Effect of agrochemicals on spatio-temporal changes in soil agrochemical properties and yield of broccoli

The aim of the study. The aim of the study was to examine the effect of agrochemicals (mineral and organo-mineral fertilizers, plant growth regulators and ameliorants) on the spatio-temporal changes in the properties of agro-gray soil and broccoli yield using a cartographic approach. Methodology. The field experiment was conducted in 2016 at the site located near the Bykovo village in the south-east of West Siberia (54°58 '02.8" N; 83°5'21.45" E, Novosibirsk region). The objects of the study were the agro-gray soil (Luvic Retic Greyzemic Phaeozem (Siltic, Aric)) and the medium-ripe broccoli cabbage variety "Linda". The experiment scheme included the following treatments: (1) Control (without fertilizers), (2) Background (N100P60K160), (3) Background + succinic acid, (4) Background + dolomite, (5) Background + mulch, (6) Organo- mineral fertilizer "Criall". Soil samples were analyzed for the content of organic carbon, nitrates, total, mineral and organic phosphorus, as well as its mobile form; exchangeable potassium, calcium and magnesium, and pH. The dried samples of broccoli inflorescences were analyzed for the total content of nitrogen, phosphorus, potassium, calcium and magnesium. Main results. After applying agrochemicals and harvesting broccoli, the variation coefficients of рН, mobile phosphorus, potassium and calcium increased by two or more times. The use of agrochemicals increased the yield and improved the nutritional value of broccoli inflorescences. The treatments with mineral fertilization (2, 3, 4 and 5) the treatment 2 (Background N100P60K160) provided the greatest return. The application of the studied agrochemicals resulted in the negative (acidification, binding of phosphorus, calcium and magnesium) and positive (increase in the content of elements) effects. The immobilization of nutrients (phosphorus, calcium, magnesium) in poorly soluble soil compounds and the respective decrease in the content of the elements’ mobile forms did not have a negative effect on the elemental composition of broccoli inflorescences. Thus, chemical immobilization, leading to the fixation of nutrients in the upper soil horizon, prevents their leaching by melt- and rainwater into the lower horizons.