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The shoot and root biomass of alfalfa cultured with 20% SMS, 30% SMS and CF treatments were significantly higher than those of CK treatment (Fig. 1, p < 0.05), but there was no significant difference between 10% SMS and CK treatments (p > 0.05). And there was no significant difference between the shoot and root biomass of 20% SMS and 30% SMS treatments compared with CF treatment (p < 0.05). CF treatment had the largest number of root nodules number, followed by 20% SMS, 30% SMS, and 10% SMS treatments, and CK treatment had the least number (Fig. 2). The number of nodules with 20% SMS and 30% SMS treatments was higher than CK treatment (Fig. 2, p < 0.05).
Figure 1.
(a) Shoot biomass, (b) root biomass and (c) picture of plant pot experiments of alfalfa under different treatments. CK: 100% soil; 10%: 10% SMS; 20%: 20% SMS; 30%: 30% SMS; CF: 100% soil with chemical fertilizers added. Different lowercase letters above the columns represent significant differences among these treatments according to Duncan tests.
Figure 2.
Number of alfalfa nodules under different treatments. CK: 100% soil; 10%: 10% SMS; 20%: 20% SMS; 30%: 30% SMS; CF: 100% soil with chemical fertilizers added. Different lowercase letters above the columns represent significant differences among these treatments according to Duncan tests.
TN and TC content of forage grass reflects its excellent quality. Our data showed that 20% SMS treatment had the highest TN and TC contents of alfalfa leaf (Table 1). The TN and TC contents of alfalfa root and stem were the highest with CF treatment, and there was no significant difference compared with 20% SMS and 30% SMS treatments (p > 0.05).
Table 1. Total carbon, nitrogen content, and carbon and nitrogen ratio (TC, TN, C/N) of alfalfa harvested in different treatments.
Treatment Root-TN (g) Root-TC (g) Root-C/N (%) Stem-TN (g) Stem-TC (g) Stem-C/N (%) Leaf-TN (g) Leaf-TC (g) Leaf-C/N (%) CK 0.53 ± 0.26b 8.05 ± 3.69b 15.44 ± 0.86b 0.27 ± 0.11b 7.27 ± 2.73c 27.17 ± 1.27a 0.73 ± 0.49a 12.51 ± 8.20b 23.32 ± 12.55ab 10% SMS 0.83 ± 0.28ab 14.13 ± 4.18ab 17.13 ± 1.09a 0.28 ± 0.09b 8.49 ± 2.96bc 29.99 ± 3.39a 0.98 ± 0.47a 23.49 ± 9.58ab 24.8 ± 3.63a 20% SMS 1.00 ± 0.30ab 17.71 ± 5.83a 17.56 ± 0.79a 0.52 ± 0.16a 14.58 ± 4.21ab 28.23 ± 2.71a 2.50 ± 2.16a 29.74 ± 7.79a 15.7 ± 6.43ab 30% SMS 1.04 ± 0.52ab 17.92 ± 8.80a 17.28 ± 0.57a 0.44 ± 0.19ab 13.16 ± 5.88abc 29.82 ± 2.14a 1.60 ± 1.09a 25.07 ± 17.19ab 11.76 ± 7.87b CF 1.16 ± 0.15a 19.77 ± 2.30a 17.13 ± 0.45a 0.58 ± 0.13a 15.53 ± 2.61a 27.78 ± 6.58a 1.93 ± 0.21a 29.06 ± 1.85ab 15.14 ± 1.13ab Different lowercase letters in the table represent significant differences among these treatments according to Duncan tests. Substrate physicochemical properties
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The concentrations of DOC and available P significantly increased with the increase of SMS addition in the substrate (Fig. 3a & b, p < 0.05), and the concentrations were the lowest in the CK treatment. There was no significant difference between the 10%SMS and CF treatments (Fig. 3b, p > 0.05).
Figure 3.
Effects of different treatments on (a) soil dissolved organic carbon (DOC), (b) available P, (c) microbial biomass nitrogen (MBN), (d) microbial biomass carbon (MBC), (e) nitrate nitrogen ($\text{NO}_3^- $) and (f) ammonium nitrogen ($\text{NH}_4^+ $). Means ± S.E. CK: 100% soil; 10%: 10% SMS; 20%: 20% SMS; 30%: 30% SMS; CF: 100% soil with chemical fertilizers added. Different lowercase letters above the columns represent significant differences among these treatments according to Duncan tests.
The MBN and MBC concentrations of 10% SMS, 20% SMS, and 30% SMS treatments were significantly higher than those of CF and CK treatments (Fig. 3c, p < 0.05). There was no difference between CF and CK treatments (p > 0.05).
concentrations of 10% SMS, 20% SMS, and 30% SMS treatments were significantly lower than that of CK and CF treatments (Fig. 3e, p < 0.05). NH4+ concentration was the lowest in 20% SMS treatment, while other treatments had no significant difference with CK treatment (Fig. 3d, p < 0.05). There was no significant difference in soil pH among all treatments (Table 2, p > 0.05).$\text{NO}_3^- $ Table 2. The pH of substrate with different treatments after harvesting.
Experimental treatment pH CK 7.12 ± 0.18a 10% SMS 7.08 ± 0.09a 20% SMS 7.06 ± 0.08a 30% SMS 7.06 ± 0.15a CF 7.10 ± 0.06a Different lowercase letters in the table represent significant differences among these treatments according to Duncan tests. Correlation analysis
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RDA was used to assess how the physicochemical properties of the substrates influenced alfalfa growth indicators. It can be seen that there are significant differences in the substrate environment among different treatments, which have a significant impact on plant physiological indicators (Fig. 4). Plant physiological indicators respond strongly to the physicochemical characteristics of the substrate. The results show that the variance contribution rate of principal component 1 (PC1) and principal component 2 (PC2) respectively are 42.72% and 26.10%, and the cumulative variance contribution rate of PC1 and PC2 is 68.82%. Obtained through RDA diagram and calculation of Pearson correlation coefficient (PCC), available P had the strongest correlation with the PC1 and treatments distribution (r2 = 0.4035, p = 0.008), followed by root nodule (r2 = 0.2829, p = 0.047).
Figure 4.
The Redundancy Analysis (RDA) shows the effects of five experimental treatments on physical and chemical properties in substrate including pH, dissolved organic carbon (DOC), microbial biomass nitrogen (MBN), microbial biomass carbon (MBC), $\text{NH}_4^+ $ and $\text{NO}_3^- $, available P (P) and plant indicators including shoot biomass, root biomass, plant total nitrogen (TN), total carbon (TC), and carbon nitrogen ratio (CN). The red arrow in the figure represents plant growth indicators, and the blue arrow in the figure represents physical and chemical properties in substrate.
The Pearson correlation analysis showed that the shoot biomass value of alfalfa was significantly correlated with the available P in the substrate (Fig. 5, p < 0.05). MBC and MBN were strongly correlated with DOC and available P (p < 0.05). Meanwhile, there is a strong correlation between DOC and P (p < 0.001).
Figure 5.
Correlation heatmaps of alfalfa growth indicators (shoot biomass and root biomass) and of nutrient concentration indicators in substrates ($\text{NO}_3^- $, $\text{NH}_4^+ $, MBC, MBN, DOC, pH and P). $\text{NO}_3^- $: nitrate nitrogen; $\text{NH}_4^+ $: ammonium nitrogen; MBC: microbial biomass carbon; MBN: microbial biomass nitrogen; DOC: dissolved organic carbon; pH: acidity and alkalinity of substrates; P: available P. The color intensity in each panel indicates the relative correlation between read numbers of two groups. Blue represents positive correlation, and red represents negative correlation. Statistically significant correlations are indicated with *p < 0.05, **p < 0.01, and ***p < 0.001.
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Thanks to the College of Grassland Science and Technology at China Agricultural University for their guidance and assistance in this experiment. Also thanks to the Beijing Academy of Agriculture and Forest Sciences and Duolun Restoration Ecology Research Station, Institute of Botany, and Chinese Academy of Sciences for their material support in this experiment. Thanks to Hengkang Xu, Lu Lian and Bin Wei for their support in this project.
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About this article
Cite this article
Shi Y, Cui X, Zhang Y, Liu M. 2023. The addition of spent oyster mushroom substrates has positive effects on alfalfa growth and soil available nutrients. Grass Research 3:19 doi: 10.48130/GR-2023-0019
The addition of spent oyster mushroom substrates has positive effects on alfalfa growth and soil available nutrients
- Received: 08 May 2023
- Accepted: 21 August 2023
- Published online: 08 October 2023
Abstract: This study aimed to investigate the effects of spent mushroom substrate (SMS, 0%, 10%, 20%, and 30%, w/w) addition to degraded grassland soil on the growth and nutrient uptake of alfalfa through a greenhouse pot experiment. Meanwhile, we compared with the inorganic fertilizer (CF, 200 N mg/kg and 30 P mg/kg) application treatment, and explored the most suitable SMS addition amount for alfalfa yield. Our results showed, that compared with the control treatment (CK), 10% SMS, 20% SMS, 30% SMS, and CF treatments increased alfalfa shoot biomass by 1.19, 1.67, 1.77, and 1.77 times, respectively. Total carbon content in leaves and total nitrogen content in stems of 20% SMS treatment were significantly higher than other treatments. Adding SMS increased the nodule number, especially the 20% SMS treatment. In addition, the concentrations of dissolved organic carbon, available phosphorus, and microbial biomass carbon and nitrogen were significantly enhanced with increasing SMS addition, and there was no significant difference between CF and CK treatments except for available phosphorus. Shoot biomass was significantly correlated with available phosphorus. In summary, adding SMS (20% and 30%) to degraded grassland soil can significantly improve soil nutrients and microenvironment to increase alfalfa yield, but considering economic benefits, 20% SMS is the most suitable application amount. This study provides the theoretical basis and technical support for the large-scale application of SMS in the field.
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Key words:
- Spent mushroom substrate /
- Root nodule /
- Alfalfa biomass /
- Nutrient uptake