EFFECT OF ORGANIC RESIDUES SOURCE AND NPK LEVELS ON SOME SOIL PROPERTIES AND YIELD OF SUNFLOWER (HELIANTHUS ANNUUS L.)

Abstract

A field experiment was carried out in the fields of College of Agriculture, University of Anbar for the spring season 2018 in soil with a silty loam texture to study the effect of organic residues at a level of 10 ton.ha-1 from three sources (reed, cows, sheep). Besides, their interaction with the chemical fertilization (NPK) at a levels of 50 and 100% of the fertilizer recommendation on the growth and production of the sunflower Shumoos CV using the randomized complete block design (RCBD with three replications. The results were analyzed statistically at a probability level of 0.05 to choose the least significant difference. The study results showed that the source of added organic residues achieved a significant increase in the studied characteristics. Furthermore, the addition of sheep residues caused the highest significant increase compared to the control treatment (without addition) in the characteristics of plant height, dry weight, leaf area, chlorophyll content and seed yield as well as the availability of P and K elements in soil and K, P, N concentrations in seeds with an averages of 172.7 cm, 185.9 g, 77.90 dm2, 41.92 mg/L, 4.69 ton.ha-1, 9.46 mg.kg-1, 97.74 mg.kg-1, 1.622%, 0.399%, and 0.751% for each of them respectively. On the other hand, the reed residues gave the highest average of available nitrogen in the soil amounted to 74.70 mg.kg-1, while the added cow residues was superior by the highest average of leaf area amounted to 77.90 dm2. Moreover, it was noticed that the levels of fertilizer recommendation had a significant effect on some of the above characteristics and the level (100%) of the full fertilizer recommendation exceeded in the chlorophyll content, grain yield, availability of (NPK) in the soil. In addition to its concentration in the seeds with the highest average reached 42.64 mg.L-1, 3.95 ton.ha-1, 75.10 mg.kg-1, 7.51 mg.kg-1, 82.21 mg.kg-1, 1.337%, 0.358%, and 0.717%, respectively. Finally, the interaction between the two study factors had a significant effect on all the studied characteristics.