Differential response of the nitrifying microbes and net nitrification rates (NNRs) between different cereal and legume crop soils with chemical fertilization

Abstract

Nitrification increases soil fertility and a higher rate of grain production in cereal and leguminous crops. However, differential response of the nitrifying microbes and net nitrification rates (NNRs) of chemical fertilizers in cereals and leguminous crop soils of Bangladesh are unknown. Hence, the current research was undertaken to find out the differential response of the nitrifying microbes and NNRs of chemical fertilizers in some cereals (Triticum aestivum and Zea mays) and leguminous crops (Lins esculenta, Pisum sativum, and Cicer arietinum) soils. The NNRs and occurrence of ammonia-oxidizing archaea (AOA)/ammonia-oxidizing bacteria (AOB), and nitrite-oxidizing bacteria (NOB) were enumerated by mass spectrophotometer and q-PCR, respectively. The ranges of NNRs were 2.84±0.41 to 12.86±1.09 mg kg−1 h−1 and significantly higher (p<0.05) in cereal and leguminous crop soils as compared with control soils. Linear mixed model analysis revealed that the NNRs were significantly affected (p<0.05) by NO3--N, NH4+-N, total N, pH, and soil organic carbon (SOC). NNRs and abundance of AOA, AOB, and NOB were significantly higher (p<0.05) in leguminous crop soils as compared with both cereal crop soils and control soils. 16S rRNA gene, AOA, AOB, and NOB were positive and significantly correlated (p<0.001) with the NNRs. Overall results revealed that the higher absolute abundance (copies per gram dry weight soil) of nitrifying microbes in leguminous crop soils than in cereal crop soils may reflect the potential role of leguminous crops in minimizing inorganic N fertilizer application. © 2021, Saudi Society for Geosciences.