In the case of the cultivation of sunflower as a single crop, a significant decrease in yield is observed (on average by 27%) already in the fifth year. This is evidenced by the results of a study conducted in the United States, writes superagronom, citing Luis Carlos Alonso, the specialist of Syngenta company.
That is why, it is worth alternating between monocotyledonous and dicotyledonous crops, Alonso notes. And to return sunflower on the field not earlier than in 2-3 years.
For example, such recommendations the Norfolk four-field crop rotation provides.
It should not be forgotten that grains withstand short-crop rotations better than dicotyledonous crops. The yield of corn, for example, improves when returning it to the field in a year.
Meanwhile, dicotyledons, such as sunflower, flax and forage crops, show a tendency to increase yields only when they return to the field after a few years.
In addition, the cultivation of sunflower as a single crop leads to an increasingly active distribution of its inherent pests and weeds. New centers of the broomrape appear in Ukraine, Bulgaria, Spain, Russia and even in Portugal.
This parasitic plant has many mutations and, according to recent studies, can persist in the soil for up to 20 years.
In addition to this weed, sunflower in Ukraine is attacked by peronosporosis, rust, sclerotinia, macrophomina, and alternariosis.
Earlier it was reported that the massive cultivation of sunflower before wheat depleted Ukrainian black soil.