| In order to investigate profile distribution feature of organic carbon and total nitrogen in typical cropland of China under various kinds of long-term fertilization, black soil, grey desert soil, lou soil, red soil and fluvo-aquic soil were collected from different cropland of climatic region. Organic carbon and total nitrogen content in different five levels of soil profile with depth of 0-100cm were analyzed and characteristic of temporal and spatial distribution of organic carbon and total nitrogen was also summarized systemically, as provides important theoretical basis for soil fertility enhancement and sustainable agricultural development in China. The main results and conclusions were listed as follows.(1)Soil carbon content decreased gradually with increase of soil depth in various soil, and the magnitude of decrease in soil layers with depth of 40-100cm turn out to be less. Through the application of NPKM or NPKM2, organic carbon content in black soil with depth of 0-40cm showed a increasing trend in the last decade during fertilization age, while organic carbon content in lou soil and grey desert soil with the same depth range increased year by year during fertilization age. In all kinds of soil with depth of 0-40cm, carbon inputs were positively correlated to changes of organic carbon content in soil, and the carbon sequestration efficiency of organic fertilizer was greater than the straw treatment.After 20 years of fertilization, in contrast to CK, application of NPKM and NPKM2 can both increase organic carbon content with soil depth of 0-40cm, but the amplitudes of carbon content were changed in difference. In the soil with depth of 0-20cm, application of NPKM and NPKM2 increased the organic carbon content by 29.0%-109.7% and 49.4%-183.1% respectively. The amplitudes of carbon content showed a increasing trend in various soil from the west to the east and from the south to the north in China, or were in an order of grey desert soil>lou soil>red soil> fluvo-aquic soil>black soil. Application of NPKM2 also increased organic carbon content in grey desert soil, lou soil and fluvo-aquic soil with soil depth of 40-60cm. Application of NPKS increased organic carbon content in various soils except black soil with depth of 0-20cm. The amplitudes of carbon content were 21.9% -69.1%, and were in an order of lou soil>fluvo-aquic soil>red soil>grey desert soil. Application of NPKS also increased organic carbon content in black soil, lou soil and fluvo-aquic soil with depth of 20-40cm, and the amplitudes of carbon content were 18.8%-63.1%. CK0 treatment can increase organic carbon content significantly in soil with depth of 0-20cm, and the amplitudes of carbon content were 20.8%-55.7%, and the amplitudes were in an order of red soil>lou soil>grey desert soil> fluvo-aquic soil>black soil. CK0 treatment also increased organic carbon content in lou soil with depth of 20-40cm and red soil with depth of 20-60cm. Long-term application of N, NK and PK was not helpful to increase of carbon content in soil, but NPK and NP can improve carbon content in lou soil, red soil, and fluvo-aquic soil with depth of 0-20cm, and the amplitudes were 21.3%-33.8%.(2) Total nitrogen in various kinds of soil decrease gradually with increase of soil depth, and the magnitude of decrease in soil layers with depth of 40-100cm turn out to be less. The change of total nitrogen with fertilization age is similar to that of organic carbon content in soil. After 20 years of fertilization, Application of chemical fertilizers combined with manure(NPKM, NPKM2)can increase total nitrogen content with soil depth of 0-40cm remarkably. Application of NPKM and NPKM2 can increase carbon content with soil depth of 0-20cm by 32.0%-106.2% and 54.7%-206.3% respectively, and the amplitudes of carbon content in different soil were in an order of grey desert soil > lou soil > fluvo-aquic soil > red soil > black soil. The treatments of NPKM and NPKM2 can improve carbon content with soil depth of 20-40cm by 15.0%-143.6% and 33.6%-306.3% respectively, and the amplitudes of carbon content in different soil were in an order of grey desert soil > black soil > fluvo-aquic soil > red soil > lou soil. Due to nitrogen leaching, total nitrogen content in soil layers with depth of 20-100cm was improved differently by all treatments in black soil, lou soil, red soil and fluvo-aquic soil, but the increase amplitudes were lower than those in soil layers with depth of 0-40cm.(3) After 11 or 12 years of fertilization, carbon and nitrogen ratio (C/N) showed no obvious change in black soil and lou soil in contrast to control treatment (CK). Different treatments resulted in changes of C/N in grey desert soil, including rise and fall, therefore C/N in grey desert soil showed no regular change.During 20 years of fertilization, C/N in black soil and lou soil increased year by year with increasing fertilization age, but C/N in grey desert soil decreased gradually with increasing fertilization age. C/N in all soil decreased with increased soil depth among 0cm and 80cm, but surprisingly, C/N in soil with depth of 80-100cm was higher than that in soil with depth of 60-80cm. After 20 years of fertilization, C/N in black soil and grey desert soil showed no notable change. Compared with control treatment (CK), the treatments of N and NK decreased C/N in lou soil and red soil with depth of 0-20cm, but other treatments increased C/N in soil. Application of chemical fertilizers combined with manure (NPKM2) increased C/N in soil layers of fluvo-aquie soil. C/N in different soil layers was between 8.72 and 11.0, and the C/N in different soil were in an order of fluvo-aquic soil > black soil > grey desert soil > lou soil > red soil.
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