摘要:

Three experiments were carried out to examine the influence of grass seed‐rate upon the amount of clover growing with different varieties of perennial ryegrass. The bred varieties S23 and S24 were compared with Irish ryegrass. A larger quantity of clover grew with Irish ryegrass than with bred varieties at any given seed‐rate. If the varieties were to be compared in terms of herbage of similar clover content, then Irish ryegrass sown at 20 lb/ac had to be compared with S23 or S24 sown at about a quarter of that rate. Reducing the seed‐rate of the bred varieties from 20 to 5 lb/ac had only a small effect upon yield of ryegrass, and this was offset by an increase in yield of clover. Since weed grasses also took advantage of low grass seed‐rate, it is concluded that other factors in the management of variety trials must be so controlled as to produce a satisfactory clover content without too drastic a reduction in the seed‐rate of any variety. The relationship between grass seed‐rate and yield of clover varied markedly with the availability

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1965.tb00426.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

An instrument for estimating pasture yield electronically was constructed. It was a modification of that described by Campbellet al(1). A transistorized crystal oscillator was incorporated to provide a highly stable frequency standard for use in the field. This provided a zero reference point for both the measuring head oscillator and the reading oscillator before and during use. The instrument is fully described and details are given of its field adjustment and operation.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1965.tb00427.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

It was found that in terms of the relationship between capacitance and yield of pasture as measured by a modified electronic probe and by cutting, respectively, that: differences existed between the types of pastures studied; dry‐matter estimation was inferior to either the fresh‐material or the ‘total–water’ yield estimation; the degree of curvilinearity of the fresh‐material regression was not constant; the presence of dew on the plants resulted in a small increase hi capacitance reading. The possible significance of these results i

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1965.tb00428.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

A conservation experiment is described in which the losses in ensiling heavily‐wilted herbage, of approximately 50% dry matter, in lined trench silos, with and without a polyethylene film seal, are compared. The composition and digestibility of the silages produced in the sealed silos were comparable with those of the original herbage. The content of organic acids in the sealed silos was low, suggesting that fermentation was suppressed by the partially gas‐tight seal. In the unsealed silos there was considerable spoilage, 70% of the material being inedible. In the 2 sealed silos losses of dry matter were 8·2 and 5·2% and losses of SE 11·5 and 7·8%, respectively. The losses recorded are compared with those usually encountered in lined trenc

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1965.tb00429.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

The use of paraquat to kill swards preparatory to pasture renewal was studied in a series of trials on 3 lowland swards. Common pasture grass species exhibited a differential response to the herbicide:Lolium perenneandDactylis glomeratahad the greatest capacity to recover after treatment; weed species such asHolcus lanatuswere among the most susceptible. The dead litter remaining after spraying provided a barrier to the penetration of sown seeds. A complementary form of cultivation was required to obtain satisfactory establishment and rotary cultivation provided the most consistent results.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1965.tb00430.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Tall fescue S170 and Italian ryegrass S22, slow‐ and rapid‐establishing grasses, respectively, were sown either with white clover or with a mixture of red and white clovers, with or without a companion‐ or cover‐crop, and with or without nitrogen. Swards established without a cover‐crop were grazed frequently or cut infrequently; swards undersown with the oat crop were grazed once in the autumn. In the year of sowing tall fescue/clover mixtures produced yields similar to those of Italian ryegrass/clover swards. Tall fescue proved sensitive to competition, even from red clover, during establishment and sowing under a cover‐crop is therefore not recommended. The yield of red‐ and white‐clover was increased when sown under a cover‐crop and when cut infrequently, compared with frequent grazing by sheep. The growth of white clover was greatly reduced by adding red clover to the mixture, particularly under a cover‐crop and when defoliation was infrequent, but red clover increased total yield. The effect of N applied to the seed‐bed varied with the method of establishment. Cereal yield was reduced under dry conditions by undersowing with a mixture

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1965.tb00431.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

The rate of growth of Italian ryegrass in the spring was measured by recording dry‐matter yield at weekly intervals over periods of 6 weeks. There were 3 levels of applied N: 25, 75 and 125 lb/ac. Yield increased fairly slowly in the first 2 weeks and level of applied N had little effect. In the final 4 weeks the grass grew at a faster and fairly constant rate, which was very much affected by the level of N. Grass receiving 25 lb N produced 2900 lb of dry matter/ac in 6 weeks, 75 lb N 4400 Ib, and 125 Ib N 4700 lb. By the end of the first week, % N and % nitrate‐N were higher at the 75 lb than at the 25 lb N level and by the end of the second week they were higher at the 125 lb than at the 75 lb N level. The effect of weather factors and the question of predictability of yield are discus

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1965.tb00432.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

A permanent pasture was ploughed, 5 rates of potassium were incorporated in the seed‐bed and a timothy/white‐clover seed mixture was sown direct without a companion crop. Plant counts were taken during the fourth week of establishment. The highest rate of potash increased the size and number of timothy/white‐clover plants considerably, without altering the timothy/white‐clover ratio. Half the plots were cut once during the seeding year and the other half twice. Increasing rates of K increased dry‐matter yields, particularly on the plots cut 7 weeks after sowing. Botanical analysis in the following year showed that, under both cutting systems, increasing rates of K tended to increase the proportion of white clover and decrease that of unsow

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1965.tb00433.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

In a lawn on sandy soil many clover patches were found, in the centres of which the clover was dead or growing poorly. A similar patch was found in another lawn. Investigation of the soil and clover roots showed that the phenomenon was probably caused by the clover cyst nematodeHeterodera trifoliiGoffart. Though it is likely that this damage will also occur in normal pastures, it may not manifest itself in the typical form found in lawns, since clover plants cannot expand as regularly in pastures as in lawns. Where clover is distributed irregularly in the field, a random sampling may give no real information on the clover cyst nematode population.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1965.tb00434.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

The distribution of natural and cultivated grasslands in relation to climate and the use of various indices and diagrams in studies of crops and climate are discussed. Attempts to establish simple linear relationships between yield and weather components have been disappointing. Studies involving light, theoretical considerations of productivity, adaptation of herbage plants in relation to climatic origin, etc. have proved more useful. Problems involved in extending the work conducted under controlled conditions to the field, are stressed. Particularly important is a better characterization of the environment prevailing in and immediately above swards of different types. The importance of winter survival in Britain is discussed.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1965.tb00435.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY