Investigating the combined effect of organic and chemical fertilizers on quantitative and qualitative yield of Quinoa (Chenopodium quinoa) under drought stress

Modification to withstand drought stress has always faced its own bottlenecks, therefore, in the first stage, cultivating drought-resistant plants such as quinoa is the best way to prevent of reduce in crop yields. Quinoa with a scientific name (Chenopodium quinoa) is a dicotyledonous plant and belongs the subfamily (chenopodiaceae). There is saponin in all parts of quinoa, including leaves, flowers, fruits, seeds, and seeds coat (Bhargava and Srivastava, 2013). Also is used as an antibiotic, fungal disinfectant and in the pharmaceutical industry (Dini et al, 2001).Potassium have an important role in quality, plant tolerance to various environmental stresses, elements displacement, equilibrium, biochemical and physiological processes including photosynthesis, protein formation and opening and closing of pores and formation of vessels. The use of livestock and poultry manures is important in soil management and sustainability and improves the physical, chemical and microbial properties of the soil. The present study was conducted to investigate the effect of livestock and chemical fertilizers on the quantitative and qualitative characteristics of quinoa under drought stress.

This experiment was conducted in the form of split-split plot in a randomized complete block design with three replications.in the field of research of the Agricultural Research Institute of Zabol University In year of 2019-2020 In this experiment, drought stress was the main plot, cow manure as a sub-plot and potassium fertilizer as a sub-sub plot. The measured traits included: number of spikes, 1000-seed weight, grain yield, biological yield, harvest index, proline, carbohydrate and protein. Protein was measured by Bradford (1976). Proline was measured using the method (Bates, 1973) as follows.

The results showed that the simple, double and triple effects of drought stress, cow manure and potassium fertilizer were significant different at the level of 1% probability on 1000-grain weight and grain yield. The highest 1000-grain weight and grain yield were obtained when using full irrigation treatment. The simple, double and triple effects of drought stress, cow manure and potassium fertilizer were significant different at the level of 1% probability on Carbohydrates and grain protein. Also, the highest amount of grain protein was obtained in the application of 20 t ha-1 of manure and no potassium fertilizer in the stage of grain filling and the highest amount of leaf carbohydrates in the treatment of 10 tons of manure and 200 kg.ha-1 of potassium in the cessation stage of irrigation in the flowering stage. The results also showed that the highest of grain yield was obtained when using 10 t.ha-1 of manure and 200 kg.ha-1 of potassium fertilizer during full irrigation.

The results showed that the combined application of manure cow and potassium in full irrigation conditions improved the quantitative and qualitative characteristics of quinoa. The triple effects of drought stress× manure× potassium increased grain yield, 1000-grain weight, harvest index, proline, protein and carbohydrates. The highest grain yield was obtained in the simultaneous use of cow manure and potassium fertilizer in the complete irrigation stage. In fact, the using of manure in addition to retaining moisture under conditions of severe stress increases the absorption of essential elements and plant growth, and the absorption of elements such as nitrogen, increases the growth of aerial parts of the plant and stores more nutrients in these areas for re-transfer during seeds ripen. On the other hand, due to its positive effect on maintaining moisture in the plant and increasing the duration of photosynthesis due to the continuity of leaf area in the reproductive stage, potassium consumption can provide more nutrients to more flowers and thus increase yield. It becomes a plant. Under stress conditions, the amount of carbohydrates and proteins increased, which is due to plant adaptation.