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Last, P. J. and Draycott, A. P. 1975. Growth and yield of sugar beet on

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J. agric. Sci., Camb. (1975), 85, 19-26

Printed in Qreat Britain19

Growth and yield of sugar beet on contrasting soils inrelation to nitrogen supply

I. Soil nitrogen analyses and yield

BY P. J. LAST AND A. P. DRAYCOTT

Broom's Barn Experimental Station, Higham, Bury St Edmunds

(Received 13 November 1974)

SUMMARY

Nine field experiments with sugar beet in 1968-70 tested eight amounts of nitrogenfertilizer (0-290 kg N/ha) on a shallow calcareous loam (Icknield Series), on a deep sandyloam (Newport Series) and on a heavy clay loam (Evesham Series). Top soils and sub-soils, sampled during autumn, winter and spring before the experiments, were analysedby several methods for available and potentially-available nitrogen. The largest in-creases in potentially-available mineral-nitrogen shown by incubation occurred in thecalcareous loams every year in both top soil and sub-soil, and the sandy loam, particu-larly the sub-soil, generally produced least. Attempts to forecast the optimum nitrogenfertilizer dressing from the soil analyses were moderately successful, the best techniquebeing anaerobic incubation of air-dry soil; the date of sampling had little effect. Theoptimum dressings were always between 0 and 125 kgN/ha, the calcareous loams gener-ally needing least nitrogen fertilizer and the loamy sands most.

INTRODUCTION

Many field experiments throughout the sugar-beet producing regions of the world show that formaximum yield the optimum nitrogen dressing is farless than the amount the crop takes up (recentlyreviewed by Draycott, 1972). Not surprisingly,there is much controversy in Great Britain (andabroad) between sugar-beet growers, advisers andscientists on nitrogen requirements of this crop.Boyd et al. (1970), in their paper on manuringsugar beet, found 75-100 kg N/ha was the averageoptimum dressing for 7 years, and less was neededin the 3 drier years of the decade, and in most years(not all), site-to-site differences in response toamounts of fertilizer nitrogen applied at more than113 kg/ha were no greater than could be expectedfrom experimental error. There was some evidenceof diminished response where sugar beet followedcrops other than wheat or barley and a slightlyenhanced response on Chalky Boulder clays. Holmes(1970) suggested that sand and oolitic limestonesoils respond to above-average dressings of nitrogenfertilizer, but Boyd et al. found no evidence forincreased response amongst sands. It was thereforedecided to make a detailed analysis of the growthand chemical composition of crops on three contrast-

ing soils to gain a fuller understanding of how sugarbeet utilizes soil and fertilizer nitrogen.

Part I describes analyses of soil samples takenduring autumn, winter and spring prior to sowingsugar beet to test methods of measuring potentially-available soil nitrogen which have shown promisefor predicting fertilizer requirement (Last & Dray-cott, 1971). Methods investigated by us previouslyand now in more detail, included the incubation offresh and air-dry soils, both aerobically and anaero-bically, barium hydroxide extractable 'glucose',total nitrogen and organic carbon. The contributionmade by the sub-soil has also been included, aswork on the pattern of root growth of sugar beet(Draycott, Durrant & Messem, 1974) suggests thismight be considerable for such a deep-rooted crop(Durrant et al. 1973).

EXPERIMENTAL PROCEDURE

Locations and soils

Nine experiments were made on commercialfarms under the supervision of the British SugarCorporation field staff, three in each of the years1968-70. In each year, one experiment was made oneach of three soil types: (a) the Icknield Series inthe Felsted sugar factory area, near Royston,

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20 P. J. LAST AND A. P. DBAYCOTT

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Herts, a shallow calcareous loam described in detailby Avery (1964); (b) the Newport Series in the New-ark factory area, near Elkesley, Nottinghamshire,a deep sandy loam described by Mackney & Burn-ham (1966); (c) the Evesham Series in the Notting-ham factory area, near Bottesford, Leicestershire,a clay loam described by Osmond etal. (1949). Someof the characteristics of these soils are shown inTable 1. Surveys have shown that about 25% ofthe beet acreage in Britain is sandy loam, 10 %clay, whilst the chalk/limestone soils account forabout 5 % of the total area of 196000 ha.

Design and fertilizer treatments1 1 '§, 1 1 n, The experiments were laid out in five randomized)§ § <j ii g < blocks and eight amounts of nitrogen tested, ranging3 £ 2 2 2 ™ from 0 to 290 kg N/ha in equal increments as 'Nitro-

Chalk'. Plots of 0-0067 ha received a basal dressing_g .g of63kgP206/ha, 125kgK2O/haand376kgNaCl/ha.8 8 All the fertilizers were spread by hand on the dates

>> u £» -P t, M shown in Table 1. The roots were also harvested by"§ a1"̂ jis s1"^ hand from 0-0029 ha at the end of the season,^ ""^ ^ " m weighed and analysed for sugar percentage, im-£ M £ § £ "* purities and juice quality at the Central Laboratorya « § a a A of the British Sugar Corporation at Peterborough.

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il W ffl ffl n (i Samples were taken from the experimental area ofeach field during autumn, winter and spring beforethe fertilizers were applied. The top soil samples

© © — © © 59 comprised 60 cores taken with a cheese auger© © © © © © Q_23 c m a n ( j ftis sub-soils 20 cores taken with a

screw auger, having removed all traces of the surfaceN O S ! <N©eq 23 cm with a spade. The depth to which the subsoil© © © © © 6 was sampled was 23-91 cm on the sandy loam,

23-76 cm on the clay loam and only 23-61 cm on thei> •* © t-ous shallow calcareous loam where sampling at depth© © -H © © »H Wfts i m m e n s e iy difficult. A thin limestone band

occurred at 46 cm in 1968 and 1969 on the clay loam^ 2 % S 6 " s ^ e s whi°h required considerable pressure to pierce

but subsequent sampling to a depth of 76 cm waspossible at all three sites. The sampling of sandy

2 g a 2 g i loams (Newport Series) in the Newark factory area' i S ' ' ! '1 1"^ created few difficulties in comparison with the other

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Agronomic details

Table 1 also lists some of the more importantagronomic factors at each trial site. To minimize theeffects on germination and emergence, fertilizersfor the beet crop should be applied at least 10 daysbefore sowing and the experimental manures were,on average, applied 24 days before sowing but on theclay loams the interval narrowed to an average of18 days, perhaps reflecting the slower drying of thesoils during early spring.

The juxtaposition of fertilizer application andsowing dates is, to some extent, reflected in the



https://doi.org/10.1017/S0021859600053375


Growth and yield of sugar beet. I 21average plant densities which ranged from 81000/haat Newark to 69 000/ha at Nottingham, and in 1969at Nottingham where the two operations differedby only 11 days, the final population was only64 000/ha. A Sharpe's seed variety was used in themajority of trials but no strictures were applied tovarieties because nitrogen fertilizer x variety inter-actions are small.

Pests and diseases were recorded on the trials bythe British Sugar Corporation field staff, anddamage attributable to pests was inconsequential.Routine virus yellows counts were made on the trialsduring August and were appreciable at Felsted onthe calcareous loams in 1969 and 1970 whereincidences reported were 13 and 10%respectively;on all other trials, less than 4% incidence wasrecorded.

No serious mineral deficiency arose in the crops,but at Felsted odd plants showed symptoms of Mnand Fe deficiency in all 3 years, although incidencewas very low and no corrective measures wereapplied. The calcareous loams also 'capped' veryreadily in 2 years and emerging plants were retardedin early growth with serious loss of yield in 1970,and all three crops grown on this soil type madevery slow progress during the seedling to 4-leaf stagegrowth.

Soil analysisAll fresh and air-dry soils were ground to less

than 2 mm, incubated aerobically by the methoddescribed by Gasser (1961), and the increases inammonium and nitrate-nitrogen measured. Ananaerobic method for the determination of poten-tially-available nitrogen in soils, originally described

by Waring & Bremner (1964) and investigated byus (Last & Draycott, 1971) was again tested onthe air-dry soils. The glucose equivalent of the air-dry soils as a measure of available nitrogen was alsotested, determined by the anthrone method (Jen-kinson, 1968). The organic carbon and total nitrogenconsidered to be coarse measures of nitrogen require-ment, were determined on air-dry soils by themethods of Tinsley and Kjeldahl respectively(Table 1).

