ISSN:0190-4167    

DOI:10.1080/01904169009364076

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0190-4167    

DOI:10.1080/01904169009364077

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The yield of a given crop is a function of all the variables or limiting factors imposed on the crop. These variables interact; and when the interaction is sequentially additive, they are adequately described by the Mitscherlich version of the Law of the Minimum. When synergistic interactions occur, it is because the Liebig version of the Law of the Minimum is in effect. With Liebig‐type stresses, no great response to yield can be obtained until the factor in greatest limitation is corrected. In contrast, with Mitscherlich‐type stresses, responses are in proportion to input and degree of deficit with predictable outcome. Order of input is of no physiological importance with Mitscherlich stresses so the emphasis may be placed on economics in choice of inputs. Successful diagnosis of problems in crop production requires that Liebig and Mitscherlich‐type stresses be identified as such since order of correction as well as decisions concerning which stresses are corrected depend upon the results. Especially when stresses are in Mitscherlich‐type limitation, numerical values of 1.00 or less can be assigned to each with 1.00 being no stress. Resulting yield will be the product of all stresses multiplied together. Inputs to overcome multiple Mitscherlich‐type limitations can result in large yield increases because of sequential additivity. Use of these concepts to develop high yields can be called the Law of the Maximum. The concepts can also be used to guide advances in biotechnology. Expectations for crop yields must variously consider the limitations imposed by land area, availability of capital and the environment.

ISSN:0190-4167    

DOI:10.1080/01904169009364078

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Stresses and procedures to overcome stresses react with each other in various ways. Some kinds of interactions are sequential additivity, various types of synergism, and various types of antagonism which at times are protective. The kind of interaction is related to whether or not the stresses or limiting factors represent Liebig or Mitscherlich conditions. Crop yields are related to all these phenomena. Because of many different situations in which sequential additivity explains the interactions among two or more stresses (or promoters) acting simultaneously on biological systems, it is suggested that sequential additivity can be one of the unifying concepts in biology. Sequential additivity is that if two or more single stresses result in various reductions in activity, the result when they stress simultaneously is the product of the numerical values of the degree of stress of each relative to 1.0. Reverse but identical effects hold for promotors. Observed or reported examples include multiple trace element toxicities in plants, effects of multiple management practices in improving crop yields in agriculture, combined effects of tobacco and alcohol on human health, effects of two simultaneously applied herbicides on plants and effects of two trace elements not known to be essential to plants on plant growth when applied simultaneously.

ISSN:0190-4167    

DOI:10.1080/01904169009364079

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Tomatoes were grown in Yolo loam soil in a glasshouse with factorial combinations of N, P and a water‐soluble polymer soil conditioner. Individual responses, respectively, were 103, 26 15 percent when used alone. When all three were used together, there were synergistic effects with 190, 80 and 64 percent responses, respectively, for each of the three inputs. Each was a Liebig‐type limiting factor but by comparing the sum of two inputs together with the total response for all three, it could be shown that sequentially additive interactions had occurred at those levels for N and polymer. The P was the most Liebig‐type limiting factor, even though there were greater responses for N. Use of the polymer was important to obtaining high yields.

ISSN:0190-4167    

DOI:10.1080/01904169009364080

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

An Fe‐efficient and an Fe‐inefficient cultivar of soybean were grown in calcareous Hacienda loam soil with FeEDDHA, P and N fertilizers in factorial combination. With the Fe‐efficient cultivar (Hawkeye), there was response to Fe alone (40 percent) and very small responses to P alone (5 percent) and N alone (13 percent). When N and P were combined there was antagonism. The Fe with P and Fe with N both gave sequentially additive interactions or very near. When all three inputs were combined the responses to Fe, P and N, respectively, were 80, 35, and 44 percent, and the interaction was synergistic. Each nutrient was a Liebig‐type limiting factor. With T‐203 soybean, FeEDDHA gave no response when used alone, and N and P singly and together were very antagonistic. When all three nutrients were supplied simultaneously, the interaction was synergistic with responses to Fe, P and N, respectively, 569, 471, and 116 percent. Even after Fe had been supplied, the N and P were Liebig‐type limiting factors. Yields were greater for this treatment with the Fe‐inefficient cultivar than with the efficient one. Iron and P analyses were partially successful for diagnosis of deficiencies.

