氮參與蛋白質、核酸等生命必需生物大分子的合成，是生物體中至關重要的成分。生物圈中的氮循環是氮的生物地球化學循環的重要組成部分之一。隨著農業和畜牧業的發展，大量畜禽糞便和農作物秸稈被閑置、浪費，并被稱為“農業廢棄物”。種養循環技術模式是促進營養物質循環利用、提高農牧業生產效率的重要農業生產方式。然而，到目前為止，種養循環系統中關于氮循環效率及其調控的研究還非常薄弱。為此，中國科學院東北地理與農業生態研究所草地農牧業學科組的科研人員基于“玉米秸稈養牛-糞便基質化-草生菌栽培”循環系統，研究了莫能菌素及秸稈種類對氮回收率的影響(氮回收率定義為蘑菇子實體中總氮與初始原料中總氮的比值)，旨在明確該循環系統中氮的回收率，并揭示莫能菌素影響循環系統中氮轉化的微生物學機制。
研究發現：在4種發酵基質(無抗牛糞+玉米秸稈、無抗牛糞+小麥秸稈、有抗牛糞+玉米秸稈、有抗牛糞+小麥秸稈)上栽培雙孢蘑菇，可以蘑菇氮的形式回收秸稈和糞便中總氮的3.33-5.88%。由于殘留的莫能菌素抑制了基質中氨化與反硝化菌的活性，從而降低了基質發酵過程中的氮損失，提高了氮轉化效率(表1)。然而，由于發酵和栽培過程中，基質中與氮轉化相關的酶活性(表2)以及微生物群落結構和演替變化(圖1)引起的氮損失變化，莫能菌素最終降低了整個循環系統中氮回收率的0.13%-1.57%。本研究結果為構建高效的種養一體化循環農業技術模式提供了數據支撐。
表1. 基質發酵、蘑菇栽培及采收過程中的氮回收率
|
Stages |
Items |
Treatment1 |
SEM |
Pvalue | |||||
|
No-antibiotic |
Antibiotic | ||||||||
|
NC |
NW |
AC |
AW |
Straw |
Antibiotic |
Straw×Antibiotic | |||
|
Start of fermentation |
Starting substrate (kg) |
15.12 |
15.22 |
15.18 |
15.21 |
0.042 |
0.129 |
0.650 |
0.378 |
|
N concentration in starting substrate (g/kg) |
16.45c |
18.96a |
16.21d |
18.73b |
0.035 |
<0.001 |
<0.001 |
0.981 | |
|
Total N in starting substrate (g) |
248.7c |
288.7a |
246.1d |
284.8b |
0.855 |
<0.001 |
0.001 |
0.462 | |
|
End of fermentation |
Fermented substrate (kg) |
11.20b |
10.65c |
11.41c |
10.38d |
0.035 |
<0.001 |
0.342 |
<0.001 |
|
N concentration in fermented substrate (g/kg) |
21.08b |
21.54b |
21.01b |
22.87a |
0.299 |
<0.001 |
0.047 |
0.029 | |
|
Total N in fermented substrate (g) |
236.1 |
229.4 |
239.6 |
237.3 |
3.316 |
0.189 |
0.098 |
0.516 | |
|
N retention rate during fermentation2(%) |
94.93a |
79.45c |
97.37a |
83.33b |
1.194 |
<0.001 |
0.016 |
0.555 | |
|
End of cultivation |
Cultivated substrate (kg) |
6.96b |
7.14a |
6.81c |
7.09a |
0.038 |
<0.001 |
0.020 |
0.190 |
|
N concentration of cultivated substrate (g/kg) |
14.54c |
17.43a |
16.21b |
17.27a |
0.192 |
<0.001 |
<0.001 |
<0.001 | |
|
Total N in cultivated substrate (g) |
101.1c |
124.3a |
110.4b |
121.2a |
1.350 |
<0.001 |
0.012 |
<0.001 | |
|
N retention rate during cultivation3(%) |
40.64c |
43.07b |
44.87a |
42.98b |
0.460 |
0.564 |
<0.001 |
<0.001 | |
|
Harvested mushroom |
Fruit body yield (kg DM) |
0.080a |
0.067b |
0.047c |
0.052c |
0.002 |
0.129 |
<0.001 |
<0.001 |
|
N concentration in fruit body (mg/kg) |
18.27 |
18.52 |
18.24 |
18.17 |
0.301 |
0.755 |
03542 |
0.600 | |
|
Total N in fruit body (g) |
1.463a |
1.247b |
0.852c |
0.948c |
0.049 |
0.231 |
<0.001 |
0.004 | |
|
N recycled rate4(%) |
5.88a |
4.31b |
3.46c |
3.33c |
0.189 |
<0.001 |
<0.001 |
0.001 | |
NC= no-antibiotic manure and corn straw, NW: no-antibiotic manure and wheat straw, AC= antibiotic manure and corn straw, AW= antibiotic manure and wheat straw, N retention rate= Total N in fermented substrate/Total N in starting substrate, N retention rate= Total N in cultivated substrate/Total N in fermented substrate, N recycled rate= Total N in fruit body of mushroom/ Total N in starting substrate.