Results for mineral-N values are expressed asmg/kg oven-dry soil. Nomenclature used throughoutis as follows:

Min-N,AMin-N,

AMin-No

mineral-nitrogen (NH4 + NO3) infresh soil

increase in mineral-nitrogen(NH4 + NO3) in fresh soil incubatedaerobically

increase in mineral-nitrogen(NH4 + NO3) in rewetted air-dry soilincubated aerobically

increase in mineral-nitrogen (NELJ inair-dry soil incubated anaerobically

RESULTS AND DISCUSSION

Soil analysisTable 2 shows the amounts of mineral-nitrogen

present in the fresh soils (i.e. before incubation)sampled during autumn, winter and spring. Most ofthe soils contained very little mineral-nitrogen inwinter and spring and it is concluded that the residueof fertilizer nitrogen in top and sub-soil available for

Table 2. Mineral nitrogen in fresh soil sampled in autumn, winter and springfrom three fields in each year, 1968-70

Top soil Sub-soil

Calcareous loam196819691970

Mean

Sandy loam196819691970

Mean

Clay loam196819691970

Mean

Autumn

188

19

15

127

10

10

92

15

9

Winter Spring(mg/kg)

1669

10

1235

7

728

6

6189

26

1243

6

1156

7

Mean

327

12

17

1246

7

93

10

7

Autumn

206

18

15

1448

9

73

10

7

Winter Spring(mg/kg)

147

12

11

725

5

81

12

7

238

10

14

935

6

837

6

Mean

197

13

13

1036

6

82

10

7



https://doi.org/10.1017/S0021859600053375


22 P. J. LAST AND A. P. DRAYCOTT

Table 3. Mineral nitrogen produced during aerobic incubation of fresh (AMin-Nf) and air-dry (AMin-Nad)soil, during anaerobic incubation of air-dry soil (AMin-N,^) and barium hydroxide glucose concentrations

Means of three sampling dates (Autumn, Winter, Spring) in 1968-70

Top soil Sub-soil

Calcareous loam196819691970

Mean

Sandy loam196819691970

Mean

Clay loam196819691970

Mean

AMin-N,

282418

23

161314

14

111515

14

AMin-Nod

(mg/kg)

363236

35

231723

21

172128

22

AMin-Nn,

683936

48

1361

7

132441

26

, Glucose(mg/lOOg)

242019

21

999

9

131420

16

AMin-N,

1337

8

127

3

448

5

AMin-N»d

(mg/kg)

241317

18

1269

9

171015

14

AMin-Nu

1973

10

310

1

76

12

8

, Glucose(mg/lOOg)

875

7

533

4

568

6

Table 4. Correlation coefficients between soil factors

Concen- Concen-tration of tration of

organic carbon nitrogen

Concentration oforganic carbon (%)

Concentration ofnitrogen (%)

Glucose

Concentration cforganic carbon (%)

Concentration ofnitrogen (%)

Glucose

0-96**

0-98**

Glucose

Top soils

0-85**

0-91**

Sub-soils

0-68*

0-76*

AMin-N,

0-39

0-48

0-76*

0-34

0-38

0-50

AMin-Nad

0-52

0-57

0-83**

0-47

0-47

0-68*

AMin-Natt

0-79*

0-82**

0-96**

0-62

0-67*

0-88**

* P < 005; ** P < 001.

the sugar-beet crop was negligibly small. An excep-tion was the calcareous loam in 1968 which con-tained over 60 mg N/kg in the surface and 20 mg/kgin the subsoil in spring, or approximately 314 kg/hain the top 60 cm of soil. The results suggest that thiswas partly residual fertilizer nitrogen and partlymineralized organic nitrogen.

