Experiments with ridge tillage for maize in a brown forest soil

There is no practical tradition of ridge tillage in Hungary, but attention has been drawn to this method by the fact that the literature clearly defin es it as a soil-protective system for use in sustainable crop production. A nother point of interest is the possibility of applying the method on slope s. Ridge tillage can be regarded as 7a special version of the seedbeds perp endicular to the slope, used for wide-rowed crops on sloping sites requirin g protection. Experiments were set up in Godollo in 1995 in order to determ ine whether the method could be adapted for small fields on brown forest so il under conditions where soil protection is a prerequirement for crop prot ection according to EU regulations. The effect of traditional and ridge tillage systems on soil status, yield a nd weed cover was studied in a comparative experiment. The traditional syst em involved autumn ploughing and two phases of seedbed preparation. The rid ges were formed on a ploughed area perpendicularly to a 3 % slope, with a w idth of 440 mm and an interrow distance of 460 mm. The height of the ridges during the vegetation period was 200-220 mm. The ridges were treated as de scribed in the literature using simple machinery adapted for the purpose. M aize was grown in the experiments without rotation. The most important conclusion reached in the first three years was that the soil status required by maize could be achieved by either traditional or r idge tillage, but that this status could be maintained throughout the veget ation period in the ridges. In the case of ridge tillage three soil environments evolve: the ridge itse lf, which is free of stubble residues, and the interrows containing stubble residues, which may be compacted or non-compacted. In the third year of th e experiment the soil penetration resistance of the ridges and non-compacte d interrows was less than or equal to 1.0 MPa in the 0-20 cm layer and 1.0- 2.0 MPa in the 20-40 cm layer. Even that of the compacted interrows was les s than the critical 3.0 MPa value. The trends in soil moisture content over the whole year were similar in the two tillage systems, but in spring a co nsiderable difference was observed. The soil was more moist in the interrow s covered with stubble residues, drier at the top of the ridge, due to its favourable heat cycle, and on the sides, and driest in the traditionally ti lled treatment. This latter proved to be unsuitable for the retention of ra inwater, so little water seeped into the soil. The yields achieved with ridge tillage were 10 % higher over a three-year a verage than in the traditional tillage treatment. However, this difference was nor significant in any of the years. It should be noted that the soil-p rotective effect of the method is of greater importance at the given growin g site than an increase in yield. The effect of erosion on the area used fo r ridge tillage was 85 % less than on traditionally tilled areas. Neither of the tillage systems proved to be disadvantageous as regards weed cover. Annual dicotyledonous late summer weeds occurred in the greatest nu mbers on the experimental areas, but the weed cover was only significant in the first year, being 33 % in the traditional system and 37 % in the ridge tillage system. Integrated weed control fits in well with the ridge tillag e system, consisting of correctly-timed interrow cultivation and a single t reatment with post-emergent herbicide. The experiments will be continued in the areas indicated. It can be conclud ed from the first three years of results that the ridge tillage system can be well adapted to sloping growing sites in Hungary provided the technology is strictly adhered to. It will be of importance in widening the range of soil-protective cultivation systems available.