The effect of liquid organic fertilizer on rapeseed yield

Introduction. Numerous experiments have proven that it is impossible to increase soil fertility and obtain high yields on sod-podzolic soils without the use of organic fertilizers. In recent years, due to the insufficient use of organic fertilizers, this problem has become even more acute. The situation can be improved by maximizing the use of liquid organic fertilizers such as pig manure. Materials and methods. The study was conducted using micro-field experiments and laboratory analyses. The micro-field experiments were carried out in an experimental field, and the laboratory studies were conducted at the Department of General Agriculture, Plant Growing, Agrochemistry, and Plant Protection at Mari State University. A modified liquid organic fertilizer was obtained (created) by neutralizing liquid pig manure with sulfuric acid (H_2SO_4) to pH 5.5‒5.7. The object of the study was spring rapeseed of the Yarilo variety, which was grown for seeds. The aim of the study was to study the effect of doses and forms of liquid pig manure on the yield of spring rapeseed. Results and discussion. It was found that liquid organic fertilizers lead to the emergence of rape seedlings in 1–2 days. The application of 30 t/ha of liquid manure increased plant survival by 5.1–5.7 %, and 60 t/ha by 7.1–9.9 %. The seed yield in the control was 160 g/m². Liquid pig manure at doses of 30 and 60 t/ha increased the yield by 70.5 and 105.5 g/m², respectively, and the modified fertilizer by 85.5 and 137.5 g/m². The use of fertilizers increased the number of pods and seeds in a pod, seed weight, and 1000-seed weight. The oil content in seeds without fertilizers was 41.2 %. The use of liquid pig manure at doses of 30 and 60 t/ha increased its concentration to 41.4 and 41.7 %, respectively, and modified fertilizer at a dose of 30 t/ha ‒ to 41.7 %, at a dose of 60 t/ha ‒ to 41.6 %. The maximum oil yield, equal to 12.39 c/ha, was obtained in the variant using modified liquid organic fertilizer at a dose of 60 t/ha.