High Nitrogen Fertilization of Tobacco Crop in Headwater Watershed Contaminates Subsurface and Well Waters with Nitrate

Abstract

Our hypothesis was that subsurface and well waters in watershed with shallow, stony soils, steep landscapes, and cropped to tobacco are contaminated by nitrate. Nitrate in soil solution was monitored in (0.20 m) and below (0.5 m) root zone with tension lysimeters, in five transects. Water from two wells (beneath tobacco field and in native forest) used for human consumption was also analyzed for nitrate. Soil bulk density, porosity, and saturated hydraulic conductivity were evaluated. Soil physical and hydrological properties showed great variation at different landscape positions and soil depths. Soil coarse grain size, high porosity, and saturated hydraulic conductivity favored leaching nitrate. Nitrate in soil solution from tobacco fields was greater than in natural environment. Nitrate reached depths bellow rooting zone with values as high as 80 mg L−1in tobacco plantation. Water well located below tobacco plantation had high nitrate concentration, sometimes above the critical limit of 10 mg L−1. Tobacco cropping causes significant water pollution by nitrate, posing risk to human health. A large amount of nitrogen fertilizers applied to tobacco and nitrate in subsurface waters demonstrate the unsustainability of tobacco production in small farming units on steeps slopes, with stony and shallow soils.

Yield Response, Quality Traits, and Nitrogen-Use Efficiency of a Burley Tobacco Crop Grown in Mediterranean Areas (Southern Italy) as Affected by Intensive N Management

“…An intensive mineral N management permitted over the past 50 years to increase the productivity of agricultural lands around the world. Nevertheless, it often determined N surplus in soils and waters, resulting in severe pollution due to nitrate contamination [1][2][3][4][5]. In Europe, this negative effect was measured already in 1980 when mineral N consumption in agriculture, as well as that of other macro-nutrients (K and P), reached maxima values [6].…”

“…Tobacco is an annual cash crop widely cultivated over the world (3.6 million ha; [6]). It generally needs great amounts of N to achieve the best yield or quality response and is usually over-fertilized [3,39,40].…”

“…Significant soil and water pollution by nitrate were frequently measured after tobacco cropping [3,41,42]. Kaiser et al [3] found that nitrate both in soil solution from tobacco field or in well water below tobacco crop was greater than that in natural conditions.…”

Pesticide bioaccumulation in epilithic biofilms as a biomarker of agricultural activities in a representative watershed

“…Nowadays, environmental contamination with pesticides has received great scientific and societal attention due to the major risk posed to the natural environment and human health (Özkara et al 2016;Tang et al 2018). The occurrence of various contaminants in the surface water is correlated with agricultural activities, exhibiting the conflict between productivity and contamination (Bastos et al 2018;Fernandes et al 2019;Kaiser et al 2015;Zafar et al 2016). Pesticide residues can be transferred to water sources by soil erosion, surface runoff, and percolation.…”

Improving the sustainability of tobacco cultivation by optimizing nitrogen fertilization

“…Morover, environmental aspects associated to water and nitrogen use in agriculture are becoming increasingly relevant since water availability for irrigation purposes is declining as a consequence of climate change (Parida and Suja, 2015;Papadopoulou et al, 2016), intensive farming and the irrigation practice per se, which is causing soil and water salinization in many areas of the world (De Pascale et al, 2012). Excessive nitrogen fertilization has also deleterious consequences on the environment and human health through contamination of the groundwater and accumulation of nitrates in plant tissues beyond safety levels (Komatsuzaki and Ohta, 2007;Kaiser et al, 2015). The need for proper water and nitrogen management for food and nonfood crops is therefore a focal point of sustainable agricultural systems.…”