrier and fails to emerge, it becomes grossly elongated and distorted before exhausting the food reserves of the seed.

The importance of the planting depth on emergence is clearly emphasised by the results contained in tables 1 and 2. For example, with a planting depth of 4 inches, 49% of seedlings failed to emerge com- pared with 16% at 3 inches. However, 3 inches also was too deep for sowing, because, although 84% of the seedlings emerged, only 32% were normal.

These results suggest the best depth to sow wheat is less than two inches and possibly within the range of 1 to 1£ inches.

However, it is stressed that the experiment has been carried out in a coarse sandy soil and so the results will not necessarily be applicable to all soil types.

ACKNOWLEDGMENTS

The author is indebted to Mr. L. Price for assistance with the field work and to Mr. M. Thornett for statistical analyses of results.

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Journal of Agriculture, Vol 2 No 4, 1961