Evaluation plant properties and chemical composition of Lathyrus rotundifolius

In order to investigate plant properties and forage value of lathyrus rotundifolius, this research was conducted in Namin rangeland. Persian everlasting pea is belong to legume family and it is a wild plant that grow at Heyran and Fandoghlo region. Based on local residents experience, they consider the forage of this plant as one of the best forage and collect it for livestock consumption. This plant is also doubly important with the biological stabilization of nitrogen, improving soil fertility, high leaf-to-stem ratio and high forage value. Due to the fact that farmers do not have enough forage, so recognizing local forage plants with high forage value and using them can play an important role in providing forage and production sustainability.

Sampling was performed to evaluation of forage properties at three growth stage including before flowering, flowering and after flowering stages. The study area is located at latitude 38.40 degrees east and longitude 48.55 degrees north (cold and humid climate). The average annual rainfall in the region is 369 mm and the average annual temperature in the region is 9.63 ° C. The area soil is brown and relatively acidic. Traits such as plant height, vegetative growth period, flowering time and ripening time were evaluated. Chemical compositions of the collected samples include dry matter, organic matter, total carbohydrates, neutral detergent insoluble fibers, acid detergent insoluble fibers, cellulose, hemicellulose, lignin, crude protein, crude fat (ether extract), crude ash, Nitrogen and minerals such as iron, copper, zinc, manganese, phosphorus, potassium were also measured.

Results showed that the highest amount of organic matter, crude protein, crude fat, nitrogen, phosphorus and copper were obtained in the early flowering stage. The quality of forage in the post-flowering stage (early seedling) was significantly reduced. And the amounts of insoluble fibers, cellulose, hemicellulose and lignin increased. The percent of organic matter decreased with increasing age of the plant, so that its amount decreased from 94.4% at the beginning of flowering to 91.8% at the beginning of seeding. The amount of total carbohydrates at the beginning of flowering was 65.7%, which increased with the age of the plant, so that its amount reached 78.6% in the early stages of seeding. Insoluble fibers in neutral and acidic detergents also increased with increasing plant age and the lowest amount was observed in early flowering and the highest amount was observed in early seeding stage. The amount of lignin also increased significantly with increasing plant age, so that its amount was 7.3% in early flowering and 12.1% in early seeding stage. The trend of changes in crude protein and crude fat in forage composition was similar and decreased with increasing plant age. Crude fat decreased with increasing plant age. So that its amount decreased from 5.2% at the beginning of flowering to 2.5% at the beginning of seeding stage, but the amount of raw ash increased with the age of the plant and its amount increased from 5.6% at the beginning of flowering to 8.2% increased in early in seeding stage.

The decrease in forage fat can be attributed to the re-transfer (remobilization) of assimilates to the seeds and the increase in ash percentage can be attributed to the accumulation of elements in the shoots. Therefore, with the increase of crude ash, the percentage of dry matter, total carbohydrates, insoluble fibers, cellulose, hemicellulose, lignin, manganese, and zinc increased. Results showed that wild lathyrus is desirable as forage crop and it can be used as desirable forage crop.