Excessive Fertilizer Usage Drives Agriculture Growth but Depletes Water Quality

Abstract

By 2050 most parts of India will be water stressed zones as most of the water resources are under heavy stress due to increasing nutrient contamination in their waters. In this scenario, studying the changes occurring in the freshwater nutrient contamination levels over a temporal scale is extremely important. This study focuses on monitoring the changes occurring in the nutrient contamination levels over a decade in a large reservoir known as Nagarjuna Sagar (NS) using remote sensing data. In this study, Landsat (5 & 8) data for the year 2005year , 2009year , 2015 data for the years 2016 and 2018 is used to study nutrient contamination in NS. The spatial spread of chlorophyll -a (chl-a) area is used as a proxy to estimate the extent of nutrient contamination in NS. In this study, only October images of NS are used as they exhibit the maximum spatial spread of Chl-a and hence help assess the contamination levels over the period 2005 -2018. The analysis shows that during this period, chl-a spatial spread area has increased from 21 Km 2 to 205 Km 2 , indicating a decrease in water quality in the reservoir. The study shows that this is accompanied by an increase in the agricultural land use area by 1000 Km 2 in addition to a steep increase in the use of agricultural inputs, primarily fertilisers like urea, P and K. Thus, while the combined effect of excessive usage of fertilizers with agricultural intensification has increased crop yields, it has also contributed to damaging the freshwater resources.

Normalized Difference Vegetation Index (NDVI) for soybean biomass and nutrient uptake estimation in response to production systems and fertilization strategies

“…Studies have shown that growing soybean production over time is accompanied by, in part, an increasing use of fertilizers (Tilman et al, 2001;FAO, 2018). In this sense, FAO (2019) estimates an average annual increase of 1.3% in world synthetic fertilizer demand for nitrogen (N), P, and K, and studies have shown that increases in fertilizer use can result in increased amounts of nutrients and toxins levels in ground and surface waters, incurring health and water purification costs and decreasing fishery and recreational values (Tilman et al, 2002;Kondraju and Rajan, 2019).…”

Controlled Release of Zinc from Soy Protein-Based Matrices to Plants

“…This filtration is due to the low assimilation of fertilizers by plants, which only captures a small part of the fertilizers incorporated in the soil. In addition, this low assimilation generates that more quantity of fertilizers must be incorporated into the soil during the crop growth, which results in a higher production cost [7].…”

Micronutrient-controlled-release protein-based systems for horticulture: Micro vs. nanoparticles

“…The conventional use of fertilizers usually leads to an excess of nutrients, due to their low assimilation by the plants. This fact makes this method ineffective, since a large quantity of fertilizer is necessary to perceive an improvement in the soil (Kondraju and Rajan, 2019). For this reason, it is necessary to find an alternative that helps introducing nutrients into plants and improves the assimilation efficiency of the conventional method.…”