Effects of Bio-Slurry and Chemical Fertilizer Application on Soil Properties and Food Safety of Tomato (Solanum lycopersicum Mill.)

Abstract

This study evaluated the effects of bio-slurry (BS) and chemical fertilizer (CF) application on soil properties and food safety of tomato (Solanum lycopersicum Mill.). A field experiment consisting of 100% BS (5 ton BS ha−1), 100% CF (90 kg N·ha−1 + 30 kg P·ha−1 + 13 kg S·ha−1), and control was conducted. Soil samples from all the treatments were collected for their physico-chemical characteristics. The level of ten heavy metals in experimental soil and tomato fruit samples was also determined. Compared to CF and control, the application of BS improved soil physico-chemical characteristics. The BC significantly reduced the mean concentrations of Cd and Mn in the tomato fruit samples. The mean concentration of Ni (18.24 ± 0.61, 23.9 ± 0.3, and 9.66 ± 1.2 mg kg−1) and Mn (15.4 ± 2.4, 38 ± 3.3 and 21.8 ± 0.99 mg kg−1) in tomato fruit samples of BS-treated, CF-treated, and control soil, respectively, was above the safety limit set by the Food and Agriculture Organization/World Health Organization for human consumption. Similarly, the mean concentration of Cd (7.98 ± 0.72 and 3.29 ± 0.37 mg kg−1) in tomato fruit samples of CF-treated and control soil was above the safety limit. From this perspective, the consumption of these tomato fruits could be unsafe for human health with respect to Ni, Mn, and Cd toxicities. The application of BS could remediate the Cd toxicities, yet other scenarios of phytoremediation would be praiseworthy to address Ni, Cd, and Ni toxicities.

Growth and marketable yield of lettuce (Lactuca sativa L.) as affected by bio-slurry and chemical fertilizer application

“…Collectively, the integrated application of chemical fertilizer and bio-slurry increased height over their separate application. Findings from previous studies indicated that the use of chemical fertilizer and bio-slurry gives premier height over the control in lettuce [ 16 , 17 ], in tomato [ 14 ] and okra [ 18 ]. This might attribute to the high nutrient and organic matter contents of bio-slurry, which optimize both the deficit and the excess nutrients in the soil [ 19 , 20 ].…”

“…Thus, the application of chemical fertilizer and bio-slurry, as sole or integration, increased both growth and yield of lettuce. A prior study found that when chemical fertilizer and bio-slurry were applied together, there was a significant positive correlation between the overall fruit yield and yield components in tomatoes [ 14 ] and in maize [ 27 ].…”

“…Major crops grown include vegetables, haricot beans, coffee, and fruit trees [ 13 ]. The tropical andosol soils surrounding the experimental areas primarily have textural classes ranging from silty loam to sandy loam [ 13 , 14 ].…”