Effects of Agricultural Management of Spent Mushroom Waste on Phytotoxicity and Microbiological Transformations of C, P, and S in Soil and Their Consequences for the Greenhouse Effect

Abstract

The huge volumes of currently generated agricultural waste pose a challenge to the economy of the 21st century. One of the directions for their reuse may be as fertilizer. Spent mushroom substrate (SMS) could become an alternative to manure (M). A three-year field experiment was carried out, in which the purpose was to test and compare the effect of SMS alone, as well as in multiple variants with mineral fertilization, and in manure with a variety of soil quality indices-such as enzymatic activity, soil phytotoxicity, and greenhouse gas emissions, i.e., CO₂. The use of SMS resulted in significant stimulation of respiratory and dehydrogenase activity. Inhibition of acid phosphatase and arylsulfatase activity via SMS was recorded. SMS showed varying effects on soil phytotoxicity, dependent on time. A positive effect was noted for the growth index (GI), while inhibition of root growth was observed in the first two years of the experiment. The effect of M on soil respiratory and dehydrogenase activity was significantly weaker compared to SMS. Therefore, M is a safer fertilizer as it does not cause a significant persistent increase in CO₂ emissions. Changes in the phytotoxicity parameters of the soil fertilized with manure, however, showed a similar trend as in the soil fertilized with SMS.

Keywords: Lepidium sativum L.; dehydrogenases; enzymatic activity; greenhouse effect; manure; phytotoxicity; soil microorganisms; soil respiration; spent mushroom substrate; waste.

Figure 1

Location of the research area: (A) location of Poland against the background of Europe; (B) location of the Lublin region in Poland; and (C) location of the “Czesławice” farm in the Lublin region.

Figure 2

Average monthly temperatures and monthly rainfall totals in the experimental area during the research period.

Figure 3

Respiratory activity in control soil and soil under different treatment strategies. (A) 1st year; (B) 2nd year; and (C) 3rd year. C—control soil; SMS—soil + spent mushroom substrate; SMS + N1P1K1—soil + spent mushroom substrate + mineral fertilization N1P1K1; SMS + N2P2K2—soil + spent mushroom substrate + mineral fertilization N2P2K2; and M—soil + manure. The vertical lines indicate the standard deviation. Different letters above the columns indicate significant differences at p < 0.05, and each year was analyzed independent of each other.

Figure 4

Activity of dehydrogenases in control soil and soil under different treatment strategies. (A)—1st year; (B)—2nd year; (C)—3rd year. C—control soil; SMS—soil + spent mushroom substrate; SMS + N1P1K1—soil + spent mushroom substrate + mineral fertilization N1P1K1; SMS + N2P2K2—soil + spent mushroom substrate + mineral fertilization N2P2K2; M—soil + manure. The vertical lines indicate the standard deviation. Different letters above the columns indicate significant differences at p < 0.05, and each year was analyzed independent of each other.

Figure 5

Acid phosphatase activity in control soil and soil under different treatment strategies. (A)—1st year; (B)—2nd year; (C)—3rd year. C—control soil; SMS—soil + spent mushroom substrate; SMS + N1P1K1—soil + spent mushroom substrate + mineral fertilization N1P1K1; SMS + N2P2K2—soil + spent mushroom substrate + mineral fertilization N2P2K2; M—soil + manure. The vertical lines indicate the standard deviation. Different letters above the columns indicate significant differences at p < 0.05, and each year was analyzed independent of each other.

Figure 6

Arylsulfatase activity in control soil and soil under different treatment strategies. (A)—1st year; (B)—2nd year; (C)—3rd year. C—control soil; SMS—soil + spent mushroom substrate; SMS + N1P1K1—soil + spent mushroom substrate + mineral fertilization N1P1K1; SMS + N2P2K2—soil + spent mushroom substrate + mineral fertilization N2P2K2; M—soil + manure. The vertical lines indicate the standard deviation. Different letters above the columns indicate significant differences at p < 0.05, and each year was analyzed independent of each other.

Figure 7

Growth index Lepidium sativum in soil under different treatment strategies. (A)—1st year; (B)—2nd year; (C)—3rd year. C—control soil; SMS—soil + spent mushroom substrate; SMS + N1P1K1—soil + spent mushroom substrate + mineral fertilization N1P1K1; SMS + N2P2K2—soil + spent mushroom substrate + mineral fertilization N2P2K2; M—soil + manure. The vertical lines indicate the standard deviation. Different letters above the columns indicate significant differences at p < 0.05, and each year was analyzed independent of each other.

Figure 8

Lepidium sativum seed germination in the control soil and soil under different treatment strategies. (A)—1st year; (B)—2nd year; (C)—3rd year. C—control soil; SMS—soil + spent mushroom substrate; SMS + N1P1K1—soil + spent mushroom substrate + mineral fertilization N1P1K1; SMS + N2P2K2—soil + spent mushroom substrate + mineral fertilization N2P2K2; M—soil + manure. The vertical lines indicate the standard deviation. Different letters above the columns indicate significant differences at p < 0.05, and each year was analyzed independent of each other.

Figure 9

Increase in root length of Lepidium sativum in control soil and soil in different treatment strategies after two days. (A)—1st year; (B)—2nd year; (C)—3rd year. C—control soil; SMS—soil + spent mushroom substrate; SMS + N1P1K1—soil + spent mushroom substrate + mineral fertilization N1P1K1; SMS + N2P2K2—soil + spent mushroom substrate + mineral fertilization N2P2K2; M—soil + manure. The vertical lines indicate the standard deviation. Different letters above the columns indicate significant differences at p < 0.05, and each year was analyzed independent of each other.

Figure 10

Increase in root length of Lepidium sativum in control soil and soil in different treatment strategies after four days. (A)—1st year; (B)—2nd year; (C)—3rd year. C—control soil; SMS—soil + spent mushroom substrate; SMS + N1P1K1—soil + spent mushroom substrate + mineral fertilization N1P1K1; SMS + N2P2K2—soil + spent mushroom substrate + mineral fertilization N2P2K2; M—soil + manure. The vertical lines indicate the standard deviation. Different letters above the columns indicate significant differences at p < 0.05, and each year was analyzed independent of each other.

Figure 11

Principal component analysis (PCA) for the results of analyzed parameters in the soil-loading plot. RES—respiration of soil, DEH—dehydrogenases, ARS—arylsulfatase, AcP—acid phosphatase, GI—growth index of L. sativum, GERM—germination of L. sativum, RL2—root length of L. sativum after two days, RL4—root length of L. sativum after four days, TOC—total organic carbon, TN—total nitrogen, and TP—total potassium.

Figure 12

Heat map displaying the Pearson correlation coefficients between environmental factors (rainfall and temperature); biochemical and enzymatic activity; and phytotoxic parameters; as well as physicochemical and chemical properties at the combination level. Significance noted at * p < 0.05; ** p < 0.01; and *** p < 0.001, respectively. RL4—root length of L. sativum after four days, RL2—root length of L. sativum after two days, GERM—germination of L. sativum, GI—growth index of L. sativum, AcP—acid phosphatase, ARS—arylsulfatase, DEH—dehydrogenases, RES—respiration of soil, C—control soil; SMS—soil + spent mushroom substrate; SMS + N1P1K1—soil + spent mushroom substrate + mineral fertilization N1P1K1; SMS + N2P2K2—soil + spent mushroom substrate + mineral fertilization N2P2K2; M—soil + manure.

Figure 13

Heat map displaying the Pearson correlation coefficients between chemical and physico-chemical properties; biochemical and enzymatic activity; and phytotoxic parameters at the combination level. Significance noted at * p < 0.05; ** p < 0.01; and *** p < 0.001, respectively. TOC—total organic carbon, TN—total nitrogen, TP—total potassium, RL4—root length of L. sativum after four days, RL2—root length of L. sativum after two days, GERM—germination of L. sativum, GI—growth index of L. sativum, AcP—acid phosphatase, ARS—arylsulfatase, DEH—dehydrogenases, RES—respiration of soil, C—control soil; SMS—soil + spent mushroom substrate; SMS + N1P1K1—soil + spent mushroom substrate + mineral fertilization N1P1K1; SMS + N2P2K2—soil + spent mushroom substrate + mineral fertilization N2P2K2; M—soil + manure.