Effect of Nitrogen and Potassium on Growth, Yield, and Seed Quality of Quinoa in Ferralsols and Acrisols under Rainfed Conditions

Abstract

The study has investigated the individual and combined effects of nitrogen and potassium on the growth, grain yield, and quality of quinoa in ferralsols and acrisols. The experiments were conducted during the dry season under rainfed conditions in Central Highland, Vietnam. The factorial design was a randomized complete block design with three replications. The results revealed the positive impacts of nitrogen and potassium on the growth and yield of quinoa. However, after the application of an optimum dose of nitrogen, growth, and yield were not significantly changed and even decreased when the dose continued increasing. Higher levels of nitrogen and potassium application resulted in greater protein and fat content, but lower starch and fiber contents, compared to lower levels. The fertilizer practice has to rely on soil fertility. The study shows that the application of 150 kg N and 105 kg K 2 O ha -1 could be the optimum rate of nitrogen and potassium for quinoa production in ferralsols and acrisols in Central Highland.

Enhancement of Quinoa Grain Yield and Nutritional Quality by Potassium Fertilization Combined with Foliar Spraying of Seaweed Extract

“…They illustrated that potassium not only affected yield but also improved the nutritional profile and chemical composition, which in turn reflected on the quality. In addition, potassium led to an increase in yield and protein and fat contents but decreased fiber and starch contents in quinoa grains (Minh et al, 2022).…”

“…Moreover, Petropoulos et al (2022) showed that using 100 or 75% of the recommended potassium fertilizer dose recorded the best values for yield, quality parameters and chemical compositions of globe artichokes, without significant differences between them. However, Minh et al (2022) showed that the optimum rate of potassium for quinoa grain yield was found to be 105 kg K 2 O/ha which resulted in higher protein and fat contents but lower starch and fiber contents in grains. Furthermore, Kubar et al (2019) found that application of potassium at 100 kg K 2 O/ha markedly increased the yield attributes as well as N, P and K contents in wheat grains.…”

Effect of Some Fertilizer Combinations of Nitrogen, Phosphorus and Potassium on Some Qualitative Characteristics of Quinoa in Seed

“…As for the effect of the interaction between nitrogen and potassium on the proportion of protein, its effect was significant, as it reached a highest value of 12.88% at moderate levels N1K3, while increasing nitrogen levels and decreasing potassium levels led to a decrease in protein content as it gave the lowest value of 10.11% at the level of fertilizer N2K2, and the reason for this is that potassium participates in a number of steps involved in the formation of protein [28] and for this reason, changes in nitrogen and protein formation in plants depend on their content of potassium [29]. To what was mentioned in his study by [16] that high levels of application of N and K led to an increase in protein and oil content, but lower content of starch and charcoal, compared to lower levels.…”

“…These results are consistent with the correlation coefficient, as it reached a weak positive correlation, r = 0.08. [16] mentioned that the percentage of protein was 21.8% when applying the fertilizer recommendation of 150 kg K h -1 18.0%, 19.4%, and 20.9 % when adding fertilizer recommendations of 60, 90 and 120 kg h -1 . These results agree with what was reached by [27] that a decrease in potassium level led to a decrease in protein synthesis, which is reflected in the accumulation of decarboxylated amino acids.…”

“…60:50:40 and 19.65% for the combination 90:75:60 and 22.55% for the combination 120:100:80 and 21.35% for the combination 150:125:100 and 20.75% for the combination 180:150:120. Also, [16] found that the application of N and K was significant for the protein content in both sites, and the best values resulted from the combinations of K at a rate of 105 kg h -1 with higher application rates of nitrogen, and that potassium is absorbed from the soil in the form of potassium ion K + and leads to It plays many roles, including activating more than 60 enzymes. Therefore, it plays a vital role in the synthesis of carbohydrates and proteins.…”