Species Composition and Density of Weeds in Some Spring Crops after Different Main Soil Tillage Systems. I. Sunflower | ВИДОВ СЪСТАВ И ПЛЪТНОСТ НА ПЛЕВЕЛИТЕ В ПОСЕВИ ОТ НЯКОИ ПРОЛЕТНИ КУЛТУРИ ПРИ РАЗЛИЧНИ НАЧИНИ ЗА ОСНОВНА ОБРАБОТКА НА ПОЧВАТА. I. СЛЪНЧОГЛЕД
2012
Yankov, P., Dobrudzha Agricultural Institute, General Toshevo (Bulgaria) | Klochkov, B., Dobrudzha Agricultural Institute, General Toshevo (Bulgaria)
The investigation was carried out during 2005 – 2010 in the trial field of Dobrudzha Agricultural Institute on slightly Leached Chernozem Haplic Chernozem soil type. In a stationary field trial the species composition and the density of the weeds was followed after the variants of soil tillage of sunflower given bellow: plowing at 24 – 26 cm, autumn disking and spring double disking check variant; cutting at 24 – 26 cm, autumn disking and double cultivation in spring; direct sowing or no tillage – pre-sowing treatment of the area with total herbicides. To control the weed vegetation, soil herbicides were also applied. Weeds were identified as total number per species, by sampling plots for yield estimation in eight replications, by the diagonals of the harvest plots. Reading was done in spring before pre-sowing tillage of soil and treatment with total herbicides, as well as during certain growth stages of the crop. In spring and during the early stages of the development of sunflower the number of weeds was highest in the soils subjected to intensive cultivation and lowest – after no tillage. During the summer period and in autumn, the crops were most attacked by weeds after cutting and no tillage. The number of the weed species after the reduced tillages of soil was highest in comparison to plowing.
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