Schechtner


Die Bodenkultur - Journal for Land Management, Food and Environment

G. SCHECHTNER:

Efficiency of liming on grassland

Summary

The results of seven long-term field trials are summarized in order to clarify the role of liming on grassland and to improve the recommendations for liming.

Four of the trials ran on permanent grassland, two on arable grassland (leys).

The soils of the trial areas were exclusively mineral soils, mainly brown earth.

Essentially the following results were gained:

1. Clear positive effects of liming - with respect to yield and the botanical composition of the sward - were only gained on strong acid soils, that means soil pH-values distinctly below 5.0.

2. Even on grassland it may occur under climatic conditions like in the Styrian Enns-valley that soil-pH is dropping below 5.0 in the course of time if fertilization with calcium is neglected.

3. Especially if acidifying nitrogen fertilizers like urea are used and liming is neglected soil acidity may increase relative quickly.

4. As basis for productive grassland a soil pH between 5.0 and 5.5 is sufficient on sandy and loamy soils. With higher pH targets lime requirements are increasing over-proportionally, To maintain pH of brown earth soils within this magnitude for a langer time on an average the following dressings of CaO (+MgO) per ha and year are necessary under climatic conditions like in the Styrian Enns-valley:

150-200 kg CaO on sandy soils

200-250 kg CaO on loamy soils

The calcium and magnesium supplies by farmyard manure and cattle slurry may be taken into account by using these figures as guide lines for maintenance fertilization, just as the calcium supplies by basic acting fertilizers like basic sl ag or soft rock phosphates corresponding to their liming effects.

5. Calcium dressings which exceed these standard values for maintenance fertilization very much and for a longer time are not only uneconomic but may have unfavourable effects also to yield and the botanical composition of the sward. This valids not only for permanent grassland but also for leys.

Key-words: soil p H, lime requirement, Nardus grassland, permanent meadows, leys.