The effect of some organic and mineral amendments on soil macronutrient and micronutrient under Quinoa cultivation in stress status (water)

In drought stress, in addition to inhibiting water uptake, the availability and uptake of various nutrients is also limited. Proper soil nutrition through the use of organic and inorganic modifiers is known as one of the soil management methods under various environmental stresses.the main objective of this research is to test the performance of concurrent application of amendents in field under qinoa.

In order to investigate the changes in the concentration of nutrients (phosphorus, potassium, copper, iron, manganese, zinc) in soil by application of organic amendments (rice straw biochar, municipal waste compost) and mineral amendments (bentonite and zeolite) under drought stress, a factorial experiment was conducted based on randomized complete block design with three replications in research greenhouse of faculty of agricultural, University of Tarbiat Modares in 2019. Organic amendments (biochar, compost) in 2 levels (0.4 and 0.8%) and mineral amendments (bentonite and zeolite) in 2 levels (0.75 aand 1.5%) were used and drought stress in 4 levels (discharge of 25 % available water (control), 40%, 55% and 70% (servere stress) was applied to the soil, which was a total of 108 pots. Soil sampling was done in three stages four-leaf stage, flowering and harvesting of quinoa.

The results showed that organic and mineral amendments under different levels of drought affected significantly on the P concentration (in four-leaf stage and flowering stage), K (in each three stages), Cu (in each three stages), Fe in four-leaf stage and available Zn in four-leaf stage and flowering stages of quinoa. With increasing drought levels, Application of organic and mineral amendments increased P, K, Cu, Fe, Mn and Zn in all three sampling stages .While the concentration of these elements in the first stage of sampling (four-leaf stage) was more than others.

The results showed that the application of four soil amendments increased the concentration of macro and micronutrient compared to control in drought stress status , but municipal waste compost at 0.8% level and then biochar at 0.8% level could provide the most suitable nutritional conditions in loam soil. Therefore, according to the results obtained in this experiment, Based on the findings of this study, in drought stress conditions, the use of municipal waste compost and biochar compared to zeolite and bentonite is recommended to improve soil nutritional status.Key words: Biochar, Bentonite, Drought Stress, Zeolite, Compost.