| Based on the long-term fertilizer experiment in 'China National Soil Fertilizer Efficiency Long-term Monitoring Net Work (CNFFEMN)', the research systematically investigated the evolution of soil organic matter in different fertilization systems, systematically explored the effects of different fertilization on component of soil humus. The main results are as follows: (1) Long-term fertilizer absence, the content of soil organic matter is the lowest. Compared with the original, In Jilin black soil, Xinjiang gray desert soil and Chongqing purple soil, the contents of soil organic matter are increased; in Beijing drab fluvo-aquic soil, Shanxi loess soil, Hunan red soil and Chongqing purple soil, the contents of soil organic matter increased; in Henan fluvo-aquic soil, the contents of are decreased slightly. (2) Long-term fertilization of chemical fertilizers, in Beijing drab fluvo-aquic soil, Shanxi loess soil, Hunan red soil and Chongqing purple soil, the contents of soil organic matter are increased; in Henan fluvo-aquic soil, the content of soil organic matter almost has no change; in Zhejiang paddy soil, the content is increased slightly; in Jilin black soil andXinjiang gray desert soil, the contents of organic matter are decreased, compared with the original.(3) Long-term fertilizer absence, the contents of soil organic matter, humus and combination humus are all lower. Long-term fertilization of chemical fertilizer, the contents of soil organic matter, humus and combination humus are all higher. Long-term fertilization NPK combined with manure can remarkable increase the contents of soil organic matter, humus and combination humus. (4) Long-term fertilizer absence, the contents of soil humic acid, loose humus, and the ratio of humus acid to fulvic acid, the ratio of loose humus to tight humus are all decreased. The soil humus condition becomes poor. Long-term fertilization, especially NPK combined with manure (NPK+M), can remarkably increase the content of soil humic acid, fulvic acid and loose humus, increases the ratio of humic acid to fulvic acid and of loose humus to tight humus. The soil humus condition is improved, activation and renew of soil organic matter are prompt. Based on the long-term fertilizer experiments in 'China National Drab Fluvo-aquic Soil Fertilizer Efficiency Long-term Monitoring Net Work (CNSFFEMN)', the research systematically explored the evolution of the soil P fertility and effect on the forms, transformation and availability of soil inorganic P and organic P in different fertilization systems. The main results are as follows: (1) Inorganic P is the majority, makes up 70--80%of total P. Long-term P fertilizer absence, the contents of soil total P haven't changed too much in the majority of the sites, only in Hunan red soil where the available P content is lower, the reduction of soil total P is evident. But long-term P fertilizer absence, the contents of available P are greatly decreased, the soil is severely scant of P, P becomes the limiting factor of crops growth. (2) Long-term P fertilization, the contents of soil total P, especially available P, is increased. Chemical P fertilizer combined with manure (NPK+M) can prompt the accumulation of soil total P and available P, making the available P reaching a very high level in some soil. In such soil we might apply P fertilizer for3～5 years, then stop using P fertilizer and utilize the after-effect of P fertilizer. (3) In Zhejiang paddy soil, because the soil is submerged, the P is activated, further more a great amount of P is brought in with irrigation, whether applying P fertilizer or not, the contents of soil total P and available P are all increased in varying degrees. (4) Long-term P fertilizer absence can decrease the soil inorganic P obviously. In Beijing drab fluvo-aquic soil, Chongqing purple soil and Hunan red soil, the soil inorganic P content is decreased, but in Xinjiang gray desert soil inorganic P content is increased, this is probably resulted from its special planting system. (5) In Beijing drab fluvo-aquic soil, Chongqing purple soil and Xinjiang gray desert soil, Ca-P is the major form of soil inorganic P, the next is O-P. The percentage of Ca-P to total P is Xiniiang gray desert soil more than Beijing drab fluvo-aquic soil and its more than Chongqing purple Soil, the percentage ordered O-P opposite. In Hunan red soil, O-P is the majority of total inorganic P, the next is Fe-P. (6) Long-term P fertilizer absence, in Beijing drab fluvo-aquic soil, Chongqing purple soil and Hunan red soil Ca2-P, Ca8-P, Al-P and Fe-P content are all decreased, and O-P and Ca-10-P content which is hardly assimilated by crops are decreased too; and Ca2-P, Al-P, Fe-P and Ca10-P content are all decreased, but Ca8-P and O-P content increased in Xinjiang gray desert soil. Long-term application of P fertilization, the total inorganic P and various inorganic forms are all increased in each site. (7) Long-term P fertilization absence, the soil P is seriously exhausted; in Beijing drab fluvo-aquic soil, CaB-P, Ca2-P, O-P is the major source of available P, the next is Al-P and Fe-P, Ca10-P which is hardly assimilated may gradually transformed to available form; in Chongqing purple soil, the contribution of Ca2-P and Ca8-P to wheat and rice is far less than that of Al-P, Fe-P and O-P, with the reduction of available P O-P may