發(fā)布時間：2018-05-05 17:49

  本文選題：土壤磷素 + 淋溶閾值��； 參考：《西北農(nóng)林科技大學》2015年碩士論文

【摘要】：磷是作物必需的大量元素,土壤磷素水平和施磷量是保障農(nóng)作物高產(chǎn)和影響農(nóng)田磷素流失的主要因素。本研究選擇全國分布面積較廣的18種土壤,應(yīng)用室內(nèi)模擬結(jié)合數(shù)學模型,研究了不同類型土壤磷素淋溶的環(huán)境閾值,結(jié)合理化性質(zhì)探討了影響磷素淋溶風險的主要影響因子;以盆栽試驗為基礎(chǔ),根據(jù)作物產(chǎn)量對土壤有效磷的相應(yīng)關(guān)系研究了不同土壤冬小麥夏玉米達到最佳產(chǎn)量時的農(nóng)學閾值;以“國家黃土肥力與肥料效益監(jiān)測基地”24年長期肥料定位試驗為基礎(chǔ),利用長期試驗積累數(shù)據(jù)并結(jié)合相關(guān)土壤分析,探討X土上有效磷對冬小麥和夏玉米產(chǎn)量的影響、土壤有效磷隨全磷累積的變化規(guī)律、土壤磷的淋溶閾值;結(jié)果可為土壤磷素淋溶風險評價和預(yù)測、磷肥的合理施用和優(yōu)化土壤磷素管理提供科學依據(jù)。主要結(jié)論如下:(1)X土區(qū)冬小麥高產(chǎn)時土壤有效磷臨界值為26.2 mg·kg-1,夏玉米為13.9 mg·kg-1。土壤有效磷隨全磷的增加存在明顯的臨界點,當全磷含量為1.15 g·kg-1時,有效磷含量為34.8 mg·kg-1,高于此值后有效磷隨全磷快速增加。土壤有效磷含量大于39.3 mg·kg-1時,磷素淋溶風險增大。在無輪作體系的情況下,當土壤有效磷含量分別為25、25~40和40 mg·kg-1時,冬小麥施磷量分別為80~95、60~80和10~15 kgP2O5·hm-2;當土壤有效磷15、15~40和40 mg·kg-1時,夏玉米施磷量分別為70~85、55~70和10~15kgP2O5·hm-2。在冬小麥-夏玉米輪作體系下,當土壤有效磷含量分別為15、15~25、25~40和40 mg·kg-1時,冬小麥施磷量分別為100~120、90~100、80~90和15~20 kgP2O5·hm-2;夏玉米施磷量分別為50~60、45~50、25~40和5~10 kgP2O5·hm-2。(2)18種供試土壤P淋失臨界點處Olsen-P含量為14.9~119.2 mg·kg-1,CaCl2-P含量范圍為0.11~2.26 mg·kg-1。不同土壤磷素淋失閾值差異很大,與土壤pH、交換性鈣含量及呈極顯著負相關(guān)而與活性鐵鋁含量、粘粒含量及初始有效磷水平呈極顯著正相關(guān)(p0.01)。以土壤pH、有機碳、活性鋁、交換性鈣、交換性鎂、碳酸鹽、粘粒、初始Olsen-P和初始CaCl2-P含量為影響因素建立的數(shù)學模型,可為綜合評價土壤土壤理化性質(zhì)對土壤磷素淋溶風險的影響提供參考。(3)由8種土壤盆栽實驗得出,冬小麥土壤有效磷農(nóng)學閾值為13.1~26.2 mg·kg-1,夏玉米農(nóng)學閾值為9.78~16.0 mg·kg-1。有效磷含量為12 mg·kg-1可作為潮土農(nóng)學閾值。有效磷20mg·kg-1可作為X土、黃棕壤、紅壤和水稻土的農(nóng)學閾值。(4)供試土壤環(huán)境閾值約為農(nóng)學閾值1~4倍,不同土壤類型保障作物高產(chǎn)和水環(huán)境安全的有效磷含量范圍差異較大。小麥玉米輪作模式下,對于潮土、灰漠土、灌淤土等容易發(fā)生磷素淋溶的堿性土壤,有效磷含量應(yīng)控制在12~20mg·kg-1范圍內(nèi)。對于紅壤等酸性土壤,有效磷含量應(yīng)控制在20~40mg·kg-1。對于X土等石灰性土壤,有效磷含量應(yīng)控制在20~40mg·kg-1,但合理的施磷量應(yīng)低于紅壤等酸性土壤。
[Abstract]:Phosphorus is a necessary element in crops. Soil phosphorus level and phosphorus application amount are the main factors to ensure high yield of crops and to affect the loss of phosphorus in farmland. In this study, the environmental threshold of phosphorus leaching in different types of soils was studied by using indoor simulation and mathematical model, and the main influencing factors affecting phosphorus leaching risk were discussed in combination with physical and chemical properties. Based on pot experiment, the agronomic threshold of winter wheat and summer maize in different soils was studied according to the relationship between crop yield and soil available phosphorus. Based on the long-term fertilizer location test of "National Loess Fertility and Fertilizer benefit Monitoring Base" for 24 years, the effects of available phosphorus on winter wheat and summer maize yield were studied by using long-term experiment data and soil analysis. The change of soil available phosphorus with the accumulation of total phosphorus and the leaching threshold of soil phosphorus can provide scientific basis for evaluating and predicting the risk of soil phosphorus leaching, rational application of phosphorus fertilizer and optimization of soil phosphorus management. The main conclusions are as follows: the critical value of available phosphorus in winter wheat is 26.2 mg 路kg ~ (-1) and 13.9 mg / kg ~ (-1) in summer maize and 26.2 mg 路kg ~ (-1) in winter wheat. When the total phosphorus content was 1.15 g / kg-1, the available phosphorus content was 34.8 mg / kg ~ (-1). When the total phosphorus content was 1. 