The effects of potassium on uptake and allocation of nitrogen on lentil under dry land condition.

According to the alkaline soils and high values of soil pH in Iran specially in Ardabil region, nitrogen uptake and availability for protein crop plants such as lentil is highly restricted in rain-fed cultures. Factors with positive (significant) effects on uptake and transfer of nitrogen can solve difficulties of nitrogen deficit to raise seed yield and protein in lentil crop. So, a factorial experiment based on randomized complete block design with three replications was conducted in Ardabil research center for agriculture and natural resources, Ardabil, Iran in 2008 to investigate effect of potassium on uptake, transfer and allocation of nitrogen to the seed of lentil cultivars. Factors included 0, 30 and 60 kg ha-1 potassium and 0, 25 and 50 kg ha-1 nitrogen. The third factor included local and ILL1180 cultivar. Results showed that by application of 60 kg ha-1 potassium was obtained the highest seed nitrogen percent, seed protein percent (27.68 percent) and aerial part nitrogen percent. In terms of phonological traits, aspects of time to 50% emergency, reproductive stage, time to 50% flowering and date of maturity as affected by 50 kg ha-1 nitrogen was highly increased than other nitrogen levels. maturity period length is increased, traits such as number of lateral stems, number of full pods, number of single-seeds pods, number of total pods, and number of seed per plant were placed in the superior group and the highest seed yield (1465.06 kg/ha) by using 50 kg ha-1 N fertilizer was resulted. Such a trend was observed for seed nitrogen percent, seed nitrogen uptake, seed protein percent, seed protein yield, aerial part nitrogen percent, nitrogen uptake by whole plant and seed potassium uptake was found in this level. In main cultivar effect, local cultivar was superior in plant height, number of single-seeds pods 100-seed weight, seed potassium percent and seed potassium uptake than ILL1180 but ILL1180 cultivar had the higher lateral branches, filled pods, seeds per plant and aerial part potassium percent then local cultivar. The interaction effect of cultivar×potassium and cultivar×nitrogen, the highest percent and uptake (yield) of nitrogen and seed protein was obtained by application of 60 kg ha-1 potassium and 50 kg ha-1 nitrogen on local cultivar which showed significant difference than control (without nitrogen and potassium application). By considering the interaction effect of potassium×nitrogen, percent and uptake of nitrogen and seed protein was placed in a group using 60 kg ha-1 potassium and 50 kg ha-1 nitrogen and potassium usage in nitrogen treatment combinations (25 and 50 kg ha-1) led to the increase in nitrogen percent and seed protein but potassium application at 50 kg ha-1 nitrogen level significantly increased nitrogen uptake and seed protein yield and this is because of uptake, transfer and allocation of nitrogen to the seeds in higher potassium rates. The interaction effect of cultivar×nitrogen, the highest nitrogen uptake of plant aerial parts and total plant nitrogen content was obtained using 50 kg ha-1 nitrogen on local cultivar. Also, percent and nitrogen uptake of aerial parts and total nitrogen content was increased by using 60 kg ha-1 potassium and 50 kg ha-1 nitrogen. Finally it was cleared that potassium application plays an important role in uptake, transfer and allocation of nitrogen to the seed.