easily transformed to available P; in Hunan red soil the contribution of Al-P, especially Fe-P, is far more than that of Ca8-P, Ca2-P, with the exhaustion of P, Ca10-P which is hardly assimilated by crops can be gradually absorbed; in Xinjiang gray desert soil, Ca2-P, Al-P and Fe-P and a bit of Ca10-P is the available source of P. (8) In Beijing drab fluvo-aquic soil, long-term application of chemical P fertilizer can prompt the transformation to available inorganic P, chemical P combined with manure can further prompt the transformation to available inorganic P, chemical P fertilizer combined with straw prompt the transformation from inorganic P to Ca10-P which is hardly absorbed by corp. In Chongqing purple soil, long-term application of chemical P fertilizer can improve the available transformation of soil inorganic P, application of chemical P fertilizer combined with straw can further improve the available transformation of inorganic P, application of chemical fertilizer combined with manure can prompt the transformation from inorganic P to O-P. In Hunan red soil, O-P, Fe-P that is hardly uptake is major form of soil inorganic P, application of chemical P fertilizer combined with manure there will be a large accumulation of Ca2-p, CaB-P, especially Al-P and Fe-P. (9) Moderately labile organic P is the major form of soil organic P, the moderately resistant organic P comes next, labile organic P and highly resistant organic P are less. Long-term P fertilizer absence, the content of labile organic P, moderately labile organic P and he moderately resistant organic P are all decrease at depth of 0～20cm, at depth of 20～40cm, the content of labile organic P, moderately labile organic P and the moderately resistant organic P are all decrease, but the Highly resistant organic P content is remarkably increase. Long-term application of chemical P fertilizer and chemical P fertilizer combined with straw, the content total, labile, moderately labile and are all increased, but the moderately resistant organic P content decrease at depth of 0～20cm; at depth of 20～40cm the content total, highly and moderately resistant organic P are all increased, while and the labile and moderately resistant content are decrease. Long-term application of chemical P fertilizer combined manure, content of soil total and all forms of organic are all remarkably increased; the order of the increment range is :labile organic P＞highly resistant organic P＞moderately labile organic P＞moderately resistant organic P. (10) Long-term P fertilizer absence, with the exhaustion of soil P, the potential availability of moderately resistant organic P is greater at depth of 0～20cm; the availability of labile organic is greatest at depth of 20～40cm; and main form by crop uptake is moderately labile organic P, crop may uptake moderately resistant organic P as well, the labile organic P contributes little to crop. Long-term application of P fertilizer and its cornbined with straw not only makes organic P accumulated in soil transformed to moderately labile form, but also makes the moderately resistant organic P transformed to other forms. Long-term application of chemical P fertilizer combined with manure, the soil organic P is mainly transformed moderately labile and labile forms. Basing on Beijing Changping fluvo-aquic soil long-term located fertilization experiment, the studies explore the effect of long-term different fertilization systems on the nutrient content, enzyme activity, micropopulation and microbiota and its relation to soil fertility. The main results are followed: (1)Long-term fertilization can increase soil organic matter, and available N content to different extent. Soil total P, and special available P content were lower without P fertilizer in long-term, and greatly lower than critical size 5ug/kg, become restriction element of crop growth. Long-term applying P fertilizer can promote soil total P and available P content significantly. Soil nutrient content can promote further when chemical fertilizers applied combining with organic manure and straw in the long-term. (2) Long-term balanced fertilization of NPK and especially combining NPK with manure or plant straw can improve the activity of soil enzymes as invertase, urease, phosphatase; long-term single fertilizing N, NK, PK, NP, decrease these enzymes activity; long-term fertilization decrease the activity of hydrogen peroxidase in soil. (3)The amount of soil microbe in the treatments of applying chemical fertilizers only was less than that of in long-term fallow soil. Soils of applying chemical fertilizers only had higher amount of microbe in the extent, and be greatly higher amount of some microbiota, such as nitfifiers and cellulose-decomposing bacteria. Soil of balanced fertilization of N, P, K (NPK treatment) had similar amount of bacteria, fungi and actinomycetes, but more amount of ammonifiers, nitrifiers and cellulose-decomposing bacteria in the extent, compare with N, NP, NK, PK treatments (unbalanced fertilization). Combined application N, P, K chemical fertilizers with manure or crop straw had a significant effect of increasing amount of soil microbe. Treatments of NPK+M, NPK+1.5M and NPK+S not only had more amount of soil bacteria, fungi and actinomycetes than those of in CK, N, NP, NK, PK, NPK treatments, but also had more amount of bacteria and actinomycetes