Mitigating Ammonia and Greenhouse Gaseous Emission From Arable Land by Co-application of Zeolite and Biochar

Abstract

The intensive use of chemical fertilizers in arable farming dramatically increased environmental pollution through anthropogenic ammonia (NH3) and greenhouse gaseous emissions. Therefore, there is a need to develop improved fertilizer management practices that can reduce these losses. An experiment was conducted to assess the mitigating effects of sole or combined application of zeolite with biochar on gaseous emissions from arable land. For this purpose, zeolite (clinoptilolite) was mixed with different doses of biochar (produced from Dalbergia Sissoo wood chips) and applied along with the recommended dose of chemical fertilizer (NPK @ 150, 100, and 60 kg ha–1, respectively) on arable land in years 2013–14 and 2014–15. Immediately after application, these were incorporated into the top 10 cm of the soil layer and wheat was sown. Treatments were as follows: C = control, Z = zeolite @ 5 t ha–1, B1Z = biochar @ 3 t ha–1 + zeolite @ 5 t ha–1, B2Z = biochar @ 6 t ha–1 + zeolite @ 5 t ha–1, and B3Z = biochar @ 9 t ha–1 + zeolite @ 5 t ha–1. The experiment was laid out in a randomized complete block design (RCBD) with three replicates. The experimental plot size was 6 m × 4 m. Randomly, ten soil samples from each plot were taken at a depth of 0–15 cm and mixed to get a composite sample. All the samples were immediately stored in a freezer at −18°C until gaseous analysis in order to prevent N transformations. Each soil sample was analyzed for emission of NH3, CO2, and CH4 by using a selected-ion flow-tube mass spectrometer (SIFT-MS). Co-application of zeolite and biochar reduced NH3 and CH4 emissions by an average of 87 and 58% compared to the control, respectively. However, CO2 emission was increased by 104% relative to the control. The NH3 emission was decreased by an average of 61, 78, 90, and 92% by Z, B1Z, B2Z, and B3Z treatments compared to the control. Similarly, the decrement in CH4 emission was 47, 54, 55, and 65%. In contrast, the increment in CO2 emission was 42, 110, and 160% for B1Z, B2Z, and B3Z, respectively, while interestingly, a reduction of 12% was observed in Z treatment. Besides, co-application of zeolite and biochar at the highest dose (B3Z) improved soil chemical properties such as soil EC, OM, total N, as well as available P and K relative to zeolite alone. It is concluded that the combined application of zeolite and biochar can mitigate NH3 and greenhouse emissions and improve soil chemical characteristics, thus enhancing the environmental worth of arable farming.