Using of Soybean Inoculation Spraying System in Pneumatic Row Crop Planter

Soybean cultivation has an important among oilseeds due to the biological fixation of nitrogen by creating symbiosis with rhizobium bacteria. It is one of the important plants as sources of protein and oil supply. In the traditional methods, seed impregnation is done manually, which increases energy consumption and labor costs, and wastes the time between seed impregnation and planting. In hot regions, by time waste also most rhizobium-producing bacteria might be lost. In this research, a system for direct spraying of inoculum solution on a four-row pneumatic crop planter (8 lines) was designed and constructed and evaluated in laboratory conditions. The experiments were in the form of a randomized complete block design and in factorial form. Two factors were forward speed (with three levels of 3.6, 5.2 and 7.2 km/h) and nozzle flow rate (with three levels of 200, 300 and 400 ml/min) in three replications. The results showed that the average seed coverage percentage was 88.11%; the forward speeds of 3.6 and 5.2 km/h with 89.7% and 88.7% were preferable to the forward speed of 7.2 km/h with a coverage percentage of 84.8 percent. The output flow rate of the nozzles did not show a significant difference on the percentage of unplanted and few planted seeds. However, the effect of forward speeds of 7.2 and 5.2 compared to 3.6 km/h increased these percentages. Uniformity of seed planting at two speeds of 3.6 and 5.2 km/h, did not show a statistically significant difference with 90.9 and 88.5%, respectively, but with 7.2 km/h was significant at the level of 5%. In general, with increasing forward speed, the uniformity of seed planting was decreased. Therefore, the use of a pneumatic row crop planter equipped with an inoculum spraying system was recommended due to the reduction in the percentage of no-planting and low multiple plantings, and also proper coverage of the inoculum and uniformity of spraying.