Effects of lignite based organic fertilizer combining straw application on soil fertility and oil sunflower growth

In this field experiment, we planted oil sunflower to explore the effects of straw combined with urea and lignite based organic fertilizer on soil fertility and the growth of oil sunflower.The results showed that: compared with single application of corn stalk (CK), corn stalk+urea (T1) and corn stalk + lignite organic fertilizer (T2) significantly increased the contents of soil nitrogen, phosphorus and potassium.At squaring stage, the nitrogen contents of T1 and T2 increased by 13.3% and 5.6%, and the potassium content both increased by 10.0%, respectively.The phosphorus contents of T1 and T2 increased by 10.5% and 12.4% during the squaring and the harvest stages, respectively.In addition, the effects of T1 and T2 on soil organic carbon content significantly increased by 15.0% and 31.0% at the harvest period, respectively.As for soil trace elements, the content of boron significantly increased, while the contents of zinc and iron significantly reduced; As for heavy metals, T2 significantly reduced the contents of arsenic and cadmium, while T1 and T2 significantly increased the contents of lead, which would be related to microbial activities.As for the biological characteristics of oil sunflower, the plant height significantly increased by 9.2% and 13.8%, the root fresh weight significantly increased by 21.2% and 17.0%, and the yield significantly increased by 12.1% and 17.4%, respectively.After controlling C/N ratio, corn stalk application would improve soil fertility and promote the growth of oil sunflower, with a better effect combining lignite based organic fertilizer than urea.