The present study was carried out on black gram in at the research division of Urmia University in the 2017 crop year. This farm is located at the latitude of 37° 39′ N and the longitude of 44° 58′ E and at an altitude of 1,365 m above the sea level in northwestern Iran21. The climate in Urmia city is semi-arid and cold semi-arid, according to the Embereger and De Martonne Methods. Important growth stages of black gram as well as other operations are presented in Table Table1.1. The dimensions of the plots were 3 m × 2 m and the distance between the plots was 2 m. In the next step, seedlings of black gram were planted on rows 50 cm apart and on rows 10 cm apart. Soil samples were also taken to determine soil physical properties (Table (Table22).

Agronomic details and dates for field experiment.

Planting population


Fertilization date of macro elements

(N, P, K)

Physical properties of the experimental soil.

Clay (< 0.002 mm), silt (0.002–0.05 mm), sand (0.05–2 mm) (USDA classification). FC: field capacity; PWP: permanent wilting point; BD: bulk density.