ABSTRACT
Agricultural sky is a large source of nutrient elements essential to crops. It serves global agroecosystems. The elemental composition varies in the atmosphere with geographic location, altitude, season, weather patterns, and diurnal period. It is not easy to provide a standard nutrient distribution profile of the atmospheric layers. Among several elements traced in the atmosphere, we are concerned here with nutrients required for crop’s growth and productivity. Nutrient elements are found in particulate, fluid, or gaseous/ vapor forms. They are easily absorbed by crop’s foliage. The geographic features, soils, crops, and the agroecosystem per se may yet support a unique atmosphere with specific nutrients. Nutrient dynamics too could be specific to agrarian sky above each crop belt. We need to characterize them in detail and reap advantages. The agrarian sky may induce or impose restriction on crop productivity via nutrient dynamics. We have to realize that agrarian sky is actually an important portion of global nutrient cycle.
Wind is a major atmospheric factor capable of affecting the nutrient dynamics. Wind affects nutrient distribution in the agrarian sky. Wind brings nutrients into farms via sand particles and organic particulate matter. At the same time, turbulence in wind may remove massive quantities of nutrients from soil surface. They transport soil particles via dust storms and deposit them at a relatively nearer or farther location. Farm belts often suffer loss of nutrients as topsoil. Globally, there are specific dust/nutrient-bearing storms experienced like the Harmattan in Sahel, Haboob, Khamsin, Schekele in Northeast Africa, or Sirocco in Southern Europe etc. Factors, such as dust 144storms, tornadoes, droughts, and heat waves generally affect crops detrimentally. They affect the nutrient dynamics in the atmosphere. Strong local wind leads to reduction in fertility, eventually causing lower crop productivity. Wind aids movement of dust particles, microbes, and nutrients across continents. Transcontinental dispersal of sand/dust and nutrients is an important phenomenon related to agricultural sky. It is often induced by the highaltitude wind jet streams. Several giga tons of dust, sand, and nutrients transit across large distances over 15,000 km. Microbes with potential to transform nutrients too move between continents via high-altitude jet streams in the sky.
Clouds, rain, fog frost, snow, and even smog bring in nutrients into soil phase via deposition. Nutrients are found in dissolved form. Ambient temperature can affect nutrient absorption by crops. There are also physicochemical transformations of nutrient elements that occur in the atmosphere. These are aerobic transformations.
During farming, greenhouse gas (GHG) emission is a major atmosphererelated phenomenon that farmers have to encounter. Gaseous compounds, such as NH4, NO2, N2, CH4, CO, CO2, and volatile organic compounds (VOCs) affect atmosphere. Like soils, agricultural sky too may experience deterioration, if emissions are in excess of threshold. It seems in 2005, 10–12% of emissions were caused by anthropogenic activity. Agriculture contributed 60% of anthropogenic emissions. Yet, we may realize that based on geographic features, crops may reap benefits or loss due to GHG emissions/warming. Carbon sequestration procedures that reduce C emissions into atmosphere above cropping belts is worth exploring. Equally so, C sequestration is essential. It seems atmospheric C is increasing at the rate of 2 ppm y-1.
Agricultural sky supports large-scale emissions of sulfur compounds. Sulfur is a pollutant noticed in the atmosphere. It has the potential to induce acid rains. There are other emissions in agrarian sky, such as the VOCs, ozone, acid rains. Crop residue burning induces accumulation of particulate matter in the aerospace. It leads to formation of carbonaceous smog that drifts above cropping expanses.
Phyllosphere is a crucial region on foliage/canopy. It is a region of the agrarian sky. It is comparable to rhizosphere in the soil phase, in terms of moisture and nutrient acquisition. Foliar nutrition of crops takes advantage of agricultural sky and aerobic conditions that prevail. Foliar nutrients received via atmosphere have to compulsorily transit this region—that is, phyllosphere. The current trend to apply fertilizer N as fluid makes phyllosphere 145important. The nutrient dynamics that ensue in this region could affect crop nutrition. Microbial load, its diversity and relevance to foliar nutrition is worth greater attention. Overall, atmosphere, its characteristics, essential nutrients, and their dynamics in different strata in the agricultural sky need greater attention. We should manage nutrients in the agrarian sky better.
