Determination of effects of different nitrogen doses and deficit irrigations on yield and quality of silage sorghum (Sorghum bicolor L.)

This study was conducted to determine the effects of water levels and nitrogen applications on the yield and quality of sorghum (Sorghum bicolor L.) silage at the Isparta University of Applied Sciences, Education, Faculty of Agriculture, Research, and Application Farm during 2021-22. The Greengo variety was used in the study. For sorghum irrigated using a sub-surface drip irrigation system, six different water levels (I0, I25, I50, I75, I100, and I125) and five different nitrogen doses (N0, N8, N16, N24, and N32) were applied. The experiment was conducted in a split-plot design with three replications, within randomized complete block trials. The study examined yield response factor (ky), plant water consumption, WUE, IWUE, plant height, number of leaf, stem thickness, leaf/stem ratio, green herbage yield, dry matter ratio, hay yield, crude protein ratio, crude protein yield, NDF, ADF, crude ash, phosphorus, potassium, calcium, magnesium, chlorophyll content, and stomatal conductance. In the silage samples, pH, dry matter ratio, crude protein ratio, NDF, ADF, crude ash, phosphorus, potassium, calcium, and magnesium ratios were determined. As a result of the research, both irrigation levels and nitrogen doses statistically significantly affected all the examined traits. The yield response factor (ky) ranged from 0.805 to 1.479, plant water consumption from 387.5 to 808.3 mm, plant height from 185.0 to 327.7 cm, green herbage yield from 2929 to 11476 kg/da, crude protein ratio from 5.57% to 7.33%, NDF from 45.37% to 59.93%, and ADF from 24.26% to 36.14%. In the silage samples, pH values ranged from 3.99 to 4.39, crude protein ratio from 5.47% to 7.59%, NDF from 41.29% to 54.06%, and ADF from 21.77% to 33.59%. Considering all the results obtained from the study, that applying 16 and 24 kg/da nitrogen with I100 irrigation was the most effective for high yield and quality in silage sorghum under Isparta and similar conditions.