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Effects of fragmentation, supplementation and the addition of phase II compost to 2nd break compost on mushroom (Agaricus bisporus) yield
Bioresource Technology 101 (2010) 188–192
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Bioresource Technology journal homepage: www.elsevier.com/locate/biortech
Effects of fragmentation, supplementation and the addition of phase II compost to 2nd break compost on mushroom (Agaricus bisporus) yield Daniel J. Royse Department of Plant Pathology, 316 Buckhout Laboratory, The Pennsylvania State University, University Park, PA 16802, USA
a r t i c l e
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Article history: Received 24 February 2009 Received in revised form 17 July 2009 Accepted 18 July 2009 Available online 3 September 2009 Keywords: Agaricus bisporus Spent mushroom compost Double- and triple-cropping mushrooms Delayed release nutrients Fragmentation of compost
a b s t r a c t Double-cropping offers growers an opportunity to increase production efficiency while reducing costs. We evaluated degree of fragmentation, supplementation, and addition of phase II compost (PIIC) to 2nd break compost (2BkC) on mushroom yield and biological efficiency (BE%). One crop was extended as a triple crop in which we evaluated effect of compost type, and addition of phase II compost and supplement. All crops involved removing the casing layer after 2nd break and then using 2BkC for the various treatments. Simple fragmentation of the compost increased mushroom yield by 30% compared to nonfragmented compost. Addition of a commercial supplement to fragmented compost increased mushroom yield by 53–56% over non-supplemented, fragmented 2BkC. Fragmented, supplemented 2BkC resulted in a 99% and 108% yield increase over the non-fragmented control depending on degree of fragmentation (3, 1, respectively). A 3rd crop of mushrooms was produced from 2BkC, but yields were about one-half that of the 1st and 2nd crops. Double-cropping (and even triple-cropping) offers growers an opportunity to increase bio-efficiency, reduce production costs, and increase profitability. The cost of producing Agaricus bisporus continues to rise due to increasing expenses including materials, energy, and labor. Optimizing production practices, through double- or triple-cropping, could help growers become more efficient and competitive, and ensure the availability of mushrooms for consumers. Ó 2009 Elsevier Ltd. All rights reserved.
1. Introduction Production of the common cultivated mushroom (Agaricus bisporus) is a multimillion-dollar industry in many countries, including the United States. In 2008, sales volume of A. bisporus in the United States totaled 360 million kg, valued at 914 million dollars (USDA, 2008). Mushrooms are produced on composted raw materials including hay, straw, poultry manure, gypsum, corn stover and other ingredients. Raw materials and the preparation of selective compost for mushroom production are major cost inputs (Royse et al., 2008; Van Roestel, 1988; Wuest, 1983). Therefore, growers are seeking ways to lower their production costs by increasing bio-efficiency, i.e., producing greater mushroom yield from less raw materials. Mushroom production is a cyclical process whereby mushrooms are produced in a series of breaks or flushes at approximately 7-d intervals. After two breaks, mushroom production declines rapidly, so that each successive break produces fewer mushrooms. Growers terminate the crop at the end of the 2nd or 3rd break, because it is non-profitable to continue with declining production.
E-mail address: [email protected] 0960-8524/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.biortech.2009.07.073
Recent work in our laboratory has shown that it is possible to obtain more than one crop of mushrooms from the same compost (Royse et al., 2008; Royse and Sanchez, 2008a,b; Royse and Chalupa, 2009). The addition of commercial supplements, certain amino acids, and hydrolyzed proteins, increase yields of the 2nd crop. The ability to double-crop mushroom compost provides growers an opportunity to increase bio-efficiency while reducing the amount of ‘‘spent” mushroom compost (SMC) that requires disposal. It is estimated that at least 36 million m3 of SMC are disposed of each year in the United States (AMI, 2005). During the mushroom crop cycle, compost dry matter loss due to mushroom production may range from 20% to 30% from time of spawning to the end of the second or third break (D.J. Royse, unpublished). If compost is re-supplemented after 2nd break, expected mushroom yield/m2 is 20–30% lower due to compost dry matter loss from the 1st crop. Therefore, it may be desirable to increase dry matter/m2 by adding either fresh phase II compost, or by consolidating 2nd break compost to achieve a dry wt similar to the 1st crop. In order to practice double-cropping, a grower must remove the casing layer after one, two or three breaks and incorporate various supplements into the compost (Royse et al., 2008). Supplements may be incorporated into the compost by spawning machine or by removing the compost from the tray or bed, adding the
D.J. Royse / Bioresource Technology 101 (2010) 188–192
supplement and then returning the supplemented compost to the tray or bed. The type of machine used to fragment the compost may affect extent of fragmentation and subsequently affect aeration, nutrient absorption and water availability from the compost. It is unknown if degree of fragmentation may ultimately influence mushroom yield. The objectives of this research were to determine the effects of various treatments of 2nd break compost (2BkC) on mushroom yield as follows: (1) degree of compost fragmentation, (2) supplementation with delayed release nutrient, (3) addition of 20% phase II compost, and (4) exploration of the production of a 3rd crop of mushrooms from the same compost or ‘‘triple-cropping”. 2. Methods
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(3). No attempt was made to quantify particle sizes of fragmented 2BkC for either treatment but 3 was visually finer than 1. 2.3. Harvesting and determination of yield and biological efficiency Closed (lamellae not exposed) mushrooms were harvested, counted and weighed daily. At the end of each break, yield and biological efficiency (BE) were determined. BE was defined as the ratio of (g) of fresh mushrooms harvested per dry compost weight (g), including the weight of the supplement, and expressed as a percentage. Compost samples were selected randomly from each crop at spawning and delivered to the Agricultural Analytical Laboratory for moisture and nitrogen content analysis. Yield was expressed as kg/m2.
2.1. General crop description 2.4. Experimental design and data analysis Three cropping experiments were conducted to determine the effect of various treatments of 2BkC compost on mushroom yield and biological efficiency (BE%). Degree of fragmentation and addition of delayed release supplement and their interaction was evaluated in Crop 0806B, while addition of 20% phase II compost and supplement level was evaluated in Crops 0809B and 0810B. Crop 0810C was extended as a triple-crop that evaluated the effect of compost type, as well as addition of phase II compost and supplement. All crops involved removing the casing layer after 2nd break and then using the 2BkC for the various treatments. 2.2. Composts and preparation Compost for mushroom production was prepared from wheat straw-bedded horse manure mixed with switch grass supplemented with dried poultry manure and gypsum as described by Royse et al. (2008) and Royse and Sanchez (2008a,b). After phases I and II composting, phase II compost was supplemented with Remo’s All Season Regular (Remo’s Mushroom Services, Avondale, PA), a delayed release nutrient, at 4% dry wt at time of spawning with Sylvan 140 (Sylvan Spawn Co., Kittanning, PA) spawn (a white U1-type hybrid). Spawned, supplemented compost (25 kg) was filled into plastic bins (56 44 24 cm) and incubated for 16 d at 24 ± 2°C (compost temperature). Immediately after spawning, compost was covered with a woven landscape fabric (Ultra Web 3000 ground cover, Gempler’s, Madison, WI). Relative humidity was maintained at ca. 95–98% using a spinning disc humidifier connected to a timer. Following a 16-d spawn run, casing (sphagnum peat moss and limestone at ca. 80% moisture) was overlaid on the landscape fabric that was used to ease removal of the casing after mushroom harvest. Casing inoculum (CI, Sylvan 140–500 g/m2) was added to the casing prior to application. During the case hold (time during mycelial colonization of the casing), air temperature was maintained at 16 °C maintaining compost temperatures at 21 ± 1 °C. Relative humidity was maintained at 95–99% with a spinning disc humidifier. The crop was watered according to visual observations of mycelial growth and moisture content of the casing. Carbon dioxide levels were not controlled but generally ranged between 500 and 1500 ppm. Additional water was applied to the casing after harvest of first break to maintain casing moisture levels near field capacity. Mushrooms were harvested for two breaks and casing removed. The de-cased 2BkC was fragmented, re-supplemented and re-cased. Fragmentation was accomplished by passing 2BkC through a turner fitted with a rotating (>1000 rpm) drum. The drum contained four circumferentially-spaced, longitudinally extended bars that contacted the 2BkC as it was passed through the turner either once (1) or three times
All three crops utilized factorial designs (SAS, 2008). Crop 0806B was a 2 2 factorial with two degrees of fragmentation (1, 3) two levels of supplement (0, 3.7% dry wt; supplement percentage levels [dry wt] were estimated after determination of compost moisture contents) plus one non-fragmented control treatment (5 treatments 7 replicates = 35 experimental units). Crop 0809B was a 2 2 factorial with two levels of phase II compost (0, 20%) two levels of supplement (0, 3.53% dry wt) plus one treatment where phase II compost (20%) layered on top of non-fragmented 2BkC and one check treatment with phase II compost (100%) (6 treatments 6 replicates = 36 experimental units). Crop 0810 was a triple-crop (0810A, 0810B, 0810C). Crop 0810A was the 1st crop with production of two breaks on phase II compost. Crop 0810B used 2BkC from 0810A and was a 2 2 factorial with two levels of phase II compost (0, 20%) two levels of supplement (0, 3.57%). Treatments 1 and 2 had 6 replicates each while treatments 3 and 4 had 17 replicates each (6 + 6 + 17 + 17 = 46 experimental units). More replicates were used for treatments 3 and 4 (with and without 20% phase II compost) because 2BkC from these treatments was used for the 3rd crop, 0810C. Crop 0810C was a 2 2 2 factorial with two types of 2BkC from Crop 0810B, two levels of phase II compost (0, 20%), and two levels of supplement (0, 3.6%). This crop was produced in plastic bins (17 22 28 cm) filled with 3.64 kg 2BkC at time of re-casing. For Crop 0810C, there were 8 treatments 9 replicates = 72 experimental units. Mushrooms were harvested for two or three breaks depending on the experiment. The SAS program JMP was used to analyze data (SAS, 2008). Data were examined with a one-way analysis of variance (ANOVA) and the Tukey–Kramer Honestly Significant Difference (HSD) was used to evaluate significant differences among treatment means. Data were also evaluated using standard least squares modeling with effect screening (SAS, 2008). 3. Results Mushroom yields and BEs for the effect of degree fragmentation and supplement added to 2BkC are shown in Table 1. Highest yields were obtained from fragmented 2BkC that was passed through a turner (described earlier) and supplemented with 3.7% nutrient before re-casing. Non-fragmented, re-cased 2BkC yielded only 10.07 kg/m2 while 1- and 3-fragmented, non-supplemented compost yielded 13.45 and 13.09 kg/m2 (+33.6%, +30%), respectively (Table 1). The addition of 3.7% (dry wt) supplement to 1- and 3-fragmented 2BkC increased yield by 108.1% and 99.3%, respectively, compared to the non-fragmented, non-supplemented control. Yields tended to decrease ( 2.8%, 4.4% on non-
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Table 1 Effect of degree of fragmentation and supplementation on yield and biological efficiency (BE%) of mushrooms produced on 2nd break compost (2BkC) for three breaks (Crop 0806B). Degree of fragmentationA
SupplementB (% dry 2BkC wt)
Yield (kg/m2)C
BE (%)C
1 1 3 3 None (check)
3.7 0 3.7 0 0
20.96 13.45 20.07 13.09 10.07
89.2 59.9 88.1 58.3 44.9
a b a b c
a b a b c
A 2BkC was non-fragmented (none) or fragmented by passing the compost through a turner either one (1) or three times (3). B Remo’s All Season Regular (Remo’s Mushroom Services, Avondale, PA). C Yields and BE (%) followed by the same letter within the same crop and column are not significantly different according to the Tukey–Kramer honestly significant difference (P = 0.05).
Table 2 Probabilities > F from analysis of variance for the addition of supplement and 20% phase II compost to 2nd break compost (2BkC) tested for yield and biological efficiency (BE%) for two crops. Source
df
Crop no. 0809B
Supplement (S) Phase II compost (PIIC) S PIIC A
1 1 1
0810B
YieldA
BE (%)A
YieldA
BE (%)A
<0.0001 0.0098 0.3177
<0.0001 0.0106 0.3437
<0.0001 0.0791 0.0832
<0.0001 0.0759 0.0774
Values of less than 0.05 were considered significant according to Fisher’s LSD.
supplemented and supplemented 2BkC, respectively) as degree of fragmentation increased (1 vs. 3), but the difference was not significant. Probabilities > F from analysis of variance for the addition of supplement and 20% phase II compost to 2BkC tested for yield and biological efficiency (BE) for two Crops (0809B, 0810B) are presented in Table 2. For Crop 0809B, significant sources of variation for both yield and BE included supplement (S) and phase II com-
post (PIIC) while for Crop 0810B, only supplement significantly influenced yield and BE. There were no significant interactions for S PIIC for either crop. For Crop 0809B, highest yield (26.17 kg/m2) and BE (82.7%) were obtained from fragmented compost containing 20% PIIC and 3.53% supplement (Table 3). Mushroom yield from this treatment was higher (+5.4%) than the supplemented phase II compost (check), but the difference was not significant. Lowest yields were obtained from non-supplemented treatments with or without PIIC. Yield from non-fragmented 2BkC overlaid with 20% PIIC supplemented with 3.53% nutrient was 27.1% less than the treatment where PIIC and supplement were through-mixed into fragmented 2BkC (20.59 kg/m2 vs. 26.17 kg/m2, respectively). For Crop 08010B, highest yield (22.5 kg/m2) was from 2BkC containing 20% PIIC plus 3.57% supplement; however, this treatment was not significantly different from the supplemented treatment without PIIC (Table 4). PIIC added to non-supplemented 2BkC did not significantly influence mushroom yield. BEs ranged from a low of 48.3% on 2BkC without additions to 71% on 2BkC containing 20% PIIC plus 3.57% supplement. Means and groupings from analysis of variance for supplementation of 2BkC for Crops 0809B and 0810B for yield and BE are shown in Table 5. Yield (3 breaks) for Crop 0809B was 26.6% higher on 2BkC containing 3.53% Remo’s supplement compared to the non-supplemented treatments. In Crop 0810B, yield (2 breaks) was 43% higher on supplemented treatments compared to nonsupplemented treatments. Means and groupings from analysis of variance for addition of PIIC to 2BkC in Crops 0809B and 0810B for yield and BE are shown in Table 6. Yields were greater with the addition of PIIC, but this trend was significant only in Crop 0809B. Yield stimulation with PIIC was confined to the 1st break. Probabilities > F from analysis of variance for compost type and the addition of supplement and 20% phase II compost to 2nd break compost (2BkC) tested for yield and biological efficiency (BE%) for a 3rd crop from the same compost are presented in Table 7. The only significant source of variation for both yield and BE was supplement. There were no significant 2-way or 3-way interactions. Yield and BE were substantially lower in the 3rd Crop (0810C) compared
Table 3 Effects of addition of phase II compost and supplement to 2nd break compost (2BkC) on mushroom yield and biological efficiency (BE%) (Crop 0809B).
A B C
2Bk Treatment
2BkC (kg/m2)A
Phase II compost (kg/m2)A
SupplementB (% dry wt)
Yield (kg/m2)
BE (%)
Fragmented/mixed Fragmented/mixed Fragmented/mixed Fragmented/mixed Phase II layered on top 2BkC–no fragmentation Phase II (check)C
24.5 30.6 24.5 30.6 24.5 0
6.1 0 6.1 0 6.1 30.6
3.53 3.53 0 0 3.53 3.53
26.17 23.02 20.17 18.68 20.59 24.83
82.7 72.8 66.0 61.1 65.1 78.5
a bc cd d cd ab
Oven dry wt basis. Remo’s All Season Regular (Remo’s Mushroom Services, Avondale, PA). 4-d Spawn run; supplemented with 3.53% Remo’s supplement.
Table 4 Effects of addition of phase II compost and supplement to 2nd break compost (2BkC) on mushroom yield and biological efficiency (BE%) (Crop 0810B).
C
2BkC Treatment
2BkC (kg/m2)A
Phase II compost (kg/m2)A
SupplementB (% dry wt)
YieldC (kg/m2)
BEC (%)
Fragmented/mixed Fragmented/mixed Fragmented/mixed Fragmented/mixed
24.5 30.6 24.5 30.6
6.1 0 6.1 0
3.57 3.57 0 0
22.50 22.23 16.53 14.77
71.0 70.1 54.0 48.3
a a b b
a a b b
14-d Spawn run; supplemented with 3.53% Remo’s supplement. A Oven dry wt basis. B Remo’s All Season Regular (Remo’s Mushroom Services, Avondale, PA). C Yields and BE followed by the same letter within the same crop and column are not significantly different according to the Tukey–Kramer honestly significant difference (P = 0.05).
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Table 5 Means and groupings from analysis of variance for supplementation of two crops (0809B and 0810B) produced on 2nd break compost (2BkC) for (Agaricus bisporus) yield and biological efficiency (BE%). Supplement (% dry 2BkC wt)
No. reps
Yield (kg/m2)A
BE (%)A
Total
Break 1st
2nd
Crop 0809B 3.53 0
12 12
24.59 a 19.42 b
12.80 a 7.58 b
7.85 a 8.49 a
Crop 0810B 3.57 0
33 12
22.40 a 15.67 b
11.79 a 10.17 b
10.61 a 5.50 b
3rd 3.94 a 3.35 a
77.7 a 63.6 b
–B –B
71.9 a 52.0 b
A Yields and BE (%) followed by the same letter within the same crop and column are not significantly different according to the Tukey–Kramer honestly significant difference (P = 0.05). B Third break not harvested due to use of 2BkC for a 3rd Crop (0810C).
Table 6 Means and groupings from analysis of variance for addition of phase II compost to two crops (0809B and 0810B) produced on 2nd break compost (2BkC) for (Agaricus bisporus) yield and biological efficiency (BE%). Phase II compost (% dry 2BkC wt)
No. reps
Yield (kg/m2)A Total
Crop 0809B 20.2 0
12 12
Crop 0810B 19.9 0
23 22
BE (%)A Break 1st
2nd
3rd
23.17 a 20.85 b
11.38 a 9.00 b
7.76 a 8.58 a
4.03 a 3.27 a
74.4 a 67.0 b
20.97 a 20.22 a
11.84 a 10.85 b
9.13 a 9.37 a
–B –B
67.8 a 65.3 a
A Yields and BE (%) followed by the same letter within the same crop and column are not significantly different according to the Tukey–Kramer honestly significant difference (P = 0.05). B Third break not harvested – 2BkC was used for a 3rd Crop (0810C).
Table 7 Probabilities > F from analysis of variance for compost type and the addition of supplement and 20% phase II compost to 2nd break compost (2BkC) tested for yield and biological efficiency (BE%) for a 3rd crop from the same compost (Crop 0810C).
A
Source
df
YieldA
BE (%)A
Compost type (CT) Phase II compost (PIIC) CT PIIC Supplement (S) CT S PIIC S CT PIIC S
1 1 1 1 1 1 1
0.1756 0.4001 0.7607 <0.0001 0.5999 0.0747 0.5305
0.2598 0.2713 0.4600 <0.0001 0.4358 0.1183 0.8383
Values of less than 0.05 were considered significant according to Fisher’s LSD.
to the 1st (0810A) and 2nd (0810B) crops due mainly to the reduction in 1st break output (Table 8). Total yields were 46–61% lower depending on treatment. BEs for the 3rd crop were in the mid 40s compared to the upper 60s to mid 70s in the 1st and 2nd crops. 4. Discussion Double-cropping offers growers an opportunity to increase production efficiency while reducing costs. Several factors have been identified that contribute to increasing production efficiency on ‘‘spent” compost. In this work, we evaluated the degree of fragmentation, supplementation and addition of PIIC to 2BkC on mushroom yield. Simple compost fragmentation increased mushroom yield by 30% compared to the non-fragmented control. These findings were in agreement with Schisler (1964) who found that fragmentation
of 2BkC resulted in a yield increase of 42% over the non-fragmented control. Yields tended to decrease as the degree of fragmentation increased, but this difference was not significant. Our method of fragmentation was similar to that used on a tray farm, where 2BkC is dumped from trays, mixed, supplemented and then returned to the trays. In contrast, growers at shelf farms use spawning machines to fragment compost and incorporate supplement. Commercial growers who have experimented with double cropping on bed farms have suggested that 2BkC becomes too fine when spawning machines of current design are used to mix in supplement. They suggest use of spring-like tines as a substitute for the fixed tines used presently. Additional work is warranted in this area to determine optimum degree of fragmentation and its influence on mushroom yield. How compost/mycelial fragmentation influences mushroom yield remains unexplained. One possibility is that new mycelium, formed after fragmentation, is able to reach additional nutrients in the compost that were not accessible in the 1st crop. Another possible explanation is that aged mycelium gradually loses its capacity to access and transport nutrients through mycelial cords to the fruit bodies. Calcium oxalate crystals are formed on older mycelium (Masaphy et al., 1987) that may hinder the ability of the fungus to absorb nutrients. The growth and development of new mycelium would provide a more efficient connection, through mycelial cords, from compost mycelium to developing mushrooms. We routinely observed the rapid growth and development of new mycelium from mycelial cords after compost fragmentation. This new mycelium would be able to access not only left over nutrients in the compost, but also the new supply of nutrients provided by the supplement. Addition of a commercial supplement to fragmented compost increased mushroom yield by 53–56% over non-supplemented,
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Table 8 Triple-cropping Agaricus bisporus. Yield and biological efficiency (BE%) for three crops (2 breaks each) from phase II and 2nd break compost (2BkC) non-supplemented or supplemented with 20% phase II compost and delayed release nutrient (Remo’s). Crop no.
