Sorghum halepense

Johnson grass

Johnson grass (Sorghum halepense) is a perennial grass species originally from southern Eurasia. The plant can reach a height of up to 2 metres and is characterised by long, flat and pointed leaves with a prominent central vein. The inflorescences are dense, plume-like panicles that reach a length of up to 30 cm and contain a multitude of small, mostly reddish to purple flowers. The flowering period is from July to September. Wild sorghum prefers sunny to semi-shady locations and often grows along roadsides, in disturbed areas and along bodies of water. It has excellent drought resistance and can thrive in a wide range of soil conditions.

Types of damage

Ecological damage

Johnson grass can form dense stands and spread rapidly, also through its underground rhizomes. Especially in agricultural areas, ruderal areas and along fields, it can overgrow native vegetation and thus endanger rare arable plants.

Economical damage

Sorghum halepense is particularly problematic in agricultural areas because it competes with crops and can reduce their yields. In some cases, yield losses of up to 30% have been observed in maize fields. Control and eradication can be costly.

Region of origin

Southern Eurasia

Introduction vectors

Agriculture

Johnson grass can be accidentally mixed with seeds of other crops and thus transported over long distances. In addition, it can spread through agricultural machinery moved from an infected to an uninfected field.

Current distribution

Based on the FlorKart Database of the Federal Agency for Nature Conservation, as of 2013

Miscellaneous

Family

The Poaceae family comprises about 780 genera with around 12,000 species. They are distributed worldwide and are one of the ecologically and economically most important plant families. The family includes mostly herbaceous plants with hollow, rounded or flattened stems and long, narrow leaves. Characteristic are the spikes or panicles as inflorescences and the small, mostly inconspicuous flowers. Many species serve as the basis of human nutrition (wheat, maize, rice, barley, oats, millet), as fodder plants or as ornamental plants (bamboo, ornamental grasses). Sugar cane (Saccharum officinarum) also belongs to this family.

Climate change

Sorghum halepense has not yet filled its potentially suitable habitat under current climate conditions. It benefits from climate change because in the future its potentially suitable habitat will increase. The environmental factors that most influence its spread are soil type, rail infrastructure, road infrastructure, spring temperature and summer precipitation.

Dispersion forecast

Indicates the proportion of land suitable for habitat under current and future climate conditions (2060-2080) under three emission scenarios (RCP26, RCP45 & RCP85).

Habitat suitability maps

Instructions for use: Click here

Habitat suitability under current climate conditions

These habitat suitability maps show for Sorghum halepense where suitable habitat conditions exist.

The map on the left shows this for current climate conditions. Below this are maps for the time classes 2040-2060 and 2061-2080, in which three different emission scenarios can be selected.

The slider at the top left allows you to adjust the opacity of the map to make orientation easier.

By clicking on the respective quadrant, information on the environmental conditions present in it can be called up.

The methodology is explained here .

Habitat suitability 2040 - 2060

2040-2060: In the RCP2.6 scenario, GHG emissions are expected to peak by 2040 through comprehensive mitigation measures and to decline rapidly thereafter. By 2060, global warming would stabilise at about 1.5°C above pre-industrial levels. Subtle changes in precipitation patterns could vary regionally, with some areas facing increased drought and others increased precipitation.

2040-2060: Under RCP4.5, GHG emissions would continue to increase until 2040, but stabilise at a high level thereafter. By 2060, there could be a global temperature increase of about 2°C above pre-industrial levels. This scenario would likely cause moderate changes in precipitation patterns, with potential regional differences.

2040-2060: Under RCP8.5, which assumes continued intensive use of fossil fuels, greenhouse gas emissions would rise sharply by 2060. The global temperature increase could be around 2.5-3°C. In this scenario, significant changes in precipitation patterns could occur, with an increased likelihood of extreme weather events.

Habitat suitability 2061 - 2080

2060-2080: By 2080, global warming could be limited to below 2°C in the RCP2.6 scenario, provided emission reductions are consistently pursued. Impacts on precipitation patterns would likely stabilise, although regional variance would remain significant.

2060-2080: In the RCP4.5 scenario, global temperatures would continue to increase and could be around 2.5°C above pre-industrial levels by 2080. Changes in precipitation patterns would likely increase and regional differences could become more pronounced.

2060-2080: Under RCP8.5, global temperatures could rise by more than 4°C above pre-industrial levels by 2080. Precipitation patterns would be expected to change significantly, with further increases in the frequency and intensity of extreme weather events. This would have far-reaching impacts on ecological and socio-economic systems.