Crops questions

Hydroponics is a subset of hydroculture and is a method of growing plants using mineral nutrient solutions, in water, without soil. Terrestrial plants may be grown with their roots in the mineral nutrient solution only or in an inert medium, such as perlite or gravel.

Tobacco is easy to be recognized because of its large leaves. Production of tobacco hit its top in 1992, during which 7.5 million tons of leaf were produced. Later, it dropped to 5.7 million tons in 1997. Today, however, the production is growing due to increased productivity by developing nations. It was 7.1 million tons in 2010.

Hilling, earthing up or ridging is the technique of piling soil up around the base of a plant, which buries the normally aboveground part of the plant. Hilling promotes the desired growth of asparagus, it also prevents the production of chlorophyll, which keeps asparagus pale and delicate.

Young shoots of asparagus are covered to exclude light to prevent photosynthesis and the production of chlorophyll, and thus remain pale in color and delicate in flavor and texture. This technique is called blanching.

Lavender is grown commercially for the extraction of essential oils. It is also grown as a condiment and used in salads and dressings. There is a color named for the shade of its flowers.

Rapeseed was the third leading source of vegetable oil in the world in 2000, after soybean and oil palm. In Europe, rapeseed is primarily cultivated for animal feed. The crop is also grown as a winter-cover crop. It provides good coverage of the soil in winter, and limits nitrogen run-off.