2BkC type
2BkC amount (%)
Phase II amount (%)
Yield (kg/m2)A Total
BE (%)A Break 1st
0810A (Crop 1) 0810B (Crop 2)
100B
0810C (Crop 3)
100C 80/20D
100 80 100 80 100 80
100 0 20 0 20 0 20
20.98 22.53 22.26 14.21 13.85 14.35 14.17
a a a a a a
11.79 12.23 11.32 5.21 5.91 5.40 6.27
2nd a a a a a a
9.19 10.30 10.94 9.00 7.94 8.95 7.90
a a a a a a
69.7 74.9 74.0 45.8 44.6 45.3 44.8
a a a a a a
A Yields and BE (%) followed by the same letter within the same crop and column are not significantly different according to the Tukey–Kramer honestly significant difference (P = 0.05). B 2BkC Type from Crop 0810A. C 2BkC Type from Crop 0810B (100% 2BkC). D 2BkC Type from Crop 0810B (80% 2BkC, 20% phase II).
fragmented 2BkC. Fragmented, supplemented 2BkC resulted in a 99–108% increase over the non-fragmented control depending on degree of fragmentation (3, 1, respectively). Therefore, for optimum productivity, it would be necessary to fragment and add supplement to 2BkC before re-casing. Another method to increase yield/m2 of production surface would be to increase the dry wt of 2BkC via the addition of 20% PIIC. Approximately 20–30% of the dry compost wt is lost during production of the 1st crop, so replacement of this dry wt with fresh compost could potentially boost yield/m2 to a level equivalent of the 1st crop. PIIC and supplement could be layered on top of the de-cased 2BkC and then incorporated with a spawning machine to through-mix the materials. Through-mixing appears necessary because treatments with phase II compost and supplement overlaid on 2BkC without mixing yielded 27.1% less than treatments where PIIC and supplement were through-mixed. The addition of PIIC to 2BkC resulted in a significant yield stimulation for one Crop (0809B) but not for the other (0810B). This yield increase was confined to the first break only. The reason for the differential response likely was related to the difference in the nitrogen content of the phase II compost added to 2BkC. PIIC nitrogen contents for Crops 0809B and 0810B were 2.4% and 2.0%, respectively. Thus, the additional nitrogen available in PIIC added to Crop 0809B would have provided additional nutrition to the crop that stimulated mushroom yield. In these experiments, there was no significant interaction between the addition of supplement and PIIC to 2BkC, although for Crop 0810B the P-value for this interaction was nearly significant (P = 0.08). In a previous experiment we found a significant interaction for these factors (Royse and Chalupa, 2009). It appears that the nutritional status of the PIIC added to 2BkC influences the interaction of the supplement. That is, lower-nitrogen PIIC responds to supplement to a greater extent than higher-nitrogen PIIC. We were successful in producing a 3rd crop of mushrooms from two types of 2BkC. Supplement was the only factor that had a significant impact on mushroom yield. The type of compost and addition of PIIC did not have a significantly impact yield. Overall yields of the 3rd crop were 57–63% less than the 2nd crop and 46–51% less than the 1st crop. Most yield loss was attributed to first break. Nitrogen content of the 2BkC was 2.5% for both types of compost (100% 2BkC and 80/20 mixture of 2BkC/PIIC), so this would not appear to be the reason for reduced yield. One possible explanation for the yield reduction was the drier casing overlay used for the triple-crop. Moisture content of the casing overlay was ca. 75% vs. our normal casing moisture content of ca. 80%. A drier casing overlay
takes longer to hydrate to field capacity, so this may have limited yield initially until the casing moisture could be raised to the desired level. A drier casing layer coupled with compost moistures of 61.9% and 62.6% for 100% 2BkC and 80/20 mixture of 2BkC/PIIC, respectively, could have reduced yield due to inadequate moisture. Another possible explanation for suppressed mushroom yield is the depletion of specific nutrients that became further limiting in the 3rd crop. This area of research warrants further exploration that is now underway in our laboratory. Double-cropping (and even triple-cropping) offers growers an opportunity to increase bio-efficiency, reduce production costs, and increase profitability. The cost of producing A. bisporus continues to rise due to increasing expenses including materials, energy and labor. Optimizing production practices, through double- or triple-cropping, could help growers become more efficient and competitive and ensure the availability of mushrooms for consumers. Acknowledgements The author is grateful to Doug Keith, Henry Shawley, Joey Martain and John Pecchia for technical assistance. References American Mushroom Institute (AMI), 2005. Spent Mushroom Substrate: Scientific Research and Practical Applications (23p). Masaphy, S., Levanon, D., Tchelet, R., Henis, Y., 1987. Scanning electron microscope studies of interactions between Agaricus bisporus (Lang) Sing hyphae and bacteria in casing soil. Appl. Environ. Microbiol. 53, 1132–1137. Royse, D.J., Sanchez, J.E., Beelman, R.B., Davidson, J., 2008. Re-supplementing and recasing mushroom (Agaricus bisporus) compost for a second crop. World J. Microbiol. Biotechnol. 24, 319–325. Royse, D.J., Sanchez, J.E., 2008a. Supplementation of first break mushroom compost with hydrolyzed protein, commercial supplements and crystalline amino acids. World J. Microbiol. Biotechnol. 24, 1333–1339. Royse, D.J., Sanchez, J.E., 2008b. Supplementation of 2nd break mushroom compost with isoleucine, leucine, valine, pheylalanine, FermentenÒ and SoyPlusÒ. World J. Microbiol. Biotechnol. 24, 2011–2017. Royse, D.J., Chalupa, W., 2009. Effects of spawn, supplement, and phase II compost additions and time of re-casing second break compost on mushroom (Agaricus bisporus) yield and biological efficiency. Biores. Technol. 100, 5277–5282. SAS Institute (SAS), 2008. JMP. SAS Institute Statistical Analysis System, Cary, NC. Schisler, L.C., 1964. Nutrient supplementation of compost during the mushroom growth cycle. Mushroom Growers Assoc. Bull. 179, 503–541. United States Department of Agriculture (USDA), 2008. Mushrooms. National Agricultural Statistics Service, Agricultural Statistics Board. Washington, DC. Van Roestel, A.J.J., 1988. Costs and returns. In: Van Griensven, L.J.L.D. (Ed.), The Cultivation of Mushrooms. Mushroom Experimental Station, Horst, The Netherlands, pp. 447–483. 515p. Wuest, P.J., 1983. Resources need to farm the ‘‘champignon”. Mycologia 75, 341– 350.
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Bioresource Technology journal homepage: www.elsevier.com/locate/biortech
Effects of fragmentation, supplementation and the addition of phase II compost to 2nd break compost on mushroom (Agaricus bisporus) yield Daniel J. Royse Department of Plant Pathology, 316 Buckhout Laboratory, The Pennsylvania State University, University Park, PA 16802, USA
a r t i c l e
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Article history: Received 24 February 2009 Received in revised form 17 July 2009 Accepted 18 July 2009 Available online 3 September 2009 Keywords: Agaricus bisporus Spent mushroom compost Double- and triple-cropping mushrooms Delayed release nutrients Fragmentation of compost
a b s t r a c t Double-cropping offers growers an opportunity to increase production efficiency while reducing costs. We evaluated degree of fragmentation, supplementation, and addition of phase II compost (PIIC) to 2nd break compost (2BkC) on mushroom yield and biological efficiency (BE%). One crop was extended as a triple crop in which we evaluated effect of compost type, and addition of phase II compost and supplement. All crops involved removing the casing layer after 2nd break and then using 2BkC for the various treatments. Simple fragmentation of the compost increased mushroom yield by 30% compared to nonfragmented compost. Addition of a commercial supplement to fragmented compost increased mushroom yield by 53–56% over non-supplemented, fragmented 2BkC. Fragmented, supplemented 2BkC resulted in a 99% and 108% yield increase over the non-fragmented control depending on degree of fragmentation (3, 1, respectively). A 3rd crop of mushrooms was produced from 2BkC, but yields were about one-half that of the 1st and 2nd crops. Double-cropping (and even triple-cropping) offers growers an opportunity to increase bio-efficiency, reduce production costs, and increase profitability. The cost of producing Agaricus bisporus continues to rise due to increasing expenses including materials, energy, and labor. Optimizing production practices, through double- or triple-cropping, could help growers become more efficient and competitive, and ensure the availability of mushrooms for consumers. Ó 2009 Elsevier Ltd. All rights reserved.
1. Introduction Production of the common cultivated mushroom (Agaricus bisporus) is a multimillion-dollar industry in many countries, including the United States. In 2008, sales volume of A. bisporus in the United States totaled 360 million kg, valued at 914 million dollars (USDA, 2008). Mushrooms are produced on composted raw materials including hay, straw, poultry manure, gypsum, corn stover and other ingredients. Raw materials and the preparation of selective compost for mushroom production are major cost inputs (Royse et al., 2008; Van Roestel, 1988; Wuest, 1983). Therefore, growers are seeking ways to lower their production costs by increasing bio-efficiency, i.e., producing greater mushroom yield from less raw materials. Mushroom production is a cyclical process whereby mushrooms are produced in a series of breaks or flushes at approximately 7-d intervals. After two breaks, mushroom production declines rapidly, so that each successive break produces fewer mushrooms. Growers terminate the crop at the end of the 2nd or 3rd break, because it is non-profitable to continue with declining production.
E-mail address: [email protected] 0960-8524/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.biortech.2009.07.073
Recent work in our laboratory has shown that it is possible to obtain more than one crop of mushrooms from the same compost (Royse et al., 2008; Royse and Sanchez, 2008a,b; Royse and Chalupa, 2009). The addition of commercial supplements, certain amino acids, and hydrolyzed proteins, increase yields of the 2nd crop. The ability to double-crop mushroom compost provides growers an opportunity to increase bio-efficiency while reducing the amount of ‘‘spent” mushroom compost (SMC) that requires disposal. It is estimated that at least 36 million m3 of SMC are disposed of each year in the United States (AMI, 2005). During the mushroom crop cycle, compost dry matter loss due to mushroom production may range from 20% to 30% from time of spawning to the end of the second or third break (D.J. Royse, unpublished). If compost is re-supplemented after 2nd break, expected mushroom yield/m2 is 20–30% lower due to compost dry matter loss from the 1st crop. Therefore, it may be desirable to increase dry matter/m2 by adding either fresh phase II compost, or by consolidating 2nd break compost to achieve a dry wt similar to the 1st crop. In order to practice double-cropping, a grower must remove the casing layer after one, two or three breaks and incorporate various supplements into the compost (Royse et al., 2008). Supplements may be incorporated into the compost by spawning machine or by removing the compost from the tray or bed, adding the
D.J. Royse / Bioresource Technology 101 (2010) 188–192
supplement and then returning the supplemented compost to the tray or bed. The type of machine used to fragment the compost may affect extent of fragmentation and subsequently affect aeration, nutrient absorption and water availability from the compost. It is unknown if degree of fragmentation may ultimately influence mushroom yield. The objectives of this research were to determine the effects of various treatments of 2nd break compost (2BkC) on mushroom yield as follows: (1) degree of compost fragmentation, (2) supplementation with delayed release nutrient, (3) addition of 20% phase II compost, and (4) exploration of the production of a 3rd crop of mushrooms from the same compost or ‘‘triple-cropping”. 2. Methods
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(3). No attempt was made to quantify particle sizes of fragmented 2BkC for either treatment but 3 was visually finer than 1. 2.3. Harvesting and determination of yield and biological efficiency Closed (lamellae not exposed) mushrooms were harvested, counted and weighed daily. At the end of each break, yield and biological efficiency (BE) were determined. BE was defined as the ratio of (g) of fresh mushrooms harvested per dry compost weight (g), including the weight of the supplement, and expressed as a percentage. Compost samples were selected randomly from each crop at spawning and delivered to the Agricultural Analytical Laboratory for moisture and nitrogen content analysis. Yield was expressed as kg/m2.
2.1. General crop description 2.4. Experimental design and data analysis Three cropping experiments were conducted to determine the effect of various treatments of 2BkC compost on mushroom yield and biological efficiency (BE%). Degree of fragmentation and addition of delayed release supplement and their interaction was evaluated in Crop 0806B, while addition of 20% phase II compost and supplement level was evaluated in Crops 0809B and 0810B. Crop 0810C was extended as a triple-crop that evaluated the effect of compost type, as well as addition of phase II compost and supplement. All crops involved removing the casing layer after 2nd break and then using the 2BkC for the various treatments. 2.2. Composts and preparation Compost for mushroom production was prepared from wheat straw-bedded horse manure mixed with switch grass supplemented with dried poultry manure and gypsum as described by Royse et al. (2008) and Royse and Sanchez (2008a,b). After phases I and II composting, phase II compost was supplemented with Remo’s All Season Regular (Remo’s Mushroom Services, Avondale, PA), a delayed release nutrient, at 4% dry wt at time of spawning with Sylvan 140 (Sylvan Spawn Co., Kittanning, PA) spawn (a white U1-type hybrid). Spawned, supplemented compost (25 kg) was filled into plastic bins (56 44 24 cm) and incubated for 16 d at 24 ± 2°C (compost temperature). Immediately after spawning, compost was covered with a woven landscape fabric (Ultra Web 3000 ground cover, Gempler’s, Madison, WI). Relative humidity was maintained at ca. 95–98% using a spinning disc humidifier connected to a timer. Following a 16-d spawn run, casing (sphagnum peat moss and limestone at ca. 80% moisture) was overlaid on the landscape fabric that was used to ease removal of the casing after mushroom harvest. Casing inoculum (CI, Sylvan 140–500 g/m2) was added to the casing prior to application. During the case hold (time during mycelial colonization of the casing), air temperature was maintained at 16 °C maintaining compost temperatures at 21 ± 1 °C. Relative humidity was maintained at 95–99% with a spinning disc humidifier. The crop was watered according to visual observations of mycelial growth and moisture content of the casing. Carbon dioxide levels were not controlled but generally ranged between 500 and 1500 ppm. Additional water was applied to the casing after harvest of first break to maintain casing moisture levels near field capacity. Mushrooms were harvested for two breaks and casing removed. The de-cased 2BkC was fragmented, re-supplemented and re-cased. Fragmentation was accomplished by passing 2BkC through a turner fitted with a rotating (>1000 rpm) drum. The drum contained four circumferentially-spaced, longitudinally extended bars that contacted the 2BkC as it was passed through the turner either once (1) or three times
All three crops utilized factorial designs (SAS, 2008). Crop 0806B was a 2 2 factorial with two degrees of fragmentation (1, 3) two levels of supplement (0, 3.7% dry wt; supplement percentage levels [dry wt] were estimated after determination of compost moisture contents) plus one non-fragmented control treatment (5 treatments 7 replicates = 35 experimental units). Crop 0809B was a 2 2 factorial with two levels of phase II compost (0, 20%) two levels of supplement (0, 3.53% dry wt) plus one treatment where phase II compost (20%) layered on top of non-fragmented 2BkC and one check treatment with phase II compost (100%) (6 treatments 6 replicates = 36 experimental units). Crop 0810 was a triple-crop (0810A, 0810B, 0810C). Crop 0810A was the 1st crop with production of two breaks on phase II compost. Crop 0810B used 2BkC from 0810A and was a 2 2 factorial with two levels of phase II compost (0, 20%) two levels of supplement (0, 3.57%). Treatments 1 and 2 had 6 replicates each while treatments 3 and 4 had 17 replicates each (6 + 6 + 17 + 17 = 46 experimental units). More replicates were used for treatments 3 and 4 (with and without 20% phase II compost) because 2BkC from these treatments was used for the 3rd crop, 0810C. Crop 0810C was a 2 2 2 factorial with two types of 2BkC from Crop 0810B, two levels of phase II compost (0, 20%), and two levels of supplement (0, 3.6%). This crop was produced in plastic bins (17 22 28 cm) filled with 3.64 kg 2BkC at time of re-casing. For Crop 0810C, there were 8 treatments 9 replicates = 72 experimental units. Mushrooms were harvested for two or three breaks depending on the experiment. The SAS program JMP was used to analyze data (SAS, 2008). Data were examined with a one-way analysis of variance (ANOVA) and the Tukey–Kramer Honestly Significant Difference (HSD) was used to evaluate significant differences among treatment means. Data were also evaluated using standard least squares modeling with effect screening (SAS, 2008). 3. Results Mushroom yields and BEs for the effect of degree fragmentation and supplement added to 2BkC are shown in Table 1. Highest yields were obtained from fragmented 2BkC that was passed through a turner (described earlier) and supplemented with 3.7% nutrient before re-casing. Non-fragmented, re-cased 2BkC yielded only 10.07 kg/m2 while 1- and 3-fragmented, non-supplemented compost yielded 13.45 and 13.09 kg/m2 (+33.6%, +30%), respectively (Table 1). The addition of 3.7% (dry wt) supplement to 1- and 3-fragmented 2BkC increased yield by 108.1% and 99.3%, respectively, compared to the non-fragmented, non-supplemented control. Yields tended to decrease ( 2.8%, 4.4% on non-
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Table 1 Effect of degree of fragmentation and supplementation on yield and biological efficiency (BE%) of mushrooms produced on 2nd break compost (2BkC) for three breaks (Crop 0806B). Degree of fragmentationA
SupplementB (% dry 2BkC wt)
Yield (kg/m2)C
BE (%)C
1 1 3 3 None (check)
3.7 0 3.7 0 0
20.96 13.45 20.07 13.09 10.07
89.2 59.9 88.1 58.3 44.9
a b a b c
a b a b c
A 2BkC was non-fragmented (none) or fragmented by passing the compost through a turner either one (1) or three times (3). B Remo’s All Season Regular (Remo’s Mushroom Services, Avondale, PA). C Yields and BE (%) followed by the same letter within the same crop and column are not significantly different according to the Tukey–Kramer honestly significant difference (P = 0.05).
Table 2 Probabilities > F from analysis of variance for the addition of supplement and 20% phase II compost to 2nd break compost (2BkC) tested for yield and biological efficiency (BE%) for two crops. Source
df
Crop no. 0809B
Supplement (S) Phase II compost (PIIC) S PIIC A
1 1 1
0810B
YieldA
BE (%)A
YieldA
BE (%)A
<0.0001 0.0098 0.3177
<0.0001 0.0106 0.3437
<0.0001 0.0791 0.0832
<0.0001 0.0759 0.0774
Values of less than 0.05 were considered significant according to Fisher’s LSD.
supplemented and supplemented 2BkC, respectively) as degree of fragmentation increased (1 vs. 3), but the difference was not significant. Probabilities > F from analysis of variance for the addition of supplement and 20% phase II compost to 2BkC tested for yield and biological efficiency (BE) for two Crops (0809B, 0810B) are presented in Table 2. For Crop 0809B, significant sources of variation for both yield and BE included supplement (S) and phase II com-
post (PIIC) while for Crop 0810B, only supplement significantly influenced yield and BE. There were no significant interactions for S PIIC for either crop. For Crop 0809B, highest yield (26.17 kg/m2) and BE (82.7%) were obtained from fragmented compost containing 20% PIIC and 3.53% supplement (Table 3). Mushroom yield from this treatment was higher (+5.4%) than the supplemented phase II compost (check), but the difference was not significant. Lowest yields were obtained from non-supplemented treatments with or without PIIC. Yield from non-fragmented 2BkC overlaid with 20% PIIC supplemented with 3.53% nutrient was 27.1% less than the treatment where PIIC and supplement were through-mixed into fragmented 2BkC (20.59 kg/m2 vs. 26.17 kg/m2, respectively). For Crop 08010B, highest yield (22.5 kg/m2) was from 2BkC containing 20% PIIC plus 3.57% supplement; however, this treatment was not significantly different from the supplemented treatment without PIIC (Table 4). PIIC added to non-supplemented 2BkC did not significantly influence mushroom yield. BEs ranged from a low of 48.3% on 2BkC without additions to 71% on 2BkC containing 20% PIIC plus 3.57% supplement. Means and groupings from analysis of variance for supplementation of 2BkC for Crops 0809B and 0810B for yield and BE are shown in Table 5. Yield (3 breaks) for Crop 0809B was 26.6% higher on 2BkC containing 3.53% Remo’s supplement compared to the non-supplemented treatments. In Crop 0810B, yield (2 breaks) was 43% higher on supplemented treatments compared to nonsupplemented treatments. Means and groupings from analysis of variance for addition of PIIC to 2BkC in Crops 0809B and 0810B for yield and BE are shown in Table 6. Yields were greater with the addition of PIIC, but this trend was significant only in Crop 0809B. Yield stimulation with PIIC was confined to the 1st break. Probabilities > F from analysis of variance for compost type and the addition of supplement and 20% phase II compost to 2nd break compost (2BkC) tested for yield and biological efficiency (BE%) for a 3rd crop from the same compost are presented in Table 7. The only significant source of variation for both yield and BE was supplement. There were no significant 2-way or 3-way interactions. Yield and BE were substantially lower in the 3rd Crop (0810C) compared
Table 3 Effects of addition of phase II compost and supplement to 2nd break compost (2BkC) on mushroom yield and biological efficiency (BE%) (Crop 0809B).
