Nitrogen application and intercropping change microbial community diversity and physicochemical characteristics in mulberry and alfalfa rhizosphere soil

Abstract

Intercropping of mulberry (Morus alba L.) and alfalfa (Medicago sativa L.) is a new forestry-grass compound model in China, which can provide high forage yields with high protein. Nitrogen application is one of the important factors determining the production and quality of this system. To elucidate the advantages of intercropping and nitrogen application, we analyzed the changes of physicochemical properties, enzyme activities, and microbial communities in the rhizosphere soil. We used principal components analysis (PCA) and redundancy discriminators analysis to clarify the relationships among treatments and between treatments and environmental factors, respectively. The results showed that nitrogen application significantly increased pH value, available nitrogen content, soil water content (SWC), and urea (URE) activity in rhizosphere soil of monoculture mulberry. In contrast, intercropping and intercropping + N significantly decreased pH and SWC in mulberry treatments. Nitrogen, intercropping and intercropping + N sharply reduced soil organic matter content and SWC in alfalfa treatments. Nitrogen, intercropping, and intercropping + N increased the values of McIntosh diversity (U), Simpson diversity (D), and Shannon–Weaver diversity (H′) in mulberry treatments. However, PCA scatter plots showed clustering of monoculture mulberry with nitrogen (MNE) and intercropping mulberry without nitrogen (M0). Intercropping reduced both H′ and D but nitrogen application showed no effect on diversity of microbial communities in alfalfa. There were obvious differences in using the six types of carbon sources between mulberry and alfalfa treatments. Nitrogen and intercropping increased the numbers of sole carbon substrate in mulberry treatments where the relative use rate exceeded 4%. While the numbers declined in alfalfa with nitrogen and intercropping. RDA indicated that URE was positive when intercropping mulberry was treated with nitrogen, but was negative in monoculture alfalfa treated with nitrogen. Soil pH and SWC were positive with mulberry treatments but were negative with alfalfa treatments. Intercropping with alfalfa benefited mulberry in the absence of nitrogen application. Intercropping with alfalfa and nitrogen application could improve the microbial community function and diversity in rhizosphere soil of mulberry. The microbial community in rhizosphere soil of mulberry and alfalfa is strategically complementary in terms of using carbon sources.

Keywords

Mulberry intercropped with alfalfa / Nitrogen application / Principal components analysis / Redundancy discriminators analysis / Rhizosphere soil

References

[1] Amador JA, Gorres JH. Microbiological characterization of the structures built by earthworms and ants in an agricultural field. Soil Biol Biochem, 2007, 39(8): 2070-2077.

[2] Ashworth AJ, West CP, Allen FL, Keyser PD, Weiss SA, Tyler DD, Taylor AM, Warwick KL, Beamer KP. Biologically fixed nitrogen in legume intercropped systems: comparison of nitrogen-difference and nitrogen-15 enrichment techniques. Agron J, 2015, 107(6): 2419-2430.

[3] Bandick AK, Dick RP. Field management effects on soil enzyme activities. Soil Biol Biochem, 1999, 31(11): 1471-1479.

[4] Baslam M, Antolín M, Gogorcena Y, Muñoz F, Goicoechea N. Changes in alfalfa forage quality and stem carbohydrates induced by arbuscular mycorrhizal fungi and elevated atmospheric CO₂. Annal Appl Biol, 2014, 164(2): 190-199.

[5] Chalk P. Dynamics of biologically fixed N in legume-cereal rotations: a review. Aust J Agric Res, 1998, 49(3): 303-316.

[6] Chu H, Grogan P. Soil microbial biomass, nutrient availability and nitrogen mineralization potential among vegetation-types in a low arctic tundra landscape. Plant Soil, 2010, 329(1): 411-420.

[7] Classen AT, Boyle SI, Haskins KE, Overby S, Hart SC. Community-level physiological profiles of bacteria and fungi: plate type and incubation temperature influences on contrasting soils. FEMS Microbiol Ecol, 2003, 44(3): 319-328.

[8] Condron LM, Stark C, O'Callaghan M, Clinton P, Huang Z. Dixon GR, Tilston EL. The role of microbial communities in the formation and decomposition of soil organic matter. Soil microbiology and sustainable crop production, 2010, Netherlands: Springer 81 118

[9] Davis JHC, Woolley JN. Genotypic requirement for intercropping. Field Crops Res, 1993, 34: 407-430.

[10] Delgadoâ Baquerizo M, Brajesh KS, Jasmine G, Peter BR. Relative importance of soil properties and microbial community for soil functionality: insights from a microbial swap experiment. Funct Ecol, 2016, 30(11): 1862-1873.

