1,802 research outputs found
Oxygen-induced structural change of zirconia by adding rare earth oxides with solid state method
No full text1959 W.K. Kellogg Foundation Annual Report
Full text linkThe thought conveyed in our title was expressed by De Tocqueville in the19th Century but it surely is even more appropriate today. Hemisphericcooperation has become a significant reality in numerous fields of humanendeavor and through the programs of many international institutions andagencies not a few aspirations of man are global in scale. As man evolves,so grows his vision, so enlarge the potentialities from his strivings, and sodisappears much of his provincialism.The definition of a community — groups of persons bound together bya common interest and working for common purposes — can be applied notonly to a town and its area of influence but also to a nation or group ofnations. For a recent instance, two neighboring countries of North America,the United States and Canada, have, as a community venture, jointly ex-pended a billion dollars and four years of cooperative effort to build a newcoast for the continent.Several centuries after early explorers dreamed of a Northwest Passage,there came into reality last year a greater St. Lawrence Seaway that is chang-ing international trade routes, building immense ports on the Great Lakes,and booming industries and cities in Canada and the United States. Thisnew coast line of some 8,400 miles for North America is a working monu-ment to the friendship of the people of the two nations. Perhaps never beforein peacetime have two countries so united their resources for the commonwelfare
An Evaluation Method on Degree of Graphitization of Carbon Materials Under High Temperature and High Pressure
No full textAn Austral Christmas / by J.C.F. Johnson, author of "A fine fortune", "Over the island", "Moses and me", etc
No full text1st ed.: Adelaide : W.K. Thomas, 1888.Sketches and poems.Electronic reproduction.Johnson, J.C.F. (Joseph Colin Francis
The asymptotic global power comparisons of the GMM overidentifying restrictions tests
Full text linkIn this paper, the asymptotic power comparisons of two versions of GMM overidentifying restrictions tests are conducted globally through the concept of approximate slopes. It is found that the GMM overidentifying restrictions test with the consistent mean deviation variance-covariance matrix estimator is more powerful than the test with the conventional non-mean deviation one. The results shed new light on the findings of Chang (2005) and Hall (2000).Approximate Slopes Overidentifying Restrictions Test.
(26(1):25-41)GRAIN YIELD AND P-UPTAKE OF RICE PLANT AS RELATED TO P-FRACTION IN THE SOILS OF CENTRAL TAIWAN
No full text利用磷形態分佈，以研究土壤中有效態磷供應狀況，過去多以盆栽為主，田間資料缺乏。本試驗之用的在探討中部土壤所含磷形態對於盆栽與田間稻穀收量與磷吸取量之關係，俾供改進稻田磷肥管理與估計計磷肥供應之參考。經在本省中部（南投、影化、雲林及臺中）四種不同類別土壤土，選取20地點，同時舉行盆找與田問試驗以及室內化驗，所得結果摘要於下：
土壤中全磷及各形態磷含量與土壤母質及其化學性狀有密切關係。點板岩沖積土全磷含量最高，以Ca-P為主。其次為砂頁岩沖積土，以Fe-P為主。再次為混合沖積土，則以Ca-P與Fe-P為主。
稻穀收量或磷吸下量與土壤中各形態磷之關係，經單相關與複相關計算結果，以及栽培前後土壤中各形態磷之變異情形，均顯示水稻所攝取之磷以Fe-P為主；但Ca-P與一有機磷則有干撓作用，尤其在田間更為顯著，因而田間水稻磷吸取量與Fe-P之相關係數顯然較盆栽者為低，相對地降低其重要性。
在盆栽情形，水稻磷吸取量與土壤PH亦呈極顯著之負相關，而在田間更與粘土及有機物含量各呈顯著之負相關；相反地，土壤中Ca-P與有機磷之含量則與土壤pH、粘土及有機物含量有密切之正相關。因此，土壤中Ca-P與有機磷阻礙水稻磷吸不者，可能主要受土壤pH與粕土及有機物含量之影響。
綜上所言，水稻磷吸取量確與土壤中Fe-P有關，但其相關程度，在田間不如盆栽者強，此可能因在盆栽不排水情形與田間自然環境之下，由於粘土與有機物呈現不同效應所致。
The application of phosphorus fractionation to the study of plant available phosphorus has been applied by several workers. However, most of them were conducted in pot culture. Information regarding the response of rice plant to various forms of soil phosphorus in field conditions is still in meager. This experiment was carried out for understanding the relationship of soil P-fraction to grain yield as well as P-uptake of rice plant under both pot culture and field conditions in order to find out the behavior of soil phosphorus between them. Twenty field trials were conducted on four categories of alluvial soils (sandstone and shale alluvial soil, slate older alluvial soil, slate recent alluvial soil, and mixed alluvial soil) scattered in central Taiwan. Soil samples for pot culture were taken from the sites where field trials had been carried out. The result may be summarized as follows:
1. The analysis of total phosphorus content showed that slate alluvial soil was the highest, sandstone and shale alluvial soil, the second, and mixed alluvial, the third.
