UNSIFRAN

Motivation

Silage maize occupies a special position in field forage production for ruminant feeding due to its high biomass yield potential, energy content and good digestibility. There is also a growing interest in corn cultivation in organic farming (ÖL) and the area under corn has increased almost tenfold nationwide from 2007 with about 4,500 ha to 2018 with about 40,000 ha.

The particular challenge in silage corn cultivation is the costly weed control, which at the same time inhibits many farmers from entering silage corn cultivation. Furthermore, there are concerns in OIL about silage corn cultivation due to soil erosion problems that often occur in conventional cropping systems. Various mechanical weed control strategies have been developed in the past, most of which involve intensive tillage (plowing, hoeing, harrowing, harrowing, mounding) and thus may well increase the soil erosion problem.

Objectives and approach

The general objective is to optimize weed control in silage corn production while optimizing soil protection. Weed pressure, and thus the need for regulation in silage corn, can be efficiently reduced by planting a suitable preceding crop as the first crop ("winter intercrop"), reducing tillage for corn planting, and reducing row spacing in corn planting. Harvesting the previous crop can lead to an economic advantage of the process.

In the project, weed control in silage corn cultivation will be optimized by a preventive approach in crop rotation and cultivation design. For this purpose, a systemic investigation of a crop rotation element consisting of winter peas in pure seed or in a mixture with triticale or winter vetch in pure seed or in a mixture with rye as preceding crop/first crop and subsequent maize cultivation with reduced tillage or direct seeding as well as with usual (75 cm) and reduced row spacing (37.5 cm) as second crop will be carried out.

Innovations and perspectives

The following aspects are being investigated in multi-year field trials at three locations:

• Testing of preceding crops regarding their potential of a preventive reduction of weed pressure in silage maize due to their biomass development.
• Effect of different treatment methods of the first crops: mixed harvesting around the end of May as whole plants or - like the pure seeds - mechanical destruction of the emergence with knife roller; effects on weed dynamics in maize.
• Testing of reduced tillage (after mixed harvest) for corn seeding and of direct corn seeding after mechanical destruction of the previous crop with respect to weed dynamics in corn.
• Effect of reducing seed spacing between maize rows to 37.5 cm with respect to weed dynamics in maize.