than and similar amount of fungi with that of in fallow soil. (4) By correlation, stepwise regression and path analysis showed that soil nutrient content has a negative correlation with activity of soil hydrogen peroxidase, and positively correlation with the activity of invertase, urease and phosphatase. Total P and available P content had more direct impact to hydrogen peroxidase and urease activity in soil, and soil organic matter, total N, available N and K content mainly through total and available P content had indirect impact to its. Organic matter, total N, available N and K content had More direct impact, and total P and available P content had less direct impact on invertase activity in soil, and main impact of total P and available P on invertase activity in soil were indirect through soil organic matter, available N and K. Nutrient elements had less impact on phosphatase in soil. There was a positive correlation between the contents of soil nutrient and amount of soil microbe. Based on the long-term fertilizer experiments in "China National Soil Fertilizer Efficiency Long-term Monitoring Net Work", the research systematically explored the effect of different fertilization systems on nutrition and processing quality in wheat, corn and rice grain. The main results are as follows:As for the wheat quality: (1) Long-term N fertilization, the content of protein, total amino acid and essential in wheat grain are all increased. Long-term N fertilizer absence the content of protein, total and essential amino acid are all decreased in wheat drain. Application of NPK fertilizer combined with manure (NPK+M) can obviously the protein content, but can not increase the total and essential amino acid content of wheat grain. (2) Long-term application of N fertilizer has no evident effect on increasing wet gluten content. N fertilizer absence, the wet gluten content will be decreased. Application of NPK fertilizer combined with manure (NPK+M) or straw (NPK+S), wet gluten content is lower. (3) The content of protein, total and essential amino acid and wet gluten in different sites are very different in wheat grain. In Hunan red soil, the content is higher. (4) Long-term N fertilizer absence (PK), the dough stability, anti-extensogram ability is poor. Long-term N fertilization can improve the dough stability, anti-extensogram ability. Application of NP, NK or NPK combined with manure, especially NPK can further improve the dough stability and anti-extensogram ability. (5) The dough stability and processing quality of wheat yielded from Beijing drab fluvo-aquie soil are better and its from Chongqing purple soil are all poor. (6) Application of N fertilizer can improve the starch viscosity and falling number of wheat flour in different extent. (7) In Hunan red soil and Chongqing purple soil, the starch viscosity and failing number of wheat flour are all poor, amylase content is lower, the grain and flour's endurance for storing isn't good, so it isn't suited for processing. (8) Analyzing the wheat quality index, the effect of chemical fertilizers on improving wheat processing quality is better than that of NPK+M, especially on improving the dough stability and anti-extensogram ability, the synthetic effect of NPK or NP treatments is better.As for the corn quality: (1) The nutrient quality of the southern corn is better than that of northern corn, but the corn yield in the south is far less in the north. (2) Long-term N fertilization, the contents of protein, amino acid, essential amino acid in corn grain is increased to different extent. Long-term N fertilizer absence, the contents of amino acid in corn grain is decreased, but the effects on the protein are varied in different type of the soil. (3) Long-term P fertilizer absence, the crude fat content of corn grain is decreased. Long-term P fertilization, the crude fat content of corn grain is increased in most of the soil (except in Henan soil). (4) Long-term P fertilizer absence, the ash content of corn grain is decreased. Applying P fertilizer can increase the ash content. But the application of K fertilizer can't increase the ash content. (5) Long-term P fertilizer absence, the viscosity number of corn becomes relatively poor, otherwise the viscosity number becomes better. NPK+M, NPK+S, the viscosity number of com is increased further more. (6) Analyzing the effects of different fertilization systems on corn nutrient quality and processing quality, the effect of NPK balanced fertilization is the best.As for rice quality: (1)In Zhejiang paddy soil, Long-term fertilization can all increase the protein content of rice more or less. Long-term balanced fertilization can increase the content of total amino acid, essential amino acid and their components. (2) In Chongqing purple soil, balanced fertilization of NPK, NPK+M, NPK+S can all improve the ratio of brown rice and polished rice, improve husk rice quality. (3) In zhejiang paddy soil, long-term fertilization of chemical fertilizer alone, manure alone, or NPK combined with manure (NPK+M),ean all creased the ratio of brown rice and polished rice, the husk rice quality becomes lowered. (4) The effects of different fertilization on rice alkali digestion value, Burning temperature, vicose, amylose content are not apparent. (5) Long-term P fertilization, the ash content of rice is increased. Long-term K fertilization