Species Composition and Density of Weeds in Some Spring Crops after Different Main Soil Tillage Systems. II. Grain Maize and Bean | ВИДОВ СЪСТАВ И ПЛЪТНОСТ НА ПЛЕВЕЛИТЕ В ПОСЕВИ ОТ НЯКОИ ПРОЛЕТНИ КУЛТУРИ ПРИ РАЗЛИЧНИ НАЧИНИ ЗА ОСНОВНА ОБРАБОТКА НА ПОЧВАТА. II. ЦАРЕВИЦА ЗА ЗЪРНО И ФАСУЛ
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 spring crops grain maize and bean 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 and system 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 field crops. During spring and at the early stages of weeds development, the weed species composition in grain maize and bean crops was more limited after plowing as compared to cutting and no tillage. On the other hand, the density of weed plants was higher on soils with intensive cultivation and lower after direct sowing. During the summer and autumn period the growing of these two spring crops on soils with minimal tillage and no tillage lead to considerable weed attack on the crops affecting negatively crop development and yield formation, and later causing serious technological difficulties at harvesting.
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