The effect of sulfur dose and application times on the seed quality of grass pea (Lathyrus sativus L.)

In this study, the effect of sulfur (S) dosses and application time, before and at the same time with sowing on the chemical content of grass pea seeds during the vegetation period of 2018 under Yozgat-Sorgun conditions. As plant material "Gurbuz 2001" variety of grass pea was used and, sulfur was applied at two different times before sowing (in autumn) and at the same time with sowing (in spring) in six doses (0, 25, 50, 75, 100 and 125 kg /da). The experiment was arranged according to the split plot design with three replications. Application times were at the main plots, and sulfur doses at the sub-plots. In the study, protein, mineral matter (P, K, Ca, Mg, Na, B, Cr, Co, Mn, Cu, Fe, Zn, Se, Mo and S) and toxic ODAP (N-oxalyl-L-alpha beta-diaminopropionic acid) contents of grass pea seeds were investigated. Generally, application time of S on the properties examined was more effective than the doses and, S given before sowing significantly increased the amount of mineral matter and protein content and decreased the ODAP content, as desired, compared to the control. According to this, over the dosses, avarage values of the investigated traits were as folows; K 1.59 - 1.40%, P 0.66 - 0.55%, Ca 0.38 - 0.28%, Mg 0.21 - 0.17%, Na 0.08-0.08%, Bo 25.66 - 23.94 ppm, Cr 1.96 - 1.00 ppm, Co 0.44 - 0.28 ppm, Mn 44.70 - 40.70 ppm, Cu 15.23 - 11.89 ppm, Fe 327.11 - 257.89 ppm, Zn 88.16 - 70.169 ppm, Se 0.06 - 0.05 ppm, Mo 6.57 - 2.98 ppm and S 3538.53 -3135.31 ppm, respectively between aplication times of S (pre-sowing and with sowing). Similarly, protein content of seeds varied between 26.72 - 26.03% and ODAP content ranged from 4.81 to 5.20 mg g-1. As a result, it has been observed that the mineral matter and protein content in the grass pea seed can be increased and the ODAP content can be reduced by S application in the experimental conditions. In order to achieve this effect, it was determined that sulfur application before autumn would have better results, 75 kg / da S is sufficient in terms of mineral matter and the dose can be increased up to 125 g / da in terms of protein and ODAP content. It was also determined that S is not very effective when it was given at the same time with sowing and even can be leads to negative results.