2. The result of soil phosphorus fractionation indicated that the slate alluvail soils were dominant in Ca-P, the sandstone and shale alluvial soils in Fe-P, and the mixed alluvial soils in both Ca-P and Fe-P. The Al-P and organic-P occupied in the range of 4-7 % and 14-20% of the total phosphorus of the soils, respectively. It was also found that the amount of various forms of soil phosphorus had much to do with the nature of the soils, such as pH, clay, organic matter, CEC, exchangeable Ca and Mg, and free iron oxides. It was worthwhile to mention that remarkably positive correlation was found between soil Ca-P and soil pH, and between soil organic-P and clay.
3. In comparing the change in the amount of total phosphorus and various forms of phosphorus before and after 4 consecutive cropping of rice in pot culture, it was found that the content of total phosphorus was higher in the soils treated with phosphorus but lower in the soils received no phosphorus. The Ca-P almost remained constant in the soil without phosphorus, but increased in the soils with phosphorus. The increase in organic-P was also found in the soils with phosphorus. The other forms of phosphorus including A1-P, Fe-P, and occluded-P decreased, more or less in all soils regardless whether phosphorus had been added or not . Although the transformation of various forms of soil phosphorus is influenced by the nature of the soil and cultural practices, highly positive correlation between P-uptake and Fe-P reduced in the soil treated with-out phosphorus after cropping was obtained. It provided the evidence that Fe-P was the main source of phosphate absorbed by rice plant under submerged condition.
4. The results of simple and multiple correlation of soil phosphorus to P-uptake also indicated that soil Fe-P was the main source of phosphate absorbed by rice plant. On the contrary, soil Ca-P was negatively correlated with P-uptake under both pot culture and field conditions. Furthermore, significantly negative correlation between P-uptake and soil organic-P was also found in field conditions. Consequently, the relative importance of soil Fe-P increasing P-uptake was minimized in field conditions.
5. Negatively close relationship of P-uptake to soil pH was found in both pot culture and field conditions. In addition, contents of clay and organic matter were also negatively correlated with P-uptake in field conditions at significant level. As mentioned before, soil Ca-P and organic-P was positively correlated respectively with soil pH and clay. Thus the inhibition of P-uptake of rice plant by Ca-P and organic-P may be attributed to pH and clay content of the soils tested.
In conclusion, phosphorus uptake of rice plant was highly related to soil Fe-P in pot culture provided without drainage, but less in field conditions. It is due probably to the difference in the function of clay and organic matter between them
(26(2):127-137)EFFECTS OF SOIL COMPOSITION ON THE RELA-TIONSHIPS BETWEEN SOIL TEST VALUES FOR PHOSPHORUS FERTILIZER REQUIREMENTS
No full text從20種土壤特性差異懸殊的中部土壤樣本與7種標準磷測定法所得測定值，經用直線及曲線複迥歸統計分析結果顯示各法所得磷測定值間之關係，可因參與土壤特性因子於其迥歸方程式中而獲得改善。在供試上壤中，受土壤特性因子影響最大者為pH, Cloy, Exch. Ca，及Extroctable Al，因而推測，若考慮土壤特性，則以上各法所得磷測定值對於檢定土壤中含磷狀況均具有同等功效。從而今後對於磷測定值之田間校正公式，似應包括有關影響土壤磷供應與作物對於磷吸取之土壤特性因子，藉可提高磷測定值的可靠性。
The purpose of this paper was to find out the effects of soil composition on the relationships between soil test values obtained by different procedures. Twenty soil samples including four categories covered a wide ranges in soil composition were taken in Central Taiwan where field trials were to be conducted. Soil P-test methods including Olsen, Bray, anion exchange resin, EDTA, water extract, Al-Abbas & Baber, and North Carolina, were selected to cover a wide range of testing procedures.
