Compost and Humic Acid Mitigate the Salinity Stress on Quinoa (Chenopodium quinoa Willd L.) and Improve Some Sandy Soil Properties

Enrichment of sandy soils with compost and humic acid amendments could increase the contents of nutrient availability, improve soil chemical characteristics and enhance quinoa plants growth and alleviating the hazardous effect of saline irrigation water. In the current study, compost (CT) and humc acid (HA) were used to reduce the negative effects of saline water on quinoa growth. The pots experiment treatments were as follows: CF = chemical fertilizer, CT1 = 1% compost, CT3 = 3% compost, HA1 = 1% humic acid, and HA3 = 3% humic acid of soil weight. Quinoa plants are grown on a sandy soil and irrigated with saline water (EC = 10 dS m −1 ). The results showed that Ct and HA amendments had significant effects on the soil salinity, pH, soil organic matter (SOM), nutrient availability, and plant uptake. The SOC of the soil was increased with increasing the application rates of the CT and HA amendments. The CT3 and HA3 application rates increased the SOM by 1.8 and 3.8, respectively, above the CF treatment. The application of CT and HA with different application rates increased the N, P, and K availability significantly as compared to the CF. The application of the CT and HA amendments increased the N, P, and K uptake significantly as compared to the CF as control. The application of CT significantly increased the plant height, dry matter, and fresh weight of quinoa plants compared to the control. Based on the obtained results, the application of CT and HA improves the sandy soil fertility and alleviates the negative effects of saline irrigation water on quinoa plants grown on sandy soil.