摘要:

AbstractSpraying the potato variety Ulster Supreme with triphenyltin acetate delayed the spread ofPhytophthora infestansin 1960 and increased the gross yield of tubers from 13.5 in the unsprayed controls to 16.3 tons/acre. The sprayed plants also had fewer infected tubers and consequently the net weight of healthy tubers was increased by 3.8 tons/acre.A method for measuring triphenyltin acetate residues on celery was adapted to measure residues on potato leaves and tubers. The top and bottom leaves of plants had 31 and 36 p.p.m. of triphenyltin acetate immediately after the crop was sprayed; 2 weeks later the residues were 10 and 12 p.p.m. Tubers had<0.3 p.p.m. which was indistinguishable from the apparent content of tubers from unsprayed plants.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740130701

出版商:John Wiley&Sons, Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractIn vitroexperiments showing the effect of citric, orthophosphoric and malic acids and pH on the colour of various phenol‐iron complexes are described. Citric acid was the most important of these factors in reducing the intensity of colour of the chlorogenic acid‐iron complex, thus demonstrating its importance in after‐cooking blackening of pot

ISSN:0022-5142    

DOI:10.1002/jsfa.2740130702

出版商:John Wiley&Sons, Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractThe phenolic acids of tomato fruit wall tissue have been separated by paper chromatography.p‐Coumaric, caffeic, ferulic and chlorogenic acids were identified. The levels of these acids in healthy fruit wall tissue at different stages of maturity were higher than those found in ‚cloudy’︁ tissue. ‚Cloud’︁ tissue was found to have a lower content of phenolic acids than healthy tissue of the same age. During ripening of the fruit, the relative levels of caffeic and chlorogenic acids, and to a lesser extent of ferulic a

ISSN:0022-5142    

DOI:10.1002/jsfa.2740130703

出版商:John Wiley&Sons, Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractWinter and spring wheat were grown on a light soil without fertiliser‐N or with 100 lb. of N/acre applied as ammonium sulphate or ‚calcium nitrate’︁; dressings were applied in autumn or in spring. The same treatments were also applied to uncropped soil.Most of the nitrate‐N in unfertilised soil and that from ‚calcium nitrate’︁ applied in the autumn had been leached below 36 in. by the following March. Ammonium sulphate nitrified slowly on one plot, where the soil was acid, and the dressing applied in autumn was partly retained as ammonium‐N, but on other plots most of the nitrogen was nitrified and had been leached below 36 in. by the following March.With no crops, the mineral‐N content of unfertilised plots and of those receiving fertiliser‐N in the autumn, increased from March to August. Fertiliser‐N applied in the spring remained in the surface layers and would have been available to a crop throughout the growing season.Wheat removed both soil mineral‐N and fertiliser‐N from March onwards; by the end of May most of the fertiliser‐N applied in spring had been taken up from the soil by the crop. At harvest, the soil of all plots under wheat contained similar, small amounts of mineral‐N.Both unfertilised wheat and wheat receiving fertiliser‐N in autumn had maximum dry matter and N content at harvest. Dry matter produced by wheat with fertiliser‐N in spring also increased to harvest, but most fertiliser‐N was recovered in the crop in late May. Winter wheat had a similar total‐N content at harvest as in late May, but spring wheat contained less at harvest. For both spring‐ and autumn‐sown wheats, the apparent recovery of fer

ISSN:0022-5142    

DOI:10.1002/jsfa.2740130704

出版商:John Wiley&Sons, Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractBy suitably modifying a laboratory high‐speed mixer it was possible to study the effect of pressure during the mixing of mechanically developed bread doughs using both N.S.W. and Victoria breadmaking flours.Applied pressures in the 0‐40 p.s.i. range had no noticeable effect on bread quality although the mixing times for optimum results tended to decrease with increasing pressure. The decrease was greatest between 0 p.s.i. and 10 p.s.i. The work expenditure for optimum results closely paralleled the applied pressure‐mixing time relationship. The quantity of fast‐acting oxidising agent required was independent of applied pressure over the range employed.Equally good bread was made from both the flours used, but the mixing time and work done for optimum quality were less for the Victoria than for the N.S.W. flour at any given p

ISSN:0022-5142    

DOI:10.1002/jsfa.2740130705

出版商:John Wiley&Sons, Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractAs plant roots and soil organisms absorb oxygen and evolve carbon dioxide, they alter the gaseous composition of their environment. Molecular diffusion of these two gases between soil and atmosphere opposes this change and for optimum plant growth it must provide for interchange at a sufficient rate to avoid deficits of oxygen and excesses of carbon dioxide limiting to plant growth. Diffusion of gases in soil depends on the amount and distribution of the air‐filled pore space. Its sensitivity to moisture content depends on the pore‐size distribution and hence the soil structure. Two phases may be recognized in soil aeration: (1) gases diffuse within the macro‐pore spaces (usually air‐filled at field capacity), and (2) they diffuse within the microstructure between crumb surface and root surface in both the gaseous and aqueous phases. This second phase is of importance in naturally cohesive soils where the size and internal geometry of natural peds and cultivated crumbs can determine the adequacy of aeration in the micro‐environment of the root. Four soils from the continuous wheat plots of Broadbalk illustrate the importance of microstructure for which a possible index of quality is

ISSN:0022-5142    

DOI:10.1002/jsfa.2740130706

出版商:John Wiley&Sons, Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractThis paper examines the value of cultivation experiments in which crop yields are taken as a measure of the effects of different tillage treatments The soil properties important in plant growth, which can be influenced by cultivation, are discussed together with the problems of measuring these properties in the field. In particular, the importance of cultivations in water movement, the resistance of soil to root penetration and in aeration are considered. Experiments to measure the oxygen consumption of soils and plant root systems under near‐field conditions are briefly described and a method outlined of measuring the rates of diffusion of gases in soilin situ.Results are given of some preliminary experiments to examine the effects of soil physical conditions on oxygen consumptio

ISSN:0022-5142    

DOI:10.1002/jsfa.2740130707

出版商:John Wiley&Sons, Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractAn account is given of physical conditions that have been found in the profiles of cultivated soils in the eastern region. The origin of some of them is discussed. Many are of pedological origin, others result from cultivation. The origin and causes of adverse physical conditions, e.g., slaked structures, drainage patterns and pans, should be understood and treatment based on them. Cultivations, generally, should be related to soil conditions and the changes that are likely to occur in soil structures during the growth of crops.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740130708

出版商:John Wiley&Sons, Ltd    

年代:1962

数据来源: WILEY

摘要:

AbstractThe buffering capacity to lactic acid of a number of grass and legume samples has been determined, the results being expressed as mg. lactic acid required to lower the pH of 1 g. of dried, milled herbage samples to pH 4 (LBC values).LBC values of samples examined range from 22 to 66, the higher results being obtained with legumes. Of 6 grass species examined, cocksfoot shows the highest LBC values.Although the results show that there is a relationship between crude protein content and LBC, there is evidence that crude protein itself is not mainly responsible for the buffering capacity of silage crops. The importance of organic acids is discussed.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740130709

出版商:John Wiley&Sons, Ltd    

年代:1962

数据来源: WILEY