[11] Deveryshetty J, Suvekbala V, Varadamshetty G, Phale P. Metabolism of 2-, 3- and 4-hydroxybenzoates by soil isolates Alcaligenes sp. strain PPH and Pseudomonas sp. strain PPD. FEMS Microbiol Lett, 2007, 268: 59-66.

[12] Fog K. The effect of added nitrogen on the rate of decomposition of organic matter. Biol Rev, 1988, 63(3): 433-462.

[13] Garau G, Silvetti M, Deiana S, Deiana P, Castaldi P. Long-term influence of red mud on As mobility and soil physico-chemical and microbial parameters in a polluted sub-acidic soil. J Hazard Mater, 2011, 185(2–3): 1241-1248.

[14] Garland,. Analysis and interpretation of community-level physiological profiles in microbial ecology. FEMS Microbiol Ecol, 1997, 24(4): 289-300.

[15] Garland JL, Mills AL. Classification and characterization of heterotrophic microbial communities on the basis of patterns of community-level sole-carbon-source utilization. Appl Environ Microbiol, 1991, 57(8): 2351-2359.

[16] Giller KE, Witter E, Mcgrath SP. Toxicity of heavy metals to microorganisms and microbial processes in agricultural soils: a Review. Soil Biol Biochem, 1998, 30(10–11): 1389-1414.

[17] Hauggaard-Nielsen H, Jensen ES. Evaluating pea and barley cultivars for complementarity in intercropping at different levels of soil N availability. Field Crops Res, 2001, 72(3): 185-196.

[18] Hector S. Plant diversity and productivity in European grasslands. Science, 1999, 286(5442): 1123-1127.

[19] Heichel G, Vance CP. Nitrate-N and rhizobium srain roles in alfalfa seedling nodulation and growth1. Crop Sci, 1979, 19(4): 512-518.

[20] Huang N, Wang WX, Yao Y, Zhu F, Wang WX, Chang X. The influence of different concentrations of bio-organic fertilizer on cucumber Fusarium wilt and soil microflora alterations. PLoS ONE, 2017, 12: e0171490.

[21] Janzen H. Soil organic matter characteristics after long-term cropping to various spring wheat rotations. Can J Soil Sci, 1987, 67(4): 845-856.

[22] Jenkinson D. Chemical tests for potentially available nitrogen in soil. J Sci Food Agric, 1968, 19(3): 160-168.

[23] Kitahara N, Shibata S, Nishida T. Management and utilisation of mulberry for forage in Japan 1. Productivity of mulberry-pasture association system and nutritive value of mulberry. Phys Chem Chem Phys, 2002, 15(23): 9335-42.

[24] Ladygina N, Hedlund K. Plant species influence microbial diversity and carbon allocation in the rhizosphere. Soil Biol Biochem, 2010, 42(2): 162-168.

[25] Latati M, Blavet D, Alkama N, Laoufi H, Drevon JJ, Gérard F, Pansu M, Ounane SM. The intercropping cowpea-maize improves soil phosphorus availability and maize yields in an alkaline soil. Plant Soil, 2014, 385(1): 181-191.

[26] Li Z, Wu X, Chen B. Changes in transformation of soil organic C and functional diversity of soil microbial community under different land uses. Agric Sci China, 2007, 6(10): 1235-1245.

[27] Liu Y, Delgado-Baquerizo M, Wang J, Hu H, Yang ZH, He J. New insights into the role of microbial community composition in driving soil respiration rates. Soil Biol Biochem, 2018, 118: 35-41.

[28] Machii KA, Yamanouchi H. A list of morphological and agronomical traits of mulberry genetic resources. Miscellaneous Publ Natl Inst Seric Entomol Sci, 2001, 18(6): 433-442.

[29] Mao L, Zhang L, Li W, Van der Werf W, Sun J, Spiertz H, Li L. Yield advantage and water saving in maize/pea intercrop. Field Crops Res, 2012, 138: 11-20.

[30] Motavalli P, Palm C, Parton W, Elliott E, Frey S. Soil pH and organic C dynamics in tropical forest soils: evidence from laboratory and simulation studies. Biol Biochem, 1995, 27(12): 1589-1599.

[31] Narita Y. Soil microorganisms in continuous and rotated cropping in gleyic ordinary andosols in abashiri district : (iii) fungi on roots of several crops in continuous and rotated. Japanese J Soil Sci Plant Nutr, 1983, 54(1): 15-24.

[32] Rodríguez-Kábana R, Truelove B. Effects of crop rotation and fertilization on catalase activity in a soil of the southeastern United States. Plant Soil, 1982, 69(1): 97-104.

[33] Saiya-Cork KR, Sinsabaugh R, Zak D. The effects of long term nitrogen deposition on extracellular enzyme activity in an Acer saccharum forest soil. Soil Biol Biochem, 2002, 34(9): 1309-1315.

[34] Sánchez M. Mulberry: an exceptional forage available almost worldwide. World Animal Rev, 2000, 93(1): 1-21.

[35] Sánchez MD (2002) Mulberry for animal production: mulberry, an exceptional forage available almost worldwide. Roma: Food and Agriculture Organization (FAO) of United Nations, pp 271–285

[36] Simpson EH. The measurement of diversity. Nature, 1949, 163(4148): 688-688.

[37] Stefanowicz A. The biolog plates technique as a tool in ecological studies of microbial communities. Polish J Environ Stud, 2006, 15(5): 669-676.

[38] Strong WL. Biased richness and evenness relationships within Shannon-Wiener index values. Ecol Ind, 2016, 67: 703-713.

[39] Su C, Evans L. Soil solution chemistry and alfalfa response to CaCO₃ and MgCO₃ on an acidic Gleysol. Can J Soil Sci, 1996, 76(1): 41-47.

[40] Sun YH, Yang ZH, Zhao JJ, Li Q. Functional diversity of microbial communities in sludge-amended soils. Physics Procedia, 2012, 33(1): 726-731.

[41] Tang X, Bernard L, Brauman A, Daufresne T, Deleporte P, Desclaux D, Souche G, Placella S, Hinsinger P. Increase in microbial biomass and phosphorus availability in the rhizosphere of intercropped cereal and legumes under field conditions. Soil Biol Biochem, 2014, 75: 86-93.

[42] Teuber LR, Levin RP, Sweeney TC, Phillips DA. Selection for N concentration and forage yield in alfalfa. Crop Sci, 1984, 24(3): 553-558.

[43] Tomm GO, Walley FL, Kessel CV, Slinkard AE. Nitrogen cycling in an alfalfa and bromegrass sward via litterfall and harvest losses. Agron J, 1995, 87(6): 1078-1085.

[44] Trasar-Cepeda C, Camiña F, Leirós MC, Gil-Sotres F. An improved method to measure catalase activity in soils. Soil Biol Biochem, 1999, 31(3): 483-485.

[45] Van Der Heijden MGA, Bakker R, Verwaal J, Scheublin TR, Rutten M, Van Logtestijn R, Staehelin C. Symbiotic bacteria as a determinant of plant community structure and plant productivity in dune grassland. FEMS Microbiol Ecol, 2006, 56(2): 178-187.

[46] Wang WX, Yang HJ, Bo YK, Ding S, Cao BH. Nutrient composition, polyphenolic contents, and in situ protein degradation kinetics of leaves from three mulberry species. Livestock Sci, 2012, 146(2–3): 203-206.

[47] Wei J, Gao J, Wang N, Liu Y, Wang Y, Bai Z, Zhuang X, Zhuang G. Differences in soil microbial response to anthropogenic disturbances in Sanjiang and Momoge Wetlands. China FEMS Microbiol Ecol, 2019, 95(8): 1-14.

[48] Willey RW. Intercropping: its importance and research needs.part 2, agronomy and research approaches. Field Crop Abstracts, 1979, 32: 73-85.

[49] Wu F, Wang X. Effect of monocropping and rotation on soil microbial community diversity and cucumber yield and quality under protected cultivation. Acta Hort, 2007, 76: 555-561.

[50] Xu HJ, Li S, Su JQ, Sa N, Gibson V, Li H, Zhu YG. Does urbanization shape bacterial community composition in urban park soils? A case study in 16 representative Chinese cities based on the pyrosequencing method. FEMS Microbiol Ecol, 2014, 87(1): 182-192.

[51] Yao H, Jiao X, Wu F. Effects of continuous cucumber cropping and alternative rotations under protected cultivation on soil microbial community diversity. Plant Soil, 2006, 284(1): 195-203.

[52] Zhang MM, AO H, Li X, Zhang JY, Wang N, Ju CM, Wang J, Cai DJ, Sun GY(2015) Effects of intercropping between mulberry and alfalfa on soil enzyme activities and microbial community diversity in rhizophere. Acta Agrestia Sinica 23(2):84–91 (Abstract in English)

[53] Zhang MM, Wang N, Hu YB, Sun GY. Changes in soil physicochemical properties and soil bacterial community in mulberry (Morus alba L.)/alfalfa (Medicago sativa L.) intercropping system. Microbiologyopen, 2018 7 2 e555