The field trial design

The field experiment is located 300 m above sea level in the Leimental near Basel (CH). The topographically sound field site is on a gentle, north facing, slope in the valley of the «Birsig»stream. In earlier times, the land in this region was used as permanent grassland («Wässermatten») due to the regular flooding and high groundwater table. Today, the soils of the region are used for intensive farming and vegetable production.

The strategies of fertilization and plant protection are the main differences between the systems, whereas crop rotation and soil tillage were almost identical.

Soil and Site

The area where the DOK-trial is located (see picture), is documented to have long been in use as arable land (1957–1973 ley rotation, 1973–1975 field legumes and cereals, 1976 oats). In May 1977 the whole area was sown with grass-clover, and in the spring of 1978 the field experiment began with potatoes, spring wheat and spring barley.

The annual mean temperature is 9.5 °C, the mean annual precipitation accounts for 792 litre per square metre.

The soil is a haplic luvisol on alluvial loess of 0.9 to 1.3 meter depth.

The treatments (systems)

The bio-dynamic and the bio-organic systems are carried out according to the regulations of the respective organic producer’s organisations; the conventional system is managed according to the guidelines of integrated farming.

In addition to these three systems, which are commonly amended with manure, another treatment was performed as a conventional system without fertilization in the first crop rotation period, then subsequently fertilized exclusively with mineral fertilizers. An unfertilized control was conducted with the use of bio-dynamic preparations only. These two initially unfertilized treatments were included to evaluate the effects of chemical plant protection and the bio-dynamic preparations.

Fertilization

The amount of farmyard manure applied in the first two crop rotation periods (CRP) corresponded to 0.6 or 1.2 livestock units per hectare in the low and high input plots, respectively. The amount of manure was increased to 0.7 and 1.4 livestock units per hectare at the beginning of the third crop rotation period. In the organic systems, manure was applied in smaller amounts, but more often than in the conventional system, where the whole amount of manure was split between the two root crops. The mineral nitrogen fertilization was adjusted according to Nmin analysis in early spring in cereals and root crops.

Main Differences of the Farming Systems

(click on graph to enlarge)