Table 3 shows that the amounts of mineral-nitro-gen produced during incubation were similar eachyear and, on average, incubation of fresh top soilincreased the amount of mineral-nitrogen (AMin-N,)

in the calcareous loams by 24 mg/kg (approximatelyequivalent to 80 kg N/ha) compared with increasesof only 14 mg/kg by the other two soil types. Thesub-soils also reflected this pattern, with the cal-careous loams increasing by 7 mg/kg and the sandyloams by only 3 mg/kg. Means of the autumn, winterand spring results are given because the time ofsampling the soils had no effect on A-Min-N,.

The interrelation between the soil values shown inTable 4 indicates that concentrations of organic car-bon and nitrogen and barium hydroxide extractable



https://doi.org/10.1017/S0021859600053375


Growth and yield of sugar beet. I 23glucose were all interrelated, highly significantlyin the top soils but in the sub-soils the glucose wasless closely related to the concentrations of organiccarbon and nitrogen present.

Concentrations of organic carbon and nitrogen intop soils were not related to mineral-nitrogen pro-duced by aerobic incubation but were significantlycorrelated with the amount of mineral-nitrogenproduced by the anaerobic technique. Glucose,however, was very strongly related to all threemineral-nitrogen values, particularly to AMin-Naa,r •=. 0-96, and for AMin-Nad a value of 0-83 wasobtained, compared with 0-73 obtained by Last &Draycott (1971) and 0-78 by Jenkinson (1968).Subsoils showed the same trend in relationshipsbut r values were generally lower.

AMin-N, and AMin-Nad for the soils were signifi-cantly interrelated, r = 0-82, compared with thevalue of 0-61 reported by Last & Draycott (1971)in a previous investigation of soils which were muchmore variable in texture and type than the soils inthis work.

Air-drying, as usual, caused more nitrogen tomineralize when subsequently incubated, and theamount produced increased on average by 50 % intop soils and by 180% in the sub-soils. Incubationof air-dry soils, however, did not change the relativeamounts produced in either top or sub-soils, com-pared with the results from fresh soils. The lowestvalues for AMin-N^ were obtained from the topand sub-soils sampled in 1969 (after the rather wetsummer of 1968). The calcareous loam top soilson average produced most nitrogen during anaero-bic incubation (AMin-N,,,,) and the sandy loamsleast; the sub-soils followed the same pattern.Anaerobic incubation produced the largest extremesbetween soil types and years. As with the air-dryaerobic incubations, soils in 1969 produced thelowest average increase.

The barium hydroxide-extractable glucose con-centration was, on average over the 3 years, largestin the calcareous loam, ranging from 19 to 25 mg/100 g, whilst the sands contained on average only9 mg/100 g in the top soil. The glucose concen-tration in the clay loams was intermediate in value,although in 1970 the value rose to 20 mg/100 g,probably attributable to the previous cropping, aley which had received a dressing of 20 t/ha of farm-yard manure. The effect of previous cropping wasalso apparent at Newark in 1968, where the rem-nants of a previous ley resulted in an above-averageglucose level in the subsoil. Time of sampling didnot affect the concentration of glucose in top orsub-soils, just as it did not affect the amounts ofnitrogen produced by incubation.

Optimum nitrogen dressing, yield and nitrogen uptake

The effects of nitrogen fertilizer on the crop are

summarized in Appendix Table 1; full details ofthe yields in these and similar experiments will bedealt with in a later paper. The optimum dressingfor sugar yield in these nine experiments differedbetween fields but was never significantly greaterthan 125 kg N/ha. All the determinations of poten-tially available nitrogen were to some degree relatedto the optimum nitrogen dressing; there was noresponse to fertilizer when AMin-Nod exceeded28 mg/kg or when AMin-Naa exceeded 36 mg/kg inthe top soil. Responses to nitrogen fertilizer werealso small when the sub-soils contained muchpotentially-available nitrogen.

The crop factor best related to the soil mineral-nitrogen data was the response in sugar yield (t/ha)to fertilizer. The differences between requirementsof different fields were clearly demonstrated byvalues of AMin-Nad and AMin-NM. Response toapplied nitrogen was always greater than 1 • 41 sugar/ha where the ammonium-nitrogen produced byanaerobic incubation did not exceed 13 mg/kg in thetop soil; also sub-soils from responsive fields pro-duced below-average amounts of ammonium-nitrogen. Response in sugar yield was also associatedwith low organic carbon and total nitrogen con-centrations in both soil horizons (Table 1).

Barium hydroxide-extractable glucose was wellcorrelated with yield response (r = —0-91,P < 0-01) and distinguished between responsesfrom the clay and calcareous loams which the othersoil factors were unable to do. The results for glucoseindicated large (1-9 t sugar/ha) yield responses onthe sands with glucose concentrations of less than10 mg/100 g, decreasing to medium response(1-0 t sugar/ha) with glucose increasing to 14 mg/100 g and small or zero response where glucose in-Creased to more than 19 mg/100 g.

A variate which might be expected to be relatedto the crop yield and/or nitrogen requirement isthe amount of mineral nitrogen present in soilssampled freshly in spring (Table 2). This reflects theimmediate nitrogen status of a soil at a time close toinitial growth of the crop, probably when deficiencyof any nutrient has a great effect on subsequentgrowth. Although the top-soil sample from the un-responsive experiment at Felsted in 1968 contained61 mg mineral-nitrogen/kg (equivalent to 205 kgN/ha), there were no appreciable differences in mag-nitude between the other fields, Perhaps for thisreason the factor was not indicative of potentialyield, fertilizer requirement or response to fertilizer.

The total nitrogen uptakes (Appendix Table 1)were derived from the analyses of total nitrogen indried plant material and the final dry-matteryields. Uptake from the unfertilized plots rangedfrom 172 to 73 kg/ha and was considerably lowerthan average at only 87 kg/ha from the sandyloams. AMin-NM and extractable glucose were good



https://doi.org/10.1017/S0021859600053375



Table 5. Correlation coefficients between optimum nitrogen requirements, yields and nitrogen uptakeand various soil measurements

Top soil

Optimum N dressingMaximum sugar yieldMaximum sugar yieldresponse to N

N uptake on un-fertilized plots

AMin-N,

-0-50-0-45-0-57

+ 0-55

Top soil

AMin-Nad

(mg/kg)-0-65*-0-77*-0-70*

+ 0-42

* P •

AMin-NM

-0-68*-0-33-0-80*

+ 0-77*

< 005; **

Glucose(mg/lOOg)

-0-82**-0-42-0-91**

+ 0-73*

P < 001.

Top soil plussub-soil

AMin-N^(mg/kg)

-0-62- 0 1 3-0-77*

+ 0'86**

, * •

Concen-tirfl.tiion nf*UlQIUlull \J *•

organiccarbon (%)

-0-70*-0-07-0-86**

+ 0-79*

,Concen-

t Hrtn c

nitrogen(%)

-0-76*-0-19-0-93**

0-72

indications of nitrogen uptake, as were organiccarbon and total nitrogen in the top soils. The trial atFelsted 1970 was exceptional where a large nitrogenuptake was indicated by soil tests, but only 84 kg/ha was present in the crop at final harvest. Thisresult is attributable to poor growth of the cropduring the spring and a small number of plants perhectare. On average, unfertilized crops on the cal-careous loam and clay loam soils contained thesame amount of nitrogen (129 kg/ha) .whilst the cropson the sandy loams took up 42 kg nitrogen/ha less.

Summated values of potentially-available nitro-gen in top soil plus sub-soil were calculated, takinginto account the sampling depth and Table 5 showsthat these values were closely related to nitrogenuptake.

CONCLUSIONS

The analytical data show few differences attribu-table to the time of sampling. If such incubationtechniques were used as a guide for the nitrogenmanuring of sugar beet in Great Britain, the resultsof this investigation suggest the soil samples couldbe taken at any time during the autumn or winter,preferably after ploughing, which would give ampletime for the analyses and subsequent recommen-dations to be made well ahead of sowing.

The mineral-nitrogen values obtained by incu-bating the fresh top soils were more variable thanthose obtained with air-dry soils; although theirmagnitudes differed, the range of values obtainedwas nearly identical. Anaerobic incubation of thesoils was best able to identify the optimum nitrogenrequirement of the crops, particularly those withvery low requirements. This confirms our previouswork (Last & Draycott, 1971).

Anaerobic incubation increased the amount ofnitrogen mineralized, compared with the othermethods, in both the calcareous and the clay loamtop soils, but the sandy loam top soils and all theirsub-soils gave smaller increases. Anaerobic incuba-tion produced large mineral-nitrogen values forfertile soils and small values where yields were small.Anaerobic incubation of all sub-soils producedrelatively small amounts of mineral-nitrogen, andwould under-estimate the potential mineral-nitro-gen in the lower horizons, compared with the valuesobtained by aerobic incubation of the same soils,indicating that, under ideal conditions of aerationand temperature, sub-soils may produce largeamounts of mineral-nitrogen during the growingseason (see Part II).

The increases in sugar yield from optimal nitrogenfertilizer and nitrogen uptake by the unfertilizedcrop were related significantly to organic carbon,total nitrogen and glucose concentrations in the soils,but extreme agronomic and climatic factors canaffect the nitrogen uptake, as at Felsted in 1970 andNottingham in 1968.

All soils within a particular series showed closelysimilar analytical values and the range for eachSeries could best be identified by AMin-N^,AMin-NM or glucose concentration in the top soil;all were related to crop performance, but thediffering nitrogen requirements within a soil Seriesfrom year to year could be accounted for only by acombination of anaerobic incubation and a know-ledge of recent previous cropping. In addition, thebarium hydroxide-extractable glucose in the topsoil indicates the different yield responses expectedfrom beet crops grown on differing soil series.



https://doi.org/10.1017/S0021859600053375


App

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x T

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1. E

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San

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1968

1969

1970 M

ean

Cla

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am 1968

1969

1970

0 6-49

5-96

3-55

5-33

5-93

5-96

4-69

5-53

7-76

6-55

7-38

41 70

16-

404-

155-

85

6-59

7-09

5-59

6-43

8-35

6-43

7-64

83 6-73

5-63

3-93

5-43

7-98

7-76

5-97

7-23

8-66

70

97-

48

125

6-59

5-38

40

25-

33

7-80

81

55-

927-

30

8-58

7-23

7-38

166

6-60

4-74

3-84

50

7

7-96

7-88

6-75

7-54

8-52

7-71

7-32

207

6-94

5-39

40

15-

44

8-52

8-53

5-81

7-61

8-53

7-66

7-21

250

6-70

5-67

3-52

5-29

7-72

8-29

5-90

7-31

8-46

71

77

13

291

6-69

4-91

3-62

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112 77 73 87 131 96 159

125

214

218

128

187

205

152

133

163

173

143

243

250

258

242

178

226

257

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208

238

240

179

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https://doi.org/10.1017/S0021859600053375



REFERENCESAVERY, B. W. (1964). The soils and land use of the dis-

trict around Aylesbury and Hemel Hempstead. Agri-cultural Research Council Memoirs of the Soil Surveyof Great Britain, England and Wales, 1964, p. 91.

BOYD, D. A., TINKER, P. B. H., DRAYCOTT, A. P. &LAST, P. J. (1970). Nitrogen requirement of sugarbeet grown on mineral soils. Journal of AgriculturalScience, Cambridge 74, 37-46.

DRAYCOTT, A. P. (1972). Sugar-beet Nutrition. London:Applied Science Publishers Ltd., pp. 9-38.

DRAYCOTT, A. P., DTTRRANT, M. J. & MESSEM, A. B.(1974). Effects of plant density, irrigation and potas-sium and sodium fertilizers on sugar beet. II. In-fluence of soil moisture and weather. Journal of Agri-cultural Science, Cambridge 82, 261-8.

DURRANI, M. J., LOVE, B. J. G., MESSEM, A. B. &DRAYCOTT, A. P. (1973). Growth of crop roots inrelation to soil moisture extraction. Annals of AppliedBiology 74, 387-94.

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and yield. the journal of agricultural science. 85 (1), pp ...j. agric. sci., camb. (1975), 85,...

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