Seeding rate of 115K vs 145K in the Low Yield Zone

This experimental field was in Lincoln County, South Dakota. Soybeans variety s28t3xf was planted in 30-inch rows in strips on May 25, 2021. The purpose of this experiment is to compare two different seeding rates. The soybean was harvested in 30 feet wide strips having two different seeding rates of 115K and 145K seeding rates. This experiment had 4 replications for each seeding rate. Soybeans were harvested on October 9,2021. For analysis purposes, the field was classified into three different yield zones: low yield zones (less than 35 bu/ac), mid yield zones (35-55 bu/ac), and high yield zones (more than 55 bu/ac). This analysis considers low yield zone.

Overall, there was no significant difference in yield comparing the two seeding rates at low yielding zone which means lowering the seeding rate from 145K to 115K did not reduce yield significantly (Figure 1 & Table 1). Out of 4 replications, 2 replications observed greater yield in 145k seeding rate whereas the remaining two observed greater yield in 115K seeding rates. On average reducing seeding rate to 115K seeding rate decreased yield by 4.54 bu/ac which was greater reduction in yield compared to medium yield zone. We have found similar results in multiple locations. Therefore, this implies that lowering the seeding rate may produce the same yield along with reducing the total input cost to farmers considering management zone, weather, and environmental factors. More research at multiple sites with more replications is required to better explain the contrast between two different treatments in different environmental conditions.