Influence of sowing date and inter-row spacing on the yield in three soybean varieties
Georgi Georgiev • Rositsa Todorova
Soybean and Cereal Crops Experimental Station – Pavlikeni
Резюме
The effect of three sowing dates was studied: early (March 28-April 5), optimal (April 19 - April 24) and late (May 8 - May 14) and three inter-row spacing: 25 cm, 45 cm and 70 cm. The study was conducted at the Soybean and Cereal Crops Experimental Station - Pavlikeni, in the period 2018-2020 under non-irrigated conditions and without the use of herbicides. Three varieties of soybeans were used – Avigeja (Bg) - early, Isidore (Euralis) - early and Richy (Bg) - middle early, each variety being a separate experiment. In agroclimatic terms, the period covers two moderately wet (2018 and 2019) and one dry year -2020. It was found that the highest yields were obtained from the first sowing period, followed by the second period and the lowest yields were from the late sowing date in all three varieties. For the row spacing factor, the highest yield was obtained at 25 cm and 45 cm row spacing in the two medium wet years (2018 and 2019), and in the dry 2020 the yields were proven to be higher at 70 cm row spacing. A strong relationship (R2=0.88) was found between rainfall during the soybean reproductive period (R1-R7) and grain yield, which can be used to relatively accurately predict soybean yield.
