The research objective was to establish the efficiency of application of direct seeding of annual herbs by sowing “Ob-4” unit in comparison to their sowing with a row seeder SZP-3.6 over winter plowing after pre-sowing cultivation and harrowing. The studies were conducted in 2015-2017 in experimental field of JSC “Sibirskaya Niva” in Irkutsk Region on typical gray forest heavy-loamy soil in grain- grass rotation with full fallow: full fallow (pea-oat) - spring wheat - spring wheat. Under pea-oats after wheat five variants of spring soil tillage on two backgrounds of fertiliz- ers were studied. It was stated that spring plowing to the depth 20-22 cm led to the loss of moisture from the whole cultivated layer 0-20 cm and made moisture reserves at critical level. In pre-sowing period the techniques of fine spring tillage to the depth 8-10 cm affected, mainly, the extent of humidification in surface layer 0-5 cm. The tillage with a cultivator KPE-3,8 and direct seeding with “Ob-4” made the least drying effect on sowing layer 0-10 cm in comparison to the disc header BDM-4, discountmevacor “Smaragd” and, especially, with spring plowing. The use of combined soil-cultivating seeder “Ob-4”, as well as heavy cultivator KPE-3.8 to the depth 8-10 cm in the unit with harrows and sowing with the seeder SZP-3.6 in the course of spring basic soil tillage and sowing was economically more beneficial than traditional spring plowing to the depth 20-22 cm under pea-oats sowing. The application of mineral fertilizers due to their high price significantly reduced economic efficiency of pea-oat. However, irre-spective to the techniques of soil tillage and seeding, it remains profitable.