Agriculture Reference
In-Depth Information
In addition pseudocereals are characterized by many health-important substances like
antioxidants - flavonoids: rutin, isovitexin, etc., flavones, phytosterols, fagopyrins and
thiamine binding proteins and prebiotic activity in buckwheat. Consumption of buckwheat
can improve diabetes, obesity, hypercholesterolemia, constipation as well as reduce blood
pressure and cellular proliferation. The most important component in amaranths is squalene,
which affected synthesis of cholesterol, possesses antisclerotic properties and may be used in
the prophylaxis against cancer (see references in Bavec and Bavec[36]. From quinoa grains
leached bitter saponins represent natural substances used in organic detergents, soaps,
shampoos, cosmetics, etc.; the high-growth cultivars of amaranth are suitable for energetic
purposes.
Among pseudocereals buckwheat is the most weed resistant crop which results from its fast
development in early growth stages and might due to allelopathy [51].
In buckwheat do not exist disease and pest infestation, which might cause economically
important damages, except emerging plants by nematodes. Also quinoa and amaranths should
not require special pest and disease control. But several species of cosmopolitan polyphagos
pests (e.g.,
Agrotis ipsilon
Hufnagel, Lepidoptera: nuctuidae) may cause economic losses. Some
of widespread pests endemic to the Andean region may cause up to 50% loss of yield in quinoa,
especially two species of moths (
Eursacca
quinoae
Povolyny,
E. melanocampta
Meyrick) [52].
Emerging plants may also be damaged by flea beatles and caterpillars. Diseases caused by
Peronospora
sp.,
Sclerotinium
sp.,
Phoma
sp.,
Botrytis
sp, and
Pseudomonas
sp. may have an
influence on yielding of quinoa. However, viruses found on spinach or beets have been
observed also in quinoa fields.
2.2. Position in rotation
Because of previously mentioned plant diseases and possible polyphagous pests which could
appear, and increase of weeds, each pseudocereal may not be planted again on the same field
for at least 3 years; 5-6 years is suggested in organic farming. A negative consequence of
incorrect buckwheat crop rotation is also increased occurrence of necrosis and the appearance
of some disease signs, especially root diseases caused by
Gaeumannomyces
sp
.
In spite of
amaranths, quinoa seeds also do not exhibit dormancy and they germinate when conditions
are suitable; the plant itself though, in wild form, may remain in soil for 2 to 3 years without
germinating.
According to different requirements about nitrogen needs in amaranths (high nitrogen
accumulative C
4
plant), recommended rest of available nitrogen (after precrop and/or addi‐
tional fertilization with organic manure) is high in comparison with buckwheat, due to lodging
in the case of high value of available nitrogen in the soil [36]. However, suitable precrops crops
are cereals, grain legumes and perennial legumes. Buckwheat appears as a very suitable
precrop for fiber flax due to its strong competitive strength against cough-grass and dicoty‐
ledonous weeds. Considering its shorter growth season can be used as stubble crop after early
harvested previous crops (early potatoes, barley, crop-legumes mixtures for green feeding).
Because amaranths and quinoa growth slowly than buckwheat during early growth stages,
the field in quinoa, and especially in amaranths, must be free of weed competition, for those
