Effects of Nitrogen Application on the Abundance and Distribution of Protist Communities in the Rhizosphere of Beta vulgaris

This experiment was carried out in the experimental base of Hulan Campus of Heilongjiang University ( Harbin City, Heilongjiang Province, China, 45 ° 59 ′ 58 ′ ′ N, 126 ° 37 ′ 47 ′ ′ E ) from April 2021 to September 2021. Sugar beet variety H004 was sown on April 26,2021, with nitrogen fertilizer treatment ( N120,120 kg · hm-2 ) and control without nitrogen fertilizer ( N0,0 kg · hm-2 ). Phosphorus and potassium fertilizers were P2O5 ( 90 kg · hm-2 ) and K2O ( 120 kg · hm-2 ), and the fertilizer types were urea, calcium superphosphate and potassium sulfate. Each treatment was repeated 3 times, and each treatment was repeated 4 ridges, a total of 12 ridges, each ridge length 10 m, width 0.65 m, plot area 78 m2. Samples were taken before the sowing period ( May ), seedling period ( June ), leaf rapid growth period ( July ), root expansion period ( August ) and harvest period ( September ). Sugar beet rhizosphere and non-rhizosphere soil samples were collected and tested at − 80 ° C ( mainly for studying rhizosphere data ).Spearman correlation analysis and RDA analysis were performed on the abundance and physicochemical properties of protozoa in the rhizosphere soil of sugar beet.

本试验于2021年4月至9月在黑龙江大学呼兰校区试验基地（中国黑龙江省哈尔滨市，北纬45°59′58″，东经126°37′47″）开展。甜菜品种H004于2021年4月26日播种，设置氮肥处理组（N120，120 kg·hm⁻²）和无氮对照组（N0，0 kg·hm⁻²）；磷钾肥用量分别为P₂O₅（90 kg·hm⁻²）和K₂O（120 kg·hm⁻²），肥料类型为尿素、过磷酸钙和硫酸钾。每个处理重复3次，每次重复4垄，共12垄；每垄长10 m，宽0.65 m，小区面积78 m²。分别于播种前期（5月）、苗期（6月）、叶片快速生长期（7月）、块根膨大期（8月）和收获期（9月）取样，采集甜菜根际（rhizosphere）与非根际土壤样品并于-80℃保存（主要用于根际数据研究）。对甜菜根际土壤中原生动物的丰度与理化性质进行Spearman相关性分析和RDA分析。