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In the years 1991 to 1993 a field stationary trial was conducted on Chernozem soils (in maize-growing region) to study the effect of some intensification factors (conventional and protective soil cultivation, fertilization and nutrition) on the grain yield and 1 000-kernel weight of pea of intermediary type. Pea was cultivated in six-plot crop rotation: winter wheat, spring barley, pea, winter wheat, silage maize, spring barley.

Treatments of fertilization and nutrition: B1 - 0 (without NPK); B2 - NPK 15 : 20: 48; after winter wheat to forecrop spring barley wheat straw was incorporated into the soil; B3 - NPK 15 : 40 : 96.

Soil cultivation: C1 - conventional - stubble ploughing, tillage by plough with mouldboard (0.18 to 0.20 m), in the spring smoothing + medium-heavy nail harrow, preseeding soil cultivation by combine cultivator; C2 - protective - stubble ploughing, soil cultivation in the fall with cultivator having passive working elements (Lemken-Smaragd 80/300) to a depth of 0.14 to 0.16 m, preseeding soil preparation by machine with active-driven working elements (combined rotary) cultivator Amazone in single operation with the sower Amazone.

Six basic treatments (combinations) occurred by combination of three treatments of fertilization and two treatments of soil cultivation. The trial was established by a block method in four replications. The Janus variety (intermediary type) was used with a sowing rate of 120 germinative grains per 1 m2.

In view of suitability of weather for pea cultivation the best was the year 1992. The vegetation period in 1991 was below normal regarding precipitation. The year 1993 was extremely arid (in the vegetation period of the pea).

The field emergence rate of pea according to the years was 73; 76; and 71% and was most affected by weather. Average pea yield (according to the years) was 3.60; 4.49; and 2.91 t.ha-1, on an average for three years of the trial it was 3.67 t.ha-1. The yield was statistically significantly influenced by fertilization and weather (highly significantly). The 1000-kernel weight was higher by 2.25% (significantly) in protective soil cultivation compared with the conventional system. There was a strong (positive) highly significant dependence (r = 0.999+++) between the pea yield and precipitation for May and first two June decades. Fertilization with wheat straw to forecrop (spring barley) and reduction of PK dose by 50% (compared with B3) decreased the pea grain yield by 6% (significantly) compared with the control and by 12.9% (highly significantly) compared with full fertilization (treatment B3).