Vineyard Fertilization Management for Iron Deficiency and Chlorosis Prevention on Carbonate Soil

Nitrogen fertilizer efficiency in grapevine production is an important objective for solving the trade-off between improving yield and quality in agroecosystems and reducing environmental impacts. Influence of soil nitrogen fertilization and Fe foliar application on iron dynamics in soil and grapevine leaves of the ‘Graševina’ cultivar on carbonate soil was conducted in a two-year study in 2018 and 2019. The experiment was settled in three replicates on a total of seven fertilization treatments that differed in used form of nitrogen fertilizer and foliar application of Fe before and after the flowering of the grapevine: control (C); calcium ammonium nitrate (KAN); calcium ammonium nitrate + foliar Fe (KAN+F); ammonium sulfate (AS); ammonium sulfate + foliar Fe (AS+F); ammonium sulfonitrate + foliar Fe (ASN+F); urea + foliar Fe (U+F). Mineral fertilization with acid-forming nitrogen fertilizers (AS and ASN) significantly affected local acidification of alkaline soil, i.e., reducing the actual and exchangeable soil pH reaction, which resulted in increased soil Fe availability. Despite the increase in soil iron availability, no increased iron bioaccumulation in the grapevine leaves was found in the flowering and veraison stages at treatments where foliar fertilization was omitted. Of all the observed treatments, only foliar fertilization had a positive effect on iron concentration in the grapevine leaves, which leads to the conclusion that this is an effective way to solve iron deficiency symptoms and chlorosis occurrence. The use of mineral fertilizers with acid-forming nitrogen fertilizers for many years can result in a reduction of required foliar treatments and thus significantly affect the ecological and economic aspects of grape production. Thus, integrated iron management is needed to meet the needs of the grapevine for this micronutrient and to reduce the occurrence of leaf chlorosis in carbonate soil.

Groundwater residence time estimates obscured by anthropogenic carbonate

Groundwater is an important source of drinking and irrigation water. Dating groundwater informs its vulnerability to contamination and aids in calibrating flow models. Here, we report measurements of multiple age tracers (14C, 3H, 39Ar, and 85Kr) and parameters relevant to dissolved inorganic carbon (DIC) from 17 wells in California’s San Joaquin Valley (SJV), an agricultural region that is heavily reliant on groundwater. We find evidence for a major mid-20th century shift in groundwater DIC input from mostly closed- to mostly open-system carbonate dissolution, which we suggest is driven by input of anthropogenic carbonate soil amendments. Crucially, enhanced open-system dissolution, in which DIC equilibrates with soil CO2, fundamentally affects the initial 14C activity of recently recharged groundwater. Conventional 14C dating of deeper SJV groundwater, assuming an open system, substantially overestimates residence time and thereby underestimates susceptibility to modern contamination. Because carbonate soil amendments are ubiquitous, other groundwater-reliant agricultural regions may be similarly affected.

Microbiological assessment of meadow-chernozem carbonated soil with different fertilization systems

Microorganisms play an important role in the formation of soil fertility, ensure their functioning as biological bodies of nature and are an indicator of qualitative soil changes. Due to the effect of anthropogenic activity on the soil there is a decrease in the number and depletion of the species composition of the microbiota. The aim of the research was to estimate the number of different physiological groups of microorganisms on meadow-chernozem carbonate soil under different fertilizer systems. Determination of the number of different groups of soil microorganisms was carried out according to the method of Zvyagintsev by sowing the soil suspension on solid nutrient media. It was established that the most favorable indicators of microbiocenosis and the highest yield of peas of Tsarevich variety were formed by the aftereffects of organic fertilizers and N45P45K45. The variant without fertilizers causes the development of mineralization of organic matter in meadow-chernozem carbonate soil by the content of pedotrophic and humatizing organisms and formed the lowest yield of peas. Application of only mineral fertilizers for growing peas formed a high rate of accumulation of humus at the level of Kak. = 1,6-1,9.