The results indicated that the correlation between the P—test values obtained by various procedures were found to be improved by allowing for the effects of soil composition, particularly with respect to pH, clay, exchangeable Ca and extractable Al. The high correlations thus obtained suggest that most of the P-test procedures will be of about equal of variation in soil composition. They also suggest that P test calibration equation should not only include the actual P-test value but also the variables representing soil factors which affecting the solubility of soil phosphorus and P-uptake of the crop
(26(2):138-146)EFFECTS OF SOIL COMPOSITION ON THE RELATIONSHIPS BETWEEN P-UPTAKE OF RICE PLANT AND SOIL TEST VALUES FOR PHOSPHORUS FERTILIZER REQUIREMENTS
No full text從20處田間試驗所得無磷區與施磷區之水稻磷吸取量與7種方法所得磷測定值以及田間供試土壤特性因子，經用直線及曲線複迴歸統計分析結果，顯示水稻磷吸取量，在供試地區受土壤特性因子的影響甚大，而受單獨磷測定值的影響則甚小。但各法所得磷測定值與水稻磷吸取量的迥歸方程式中，若參與適當土壤特性因子如pH、Clay等，則在第一期作之下，其關係均可獲得顯著改善；而在第二期作之下，若用Al-Abbas-P(NaOH-Na2C2O4）參予CEC於其迥歸方程式中，或用N. Caro ina-P(HCI-H2SO4)參與Exchangeable Ca時，兩者對於水稻磷吸取量之校正，均獲得極顯著的改進。該兩種方法所用抽取液性質懸殊，更可顯示參與土壤特性因子對於水稻磷測定值校正之重要。
從上結果，推測舉行磷測定值田間校正時，應減少土壤特性因子的過分影響，宜參照本省農田詳測資料，劃分為若干區域，分別進行，由於同一區域內，個別農田間之土壤特性未必完全一致，仍應採用本文所述方式IV或V或其他更適合公式，予以校正，藉可提高磷測定值估計稻田磷肥需要量的可靠性。
This paper was a continuation of the previous one for the purpose of obtaining the relationships between P-uptake of rice plant and soil P-test values as affected by soil composition participating in the calibration equation. The P-uptake of rice plant including grain and straw was obtained from plots treated with and without phosphorus from twenty field trials scattered in Central Taiwan. The soil composition and 8011 P-test methods were all the same as given in the previous paper.
The results indicated that P-uptake of rice plant under field condition was highly affected by soil composition but less by P-test value alone in the region. The relationships between P-uptake of rice plant and soil P-test values obtained by various procedures were generally improved, if allowance was made for the effects of soil composition, particularly with respect to pH and clay, in the case of the first crop. While in the second crop, the P-test calibration equation was remarkably improved either by adding the variable for CEC in Al-Abbas-P test value or by adding exchangeable Ca in North Carolina-P. As these two extractants (NaOH-Na2C2O4 vs HCI-H2S04) are extremely different in nature, it further confirms the importance of participating soil composition in the P-test calibration equation.
From the effects of soil composition on the relations between P-uptake of rice plant and soil P-test values that have been demonstrated, it is suggested that to reduce the effects of variation in soil composition for soil testing, a region may be partitioned into areas of relatively uniform soil and developing soil tests for these more uniform areas. As the variation in soil composition from paddy to paddy is unavoidable, the P--test calibration equation for grain yield may be improved by taking the form corresponding to regression IV or V as given in the paper or other fitting model to allow for variation in soil composition
Grondbeleid voor landbouw in de Europese unie
No full textDit artikel behandelt de interpretatieve mededeling van de Europese Commissie over de verwerving van landbouwgrond en het Europees recht. De mogelijke relevantie voor Nederland wordt besproken.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.OLD Geo-information and Land Developmen
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