Maize (Zea mays) growth on nickel contaminated soil as affected by different biochar sources receiving nickel contaminated water for irrigation

The rapid increase in population coupled with fast industrialization occupied the available space of agricultural soils. The interest of the farmers for these soils is also decreasing day by day due to number of problems like costly agriculture inputs and low net benefits. One of these problems is the availability of good quality water. Farmers in the suburbs of big cities are irrigating their soils with raw city effluents mainly originated from industries. Ghee industry is one of such industry pouring its effluents containing Ni into the sewage drains. They contaminate the food chain and have negative effects on the human health. The concentration of nickel (Ni) is continuously elevating in grain crops grown with wastewater drained from different industries. Addition of organic amendments in the soil decreases Ni availability to plant. The present study was designed to evaluate the effect of organic amendments on maize grown with Ni contaminated water. Seven treatments were used viz. control (T1), Rice Husk Biochar @ 5 t per ha (T2), Rice Husk Biochar @ 10 t per ha (T3), Rice Husk Biochar 15 t per ha (T4), Cotton sticks biochar @ 5 t per ha (T5), Cotton sticks biochar @ 10 t per ha (T6), Cotton sticks biochar @ 15 t per ha (T7). Pots were filled with soil @ 10 kg soil per pot. Pre and post harvesting soil samples were collected. The soil physicochemical properties of the samples were analyzed. The plant samples were taken at vegetative stage. The collected soil and plant samples were analyzed for Ni concentration using Atomic absorption spectrometer. The treatment (T4) with Rice Husk biochar @ 0.75 % (w/w) shows significant results as compared to control (T1). Plant height, shoot dry weight, root length, root dry weight, photosynthetic rate, chlorophyll content, transpiration rate and stomatal conductance increased by 91%, 350%, 24%, 130%, 600%, 81%, 262% and 21% respectively as compared to control (T1). The treatment (T4) shows decrease in Ni concentration in soil as well as plant shoot and root. The percentage decrease of AB-DTPA Ni in soil, shoot and root is 45%, 94% and 78% respectively as compared to control (T1). The data obtained was statistically analyzed to find out effectiveness of treatment using completely randomized design (Statistics 8.1).