دور السماد العضوي و الحيوي والنتروجيني في بعض مؤشرات النمو والحاصل والنوعية لنبات السبانخ

The role of organic, biological and nitrogen fertilizers in some indicators of growth, yield and quality of spinach plant Spinacea oleracea L

Abstract
The experiment was conducted in the vegetable field of the Department of Horticulture and Landscape Engineering /College of Agriculture / University of Karbala in the district of Al-Husayniyya of the Holy Karbala Governorate during the fall season 2021-2022 to study the role of organic, biological and nitrogen fertilizers in the growth and yield indicators of spinach plant Viroflay variety, to study the effect of two factors, the first of which is six combinations. Fertilizer from organic and bio-fertilizers as follows without organic and bio-fertilization and its symbol is (T1) and bio-fertilizer consisting of Azotobacter and Azospirillum (T2) and sheep manure (T3) and poultry manure (T4) and bio-manure + sheep manure (T5) and bio-manure + poultry manure (T6) and the second factor is nitrogen fertilizer (urea) with three levels of 100% and 50% of the fertilizer recommendation and 0% of non-addition. The experiment was designed according to the split plot design within the randomized complete block design and with three replications. Nitrogen fertilizer (urea) levels for the main plots and sub plot fertilization treatments. The experiment included 54 experimental units, and the differences were compared using the Least Significant Difference (L.S.D) test at the level of with a probability of 0.05, the most important results that were reached can be summarized as follows:
1- The results of the fertilizer application (biofertilization + poultry manure) for the treatment showed a significant superiority in increasing the leaf content of nutrients (N, P, K, and Ca), plant height, number of leaves, leaf area 86.65 cm2 plant-1, dry weight of shoots 8.82 gm plant-1, and leaf content of chlorophyll. The total yield was 212.8 mg gm-1 and the total yield was 15.94ton hectare-1. The same treatment gave a decrease and a significant effect in the leaves content of nitrates and oxalates amounting to 90.22 mg gm-1 and 61.16 gm-1, respectively.

2- The treatment of nitrogen fertilizer (urea) N100% excelled in increasing the leaf content of nutrients (nitrogen, phosphorus, potassium and calcium), plant height, average number of leaves, leaf area 66.95 cm2 plant-1, dry weight of shoots 7.92 gm plant-1, and leaves content of total chlorophyll. 206.9 mg gm-1, with a total yield of 11.62 tons hectare-1. The treatment led to a significant reduction in the content of nitrates and oxalates amounting to 120.9 mg gm-1 and 91.18 mg gm-1, respectively.
3- The interaction treatment T6 (bio-manure + poultry manure) with 100% N of the fertilizer recommendation was superior in increasing the leaf content of nutrients (N, P, K, and Ca), and in plant height, number of leaves, and leaf area 104.0 cm2 plant-1, and the dry weight of the shoot was 10.23 gm plant-1. The leaves content of total chlorophyll was 216.0 mg gm-1, and the total yield was 16.38 tons hectare-1, while the chemical characteristics recorded a clear significant difference for the same treatment between the levels of fertilization and gave a clear decrease in nitrates and oxalates amounting to 98.73 mg gm-1 and 64.20 mg gm-1, in a row.