Effects of Synergistic Phosphate Fertilizer on Photosynthetic Characteristics and Senescence of Wheat Flag Leaf in Saline-Alkali Soil

In this experiment, itaconic acid, maleic acid, acrylic acid and potassium persulphate were polymerized to form synergist, which was wrapped on the surface of phosphate fertilizer particles to make synergistic phosphate fertilizer. In order to explore the effects of synergistic phosphate fertilizer on photosynthetic characteristics and senescence of wheat flag leaf in saline-alkali land, experiments were carried out in Changyi Experimental Base of Qingdao Agricultural University from October 2019 to June 2020 and from October 2020 to June 2021. Four treatments were set in the experiment, CK: nitrogen fertilizer (containing N 306.14 kg / hm2), potassium fertilizer (containing K2O 116.67 kg / hm2), conventional phosphate fertilizer (containing P2O5 333.35 kg / hm2); T1: synergic phosphate fertilizer (containing P2O5 249.99 kg / hm2); T2: synergic phosphate fertilizer (containing P2O5 166.67 kg / hm2); T3: synergic phosphate fertilizer (containing P2O5 83.32 kg / hm2). The application amount of nitrogen and potassium fertilizer in T1, T2 and T3 was the same as that in CK. Photosynthetic characteristics and senescence indexes of wheat at 0–28 days after anthesis were measured. The results showed that the photosynthetic characteristics and the senescence of wheat treated with synergistic phosphate fertilizer were better than CK, and T2 treatment was the best.