Studing On The Nitrification Models In Calcareous Soil

The nitrification is an important nitrogen transformation in soils. Studying on nitrification is an important foundation for increasing the nitrogen using efficiency and rationally using nitrogen fertilizers. Our research used indoors fosters method, and the experiment used the fresh Cal-Ustic Isohumasols as sample soils. The two main factors of the experiment were the temperature and soil moisture with controlling the dosage of nitrogen fertilizer, N/P, and the anion of the Ammonium nitrogen. It is different monitored that contents of the NH4~+-N, NO3~--N & pH changes regulation of everyday. According to the Michaelis-menten kinetic, difference nitrification kinetics models of the NH4~+-N & NO3—N were established. The main conclusions were shown as follows:1. Difference nitrification kinetics models of the NH4~+-N & NO3~-N were established: N tNO: Dynamic content of nitrification nitrogen S NO: Approach value of nitrification nitrogen t : Time a, b: Constant The above models were modified by recruiting the absorbing NH4~+-N & NO3~--N by other creature. Get the new nitrification kinetics models shown as blow: a, b,c,d: Constant 2.The application amount of NH4HCO3 is not correlative with the rate of nitrification .The max- rate of the NH4~+-N lessening is in the range of 13.0480~19.9075 mg/kg.d, whose time (t oNH) is shorter than the rate of the NO3~--N adding to rise maximum. The max- rate of the NO3~--N adding is in the range of 13.0480~19.9075 mg/kg.d, and its time (t oNO) is longer than the rate of the NH4~+-N lessening to rise maximum. The t ois along with extension the dosage of nitrogen fertilizer rising. In the same dosage of nitrogen fertilizer, the t oNH is 0.1842~5.252 d shorter than the t oNO,In other words,the range of 13.0480~19.9075 mg/kg.d and the is in the range of 1.3662~9.8840mg/kg.d, and therefore, The results indicated that the notification of the Cal-Ustic Isohumasols is a slow-release type. The asymptotic value of the NH4~+-N lessening is bigger than the asymptotic value of the NO3~--N ( S NO < SNH). It is indicated that the part NH4~+-N was oxidized and remain was made use of other. In the 100mg/kg dry soils range dosage of nitrogen fertilizer, the rate of the NH4~+-N lessening and the NO3~--N adding move up for the dosage of nitrogen fertilizer, the rate of the NH4~+-N lessening and the NO3~--N adding is approximate in the different recovery soil.3. The nitrogen and phosphoric combination can form the phosphoric acid salt buffer system. The phosphoric acid salt could markedly decreased N loss by ammonium volatilization. Because of the decrease of differential pressures of ammonium and pH of soil increased rise, the is similar to the . It is higher than the dosage of nitrogen. The t oNH is longer than the dosage of nitrogen (3:0,2:0,1:0) and the t oNO is shorter than the dosage of nitrogen (3:0,2:0,1:0). The asymptotic value of NH4~+-N similar to the asymptotic value of NO3~--N ( S NH≈SNO).The phosphoric acid salt can repress the ammonia volatilization, and it can promote the proceeding notification. The chloride anion inconspicuous influxes rate of the NH4~+-N lessening and rate of the NO3~--N adding. Its main influence the NH4~+-N releasing, it is result that nitrifying is low. The sulfate anion can offer"O-". It advances the ammonium nitrogen boring. The anion inconspicuous influence the max-rate of the NH4~+-N lessening and rate of the NO3~--N adding. It conspicuous influence the original rate of the NH4~+-N lessening & the rate of the NO3~--N adding. The fertilizers is in the chemistry in the soil behavior, it is effected the NH4~+-N many to change.4.In the Cal-Ustic Isohumasols, the max-rate of the NO3~--N adding approximate is a constant (5.8~8.8mg/kg.d), which have nothing to do with type of fertilizers. The max-rate of the NH4~+-N lessening have a big extent (7.8~23.5 mg/kg.d), which is relative with the characteristics of fertilizers and soil's biota characters.5. There is significant different rate that the rate of the NH4~+-N lessening & the NO3~--N adding when we think creature factor in the soil (about 50%). And the rate of the NH4~+-N lessening again rise up in the indoor fosters last term, which revealed that other forms of the NH4~+-N were lessening in the prophase and the ammonium nitrogen was boring in the anaphase.