Abstract:

A field experiment was used in this research to study the application of different nitrogen in diagnosing the nitrogen nutrition of four different winter wheat cultivars on dryland of Northwest China. In Jointing stage, NO3--N, NH4+-N, NH2--N(amide nitrogen,NH2--N), Pro--N (soluble protein nitrogen, Pro--N) showed obvious differences among the different varieties. The significant correlationships were found between NH4+-N, NH2--N, Pro--N and yield and N rate. In vegetable growth stage, the yield increased with the levels of NH4+-N, NH2--N, Pro--N in the leaves of wheat. The optimum stage for nitrogen diagnosis was in the Jointing stage.The variations of NH4+-N, NH2—N and Pro--N value with the variety of wheat is needed considering during the diagnosis. The correlation coefficients between the NH4+-N, NH2—N and Pro--N value at Jointing stage and the different nitrogen rate and grain of winter wheat was higher than that of other growth stages, indicating that the Jointing stage is a suitable stage for diagnosing the nitrogen nutrition of winter wheat.