Establishment of GrasslandA good foundation of a productive sward is essential. The conditions must be right for seed germination and growth of the plant afterwards. Seeding includes 15-25 million seed pr. hectare, depending on species and seed rate. In a good establishment 15-25% of the seedlings will have survived after a few months. The aim in a field for grazing is to have 3-500 plants per m2 with 10-12 tillers per plant, that is 5-7000 tillers per m2.
The seedbed
Ploughing leaves the best conditions for germination - especially when followed by rolling in order to keep the surface moist. The seedbed must be even and with moisture to ensure even and quick germination.
Methods of sowing
Drilling is superior to broadcasting when the soil conditions are dry or the soil is light. Drilling in rows leaves better room for weeds in between the rows - this can be somewhat compensated by drilling in two directions. Broadcasting gives a better distribution and ground cover, but it must be ensured, that the seed is covered with soil and brought in good contact with moisture.
A cover crop can protect the new ley but also give competition if to dense. A cover crop must therefore be relatively open and not lodging. If the cover crop is removed at a critical time (e.g. very hot summer), it may harm the new grass. When using a cover crop, e.g. spring- or wintercereals, this must be drilled first and then immediately after the grass mixture must be sown. Seeding depth for grasses may not exceed 2 cm and for clovers 1 cm. Ryegrasses in pure stand may develop allright from 3-4 cm. Normal seeding rate: 25-35 kg per hectare.
The influence of seeding depth on the germination of different species
|
% Germination |
Seeding depth |
|
|
1 cm |
2 cm |
4 cm |
6 cm |
|
White clover |
40 |
34 |
8 |
0 |
|
Red clover |
42 |
39 |
17 |
0 |
|
Lucerne |
38 |
35 |
11 |
0 |
|
Ital. Ryegrass, 4n |
76 |
73 |
57 |
32 |
|
Ital. Ryegrass, 2n |
75 |
68 |
43 |
13 |
|
Perenn. Ryegrass |
62 |
63 |
45 |
11 |
|
Meadow Fescue |
48 |
40 |
8 |
2 |
|
Red Fescue |
64 |
53 |
12 |
1 |
|
Cocksfoot |
47 |
35 |
11 |
2 |
|
Timothy |
34 |
10 |
0 |
0 |
|
Poa pratensis |
30 |
12 |
0 |
0 |
Source: Danish Field experiments.
Methods of establishing grass leys
|
|
Spring
March/April |
Summer
August 1st |
Fall September 1st - October 1st |
|
Clover
Grass |
No
Yes |
Yes
Yes |
Yes
Yes |
Yes
Yes |
No
Yes |
|
Cover
Crop |
Winter-
cereal |
Spring-
cereal, peas |
No |
Wintercereals |
Time of sowing
Spring or late summer is the best time for sowing. In the spring, the moisture is almost always adequate - in midsummer this is often not the case. Again in august, the moisture is normally sufficient and at this time soil temperature ensures a good and quick germination.
Fertilizer application
Soil analysis is a good guide to fertilization. Normally the cover crop is fertilized according to local norms and the grass field does not need any extra until the following year (maybe some Nitrogen in late summer, if the field is used already the first year). Pure leys in spring may need some fertilization.
Weeds - pests
When sown under cover crop, weed control is normally not needed. Spraying against annual weeds can be necessary in pure leys, where there is less competition. Perennial weeds must be treated with a total herbicide before sowing the grassland. The young plants can be vulnerable to pests as leatherjackets, frit flies etc. It may, therefore, be necessary to spray against pests at this early stage of growth.
Summary –Sward Establishment
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