A B C
2Bk Treatment
2BkC (kg/m2)A
Phase II compost (kg/m2)A
SupplementB (% dry wt)
Yield (kg/m2)
BE (%)
Fragmented/mixed Fragmented/mixed Fragmented/mixed Fragmented/mixed Phase II layered on top 2BkC–no fragmentation Phase II (check)C
24.5 30.6 24.5 30.6 24.5 0
6.1 0 6.1 0 6.1 30.6
3.53 3.53 0 0 3.53 3.53
26.17 23.02 20.17 18.68 20.59 24.83
82.7 72.8 66.0 61.1 65.1 78.5
a bc cd d cd ab
Oven dry wt basis. Remo’s All Season Regular (Remo’s Mushroom Services, Avondale, PA). 4-d Spawn run; supplemented with 3.53% Remo’s supplement.
Table 4 Effects of addition of phase II compost and supplement to 2nd break compost (2BkC) on mushroom yield and biological efficiency (BE%) (Crop 0810B).
C
2BkC Treatment
2BkC (kg/m2)A
Phase II compost (kg/m2)A
SupplementB (% dry wt)
YieldC (kg/m2)
BEC (%)
Fragmented/mixed Fragmented/mixed Fragmented/mixed Fragmented/mixed
24.5 30.6 24.5 30.6
6.1 0 6.1 0
3.57 3.57 0 0
22.50 22.23 16.53 14.77
71.0 70.1 54.0 48.3
a a b b
a a b b
14-d Spawn run; supplemented with 3.53% Remo’s supplement. A Oven dry wt basis. B Remo’s All Season Regular (Remo’s Mushroom Services, Avondale, PA). C Yields and BE followed by the same letter within the same crop and column are not significantly different according to the Tukey–Kramer honestly significant difference (P = 0.05).
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Table 5 Means and groupings from analysis of variance for supplementation of two crops (0809B and 0810B) produced on 2nd break compost (2BkC) for (Agaricus bisporus) yield and biological efficiency (BE%). Supplement (% dry 2BkC wt)
No. reps
Yield (kg/m2)A
BE (%)A
Total
Break 1st
2nd
Crop 0809B 3.53 0
12 12
24.59 a 19.42 b
12.80 a 7.58 b
7.85 a 8.49 a
Crop 0810B 3.57 0
33 12
22.40 a 15.67 b
11.79 a 10.17 b
10.61 a 5.50 b
3rd 3.94 a 3.35 a
77.7 a 63.6 b
–B –B
71.9 a 52.0 b
A Yields and BE (%) followed by the same letter within the same crop and column are not significantly different according to the Tukey–Kramer honestly significant difference (P = 0.05). B Third break not harvested due to use of 2BkC for a 3rd Crop (0810C).
Table 6 Means and groupings from analysis of variance for addition of phase II compost to two crops (0809B and 0810B) produced on 2nd break compost (2BkC) for (Agaricus bisporus) yield and biological efficiency (BE%). Phase II compost (% dry 2BkC wt)
No. reps
Yield (kg/m2)A Total
Crop 0809B 20.2 0
12 12
Crop 0810B 19.9 0
23 22
BE (%)A Break 1st
2nd
3rd
23.17 a 20.85 b
11.38 a 9.00 b
7.76 a 8.58 a
4.03 a 3.27 a
74.4 a 67.0 b
20.97 a 20.22 a
11.84 a 10.85 b
9.13 a 9.37 a
–B –B
67.8 a 65.3 a
A Yields and BE (%) followed by the same letter within the same crop and column are not significantly different according to the Tukey–Kramer honestly significant difference (P = 0.05). B Third break not harvested – 2BkC was used for a 3rd Crop (0810C).
Table 7 Probabilities > F from analysis of variance for compost type and the addition of supplement and 20% phase II compost to 2nd break compost (2BkC) tested for yield and biological efficiency (BE%) for a 3rd crop from the same compost (Crop 0810C).
A
Source
df
YieldA
BE (%)A
Compost type (CT) Phase II compost (PIIC) CT PIIC Supplement (S) CT S PIIC S CT PIIC S
1 1 1 1 1 1 1
0.1756 0.4001 0.7607 <0.0001 0.5999 0.0747 0.5305
0.2598 0.2713 0.4600 <0.0001 0.4358 0.1183 0.8383
Values of less than 0.05 were considered significant according to Fisher’s LSD.
to the 1st (0810A) and 2nd (0810B) crops due mainly to the reduction in 1st break output (Table 8). Total yields were 46–61% lower depending on treatment. BEs for the 3rd crop were in the mid 40s compared to the upper 60s to mid 70s in the 1st and 2nd crops. 4. Discussion Double-cropping offers growers an opportunity to increase production efficiency while reducing costs. Several factors have been identified that contribute to increasing production efficiency on ‘‘spent” compost. In this work, we evaluated the degree of fragmentation, supplementation and addition of PIIC to 2BkC on mushroom yield. Simple compost fragmentation increased mushroom yield by 30% compared to the non-fragmented control. These findings were in agreement with Schisler (1964) who found that fragmentation
of 2BkC resulted in a yield increase of 42% over the non-fragmented control. Yields tended to decrease as the degree of fragmentation increased, but this difference was not significant. Our method of fragmentation was similar to that used on a tray farm, where 2BkC is dumped from trays, mixed, supplemented and then returned to the trays. In contrast, growers at shelf farms use spawning machines to fragment compost and incorporate supplement. Commercial growers who have experimented with double cropping on bed farms have suggested that 2BkC becomes too fine when spawning machines of current design are used to mix in supplement. They suggest use of spring-like tines as a substitute for the fixed tines used presently. Additional work is warranted in this area to determine optimum degree of fragmentation and its influence on mushroom yield. How compost/mycelial fragmentation influences mushroom yield remains unexplained. One possibility is that new mycelium, formed after fragmentation, is able to reach additional nutrients in the compost that were not accessible in the 1st crop. Another possible explanation is that aged mycelium gradually loses its capacity to access and transport nutrients through mycelial cords to the fruit bodies. Calcium oxalate crystals are formed on older mycelium (Masaphy et al., 1987) that may hinder the ability of the fungus to absorb nutrients. The growth and development of new mycelium would provide a more efficient connection, through mycelial cords, from compost mycelium to developing mushrooms. We routinely observed the rapid growth and development of new mycelium from mycelial cords after compost fragmentation. This new mycelium would be able to access not only left over nutrients in the compost, but also the new supply of nutrients provided by the supplement. Addition of a commercial supplement to fragmented compost increased mushroom yield by 53–56% over non-supplemented,
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Table 8 Triple-cropping Agaricus bisporus. Yield and biological efficiency (BE%) for three crops (2 breaks each) from phase II and 2nd break compost (2BkC) non-supplemented or supplemented with 20% phase II compost and delayed release nutrient (Remo’s). Crop no.
