Investigating the effect of different levels of irrigation and vermicomposting on yield and element concentration of quinoa seed (Chenopodium quinoa Willd.)

Quinoa (Chenopodium quinoa Willd) is a member of Amaranthaceae family. This plant is annual and has seeds with high nutritional value. Quinoa seeds contain a high percentage of protein and essential amino acids, which are low in other plants. Using high-efficiency irrigation systems such as drip irrigation system, increasing water productivity and modifying the cultivation pattern and using alternative low-consumption plants are among the effective solutions for saving water consumption and sustainable development in the agricultural sector. The use of vermicompost, which is obtained as a result of the continuous and slow passage of organic materials through the digestive system of surface earthworm species and the removal of these materials from the worm's body, is a sustainable solution to maintain production and improve fertility. The soil is especially in arid and semi-arid areas that face a lack of soil organic matter.

This experiment was conducted as a split plot based on randomized complete block design in the research farm of University of Kurdistan located in Dehgolan in 1400. The experimental factors included 4 levels of irrigation equal to 50, 75, 100 and 125% of the water requirement of the quinoa plant were assigned to main plots and 4 levels of vermicompost fertilizer equal to zero, 5, 10 and 15 tons per hectare were assigned to sub plots. The irrigation method used in this experiment was drip-strip irrigation system. In this study, the irrigation cycle was considered constant and equal to seven days. The distance between irrigation strips in each plot was equal to 50 cm. The amount of irrigation water was measured by a volumetric meter installed on the main pipe. At the end of the growth period, by removing the marginal effect of two square meters from each plot, the aerial parts were harvested in order to obtain the seed yield. Nutrient elements in quinoa seeds include nitrogen by Kjeldahl titration method, phosphorus, potassium by flame diffusion method and with the help of film-photometer device, sodium and calcium and micronutrient elements such as zinc, iron, copper and manganese by absorption device. atomic, were measured.

The results of analysis of variance obtained from the data of this research showed that the interaction effect of different levels of irrigation × vermicompost on grain yield traits, concentration of nitrogen, calcium, zinc and iron elements was significant. However, the concentration of phosphorus, potassium and magnesium elements under the influence of independent effects of different levels of irrigation and vermicompost became significant at the probability level of 1%. The concentration of sodium and copper elements were significant only under the influence of different irrigation levels. The results showed that the highest grain yield (2374.51 kg.ha-1), zinc concentration (20.22 mg.kg-1) and iron concentration (400.92 mg.kg-1) in The treatment was 125% of plant water requirement and 15 tons of vermi-compost per hectare. Also, the highest concentration of elements phosphorus (0.35%), potassium (4.31%) and copper (4.63 mg.kg-1) was observed in the treatment of 125% of plant water requirement. The highest concentration of nitrogen (2.6%), sodium (1.37%) and manganese (55.61 mg.kg-1) of quinoa seeds was observed in the treatment of 50% of plant water requirement.

The results of the present experiment showed that the application of different levels of vermicompost increases the concentration of elements in quinoa seeds. Due to the fact that vermicompost-containing substrates have a high percentage of nutrients and the release of these elements is gradual, therefore plant nutrition is more efficient and the result is an increase in the concentration of seed elements. On the other hand, due to the positive effects of vermi-compost in improving the physical and chemical properties of the soil and increasing the maintenance of soil moisture at stress levels, it increases the concentration of quinoa seed elements compared to the treatment without the use of vermi-compost.