Amending formulated compound fertilizers with zeolite to improve maize (Zea mays L.) growth and nutrient use efficiency

Excessive use and poor utilization of fertilizers can cause air, soil and water pollution. These problems could be minimized by amending compound fertilizers with clinoptilolite zeolite. Objectives of this study were to: (i) determine the effect of amending NPK fertilizers with different rates of clinoptilolite zeolite on NH3 volatilization, soil exchangeable NH4 +, and available NO3 -, and (ii) determine the effect of NPK fertilizers amending with different rates of clinoptilolite zeolite on maize (Zea mays L.) dry matter production, nutrient uptake, and nutrient use efficiency. An ammonia (NH3) volatilization study was conducted using a closed-dynamic air flow system. Seven treatments evaluated in ammonia volatilization experiment were: 250 g soil only (T1), 250 g soil + 3.28 g ammonium nitrate (AN) without additive (T2), 44.6 g 5:3:2 formulated compound containing 31.77 g zeolite (T3), 44.6 g 5:5:5 formulated compound fertilizer containing 26.36 g zeolite (T4), 37.17 g 6:6:6 formulated compound fertilizer containing 18.92 g zeolite (T5), 22.30g 10:10:10 formulated compound fertilizer containing 4.06 g zeolite (T6), and 14.87 g 15:15:15 commercial fertilizer (T7). Ammonia loss over 12 days was daily recorded following standard procedure. Soil pH, exchangeable NH4 + and available NO3 - at the end of this incubation study were determined using standard procedures. The mixture of the formulated compound fertilizers with clinoptilolite zeolite and T7 were significantly reduced NH3 volatilization. This was possible because of the temporary retention of NH4 + by clinoptilolite zeolite in the formulated compound fertilizers via sorption reaction. Application of commercial compound fertilizer had superior effect on soil exchangeable NH4 + among treatments, while available NO3 - had similar effect for treatments containing clinoptilolite zeolite and T7. This was probably due to the source of the fertilizers used. Ammonia volatilization experiment was demonstrated that amending N, P, and K compound fertilizers with clinoptilolite zeolite could minimize NH3 loss as commercial compound fertilizer (T7). A pot experiment by cultivate Masmadu maize variety as test crop was carried out in a greenhouse as further test to examine treatments effect on growth. The objective of this pot experiment was to observe the effect of the compound fertilizers amended with different rates of clinoptilolite zeolite on maize dry matter, nutrient uptake and fertilizer nutrient use efficiency. Treatments for pot experiment evaluated were: 7 kg soil only (T1), 44.6 g 5:3:2 formulated fertilizer containing 31.77 g zeolite (T2), 44.6 g 5:5:5 formulated compound fertilizer containing 26.36 g zeolite (T3), 37.17 g 6:6:6 formulated compound fertilizer containing 18.92 g zeolite (T4), 22.30 g 10:10:10 formulated compound fertilizer containing 4.06 g zeolite (T5), and 14.87 g 15:15:15 commercial fertilizer (T6). Selected soil chemical properties after planting were analyzed following standard methods. Dry weight, nutrient concentration, nutrient uptake and nutrient use efficiency at 65 DAP were also measured. Formulated compound fertilizers with zeolite increase soil pH compared to soil alone (T1) and commercial compound fertilizer (T6). Application of the formulated compound fertilizers were significantly similar effect on total N, exchangeable NH4 + and NO3 - availability in soil to commercial compound fertilizer. T6 significantly increased plant height, while total dry weight of treatments with clinoptilolite zeolite was similar to T6. Nitrogen and K concentrations in all parts of maize were statistically similar for treatments with clinoptilolite zeolite and T6, while commercial compound fertilizer had better P concentration. Formulated compound fertilizer and commercial compound fertilizer were had similar Ca concentration in all parts of maize except stems. Mg concentration was greater in maize roots when T6 was applied, while treatments with clinoptilolite zeolite had better Mg concentration in stems and leaves compared to T6. T2, T3, T4 and T5 cause lower uptake of N and P compared to T6. Application of T3, T4, and T5 had statistically similar K uptake to T6 application. Application of T6 was significantly increased N and P use efficiency, while, T2 significantly increased K use efficiency. T2 had high K use efficiency because it had lower rate K applied. A field study for at least three cropping cycles is needed to confirm the findings of this study