ISSN:0190-4167    

DOI:10.1080/01904169009364081

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

In an experiment widely discussed in the literature involving Valencia orange trees, N, P and K fertilizers were applied in factorial combinations. Individual responses were 6, 5 and 23 per cent respectively for the N, P and K. The total response when all three were applied simultaneously was 40 per cent compared with the 37 per cent predicted by sequential additivity or 34 per cent for simple addition. The individual responses for the three when applied together were 8, 7 and 26 respectively for N, P and K. When K and P and also K and N were combined, the interactions were also sequentially additive. The N, P and K in all these treatments were Mitscherlich‐type limiting factors. When N and P were applied together without K, a severe antagonism resulted with large yield decrease. Addition of K to this treatment resulted in a 69 per cent yield increase. Potassium was a Liebig‐type limiting factor only to N and P together, but not to N or P individually. An alternative procedure to DRIS analysis is suggested.

ISSN:0190-4167    

DOI:10.1080/01904169009364082

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

In a field plot experiment conducted in New Jersey with alfalfa (Medicago sativacv. Ranger) in 1945 to 1948, responses to K and P fertilizers at 66 kg ha each for K2O and P2O5were sequentially additive when combined. For the year 1948, K deficiency had decreased the yield considerably for the control and the relative yields for control, K2O, P2O5, and K2O plus P2O5, respectively were 1.00, 1.52, 1.22, and 1.64. Further yield increases were obtained for additional K2O (17%), for Mg (5%), for liming (11%), and for Mo (4%). Experimental design did not permit testing of these four additives for sequential additivity, but since sequential additivity is added to sequential additivity, a relative yield of 2.33 would be possible for simultaneous use of all four to give a maximum yield of 12.1 MG ha‐1dry weight instead of the 8.5 obtained for the 66 kg ha‐1each of K2O and P2O5in 1948.

ISSN:0190-4167    

DOI:10.1080/01904169009364083

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Responses to inputs and interactions were evaluated for test plots with alfalfa (Medicago sativaL., cv. Apollo) in two field experiments conducted in Georgia and reported in the literature. In one test, lime, K at two levels, and P at two levels were interacted in various ways to give a total of 18 treatments. When applied individually, the greatest response was to K with little response to P and intermediate response to lime. When lime and K or lime and P were combined, the interaction appeared to be slightly antagonistic. When P and K at low rates were combined, the interactions were sequentially additive with little response to P. As rates of P and K were increased, slight antagonism may be involved in the interactions. Only when the high rates of P and K were applied with the lime was it possible to correctly identify or diagnose the nature of the interactions and types of limitations involved. The K was a Liebig‐type limiting factor, lime was a modest‐type limiting factor, and the P tended, to be a Mitscherlich‐type limiting factor. One consequence is that a strong response to P could be expected only after the lime and K needs were supplied. In the second experiment, K, Mg, two levels of lime, and two levels of P were interacted. Both P and lime dominated the effects in the test. There was modest response only to K; Mg seemed to slightly increase the need for K, although the DRIS indices did not indicate this. The largest yields were obtained for the highest input of two variables—lime and P. The Mg decreased yields some without K and had no net effect with K as an average of all treatments. The P gave largely Mitscherlich‐type limitations, even though there was large response to it. The average response to P with Mg was 129% and 100% without Mg. The average response to P with K was 125% and 118% without K. The average response to P with lime was 112% and 147% without. There were greater relative yields with lime than without, however. Each pair of percentage responses should be equal to be fully Mitscherlich or sequentially additive. The increases in relative yield for P+Mg, P+K, and P+lime respectively, were 1.36 minus Mg and 1.63 plus Mg, 1.49 minus K and 1.79 plus K and 1.48 minus lime and 1.74 plus lime. The highest relative yield obtained in one experiment was 4.52 for lime and P inputs, but the data indicated that addition of K and Mg should have increased it to 5.30 or higher according to the Multiple Faction Yield Plot (MFYP). Other limiting tractors are then implicated due to K and Mg antagonisms.

ISSN:0190-4167    

DOI:10.1080/01904169009364084

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Data from a published paper [Rehm (1984)] were used to illustrate different interactions encountered between N and P fertilizers in a five‐year field test of a mixture of grasses. In a 5 × 5 factorial experiment, sequentially additive, synergistic, slightly synergistic, and Liebig‐synergistic responses were all observed. Therefore, there were instances of Liebig‐type limiting factors, Mitscherlich‐type limiting factors, and in‐between gradations. There was little indication of antagonism between N and P. The relationships observed between yields and N doses indicate an increasing critical dosage for P with increasing N.

ISSN:0190-4167    

DOI:10.1080/01904169009364085

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor