Effect of compost maturity on tomato seedling growth

Scientia Horticulturae, 27 (1985) 199--208

199

Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands

EFFECT OF COMPOST MATURITY ON TOMATO SEEDLING GROWTH Y. HADAR 1, Y. INBAR 2 and Y. CHEN 2

1Department of Plant Pathology and Microbiology, and 2The Seagram Center for Soil and Water Sciences, The Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot (Israel) (Accepted for publication 8 July 1985)

ABSTRACT Hadar, Y., Inbar, Y. and Chen, Y., 1985. Effect of compost maturity on tomato seedling growth. Scientia Hortic., 27 : 199--208. A fibrous peat-like material was obtained from digested sludge of cow manure. The slurry was sieved and leached, and the solid fraction was composted. The growth of tomato seedlings on this compost at three degrees of maturity was compared to their growth on peat. The raw material was inhibitory to tomato seedling development. Plants grown in mature compost were the largest in the unfertilized treatment and did not respond to fertilization as well as plants grown on peat. Fertilized plants grown on peat achieved the highest dry weight. The nutrient levels in the plants were compared for the different media and it was assumed that a more extensive fertilization regime may improve tomato growth in the mature compost. Properly produced compost may be a substitute for peat as the organic component of container media. Keywords : compost ; growth media; peat; tomatoes. Abbreviation: EC = electrical conductivity; IM = immature compost; MC = mature compost; PT = peat; RM = raw material.

INTRODUCTION I n t h e last d e c a d e , t h e d e m a n d f o r p e a t as a s u b s t r a t e i n h o r t i c u l t u r e h a s i n c r e a s e d w h i l e its a v a i l a b i l i t y h a s d e c r e a s e d . A n u m b e r o f o r g a n i c w a s t e s s u c h as b a r k , l e a f m o u l d , t o w n r e f u s e , s a w d u s t a n d s p e n t m u s h r o o m c o m p o s t h a v e b e e n i n t r o d u c e d as p e a t s u b s t i t u t e s i n c o n t a i n e r m e d i a a f t e r p r o p e r c o m p o s t i n g {Bik, 1 9 8 3 ; V e r d o n c k , 1 9 8 4 ; L o h r e t al., 1 9 8 4 ) . A n a e r o b i c d i g e s t i o n o f o r g a n i c m a t t e r is a w e l l - k n o w n t e c h n o l o g y w h i c h is a p p l i e d w o r l d - w i d e t o p r o d u c e e n e r g y f r o m w a s t e s s u c h as s e w a g e s l u d g e a n d m a n u r e s ( S h e l e f e t al., 1 9 8 0 ) . T h e d i g e s t e d s l u d g e is u s u a l l y a p p l i e d w i t h o u t p r e - t r e a t m e n t f o r d i r e c t a p p l i c a t i o n o n soils as m a n u r e a n d soil c o n d i t i o n e r . R e c e n t l y , it h a s b e e n r e p o r t e d t h a t b y s i e v i n g a n d l e a c h i n g

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200 the slurry of digested cow manure, a fibrous peat-like material is obtained which resembles peat in its physical properties (Chen et al., 1984a). This material can serve as a peat substitute in container media, while the effluent may be used as organic liquid fertilizer. The physical, chemical and biological properties of the sieved and leached material were compared with peat (Putievsky et al., 1983; Chen et al., 1984a, b; Levanon et al., 1984; Raviv et al., 1984). The solid fraction of the digested slurry was found to be suitable for composting. In preliminary studies, this compost was successfully used as a growth medium for vegetable seedling production and carnation rooting (Inbar et al., 1983, 1985). The aim of the present study was to compare tomato seedling growth on media containing anaerobically digested and composted cattle manure at three degrees of maturity with their growth on peat. MATERIALS AND METHODS Substrates. -- Slurry produced by methanogenic fermentation of cow manure

in Kibbutz Zikim, Israel, was sieved on a 0.75-mm vibrating screen and leached with tap water until the electrical conductivity of the leachate reached 2 dS m -1. The solid fraction that had accumulated on the screen (3 m 3) was composted in a heap for a period of 6 months. The heap was turned every 2 weeks for the first 3 months, then allowed to cure for an additional 3 months. The temperature rose to 55°C within a week and dropped after 8 weeks to ambient (30--35°C). S a m p l i n g o f materials f o r the g r o w t h e x p e r i m e n t . -- Materials were sampled

as follows: (1) raw material (RM); (2) after 8 weeks of composting (immature compost = IM); (3) after 6 months of composting (mature compost = MC). Enriched sphagnum peat moss from Finland (PT) was used as a control. Thirty percent (by volume) of vermiculite (Grade 3) was mixed with the organic substrates. The performances of the substrates were tested with and without fertilization (see below). G r o w t h e x p e r i m e n t in a c o n t r o l l e d - t e m p e r a t u r e greenhouse. -- The media

were packed into styrofoam trays which were divided into 104 conical compartments (Speedling trays). Two seeds were sown in each compartment. The experiment was conducted in 4 replicates, each consisting of one tray (104 seedlings). The test plant was tomato ( L y c o p e r s i c o n e s c u l e n t u m L. 'Marmande'). Solutions containing 200 mg 1-1 N-NO3, 200 mg 1-1 P2Os and 200 mg 1-1 K20 were applied to fertilized trays at levels of 1.51/tray, once each week from the 13th day after sowing. Plants were sampled, oven-dried (65°C for 1 week) and weighed. The first sample, consisting of the tops of 50 seedlings, was collected 12 days after sowing. The other samples were taken weekly, 8 plants per replicate. R o o t development was estimated

201

visually at the end of the experiment (45 days from sowing) as follows: 1 = poor; 2 = fair; 3 = good; 4 = very good. methods. - - The substrates were sampled and analyzed at the beginning and end of the experiment. NO3, P, K, pH and electrical conductivity (EC) were determined in a 1 : 1 0 (w/w) substrate :de-ionized water extract. Fe and Mn were determined in a DTPA solution extract at the same solid : liquid ratio (Lindsay and Norvell, 1978). At the end of the experiment, plants were sampled for elemental analysis of shoots performed by digestion with H2SO4 and H202 (Page et al., 1982). The analytical methods have been described by Chen et al. (1984a) and Inbar et al. (1984).

Analytical

RESULTS AND DISCUSSION

Tomato germination after 8 days was a b o u t 92%, irrespective of the substrate. Plants grown on unfertilized RM exhibited (significantly) the lowest yield at any sampling date throughout the experiment (Fig. 1). Plants grown on PT and MC exhibited similar weight until 25 days after sowing. From the 32nd day onwards, the highest yield was achieved in the MC substrate. Significantly lower weight was obtained from seedlings grown on PT and RM. Since Fig. 1 represents unfertilized plants, it may be concluded that the nutrient reservoir in the enriched peat lasted for 25 days only, while in MC, nutrients were available for the plants until the end of the experiment. The dry weights of fertilized plants are presented in Fig. 2. (Note the difference in scale between Figs. 1 and 2.) Seedlings grown on RM were generally inhibited and therefore did n o t respond to fertilizers. From the

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Fig. 1. Dry w e i g h t a c c u m u l a t i o n o f u n f e r t i l i z e d t o m a t o seedlings g r o w n o n p e a t or compost on different days from planting.

202

25th day onwards, plants grown on PT achieved significantly higher dry weight than those grown on MC and IM (Fig. 2). RM had some inhibitory effects on seedling development even when fertilized. Similar inhibitory effects by raw materials have been shown by other workers and have been related to low-molecular-weight fatty acids (Devleeschauwer et al., 1981; Zucconi et al., 1981; Chanyasak et al., 1983). On the other hand, the peat treatment showed the highest response to fertilization. Plants grown on fertilized MC exhibited enhanced growth as compared to RM or to unfertilized MC {Table I). The ratio of dry weight of plants grown on fertilized vs. those grown on unfertilized MC was 1.72. 800 c 2

700

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Fig. 2. Dry w e i g h t a c c u m u l a t i o n o f fertilized t o m a t o seedlings grown on peat or c o m p o s t on different days f r o m planting.

TABLE I The e f f e c t o f the organic c o m p o n e n t o f container media o n t o m a t o seedling development. P l a n t age at s a m p l i n g was 45 days. F a c t o r i a l statistical analysis was p e r f o r m e d (P = 0.05). T h e i n f l u e n c e of fertilization for e a c h s u b s t r a t e is i n d i c a t e d b y capital letters, whereas the i n f l u e n c e o f t h e s u b s t r a t e for a given t r e a t m e n t is i n d i c a t e d b y lower-case letters Treatment

Raw material (RM) I m m a t u r e c o m p o s t (IM) M a t u r e c o m p o s t (MC) Enriched p e a t (PT)

Dry w e i g h t ( m g / p l a n t ) Unfertilized

Fertilized

Fertilized Unfertilized

66 319 355 141

130 486 612 822

1.98 1.52 1.72 5.83

b a a b

A B B B

d c b a

A A A A

203

However, peat treatments showed higher response to fertilization (Table I). The possible explanations are: (1) unfertilized MC contains a high level of NPK and plant response was good; (2) unfertilized PT contained low levels of NPK and could not adequately support plant growth; (3) MC is not as biologically stable as PT. Thus, some inhibitors may still be slowly released during the growth period; (4) competition for nutrients, mostly N, may take place in MC due to decomposition. This was not observed in the unfertilized MC since it was significantly superior to the other unfertilized treatments. It should be noted that the MC was tested as a sole organic c o m p o n e n t in the media to elaborate its properties. However, for practical application, it is usually r e c o m m e n d e d that composts are mixed with peat. R o o t development was estimated at the end of the experiment (Table II). Without fertilizers, r o o t development was the best in the IM treatment, whereas poor roots were obtained for plants grown on RM. However, in the fertilized treatments, the best r o o t development was observed in the PT and MC treatments. In most cases, r o o t development was better in fertilized than in non-fertilized treatments. TABLE II R o o t development estimation in tomatoes grown in different substrates. Plant age at sampling was 45 days. Degree of development was established by marks ranging from 1 to 4 (4 = the best). Values in the same column followed by the same letter do not differ significantly (P = 0.05) according to Duncan's multiple range test Treatment

Unfertilized

Fertilized

Raw material (RM) Immature compost (IM) Mature compost (MC) Enriched peat (PT)

1.2 3.3 2.3 2.0

2.3 3.1 3.5 3.8

c a b b

c b ab a

Chemical p r o p e r t i e s o f the substrates. -- The pH of the PT was slightly acidic at the beginning, while the IM and RM exhibited slightly basic pH (Table III). MC had a neutral pH value. At the end of the experiment, the pH of the various substrates ranged from 7.1 to 7.6. EC of the MC was high in the beginning but dropped to levels similar to the other substrates after 45 days. NO~ concentration of MC was very high at the beginning. Since the NO3 levels in the IM were much lower than in the MC, one may conclude that high amounts of NO3 are released during the curing process of the c o m p o s t (DeBertoldi et al., 1982; Bishop and Godfrey, 1983; Inbar et al., 1984). A high initial NO3 level and continuous slow release of NH4 and NO3 during the plant growth period are probably some reasons for enhanced growth in the unfertilized MC. Initial phosphorus level was high in all substrates, although highest in MC. At the end of the growth period, most had been utilized in PT, b u t they remained comparatively high in MC.

Ill

Peat (PT) Raw material (RM) Immature c o m p o s t (IM) Mature c o m p o s t (MC)

Substrate

7.1 7.6

7.3

7.4

5.8 7.7

7.7

7.0

7.3

7.6

7.4 7.4

3.110

0.940

0.591 0.825

0.810

0.721

0.653 1.090

0.853

0.780

0.723 0.712

End +FER -FER

Beginning

Beginning

End +FER -FER

EC2s (dS m -1)

pH

18.75

0.60

0.28 0.36

Beginning

0.77

0.61

0.70 0.55

0.90

0.66

0.92 0.53

51.0

13.0

25.0 31.5

Beginning

P (rag 1-1)

29.0

12.0

2.3 20.0

23.3

9.0

0.9 14.8

4.01

2.67

1.02 1.87

Beginning

0.35

0.32

0.20 0.54

0.41

0.40

0.24 0.33

-FER

End

= unfertilized)

+FER

K ( m e q 1- t )

= fertilized; - F E R

End +FER -FER

solid : water extract. ( + F E R

End +FER -FER

N O ] ( m e q 1- t )

C h e m i c a l properties of the substrates. T h e m e a s u r e m e n t s w e r e p e r f o r m e d in a 1 : i 0 w / w

TABLE

t~

205

Potassium levels increased with the degree of c o m p o s t maturity, and were higher in the composts than in PT. However, no differences were observed at the end with or w i t h o u t fertilization. Manganese and iron concentrations (Table IV) were high in MC, probably due to the formation of complexes with humic substances (Stevenson, 1982), which are formed at increasing levels during c o m p o s t maturation. TABLE IV Chemical properties of the substrates. Concentration in a 1 : 1 0 w]w solid :solution DTPA extract. (+ FER = fertilized; - F E R = unfertilized) Substrate

Peat (PT) Raw material (RM) Immature compost (IM) Mature compost (MC}

Mn (m S 1-1) Beginning

5.75 2.35 2.90 4.03

End +FER -FER 3.63 3.20 4.25 5.60

3.98 2.38 3.63 4.60

Fe (m S !-1 ) Beginning

_ End +FER -FER

8.85 3.10 4.65 8.53

6.60 3.03 6.33 13.20

5.55 3.60 7.53 8.60

N u t r i e n t level in t h e p l a n t . - - Nitrogen concentrations in plants grown in

MC were lower than in the other growth media. Uptake of N was similar in PT, IM and MC despite the differences in plant weight. In fertilized PT, the uptake of N was twice as much as in MC, while the dry weight was only 1.3 times higher. Phosphorus concentrations in plants grown in MC were the highest both with or without fertilization (Table V). However, plants grown in peat responded better to P application and its concentration increased 2.8-fold. Phosphorus uptake by non-fertilized plants grown in MC was 17 times higher than in plants grown in PT, whereas the dry weight was only 2.5 times higher. It seems that the MC medium contains enough P to support seedling development, while PT requires P fertilization. Potassium concentrations increased as a result of fertilization in all the treatments. The levels were relatively low in RM. As for P and N, the highest response to fertilization was observed in PT. Calcium and magnesium concentrations were the highest in plants grown on unfertilized PT, probably as a result of liming and lack of other nutrients. Iron concentrations in non-fertilized PT and MC were similar, and twice as high as those in the IM and RM media (Table VI). As a result of fertilization, the concentrations in the seedlings grown on MC and PT decreased to half of the values of the fertilized media, thereby equalling the levels exhibited b y plants that were treated differently. Similar trends were observed for Zn and Mn.

N +FER -FER

2.141 4.343

4.60 4.47

0.71

1.808 0.638

1.26

1.51

0.44

0.22 0.49

p +FER

3.91 1.85

1.44

2.16

Uptake (mg/plant) Peat (PT) 18.08 Raw 3.70 material (RM) Immature 10.51 compost (IM) Mature 9.24 compost (MC)

material (RM) Immature compost (IM) Mature compost (MC)

C o n c e n t r a t i o n in p l a n t (%) Peat (PT) 2.20 2.77 Raw 2.84 2.81

Substrate

1.916

1.039

0.110 0.171

0.540

0.330

0.078 0.260

-FER

25.39

21.65

33.53 3.42

4.15

4.45

4.08 2.63

K +FER

11.53

10.55

3.71 1.45

3.25

3.30

2.63 2.20

-FER

13.34

8.76

13.56 2.45

2.18

1.80

1.65 1.88

Mg +FER

7.81

6.71

4.44 1.38

2.20

2.10

3.15 2.10

-FER

9.18

7.30

10.27 2.08

1.50

1.50

1.25 1.60

Ca +FER

5.32

5.11

2.96 1.15

1.50

1.60

2.10 1.75

-FER

3.67

2.92

4.11 0.95

0.60

0.60

0.50 0.73

Na +FER

2.59

2.08

1.45 0.56

0.73

0.65

1.03 0.85

-FER

Major e l e m e n t c o n c e n t r a t i o n a n d u p t a k e in t o m a t o seedlings at t h e e n d o f t h e e x p e r i m e n t . ( + F E R = fertilized, - F E R = u n f e r t i l i z e d )

TABLE V

t~

207 TABLE VI Microelement concentrations and uptake in tomato seedlings at the end of the experiment. (+ FER = fertilized;-FER = unfertilized) Substrate

Cu +FER

-FER

Concentration in plant (pg g- 1) Peat (PT) 19 22 Raw 24 11 material (RM) Immature 12 17 compost (IM) Mature 10 11 compost (MC) Uptake (rag/plant) Peat (PT) 15.61 Raw 3.13 material (RM) Immature 5.84 compost (IM) Mature 6.12 compost (MC)

Zn +FER

-FER

Mn +FER

-FER

Fe +FER

-FER

163 190

238 223

97 44

170 40

122 127

226 118

165

163

31

25

102

118

158

193

47

46

133

242

3.10 0.73

133.95 24.74

33.56 79.72 14.70 5.73

23.97 100.26 2.64 16.54

31.87 7.78

5.43

80.29

52.10

15.09

7.99

49.63

37.71

3.90

96.65

68.48

28.75

16.32

81.36

85.86

CONCLUSIONS RM was i n h i b i t o r y t o t o m a t o seedling d e v e l o p m e n t . This e f f e c t c o u l d have r e s u l t e d f r o m c o m p e t i t i o n f o r o x y g e n a n d / o r n i t r o g e n d u e t o its biologically u n s t a b l e n a t u r e , as well as f r o m t h e p r e s e n c e o f p h y t o t o x i c organic acids ( D e v l e e s c h a u w e r et al., 1 9 8 1 ; Z u c c o n i et al., 1 9 8 1 ; C h a n y a s a k et al., 1 9 8 3 ) . Fertilized p l a n t s g r o w n in p e a t a c h i e v e d t h e highest d r y weight. Plants g r o w n in m a t u r e c o m p o s t w e r e t h e largest in t h e u n f e r t i l i z e d t r e a t m e n t , b u t did n o t r e s p o n d t o f e r t i l i z a t i o n as m u c h as plants g r o w n o n p e a t . This p h e n o m e n o n m a y result f r o m f u r t h e r d e c o m p o s i t i o n o f t h e c o m p o s t during t h e g r o w t h p e r i o d a n d c o m p e t i t i o n w i t h m i c r o o r g a n i s m s o n n i t r o g e n , or f r o m residual i n h i b i t o r y effects. MC m a y be u s e d as a p e a t s u b s t i t u t e in regions w h e r e p e a t is unavailable locally a n d is i m p o r t e d at high cost. I t is possible t h a t t h e c o m p o s t s h o u l d be aged f o r a longer p e r i o d t o i m p r o v e its p e r f o r m a n c e . F a r m e r s m a y use it w h e r e c h e m i c a l f e r t i l i z a t i o n is undesirable. M o r e studies are r e q u i r e d t o i m p r o v e t h e p e r f o r m a n c e o f MC as a g r o w t h m e d i a f o r seedling p r o d u c t i o n or f o r use in m i x t u r e s w i t h p e a t (such as a 1 : 1 v/v m i x t u r e ) . T h e use o f m i x e s is usually r e c o m m e n d e d f o r c o m p o s t a p p l i c a t i o n in c o n t a i n e r m e d i a .

2O8 ACKNOWLEDGEMENTS

This research was supported by a grant from the National Council for Research and Development, Israel and the European Economic Community.

REFERENCES Bik, A.R., 1983. Substrates in floriculture. Proc. XXI Int. Hortic. Congr., 1982, Hamburg, Vol. II, I.S.H.S., Wageningen, The Netherlands, pp. 811--822. Bishop, P.L. and Godfrey, C., 1983. Nitrogen transformations during sludge composting. BioCycle, 24: 34--39. Chanyasak, V., Katayama, A., Hirai, M.F., Mori, S. and Kubota, H., 1983. Effects of compost maturity on growth of komatsuna (Brassica rapa Var. pervidis) in Neubauer's pot. Soil Sci. Plant Nutr., 29: 239--259. Chen, Y., Inbar, Y., Raviv, M. and Dovrat, A., 1984a. The use of slurry produced by methanogenic fermentation of cow manure as a peat substitute in horticulture -physical and chemical properties. Acta Hortic., 150: 553--561. Chen, Y., Inbar, Y. and Raviv, M., 1984b. Slurry produced by methanogenic fermentation of cow manure as a peat substitute in horticulture. Proc. 2nd Int. Symp. Peat in Agriculture and Horticulture, The Hebrew University, Jerusalem, pp. 297--317. DeBertoldi, M., Citernesi, V. and Griselli, M., 1982. Microbial populations in compost processes. In: Composting. JG Press, Emmaus, PA, pp. 26--33. Devleeschauwer, D., Verdonck, O. and Van Assche, P., 1981. Study of phytotoxicity of fresh town refuse compost. BioCycle, 22: 44--46. Inbar, Y., Chen, Y. and Raviv, M., 1985. Rooting of carnation cuttings, using methanogenic digested sludge -- "cabutz". Hassadeh, 6 3 : 1 9 2 0 - - 1 9 2 2 (in Hebrew). Inbar, Y., Cheu, Y. and Hadar, Y., 1985. The use of composted slurry produced by methanogenic fermentation of cow manure as a growth media. Acta Hortic., 172: 75--82. Levanon, D., Dosoretz, C., Motto, B. and Kahn, I., 1984. Recycling agricultural waste for mushroom casing. Mushroom J., 133 : 13--17. Lindsay, W.L. and Norvell, W.A., 1978. Development of a DTPA soil test for zinc, iron, manganese and copper. Soil Sci. Soc. Am. J., 42: 421--428. Lohr, V.I., O'Brien, R.G. and Coffey, D.L., 1984. Spent mushroom compost in soilless media and its effects on the yield and quality of transplants. J. Am. Soc. Hortic. Sci., 109: 693--697. Page, A.L., Miller, R.H. and Keeney, D.R., 1982. Methods of Soil Analysis. Part 2. A.S.A. and S.S.S.A., Madison, WI, 1159 pp. Putievsky, E., Raviv, M. and Chen, Y., 1983. Development and regeneration ability of Lemon Balm (Melissa officinalis L.) and Marjoram (Majorana hortensis L.) on various media. Biol. Agric. Hortic., 1: 327--333. Raviv, M., Chen, Y., Geler, Z., Medina, S., Putievsky, E. and Inbar, Y., 1984. Slurry by methanogenic fermentation of cow manure as a growth medium for some horticultural crops. Acta Hortic., 150: 563--573. Shelef, G., Kimche, S. and Grynberg, H., 1980. High rate thermophilic anaerobic digestion of agricultural wastes. Biotech. Bioeng. Syrup., 10: 341--351. Stevenson, F.J., 1982. Humus Chemistry. Wiley, New York, 443 pp. Verdonck, O., 1984. Reviewing and evaluation of new materials used as substrates. Acta Hortic., 150: 467--473. Zucconi, F., Forte, M., Monaco, A. and DeBertoldi, M., 1981. Biological evaluation of compost maturity. BioCycle, 22(4): 27--29.