Effect Of Long-term Fertilization On Organic Carbon And Available Nutrient Contents In A Mollisol Of Northeast China

The study on national soil fertility and fertilizer efficiency long term monitoring base as the platform, to explore the long-term application of chemical fertilizer,organic fertilizer, organic fertilizer and chemical fertilizer on soil organic carbon and alkaline hydrolysis nitrogen, available phosphorus, available potassium content and humic substances structural characteristics influence. The test includes two kinds of Fertilization Scheme(12, 24).12 district experiment comprises the following steps: leisure, no fertilizer(CK), chemical fertilizer(N, NP, NK, PK, NPK), organic inorganic fertilizer(NPKM1, NPKM2, 1.5NPKM), organic fertilizer(straw NPKS),corn soybean rotation(NPKM(2)); the 24 experiment includes the following treatments: no fertilizer(CK), chemical fertilizer(N,P, K, NP, NK, PK, NPK), single application of low amount of organic fertilizer(M2), low amount of organic and inorganic fertilizer(M2N,M2 P, M2 K, M2 NP, M2 NK, M2 PK, M2NPK), single application of high amount of organic fertilizer(M4), high amount of organic and inorganic fertilizer(M4N, M4 P, M4 K, M4 NP,M4NK, M4 PK, M4NPK). The main results are as follows:1、Results of long-term fertilization on soil surface and subsurface organic carbon content showed that the content of surface soil organic carbon were higher than that of the subsurface. 12 district positioning test,compared with the leisure fertilization soil organic carbon content decreased significantly; and no fertilizer and chemical fertilizer treatment compared, organic fertilizer and chemical fertilizer,soil organic carbon content was significantly increased, the order for the 1.5NPKM1 > NPKM2 > NPKM1 >NPKS, application pig manure was better than the effect of application of maize straw; continuous cropping of corn and corn- soybean rotation between no significant difference. From 2008 to 2012, with the extension of years of fertilization of soil organic carbon content tended to be stable; leisure processing performance is decreased first and then increased trend; single application of N,NP, NK, PK treatment first decreased and then tended to be stable, and NPK treatment showed a trend of first increased and then decreased; organic fertilizer and chemical fertilizer was increased.24 position test, with the increase of organic fertilizer, soil organic carbon content was also increased, which with high amount of organic fertilizer and phosphorus and potassium fertilizer(M4PK) soil organic carbon content was the highest. From 2008 to 2012, with the extension of years of fertilization, the treatment of low amount of organic fertilizer of nitrogen, potassium, phosphorus and potassium M2 NK, M2 PK outside, other treatment of soil organic carbon content are decreased with the prolonging of time and increase.2、Long term fertilization on the soil surface and sub surface alkali solution N,available P, available K content influences the results showed that soil nutrient content was higher than that in the subsurface. 12 district positioning test, compared with the leisure, no fertilization treatment on soil alkali solution N content did not significantly affect,and available P and available K content decreased significantly; with no fertilizer and chemical fertilizer treatment compared,organic fertilizer and fertilizer treatment of soil available nutrient contents. The order for the 1.5NPKM > NPKM2 > NPKM1 > NPKS, application pig manure is better than the application of maize straw, and corn continuous cropping treatment compared to corn soybean rotation on the soil alkali solution N, available phosphorus content had no significant effect, but the content of soil available K significantly increased the. From 2008 to 2012,during the 5 years of fertilization,the contents of N in soil alkaline solution were basically decreased. Effective P content changes: leisure treatment no major changes in the CK treatment, and the basically maintained at a level, the application of chemical fertilizer treatment N, NK treatment showed the first increased and then decreased with time, NP,PK treatment showed a trend of decreased first and then increased, NPK treatment varies with time showed an upward trend, with organic and inorganic Shi treatment showed a trend of decreased first and then increased. The content of available K: NPKs,NPKM2 treatment remained essentially unchanged,N、NP treatment showed a downward trend, the other fertilization treatment increased, the control treatment showed a trend of decreased first and then increased.Area 24 position test,compared with no fertilizer,chemical fertilizer nutrient content in soil did not change; with fertilizer compared to single application of low volume, high quantity organic fertilizer and organic fertilizer and chemical fertilizer treatment significantly increased the content of soil nutrients in and with the increase of organic fertilizer,soil alkali solution N, available K, available P content also increases. With the increase of fertilization period, soil available N content, chemical fertilizer treatments decreased(except for 2008 N fertilizer treatment), low amount of organic manure combined with chemical fertilizer treatment decreased at first and then increased, the high amount of organic manure combined with chemical fertilizer treatment,M4 CK, M4 P and M4 K are presented the increase trend, M4 N decreased year by year, M4 NP, M4 NK, M4 PK,M4NPK increased first and then decreased and then increased; soil P content,chemical fertilizer M0 K treatment did not change, M0 NK and M0 NPK increased first and then decreased,M0 CK, M0 N, M0 P, M0 NP, M0 PK and soil treatment decreased first and then increased; low weight(M2) organic manure combined with chemical fertilizer treatment,M2 CK, M2 N, M2 P, M2 K, M2 NP, M2 NPK basically decreased with the trend,M2 NK and M2 PK increased(M4); high amount of organic manure combined with chemical fertilizer treatment,all treatments were the change trend of first decreased and then increased. The change of soil available K,single application of chemical fertilizer treatment was first increased and then decreased trend; low amount of organic fertilizer application(M2NK, M2 PK, M2NPK) fertilizer treatment is basically an upward trend, the other treatment was first decreased and then increased trend; high amount of organic manure and inorganic fertilizer, M4 NP treatment showed a trend of decreased first and then increased,other treatment was increasing trend.3、The effects of long term fertilization on different particle size in soil organic carbon content results show that the surface soil, compared with no fertilizer, compared to single application of chemical fertilizer in addition to NK, PK treatment, sand, clay, silt content are not changed significantly; and application of chemical fertilizer, organic fertilizer and fertilizer treatment(NPKM1, NPKM2, 1.5NPKM), sand content increased significantly, the silt content no significant change,clay content decreased significantly. Compared with no fertilization, fertilization the weight of the sand in subsurface soils increased significantly while the silt,clay did not change significantly.Compared with no fertilizer and chemical fertilizer,organic fertilizer to sand, silt, clay and organic carbon significantly increased, pig manure is better than that of corn stalk and rotation effect is better than that of continuous cropping, crop rotation is most conducive to the increase of the content of organic carbon in soil.4、Reduce using elemental analysis and solid state 13 C nuclear magnetic resonance method,of soil humic substances structural characteristics research results show that: and compared to the control, chemical fertilizer, humic acid condensation, alkylation, hydrophobic degree of increase, reduce the degree of aliphatic; with fertilizer compared, nitrogen organic fertilizer and organic fertilizer and chemical fertilizer treatment after humic acid condensation degree, hydrophobic degree, alkylation, aliphatic degree increased.Compared with the control, single application of chemical fertilizer, humin condensation degree and hydrophobic degree decreased, aliphatic, alkylation levels increased; with fertilizer compared to apply organic fertilizer and organic fertilizer and humin condensation degree, aliphatic degree increased after the treatment of fertilizer application, a degree of hydrophobicity,the alkylation degree reduced.