The hidden potential of saprotrophic fungi in arable soil: Patterns of short-term stimulation by organic amendments
Clocchiatti, Anna ; Hannula, S.E. ; Berg, Marlies van den; Korthals, Gerard ; Boer, Wietse de - \ 2020
Applied Soil Ecology 147 (2020). - ISSN 0929-1393
Ascomycetes - Fungal biomass - Organic amendments - Saprotrophic fungi - Sustainable agriculture - Wood sawdust
Saprotrophic fungi are abundant in soils of (semi-)natural ecosystems, where they play a major role in ecosystem functioning. On the contrary, saprotrophic fungal biomass is remarkably low in intensively managed soils and this can have a negative impact on soil functioning. Nevertheless, arable soils harbour a diverse pool of fungi, which can be stimulated by organic amendments. Management targeted towards increasing soil organic matter often coincides with an increase of fungal biomass, but it can take years before effects are seen. However, a rapid stimulation of fungal biomass at the start of the growing season could immediately benefit crop production, by improving nutrient availability, soil structure and suppression of soil-borne diseases. The objective of this study is to realize a rapid increase of saprotrophic fungal biomass with organic amendments. In controlled pot experiments, dried and milled organic materials of different quality were added to an arable sandy soil. Ergosterol-based fungal biomass and ITS2-based fungal community structure were measured over a period of two months. Wood sawdust of deciduous tree species and paper pulp resulted in a high and lasting increase of fungal biomass, as opposed to transient effects given by cover crops and other non-woody plant materials. Little or no stimulation of fungi was seen for coniferous wood sawdust and agro-industrial by-products. Nitrogen immobilization induced by sawdust and paper pulp was compensated by supplementing mineral nitrogen, which enhanced the stimulation of saprotrophic fungi. The composition of the stimulated fungi was influenced by the quality of organic amendments. In particular, deciduous wood sawdust and paper pulp favoured saprotrophic ascomycete fungi (mainly Sordariomycetes), with no increment in potential plant-pathogenic fungi. Overall, our results point at a good perspective to use woody materials as sustainable soil improver via stimulation of saprotrophic fungi.
A Comparative Analysis of Yield Gaps and Water Productivity on Smallholder Farms in Ethiopia, South Africa and Tunisia
Jovanovic, Nebo ; Musvoto, Constansia ; Clercq, Willem De; Pienaar, Cou ; Petja, Brilliant ; Zairi, Abdelaziz ; Hanafi, Salia ; Ajmi, Tarek ; Mailhol, Jean Claude ; Cheviron, Bruno ; Albasha, Rami ; Habtu, Solomon ; Yazew, Eyasu ; Kifle, Muluberhan ; Fissahaye, Degol ; Aregay, Gebremeskel ; Habtegebreal, Kiros ; Gebrekiros, Abreha ; Woldu, Yirga ; Froebrich, Jochen - \ 2020
Irrigation and Drainage 69 (2020)S1. - ISSN 1531-0353 - p. 70 - 87.
Amendements organiques - Fertilization management - Gestion de la fertilisation - Irrigation scheduling - Modèle PILOTE - Mulching - Organic amendments - Paillis - PILOTE model - Planification de l'irrigation
Agriculture in developing countries will have to transform and increase production by an estimated 70% in order to meet demands by 2050. Although well-managed commercial farms offer little manoeuvring space for increasing agricultural water productivity, smallholder farms usually operate at low input costs and therefore provide ample opportunities to reduce the potential yield gap through agricultural intensification. The aim of this paper is to analyse and compare yields and water productivities obtained in field and modelling experiments in Ethiopia (maize, garlic, onion), South Africa (tomato) and Tunisia (tomato, potato, wheat). Innovative agricultural practices were introduced on smallholder farms: irrigation scheduling and NPS Zn fertilization in Ethiopia; high-yielding cultivar, drip irrigation, mulching and organic amendments in South Africa; and crop water modelling in Tunisia. In general, crop yields increased up to eight times with innovative practices compared to current conventional farming practices. Crop water productivities were fairly stable within the same experiments, but increased with innovations, indicating that intensive farming can be more environmentally sustainable than conventional farming. Intensive farming systems in a resource-rich environment (high radiation levels, relatively fertile, deep and well-drained soils), combined with technology transfer and capacity building could be seen as viable strategies to secure food for smallholders and communities in African rural areas, as well as to improve water utilization in water-scarce catchments.
