Thlaspi arvense

Thlaspi arvense is a foetid, hairless annual plant, growing up to tall, Later it has round, flat, winged pods with a deep apical notch, measuring across. They contain small brown-black seeds. Pennycress, has flat and circular notched pods. Its seeds have a high oil content and the species has gained interest as a potential feedstock for biofuel production. ==Morphology==

Pennycress is planted and germinates in the fall and overwinters as a small rosette. The central stem and upper side stems terminate in erect racemes of small white flowers. Flowers are self-pollinated and produce a penny sized, heart-shaped, flat seed pod with up to 14 seeds. Each dark brown seed is oval-shaped and slightly larger than a camelina seed (Camelina sativa). Pennycress grows as a winter annual across much of the Midwestern US and the world. ==Distribution==

The field pennycress is native to the temperate regions of Eurasia, in many of which it is an archaeophyte (an ancient introduction). It has been naturalised to North America, and so can be regarded as having a circumpolar distribution. It is found throughout Europe (it is missing from Iceland, the Faroese and Svalbard, relatively rarer in the Arctic and the Mediterranean mainlands, and absent from Portugal and the Mediterranean islands). Its area then extends through the Greater Caucasus, the Armenian Highlands, northwestern Iran, Kazakhstan, southern Siberia and up to the Pacific coast of Khabarovsk and Primorsky Krai, the Altai, Tian Shan and Pamir mountains, Korea and the Japanese Archipelago, all but the southeasternmost provinces of China, the mountains in the north of South Asia in Indian Jammu and Kashmir and Ladakh, in Pakistan's Chitral, Hazara, Kurram Valley, and as far south as Rawalpindi District), and Ethiopia. It has also been introduced to Australia and the Americas. In the northern parts of the United States, its habitats include cropland, fallow fields, areas along roadsides and railroads, gardens plots, weedy meadows, and waste areas. This plant prefers disturbed areas, and its capacity to invade higher quality natural habitats is low. ==Climate requirements==

Pennycress grows well in many different climates. It can produce seeds in the northern hemisphere during the winter season. In the US and the Mediterranean it is sown commonly in October and can be harvested in May/June. To reach its yield potential a precipitation of about 300mm is needed. Pennycress has a rather low water use efficiency needing 405 litres of water to produce 0.45kg of seeds. Limited water availability depresses the yield. In general, pennycress is not well adapted for arid environments without irrigation. ==Ecology==

Field pennycress is a weed of cultivated land and wasteland. The addition of pennycress to a corn rotation also increased and stabilized ground beetle diversity more effectively than a mustard (Sinapis alba)–corn rotation, a green fallow–corn rotation, or a bare fallow–corn rotation. This was mainly due to the evenness of plant cover throughout the growing season. Therefore, Bioenergy from double-cropped pennycress may support ground beetle diversity. Fall establishment can provide early spring ground cover and suppress aggressive spring germinating weeds such as common lambsquarters (Chenopodium album), giant ragweed (Ambrosia trifida), and tall waterhemp (Amaranthus tuberculatus). Johnson et al. (2015) speculated that weed suppression may have been caused by allelopathic compounds rather than ground cover when pennycress seeding rates and companion crops were taken into account. ==Agronomy==

Seeding Current studies suggest a seeding rate of 1500 seeds per meter square for Europe while 672 seeds per meter square is suggested for the US. This variability is due to different climates. Integration in soy maize crop rotations In the mid east of the US a common crop rotation is Soybean and Maize. After harvest the fields are kept as fallows. Pennycress appears to be especially well suited for oil production when cultivated before soybean. As a cover crop grown over the winter period with harvest taking place in spring, it can effectively reduce soil erosion, prevent nutrient leaching, improve soil structure and increase biodiversity. ==Uses==

Oil The first attempts to grow pennycress as an oil crop took place in 1994. However, since 2002 it is more and more considered as a potential oil crop rather than a "noxious weed". Oils with high erucic acid are especially suitable for jet fuel production. Oil characteristics are highly influenced by specific environmental conditions such as precipitation. Use as a source of biodiesel Pennycress is being developed as an oilseed crop for production of renewable fuels. The species can be planted in the fall, will germinate and form a vegetative mass which can overwinter. In the spring, the oil-rich seed can be harvested and used as a biodiesel feedstock. ==Research==

Pennycress is related to the model plant species Arabidopsis thaliana. Researchers have begun studying the genetics of pennycress in order to improve its potential use as a biofuel crop. For example, the transcriptome of pennycress has been sequenced. ==References==