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Variation of Soil Nutrients and Coupling of Soil Water-Nutrients in Typical Red Soil with Long-Term Fertilization

Author: DuZhenJie
Tutor: ChenXiaoMin
School: Nanjing Agricultural College
Course: Soil
Keywords: In red soil region Soil moisture Soil nutrients Geostatistics Spatial variability Fertilizer coupling
CLC: S158
Type: Master's thesis
Year: 2009
Downloads: 59
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Abstract

Red soil is one of the major soil types in southern China, its vast area, accounting for 22.7% of the total land area of ??the country, plays an important role in China's grain production. Caused due to the red soil of the special nature and unreasonable fertilization, soil acidification and nitrogen and phosphorus pollution, resulting in the deterioration of the ecological environment of the red soil areas. Therefore, how scientific and rational development and utilization of red soil resources, the path of sustainable development, the research focus of the discipline of our soil. Selected Hunan the Qiyang hilly district typical red soil tested soil, sentinel surveillance of the area in different periods, different fertilizer treatments nitrate, ammonium nitrogen and available phosphorus soil nutrients and moisture content, are fast-acting their transport mechanism, the spatial and temporal variability of nutrients and moisture in the soil and fertilizer coupling conditions, and the use of geostatistics interpolation processing, scientific fertilization red soil areas trying to rational use of water and fertilizer resources and take the sustainable development of agriculture road to provide a scientific basis. The main findings of this paper are as follows: (1) determination of moisture diffusion device tested red soil at four soil layers N03 - N content and the level of migration status: Horizontal Transport of Nitrate rate with soil moisture increase and a corresponding increase in an exponential curve; decreases rapidly with the increase in migration distance, exponential function curve. Have a good correlation of the nitrate level migration rate and migration distance. Horizontal Transport of Nitrate concentration is closely related to soil moisture content decreased with increasing water content, and exponential function curve. Horizontal Transport of Nitrate concentration also influenced by soil moisture diffusion rate decreased with increasing soil water diffusivity and logarithmic curve. Maximum nitrate concentration in the wetting front (wet and dry soil on the interface). (2) in the period from March 2007 to March 2009, the red soil tested four plots with soil N03 - N and NH4-N content of the time change and profiles of vertical change. The results show that: the plots with soil surface N03 - N and NH4-N content is generally low, while the bottom layer, including single of nitrogen fertilizer residential soil deposition layer in May 2007 (32-42cm) N03 - N NH4-N content of the highest and the soil surface (0-25cm) were 248.34 mg · kg-1 and 127:24 mg · kg-1, which is due in April and May for winter wheat jointing - the flowering period, the The required nutrient surge due to a large number of top-dressing. N03 - N and NH4-N content in in NPK plot and NP cell soil layer was extremely significant positive correlation between the straight-line linear, single application of the performance of the the N district and the blank cell varies; each plot soil NO3- -N and NH4-N content of the organic matter content was positively correlated with the index curve. (3) in the period from March 2007 to March 2009, four red soil tested to deal with the district soil available phosphorus content of the time change and profiles of vertical changes. The results show that: the plots with soil available phosphorus content in the surface layer higher, while the ground floor is generally low; March, May and November, with higher levels of available phosphorus and other months are relatively low. Fertilizer including nitrogen and phosphorus in March 2007 to deal with the highest content of the surface soil, 121.87 mg · kg-1. Soil organic matter, aggregate structure and pH is an important factor affecting soil available phosphorus content, organic matter and available phosphorus was a significant positive correlation (P lt; 0.05), low red soil organic matter content, organic fertilizer production should increase application rate; exponential curve the CK cell layers of soil aggregates and available phosphorus content. (4) using a combination of methods of classical statistics and geostatistics, distribution grid method stratified (0-20cm ,20-40cm) samples of the Hunan typical of upland red field scale soil moisture, organic matter and Spatial Variability of Nitrogen. The results show that: soil nitrogen and organic matter content decreases with increasing depth, the nitrate content was a tendency to increase with increasing depth. This is due to the Nitrate easily migrated to the lower layer with the water. The two soil nitrate coefficient of variation (41.96% -62.08%) is much higher than the nitrogen and organic matter coefficient of variation (5.88% -18.82%); half the variance of each variable variogram CO / (CO C) are large less than 0.75 to 0.25, moderate and weak space autocorrelation, which indicates that the total nitrogen, nitrate nitrogen, organic matter, and soil moisture in the study area has a spatial structure similar spatial correlation distance. Between soil total nitrogen, organic matter and nitrate nitrogen and soil moisture showed a significant correlation (P lt; 0.01, n = 96). (5) of the tested red soil NPK (NPK), nitrogen and phosphorus (NP), nitrogen (N), blank (CK) and organic fertilizer NPK fertilizer (NPKOM) cell nitrate, ammonium nitrogen, The coupling of the three available phosphorus available nutrients and soil moisture study results showed that the four residential soil: not organic fertilizer NPK (NPK), nitrogen and phosphorus (NP), nitrogen (N), blank (CK) in NO3 - N, NH4-N and available P and soil water content were highly significant correlation (n = 112, P lt; 0.01); organic fertilizer and NPK fertilizer the cell (NPKOM) soil NO3 - N, NH4-N and available phosphorus in three fast-acting nutrients and soil moisture also showed a significant negative correlation (n = 40; P lt; 0.01). Seen, the study area, soil moisture and available nutrients there is a better coupling;, more conducive to the role of water and fertilizer coupling organic manure can improve soil aggregate structure and physicochemical properties.

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