can't increase the ash content of flee, this differs from the results of the others'. (6) Long-term application of N fertilizer, the starch viscosity quality is decreased. Long-term NP fertilization, the starch viscosity quality is increased slightly. Long-term NK fertilization, the starch viscosity quality is improved further more. Long-term NPK balanced fertilization can improve the starch viscosity quality mostly. (7) In Zhejiang paddy soil, Long-term fertilization can all cause the rice viscosity quality decreased. In Chongqing purple soil, long-term unbalanced fertilization (N, NP, NK), the rice viscosity quality becomes poor. Long-term balanced fertilization of NPK, NPK+M, or applying manure alone, the rice viscosity quality is improved evidently. Based on the long-term fertilization experiments carried out in the CNSFFELTMN, the research explored the mechanism of soil function degradation (N, P and K unbalance) and its restoration. The main results are as follow: (1) Long-term fertilizers absence (CK), the content of soil N, P and K will be decrease, especially the available P content, available content of N, P and K are unbalanced is the principle reason of yield reduction. Applying N fertilizer alone in the CK soil can not restore the soil function and increase the yield. Only applying NP or NPK fertilizers or NPK fertilizers combined with manure can improve the soil nutrient unbalance, restore the soil function, and increase the crop yield remarkably. Of all treatments, the restoring effect of NPK and NPK+M is better and durable. (2) Long-term N or NK fertilization, the content soil available P is very lower contrasted with the available N and K content, this can cause soil N, P and K severely unbalanced, decrease the soil productivity. Applying N fertilizer alone or NK fertilizers in the soil of long-term N or NK fertilizer (N or NK treatment), the soil N, P and K unbalance will be further aggravated. Applying NP or NPK fertilizers in the same soil (N or NK treatment) can improve the absence of soil P, restore the soil function. Restoring effect is significant because the soil available N/P and K/P are decreased and available P content increases. (3) Long-term application of PK fertilizer without N fertilizer(PK treatment), the soil available P content is higher, soil available N and K content(especially N content) are very scant, the soil productivity is severely decreased. In the soil of long-term PK treatment, applying PK continually can further aggravated the unbalance of N, P and K, soil P is more and soil N is less, and the crop yield is the lowest among all the treatments. Stopping fertilization (restoration treatment CK), soil available P content is decreased, soil N, P and K unbalance is alleviated, and crop yield can be increased somewhat. Applying N or NPK fertilizer can restore the soil function, improve the N, P and K unbalance, increase the crop yield, and restoring effect is very significant. (4) Long-term applying NPK fertilizers, soil N, P and K content are high and balanced. But soil and crops is more dependence on fertilizer application. Stopping fertilization (restoration treatment CK), the reduction of soil N, P and K content is greater, the crop yield in the first season will be decreased more than 50%, the yield in the second season is very low as well. Only applying NPK fertilizer continually can sustain and increase the soil fertility and productivity. NPK fertilizer combined with manure (restoration treatment NPK+M), although the soil N, P and K content has been increased evidently, but the crop yield increment is not apparent. (5) In Hunan Red soil, long-term applying N, NK or NPK fertilizer may cause severe acidation. Soil pH is decreased from 5.7 to 4.6, and soil pH becomes the limiting factor of crop growth. Restoring this kind of soil with NPK alone can not acquire better effect, only NPK combined with lime can restore the soil function and productivity effectively. Based on the long-term fertilizer experiment in 'China National Soil Fertilizer Efficiency Long-term Monitoring Net Work (CNFFTMN)', the research synthetically investigated the effect of different fertilization system on the contents and distribution of NO3- -N in the soil. The main results are as follows: (1) Long-term N fertilizer absence (CK, CK0, PK) the NO3- -N contents in soil body are lower or extremely low. Long-term unbalanced fertilization (NK, N) without P fertilizer, the NO3 —N contents are increased in soil body. Long-term fertilization balanced N and P(NP, NPK) can decrease the NO3—N contents soil body. (2) In the different experiment sites, the effect of long-term NPK combined with manure or straw(NPK+M, NPK+1.5M, N-PK+S) on NO3 —N contents in soil body is different. In Hunan red soil, Xinjiang gray desert soil and Shanxi loess soil, long-term NPK combined with manure or straw (NPK+M, NPK+1.5M, NPK+S) can decrease NO3 —N contents in soil body further more, so it can decrease the leaching loss of soil N. But in Beijing drab fluvo-aquic soil, Henan fluvo-aquic soil and Jinlin black soil Long-term NPK combined with manure (NPK+M) or straw (NPK+S) can't obviously diminish the the NO3 —N contents; on the contrary, applying manure too much can largely increase the NO3 —N contents, so aggravates the probability of N leaching loss.
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