Results of Soil Tests on Austrian Grassland Areas

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Changed on: 08.03.2018

AGES presents the results of comprehensive soil tests on Austria’s grassland areas.

AGES presents the results of comprehensive soil tests on Austria’s grassland areas.
Grassland is crucial for agricultural production. It provides valuable staple feed for cattle husbandry, thus, making an essential contribution to providing the population proteins via milk, cheese and meat. Grassland farmers have begun to rediscover farm-own, staple feed due to major fluctuations in the prices of milk products and cost factors such as concentrated feed and energy.

The quality of this staple feed can be improved by optimising the point of time when it is used and through avoiding feed contamination. This article focuses on the nutrients available to plants, and the acidity and humus content of grassland soil.

A total of 12,000 locations provided data for the evaluation of nutritional content and pH values between 2006 and 2012, while the data from 7,000 locations was used for measuring humus content. For humus content, this data pool is the basis for documenting the development of humus contents in grassland in the future. There is too little data to compare it with earlier periods. The following table shows the number of samples organised by production areas.

Basic Data

Number of samples used to measure nutritional and PH values, as well as humus content, organised by production areas.
Alpokalja Alpine foothills High Alps Prealpine region Waldviertel/Mühlviertel
Nutrients and pH Value 1929 3007 1094 1410 4670
Humus content 841 166 797 597 3118

Slightly acidic soil is optimal

The most valuable types of grassland vegetation grow best on medium to heavy soils under slightly acidic conditions at pH values ranging from 5.6 to 6.5. Liming will only increase yields and improve feed quality on acidic locations with pH values of under 5.5.

Even on light soils, the pH value should not be under 5.0 if there are legumes (clover species), Lucernes require a pH value of 6.5 for optimal growth. A pH value of 5.0 for light soils is still considered as sufficient, for medium soils a pH value of at least 5.5 should be aimed at and for heavy soils 6.0.

Carry Out Liming Regularly

Assessment of pH Values, percentage of grassland samples (%)
Einstufung der pH-Werte, Anteile der Grünlandbodenproben (%)
Phosphor content levels, percentage of grassland samples (%)
Phosphor-Gehaltsstufen, Anteile der Grünlandbodenproben (%)

Highly acidic grassland locations with pH values under 4.6 are rare (max. two percent), while 44 percent of the samples from the Waldviertel and Mühlviertel regions and the Alpenostrand (Alpokalja) are acidic, followed by 38 percent from the High Alps region. About 10 to 15 percent of these locations show a pH value of under 5.0. The lowest share of acidic grassland, 18 percent, is found in the Prealpine region because it partly reaches the Northern Limestone Alps.

The results show that most grassland soil is in the optimal pH range. However, the soil has no relevant acid buffers so that regular liming should be carried out at most locations between 0.5 t CaO/ha to 1.0 t CaO/ha every four to six years.

Locations with very low and low phosphor supplies dominate most production areas.
This share reaches its peak at 85 percent in the Prealpine region, while it only reaches between 75 and 81 percent in other areas.



Phosphor balance is mainly negative

Given the fact that mineral fertilisation with phosphor on grassland bears little significance and that at a livestock density of 1.5 LU (livestock unit)/ha less phosphor is being brought back with farm manure than is used in grassland growth results in a negative phosphor balance.

Additional fertilisation with nitrogen results in a dilution of the phosphor in staple feed so that appropriate energy feed must be fed to ensure sufficient phosphor supply, in particular in regions where more milk must be produced. The data shows that phosphor supplies in grasslands will become a crucial topic in the future, especially if as much valuable staple feed as possible needs to be produced.

Slightly positive potassium balance

Potassium levels, percentages of grassland samples (%)
Kalium-Gehaltsstufen, Anteile der Grünlandbodenproben (%)

The share of areas with low potassium supplies (share of potassium levels A and B) is minimal, while the percentage is between 11 and 40 percent in the High Alps. Calculating with the livestock density mentioned above, farm manure adds more potassium than grassland growth uses up, which results in a slightly positive potassium balance.

The data also shows that the highest potassium levels are found in the Waldviertel and Mühlviertel regions: this can be traced to higher potassium supply potential in the crystalline substrate that forms the soil in this region. Therefore, additional mineral fertilisation with potassium is an exemption for grasslands.



Humus levels determined by location

Humus levels, percentage of grassland samples (%)
Humus-Gehalte, Anteile der Grünlandbodenproben (%)

Humus levels in grasslands are mostly determined by local climate, altitude and intensity of usage. In the lower regions of the intensively used Alpine foothills and the Waldviertel and Mühlviertel regions, where lighter soil dominates, the share of areas with humus levels under 4.5 % is highest at 26 and 23 percent.

This is in contrast to areas in the Prealpine region, High Alps and the higher areas of the Alpokalja, which often have humus levels of over 9 %: this share is between 26 and 42 percent in these regions.

Based on the these results, pH values should be kept in the optimal range to maintain and increase the productivity of grassland. Phosphor supplies and phosphor levels in staple feeds require increased attention, given the drive for increased quality. Potassium supplies are mostly sufficient to high. Humus levels depend on altitude, intensity of use and the type of soil.



Soil tests

Schüsserlbohrer - zur Beprobung von Grünlandflächen besonders geeignet. Ermöglicht eine rasche und tiefengenaue Ziehung von etwa 30 Borkernen.
Schüsserlbohrer - zur Beprobung von Grünlandflächen besonders geeignet. Ermöglicht eine rasche und tiefengenaue Ziehung von etwa 30 Borkernen.

Soil tests are a simple and cost effective method for gathering information on the soil quality of specific grassland areas. About 30 individual samples must be collected from a depth ranging from 0 to 10 cm per area. The samples are then mixed well and about 750g are sent to the laboratory.
Samples should be taken in spring or autumn, a minimum of two months should have passed since the last application of farm manure, one month for mineral fertilisers. Tests will also reflect justified, social, environmental concerns and document the development of soil quality, in addition to optimising the operational management of nutrients.

Soil samplers should be used for quick and accurate sample taking for around 30 cores.
Further information on soil testing can be found on our service site.



Soil has high importance

The importance of grassland was also highlighted in the UN’s International Year of Soils in 2015. The preservation of grassland areas is a vital goal of the ÖPUL programme, given the diverse ecological functions of grassland (e.g. no erosion and minimal nutrient losses, high carbon storage capacity) and its special significance for diversity in agriculture, habitats and species.
Austria’s permanent grassland area amounts to about 1.24 m hectares, 44 % of which is used intensively and 56 % extensively. This area is just slightly smaller than that of agricultural land with about 1.36 m hectares. Approximately 480,000 ha are used as meadows with three or more cuts per year, 250,000 ha are cut once or twice, Alpine pastures and mountain meadows make up about 345,000 ha, and 67,000 ha are used as permanent pastures.

FAO - International Year of Soils

Österreichische Bodenplattform on the International Year of Soils

Soil – AGES Work Focus 

• Dem Boden auf den Grund gegangen (Getting to the bottom of soil) - in German only
• Boden als Grundlage für das Leben (Soil as the basis for life) - in German only
• Ressource Boden - Die Haut der Erde (Resource Soil – Skin of the Earth) - in German only
• Unser Boden – wir schauen drauf (Our Soil – We keep an Eye on it)

This article was also published in:
BauernZeitung - No. 36 – 3rd September, 2015