Effect Of Combined Application Of Nitrogen Fertilizer And Humic Acid On Growth,Yield And Nitrogen Fertilizer Utilization Of Quinoa

Quinoa,as a new food crop,is considered as one of the most potential crops in the future because of its rich nutritional value.Quinoa is also often planted in barren soil because of its good stress resistance.Quinoa is suitable for growth in the "nitrogen-deficient,phosphorus-deficient" soil environment of Shanxi Province.Although quinoa is tolerant to barrenness,it does not like barrenness.In order to pursue crop yields,a large number of nitrogen fertilizers are applied to cause soil hardening,waste of resources and environmental pollution,and organic humic acid can promote crop growth,improve the utilization rate of nitrogen fertilizer and increase crop yields.Therefore,it is of great theoretical and practical significance to study the ratio of nitrogen fertilizer and humic acid in agriculture.Therefore,the experiments were carried out with different nitrogen levels(N0,N1,N2,N3,0,0.05,0.1,0.2g/kg)and different humic acid levels(H0,H,0 g/kg,1g/kg),The effect on the morphological and physiological indices,yield,yield components and nitrogen use efficiency of quinoa were sthdied,in order to select the best fertilizer combination for quinoa planted in poor soil of Shanxi Province.The main results are as follows:1.Single application of nitrogen fertilizer and combined application of nitrogen fertilizer and humic acid could obviously promote the growth of above-ground and underground parts of quinoa.With the increase of nitrogen fertilizer,the plant height,stem diameter,leaf area,biomass and the main root length,root dry weight,root diameter,root volume and root surface area of underground growth part of quinoa showed a trend of increasing first and then decreasing.Compared with single application of nitrogen fertilizer,nitrogen fertilizer showed a trend of decreasing later.The combination of fertilizer and humic acid had more significant effect on the growth of quinoa,and the combination of N2 and humic acid was the best.2.Compared with nitrogen fertilizer or humic acid alone,The proline,malondialdehyde,soluble sugar and relative conductivity of quinoa leaves decreased significantly,while the activities of soluble protein,peroxidase,superoxide dismutase,catalase,nitrate reductase,root activity and chlorophyll content increased significantly.The results showed that the osmotic adjustment of quinoa growth,protective enzyme system,root growth and accumulation of photosynthetic products in leaves were improved by combined application of nitrogen fertilizer and humic acid.And compared with the treatment of low nitrogen and high nitrogen,the physiological index of medium nitrogen + humic acid is better in the treatment combination of nitrogen fertilizer and humic acid.3.The 1000-grain weight and spikelet number per plant of the treatments with N and humic acid application were higher than those of the treatments with different N application levels.The increase of grain weight per plant with humic acid application in medium N application was 10.47% higher than that of the best treatment with N application alone.4.The rusults showed that humic acid could obviously promote Agronomic N use efficiency?Partial factor productivity of N fertilizer and Nitrogen contribution efficiency,the effect of medium nitrogen(N2)combined with humic acid treatment was the best,which could maximize the absorption of nitrogen fertilizer by quinoa and significantly improve the utilization efficiency of nitrogen fertilizer.5.The combined application of nitrogen fertilizer and humic acid can increase the amount of organic matter,alkali-hydrolyzed nitrogen,available phosphorus and available potassium in soil,and effectively regulate the pH value of soil.The results showed that the effects on soil fertility were as follows: N fertilizer combined with humic acid > N fertilizer alone > humic acid alone > no N fertilizer(control)in all treatments of single and combined fertilization;the effect of humic acid(N2H)combined with medium nitrogen was the best in the different combinations of nitrogen fertilizer and humic acid.The content of organic matter,alkali-hydrolyzed nitrogen,available phosphorus and available potassium in N2 H combination was significantly higher than that in pre-test soil.The application of humic acid could regulate the neutral value of PH value in soil,which was beneficial to quinoa growth.