2BkC type
2BkC amount (%)
Phase II amount (%)
Yield (kg/m2)A Total
BE (%)A Break 1st
0810A (Crop 1) 0810B (Crop 2)
100B
0810C (Crop 3)
100C 80/20D
100 80 100 80 100 80
100 0 20 0 20 0 20
20.98 22.53 22.26 14.21 13.85 14.35 14.17
a a a a a a
11.79 12.23 11.32 5.21 5.91 5.40 6.27
2nd a a a a a a
9.19 10.30 10.94 9.00 7.94 8.95 7.90
a a a a a a
69.7 74.9 74.0 45.8 44.6 45.3 44.8
a a a a a a
A Yields and BE (%) followed by the same letter within the same crop and column are not significantly different according to the Tukey–Kramer honestly significant difference (P = 0.05). B 2BkC Type from Crop 0810A. C 2BkC Type from Crop 0810B (100% 2BkC). D 2BkC Type from Crop 0810B (80% 2BkC, 20% phase II).
fragmented 2BkC. Fragmented, supplemented 2BkC resulted in a 99–108% increase over the non-fragmented control depending on degree of fragmentation (3, 1, respectively). Therefore, for optimum productivity, it would be necessary to fragment and add supplement to 2BkC before re-casing. Another method to increase yield/m2 of production surface would be to increase the dry wt of 2BkC via the addition of 20% PIIC. Approximately 20–30% of the dry compost wt is lost during production of the 1st crop, so replacement of this dry wt with fresh compost could potentially boost yield/m2 to a level equivalent of the 1st crop. PIIC and supplement could be layered on top of the de-cased 2BkC and then incorporated with a spawning machine to through-mix the materials. Through-mixing appears necessary because treatments with phase II compost and supplement overlaid on 2BkC without mixing yielded 27.1% less than treatments where PIIC and supplement were through-mixed. The addition of PIIC to 2BkC resulted in a significant yield stimulation for one Crop (0809B) but not for the other (0810B). This yield increase was confined to the first break only. The reason for the differential response likely was related to the difference in the nitrogen content of the phase II compost added to 2BkC. PIIC nitrogen contents for Crops 0809B and 0810B were 2.4% and 2.0%, respectively. Thus, the additional nitrogen available in PIIC added to Crop 0809B would have provided additional nutrition to the crop that stimulated mushroom yield. In these experiments, there was no significant interaction between the addition of supplement and PIIC to 2BkC, although for Crop 0810B the P-value for this interaction was nearly significant (P = 0.08). In a previous experiment we found a significant interaction for these factors (Royse and Chalupa, 2009). It appears that the nutritional status of the PIIC added to 2BkC influences the interaction of the supplement. That is, lower-nitrogen PIIC responds to supplement to a greater extent than higher-nitrogen PIIC. We were successful in producing a 3rd crop of mushrooms from two types of 2BkC. Supplement was the only factor that had a significant impact on mushroom yield. The type of compost and addition of PIIC did not have a significantly impact yield. Overall yields of the 3rd crop were 57–63% less than the 2nd crop and 46–51% less than the 1st crop. Most yield loss was attributed to first break. Nitrogen content of the 2BkC was 2.5% for both types of compost (100% 2BkC and 80/20 mixture of 2BkC/PIIC), so this would not appear to be the reason for reduced yield. One possible explanation for the yield reduction was the drier casing overlay used for the triple-crop. Moisture content of the casing overlay was ca. 75% vs. our normal casing moisture content of ca. 80%. A drier casing overlay
takes longer to hydrate to field capacity, so this may have limited yield initially until the casing moisture could be raised to the desired level. A drier casing layer coupled with compost moistures of 61.9% and 62.6% for 100% 2BkC and 80/20 mixture of 2BkC/PIIC, respectively, could have reduced yield due to inadequate moisture. Another possible explanation for suppressed mushroom yield is the depletion of specific nutrients that became further limiting in the 3rd crop. This area of research warrants further exploration that is now underway in our laboratory. Double-cropping (and even triple-cropping) offers growers an opportunity to increase bio-efficiency, reduce production costs, and increase profitability. The cost of producing A. bisporus continues to rise due to increasing expenses including materials, energy and labor. Optimizing production practices, through double- or triple-cropping, could help growers become more efficient and competitive and ensure the availability of mushrooms for consumers. Acknowledgements The author is grateful to Doug Keith, Henry Shawley, Joey Martain and John Pecchia for technical assistance. References American Mushroom Institute (AMI), 2005. Spent Mushroom Substrate: Scientific Research and Practical Applications (23p). Masaphy, S., Levanon, D., Tchelet, R., Henis, Y., 1987. Scanning electron microscope studies of interactions between Agaricus bisporus (Lang) Sing hyphae and bacteria in casing soil. Appl. Environ. Microbiol. 53, 1132–1137. Royse, D.J., Sanchez, J.E., Beelman, R.B., Davidson, J., 2008. Re-supplementing and recasing mushroom (Agaricus bisporus) compost for a second crop. World J. Microbiol. Biotechnol. 24, 319–325. Royse, D.J., Sanchez, J.E., 2008a. Supplementation of first break mushroom compost with hydrolyzed protein, commercial supplements and crystalline amino acids. World J. Microbiol. Biotechnol. 24, 1333–1339. Royse, D.J., Sanchez, J.E., 2008b. Supplementation of 2nd break mushroom compost with isoleucine, leucine, valine, pheylalanine, FermentenÒ and SoyPlusÒ. World J. Microbiol. Biotechnol. 24, 2011–2017. Royse, D.J., Chalupa, W., 2009. Effects of spawn, supplement, and phase II compost additions and time of re-casing second break compost on mushroom (Agaricus bisporus) yield and biological efficiency. Biores. Technol. 100, 5277–5282. SAS Institute (SAS), 2008. JMP. SAS Institute Statistical Analysis System, Cary, NC. Schisler, L.C., 1964. Nutrient supplementation of compost during the mushroom growth cycle. Mushroom Growers Assoc. Bull. 179, 503–541. United States Department of Agriculture (USDA), 2008. Mushrooms. National Agricultural Statistics Service, Agricultural Statistics Board. Washington, DC. Van Roestel, A.J.J., 1988. Costs and returns. In: Van Griensven, L.J.L.D. (Ed.), The Cultivation of Mushrooms. Mushroom Experimental Station, Horst, The Netherlands, pp. 447–483. 515p. Wuest, P.J., 1983. Resources need to farm the ‘‘champignon”. Mycologia 75, 341– 350.