The possibility for improvement of flowering, corm properties, bioactive compounds, and antioxidant activity in saffron (Crocus sativus L.) by different nutritional regimes
Ghanbari, Jalal ; Khajoei-Nejad, Gholamreza ; Ruth, Saskia M. van; Aghighi, Sonia - \ 2019
Industrial Crops and Products 135 (2019). - ISSN 0926-6690 - p. 301 - 310.
Apo-carotenoids - Arbuscular-mycorrhizal fungus - Chemical fertilizer - Corm - Organic amendments - Saffron
Saffron as one of the most precious spices and medicinal plants, is highly valued for its bioactive compounds. Quantity and quality in spices and medicinal plants can be improved by the plant nutrition. In this field study the sole and integrated application of various fertilizers types and arbuscular-mycorrhizal fungus (AM), Glomus mosseae with respect to the flower-related traits, corm properties, quality, bioactive compounds and antioxidant activity of saffron at Kerman region, Iran was examined over a three years period. The fertilizer treatments comprised control (non-amended soil); 20 Mg ha −1 compost; 10 Mg ha −1 compost+ 8 Mg ha −1 biochar and chemical fertilizers. In each fertilizer treatment, planting bed was inoculated or non-inoculated with AM. The results showed that during the first flowering period (2015–16), neither AM nor fertilizer types affected flowering. Inoculation with AM particularly in the application of fertilizer treatments through positive effects on different corm properties during the vegetative growing seasons of 2015–16 and 2017–18, improved flower-related traits in the next flowering periods of 2016–17 and 2017–18. Picrocrocin and safranal content as well as total phenolic content and total flavonoid content in tepals were considerably enhanced by organic amendments and chemical fertilizers compared with the control. While the total phenolic content in stigmata was reduced by AM-inoculation, the total flavonoid content and antioxidant activity of stigmata and tepals were not significantly influenced. Principal Component Analysis clearly discriminated the integrated nutritional treatments from the sole ones based on flower-related traits and corm properties which were positively related with integrated treatments. Organic amendments were characterized by a higher total phenolic content and antioxidant activity in stigmata. Chemical fertilizers alone or in AM-inoculation associated with quality attributes and total flavonoid content in tepals. Research findings confirmed that the integrated application of mycorrhizal fungus, organic, and chemical fertilizers significantly influences the overall production of saffron.
Responses of soil biota to non-inversion tillage and organic amendments : An analysis on European multiyear field experiments
Hose, Tommy D'; Molendijk, Leendert ; Vooren, Laura Van; Berg, Wim van den; Hoek, Hans ; Runia, Willemien ; Evert, Frits van; Berge, Hein ten; Spiegel, Heide ; Sandèn, Taru ; Grignani, Carlo ; Ruysschaert, Greet - \ 2018
Pedobiologia 66 (2018). - ISSN 0031-4056 - p. 18 - 28.
Earthworms - Microbial biomass - Multiyear field experiments - Nematodes - Non-inversion tillage - Organic amendments
Over the last two decades, there has been growing interest on the effects of agricultural practices on soil biology in Europe. As soil biota are known to fluctuate throughout the season and as agro-environmental conditions may influence the effect of agricultural practices on soil organisms, conclusions cannot be drawn from a single study. Therefore, integrating the results of many studies in order to identify general trends is required. The main objective of this study was to investigate how soil biota are affected by repeated applications of organic amendments (i.e. compost, farmyard manure and slurry) or reduced tillage (i.e. non-inversion tillage and no till) under European conditions, as measured in multiyear field experiments. Moreover, we investigated to what extent the effects on soil biota are controlled by soil texture, sampling depth, climate and duration of agricultural practice. Experimental data on earthworm and nematode abundance, microbial biomass carbon and bacterial and fungal communities from more than 60 European multiyear field experiments, comprising different climatic zones and soil texture classes, were extracted from literature. From our survey, we can conclude that adopting no tillage or non-inversion tillage practices and increasing organic matter inputs by organic fertilization were accompanied by larger earthworm numbers (an increase between 56 and 125% and between 63 and 151% for tillage and organic amendments, respectively) and biomass (an increase between 108 and 416% and between 66 and 196% for tillage and organic amendments, respectively), a higher microbial biomass carbon content (an increase between 10 and 30% and between 25 and 31% for tillage and organic amendments, respectively), a marked increase in bacterivorous nematodes (an increase between 19 and 282% for organic amendment) and bacterial phospholipid-derived fatty acids (PLFA; an increase between 31 and 38% for organic amendment). Results were rarely influenced by soil texture, climate and duration of practice.