15 g / kg-1, the effective phosphorus content was 34.8 mg / kg ~ (-1). The risk of phosphorus leaching increased when the available phosphorus content was more than 39.3 mg kg-1. Under the condition of no rotation system, when the available phosphorus content in soil was 25 ~ 25N ~ 40 and 40 mg / kg-1, the P application rates of winter wheat were 80 ~ 95 ~ 5 ~ 60 ~ (-80) and 1015 kgP2O5 ~ (-2) h ~ (-2), respectively, and that of summer maize were 70855 ~ 55 ~ 70 and 10~15kgP2O5 h ~ (-2) when soil phosphorus was 15 ~ 1540 mg / h ~ (-1) and 40 mg / m ~ (-1) kg-1, respectively. Under the winter wheat-summer maize rotation system, when the available phosphorus content of soil was 15 ~ 15 ~ 15 ~ 25 ~ 25 ~ 2540 mg / kg-1 and 40 mg / kg-1, respectively, The amount of phosphorus applied in winter wheat was 100 ~ (120) ~ (90) ~ (90) ~ 100 ~ (-1) kgP2O5 ~ (-1) h ~ (-2) and that of summer maize was 50 ~ (60) ~ (45) ~ 50 ~ (25) C ~ (-40) and 5 ~ (10) kgP2O5 hm-2.(2)18, respectively. The content of Olsen-P at the critical point of P leaching was 14.9 ~ 119.2 mg 路kg ~ (-1) CaCl _ (2-P) in the soil, the range of which was 0.11 ~ 2.26 mg 路kg ~ (-1). There were significant differences in P leaching threshold between different soils, which were negatively correlated with soil pH, exchangeable calcium content and active iron and aluminum content, clay content and initial available phosphorus level, but positively correlated with soil pH, exchangeable calcium content and initial available phosphorus level. The mathematical model was established with soil pH, organic carbon, active aluminum, exchangeable calcium, exchangeable magnesium, carbonate, clay, initial Olsen-P and initial CaCl2-P as the influencing factors. The results showed that the threshold of available phosphorus in winter wheat soil was 13.1 ~ 26.2 mg 路kg ~ (-1) and that in summer maize was 9.78 ~ (16.0 mg 路kg ~ (-1). The available phosphorus content of 12 mg kg-1 can be used as the agronomic threshold. Available phosphorus 20mg kg-1 can be used as the agronomic threshold of X soil, yellow brown soil, red soil and paddy soil. The environmental threshold of tested soil is about 1 ~ 4 times that of agronomic threshold. The range of available phosphorus content in different soil types to ensure high yield of crops and safety of water environment is quite different. Under the wheat-maize rotation model, the available phosphorus content in alkaline soils, such as aquic soil, grey desert soil and irrigated silt soil, which is prone to phosphorus leaching, should be controlled within the range of 12~20mg kg-1. For acidic soils such as red soil, the available phosphorus content should be controlled at 20~40mg kg-1. For calcareous soils such as X soil, the content of available phosphorus should be controlled in 20~40mg kg-1, but the reasonable amount of phosphorus application should be lower than that in acidic soils such as red soil.
【學位授予單位】：西北農(nóng)林科技大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：S153;X144

【參考文獻】

相關(guān)博士學位論文 前1條

1 習斌;典型農(nóng)田土壤磷素環(huán)境閾值研究[D];中國農(nóng)業(yè)科學院;2014年

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本文編號：1848696