發(fā)布時(shí)間：2018-03-03 21:28

  本文選題：延安市　切入點(diǎn)：土壤養(yǎng)分　出處：《西北農(nóng)林科技大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：以縣域測(cè)土配方施肥項(xiàng)目為依托,選取陜西省延安市各區(qū)縣耕地地力評(píng)價(jià)土壤采樣檢測(cè)數(shù)據(jù),其中,有機(jī)質(zhì)31428個(gè),有效磷31201個(gè),速效鉀31248個(gè),全氮23816個(gè),速效氮30252個(gè)以及pH30907個(gè),應(yīng)用地統(tǒng)計(jì)學(xué)與GIS相結(jié)合、層次分析和多元回歸分析相結(jié)合的方法,分析延安市土壤養(yǎng)分空間變異和影響因素,進(jìn)行區(qū)域耕地地力評(píng)價(jià)。取得的主要研究成果如下:(1)研究區(qū)土壤有機(jī)質(zhì)含量平均值為9.24 g/kg,位于陜西省第二次土壤普查土壤養(yǎng)分含量分級(jí)標(biāo)準(zhǔn)的第7級(jí),土壤全氮、有效磷、速效氮含量平均值分別為0.59 g/kg、9.94 mg/kg、40.46 mg/kg,均位于分級(jí)標(biāo)準(zhǔn)的第6級(jí),速效鉀含量平均值為121.57 mg/kg,符合3級(jí)標(biāo)準(zhǔn),土壤酸堿度pH值在6.8~9.4之間,平均值為8.09,符合4級(jí)標(biāo)準(zhǔn)。延安市土壤養(yǎng)分除速效鉀外均處于較低水平,土壤整體呈弱堿性。(2)研究區(qū)土壤有機(jī)質(zhì)、全氮、速效氮擬合的最優(yōu)半方差函數(shù)模型為球狀模型,有效磷和速效鉀擬合的最優(yōu)半方差函數(shù)模型為指數(shù)模型,pH值擬合的最優(yōu)半方差函數(shù)模型為高斯模型。6種土壤養(yǎng)分塊金系數(shù)均介于34%~53%之間,均屬于中等程度相關(guān);土壤養(yǎng)分分維數(shù)較高,均介于1.832~1.939之間。綜合半方差函數(shù)、分維數(shù)分析,研究區(qū)6種土壤養(yǎng)分空間相關(guān)性明顯。(3)研究區(qū)土壤有機(jī)質(zhì)呈南高北低,西高東低;土壤pH、速效氮呈南高北低,東高西低;土壤全氮從西南向東北方向遞減;土壤速效鉀、有效磷呈南高北低格局。(4)研究區(qū)土壤養(yǎng)分對(duì)年降水量、≥10℃積溫和日照時(shí)數(shù)等氣象因子均在0.01水平上達(dá)到顯著相關(guān),年降水量、日照時(shí)數(shù)對(duì)速效鉀和有機(jī)質(zhì)影響強(qiáng)于其他養(yǎng)分,≥10℃積溫對(duì)速效氮的影響最大;除有效磷與坡度不相關(guān)外,均與海拔、坡度和起伏度等地形因子在0.01水平上呈顯著相關(guān)性;地貌類型對(duì)土壤養(yǎng)分含量有影響,土壤類型對(duì)土壤養(yǎng)分含量影響顯著。(5)研究區(qū)耕地總面積4266.64km2,其中,一級(jí)地16.80%,二級(jí)地18.52%,三級(jí)地10.65%,四級(jí)地21.78%,五級(jí)地24.55%,六級(jí)地7.70%,一、二、三級(jí)地主要分布在延安南部洛川-黃陵-富縣一帶的黃土塬地貌區(qū)和東部延川-延長-宜川一帶的黃土塬、梁地貌區(qū),四、五、六級(jí)地大面積分布在延安北部各縣。
[Abstract]:Based on the county soil test and fertilizer application project, the soil sampling data of farmland land fertility evaluation in Yanan City, Shaanxi Province were selected. Among them, 31428 organic matter, 31201 available phosphorus, 31248 available potassium, 23816 total nitrogen, 30252 available nitrogen and pH30907. The spatial variation and influencing factors of soil nutrients in Yan'an were analyzed by combining geostatistics with GIS, hierarchical analysis and multiple regression analysis. The main results obtained are as follows: 1) the average value of soil organic matter content in the study area is 9.24 g / kg, which is located in the 7th grade of the classification standard of soil nutrient content in the second soil census of Shaanxi Province, with total nitrogen and available phosphorus in the soil. The average available nitrogen content was 0.59 g / kg ~ 9.94 mg / kg ~ (-1) mg 路kg ~ (-1) 路kg ~ (-1), respectively, which were in the sixth grade of the classification standard, and the average available potassium content was 121.57 mg / kg, which was in accordance with the third grade standard, and the pH value of soil pH was between 6.8 mg / kg and 9.4, respectively. The average value is 8.09, which accords with the 4th grade standard. The soil nutrients in Yan'an are at a lower level except available potassium, and the soil is weak alkaline. 2) the optimal semi-variance function model for fitting soil organic matter, total nitrogen and available nitrogen in the study area is spherical model. The optimal semi-variance function model for fitting available phosphorus and available potassium was exponential model and pH value fitting. The best semi-variance function model was Gao Si model. The gold coefficients of 6 kinds of soil nutrients were between 34% and 53%, which were all of moderate correlation. The fractal dimension of soil nutrients was between 1.832 and 1.939.Comprehensive semi-variance function and fractal dimension analysis showed that the spatial correlation of 6 kinds of soil nutrients in the study area was obvious. The soil organic matter in the study area was high in the south and low in the north and the east in the west. Soil pH, available nitrogen was high in the south, low in the north, low in the east and high in the west; total nitrogen in the soil decreased from southwest to northeast; available potassium and available phosphorus were in the pattern of high and low in the south and north. Meteorological factors such as accumulated temperature 鈮，

本文編號(hào)：1562758