Nitrogen fertiliser replacement values for organic amendments appear to increase with N application rates
Hijbeek, R. ; Berge, H.F.M. ten; Whitmore, A.P. ; Barkusky, D. ; Schroder, J.J. ; Ittersum, M.K. van - \ 2018
Nutrient Cycling in Agroecosystems 110 (2018)1. - ISSN 1385-1314 - p. 105 - 115.
Crop yield - Mineral fertiliser - Mineral fertiliser equivalent - Nitrogen - Nitrogen fertiliser replacement value - Organic amendments - Soil fertility
Nitrogen (N) supply from organic amendments [such as farmyard manure (FYM), slurries or crop residues] to crops is commonly expressed in the amendment’s Nitrogen Fertiliser Replacement Value (NFRV). Values for NFRV can be determined by comparison of crop yield or N uptake in amended plots against mineral fertiliser-only plots. NFRV is then defined as the amount of mineral fertiliser N saved when using organic amendment-N (kg/kg), while attaining the same crop yield. Factors known to affect NFRV are crop type cultivated, soil type, manuring history and method or time of application. We investigated whether long-term NFRV depends on N application rates. Using data from eight long term experiments in Europe, values of NFRV at low total N supply were compared with values of NFRV at high total N supply. Our findings show that FYM has a significant higher NFRV value at high total N supply than at low total N supply (1.12 vs. 0.53, p = 0.04). For the other amendment types investigated, NFRV was also higher at high total N supply than at low total N supply, but sample sizes were too small or variations too large to detect significant differences. Farmers in Europe usually operate at high rates of total N applied. If fertiliser supplements are based on NFRV of the manure estimated at low total N supply, N fertiliser requirements might be overestimated. This might lead to overuse of N, lower N use efficiency and larger losses of N to the environment.
Plant biomass, soil microbial community structure and nitrogen cycling under different organic amendment regimes; a 15N tracer-based approach
Heijboer, Amber ; Berge, Hein F.M. ten; Ruiter, Peter C. de; Jørgensen, Helene Bracht ; Kowalchuk, George A. ; Bloem, Jaap - \ 2016
Applied Soil Ecology 107 (2016). - ISSN 0929-1393 - p. 251 - 260.
Immobilization - Mineral fertilizer - Mineralization - Organic amendments - Phospholipid fatty acids - Soil microbial community
Sustainable agriculture requires nutrient management options that lead to a profitable crop yield with relatively low nitrogen (N) losses to the environment. We studied whether the addition of contrasting organic amendments together with inorganic fertilizer can promote both requirements simultaneously. In particular we studied how the chemical composition of organic amendments affects the biomass, activity and composition of the soil microbial community and subsequently carbon (C) and N mineralization, microbial N immobilization and plant growth and nutrient uptake. In a pot experiment, Brussels sprouts (Brassica oleracea, cvar. Cyrus) were grown on arable soil, mixed with 15N-labelled mineral fertilizer and different kinds of organic amendments (cattle manure solid fraction, maize silage, lucerne silage, wheat straw) differing in C:N ratio and lignin content. After 69 and 132 days, destructive sampling took place to assess the effects of the different treatments on soil microbial biomass (microscopic measurements), microbial community composition (phospholipid fatty acid profiles), soil microbial activity (14C-leucine incorporation), C and N mineralization, plant biomass and 15N retrieval in soil pools, microbial biomass and plant biomass. Addition of organic amendments increased soil microbial biomass, activity and fungal/bacterial ratio and created distinct microbial community compositions, whereby high C:N ratio organic amendments had stronger effects compared to low C:N ratio amendments. Structural equation modelling showed that higher values of soil microbial activity were associated with increased N mineralization rates, increased plant biomass and plant 15N uptake, while microbial 15N immobilization was associated with soil microbial community composition. The outcomes of this study highlight the importance of the chemical composition and the amount of the organic amendments for finding a balance between plant N uptake, microbial N immobilization and N retention in labile and stable soil pools through the effects on the composition and activity of the soil microbial community. The results provide insights that can be used in designing combined input (nutrient and organic) nutrient management strategies for a more sustainable agriculture.