本文關(guān)鍵詞： 土壤肥力 空間變異 隸屬度函數(shù) 砂田 評(píng)價(jià)　出處：《中國農(nóng)業(yè)科學(xué)》2016年23期 　論文類型：期刊論文

【摘要】：【目的】砂田是西北干旱、半干旱地區(qū)農(nóng)民在惡劣的氣候、土壤和地形等自然條件下,為了生存經(jīng)過長期生產(chǎn)實(shí)踐不斷總結(jié)創(chuàng)新所形成的一種獨(dú)特的耕作方式。保持和提高砂田土壤肥力質(zhì)量是改善土地生產(chǎn)力、延緩砂田退化的基礎(chǔ)。【方法】按照10 m×10 m網(wǎng)格方式采集110個(gè)砂田土壤表層(0—20 cm)樣品,選取土壤有機(jī)碳、全氮、全磷、全鉀、速效磷、速效鉀、pH和電導(dǎo)率作為土壤肥力特征的評(píng)價(jià)因子,采用相關(guān)系數(shù)法確定各土壤肥力指標(biāo)的權(quán)重,根據(jù)寧夏砂田土壤特征和作物品種,選擇隸屬度函數(shù)曲線類型,同時(shí)確定隸屬度函數(shù)轉(zhuǎn)折點(diǎn)取值,然后根據(jù)各土壤肥力因子的權(quán)重和隸屬度值計(jì)算土壤綜合肥力指數(shù)值;利用地統(tǒng)計(jì)學(xué)分析方法構(gòu)建土壤各肥力因子的最適半方差函數(shù)模型,確定砂田土壤各肥力因子的空間變異特征和空間格局;結(jié)合土壤綜合肥力指數(shù)值及其空間分布狀況對(duì)砂田土壤肥力特征進(jìn)行分級(jí)評(píng)價(jià)�！窘Y(jié)果】經(jīng)典統(tǒng)計(jì)表明,pH的變異系數(shù)最小僅為0.01,表現(xiàn)為弱變異,均值為9.15,土壤呈堿性。其他肥力指標(biāo)變異系數(shù)處于0.10—0.72,屬于中等變異。通過極差可以看出各項(xiàng)土壤性質(zhì)含量在農(nóng)田尺度存在明顯的差異。研究區(qū)土壤綜合肥力指數(shù)值在0.18—0.59,平均值為0.34。地統(tǒng)計(jì)學(xué)表明,砂田土壤各項(xiàng)肥力指標(biāo)塊金系數(shù)均小于25%,呈現(xiàn)出較強(qiáng)空間自相關(guān)性。通過普通克里格空間插值圖可以看出,土壤有機(jī)碳在田塊尺度上分布較為均勻,含量集中在1.5—2.5 g·kg-1,在研究區(qū)南側(cè)有機(jī)碳有島狀高含量點(diǎn)存在;電導(dǎo)率分布也較為均勻,集中在100—300μs·cm~(-1),其在北部含量較高;土壤全氮、全磷和全鉀含量普遍較低,在空間呈現(xiàn)出明顯的斑塊狀分布特征;土壤速效磷和速效鉀在研究區(qū)北部有島狀高含量點(diǎn)存在;pH在整個(gè)研究區(qū)呈現(xiàn)明顯的斑塊狀分布特征。土壤綜合肥力指數(shù)值空間分布狀況表明,研究區(qū)Ⅲ類地分布最廣,占整個(gè)研究區(qū)面積的56%,屬中等肥力狀況。砂田南部以Ⅱ類地為主,占整個(gè)研究區(qū)面積的25%,肥力狀況良好。Ⅳ類地占整個(gè)區(qū)域面積18%,其肥力狀況較差。【結(jié)論】土壤性質(zhì)和土壤肥力指數(shù)在田塊尺度上空間分布復(fù)雜、規(guī)律性不明顯,呈斑塊狀分布特征。根據(jù)各項(xiàng)土壤屬性指標(biāo)和土壤綜合肥力指數(shù)值的分布情況判斷,砂田土壤肥力總體水平較低,其中有機(jī)碳和全氮是制約砂田土壤肥力的主要限制因子。應(yīng)通過增施有機(jī)肥、輪作和休耕等方式改良和培肥土壤。
[Abstract]:[objective] the sandy field is a kind of natural condition in the arid and semi-arid areas of northwest China, such as harsh climate, soil and topography. In order to survive, a unique farming method is formed through long-term production practice and innovation. To maintain and improve the soil fertility is to improve the land productivity. [methods] 110 soil samples of 10 m 脳 10 m grid were collected, and soil organic carbon, total nitrogen, total phosphorus and total potassium were selected. Available phosphorus, available potassium and pH and electrical conductivity were used as evaluation factors of soil fertility characteristics. The weight of soil fertility indexes was determined by correlation coefficient method, according to the soil characteristics and crop varieties in Ningxia sandy field. Selecting the type of membership function curve and determining the turning point of membership function, then calculating the soil comprehensive fertility index value according to the weight and membership value of soil fertility factor. The optimum semi-variance function model of soil fertility factors was constructed by using geostatistical analysis method, and the spatial variation characteristics and spatial pattern of soil fertility factors in sandy fields were determined. Combined with soil comprehensive fertility index value and its spatial distribution, the soil fertility characteristics of sandy field were evaluated. [results] Classical statistics showed that the minimum coefficient of variation of pH was only 0.01, showing weak variation. The mean value was 9.15, the soil was alkaline, and the coefficient of variation of other fertility indexes was 0.10-0.72. Through the range, we can see that there are obvious differences of soil properties in farmland scale. The comprehensive fertility index value of soil in the study area is 0.18-0.59. The average value was 0.34. Geostatistics showed that the block gold coefficient of each fertility index of sandy soil was less than 25, showing a strong spatial autocorrelation, which can be seen by the ordinary Kriging spatial interpolation map. The distribution of soil organic carbon in the field scale was more uniform, with the concentration of 1.5-2.5 g 路kg ~ (-1), while in the southern side of the study area, there were island high organic carbon content points. The conductivity distribution is also uniform, concentrated in 100-300 渭 s 路cm ~ (-1) ~ (-1), and its content is higher in the north. The contents of total nitrogen, total phosphorus and total potassium in soil were generally low, showing obvious patch distribution characteristics in space. Soil available phosphorus and potassium were found in the northern part of the study area. The distribution of pH in the whole study area showed obvious patch shape. The spatial distribution of soil comprehensive fertility index showed that the study area was the most widely distributed, accounting for 56% of the total area of the study area. In the south of the sand field, the type 鈪，

本文編號(hào)：1485791