表2. 基質發酵和蘑菇栽培過程中的關鍵酶活性
|
Index |
Stage |
Treatment1 |
SEM |
Pvalue | |||||
|
No-antibiotic |
Antibiotic | ||||||||
|
NC |
NW |
AC |
AW |
Straw |
Antibiotic |
Straw × Antibiotic | |||
|
Urease (U/g) |
End of feeding |
5770.3b |
5775.5b |
8556.4a |
8125.7a |
277.74 |
0.453 |
<0.001 |
0.442 |
|
End of fermentation |
3014.6b |
3911.0a |
2345.1c |
2173.2d |
24.30 |
<0.001 |
<0.001 |
<0.001 | |
|
End of cultivation |
43.38b |
218.80a |
45.10b |
32.01c |
0.704 |
<0.001 |
<0.001 |
<0.001 | |
|
Nitrate reductase (U/g) |
End of feeding |
7.43b |
7.25b |
13.61a |
13.63a |
0.147 |
0.611 |
<0.001 |
0.529 |
|
End of fermentation |
1.04b |
1.18a |
0.74c |
0.90d |
0.012 |
<0.001 |
<0.001 |
0.631 | |
|
End of cultivation |
38.75bc |
49.2b |
30.24c |
152.4a |
4.104 |
<0.001 |
<0.001 |
<0.001 | |
|
Nitrite reductase (U/g) |
End of feeding |
15.77b |
15.79b |
15.94a |
15.95a |
0.078 |
0.731 |
0.002 |
0.890 |
|
End of fermentation |
14.20a |
10.49d |
11.22c |
13.02b |
0.018 |
<0.001 |
<0.001 |
<0.001 | |
|
End of cultivation |
11.22a |
9.49b |
8.58c |
8.48d |
0.028 |
<0.001 |
<0.001 |
<0.001 | |
圖1. 基質發酵第0天(a)、14天(b)、35天(c)基于 16S rDNA 測序的門水平相對豐度;堆肥第0天(d)、14天(e)、35 天(f)基于 ITS 測序的門水平相對豐度。
研究成果于近期發表在國際期刊Waste Management上，由王菲研究實習員(第一作者)和鐘榮珍研究員(通訊作者)共同完成。該研究得到了中國科學院戰略性先導科技專項(XDA28020400 ; XDA28080400 ; XDA23070503 );吉林省與中國科學院科技合作高技術產業化專項資金項目(2021SYHZ0033);吉林省科技發展計劃項目(20200602016ZP )和中國科學院青年創新促進會優秀會員人才專項( Y201949 )的聯合資助。
文章信息：Wang F., Fang Y., Wang L. X., Xiang H., Chen G. S., Chang X., Liu D., He X. M., Zhong R. Z.*2022. Effects of residual monensin in livestock manure on nitrogen transformation and microbial community during “crop straw feeding-substrate fermentation-mushroom cultivation” recycling system. Waste Management. 149. 333-344. https://doi.org/10.1016/j.wasman.2022.06.015.
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