Micronutriënten in bodem en gewas na toediening van verschillende organische producten : rapportage in het kader van het TKI-project Micronutrienten in de kringloop (LWV20.249)

Het effect van toediening van tien zeer verschillende organische producten op micronutriënten in bodem en gewas is bekeken in een veldproef met achtereenvolgens aardappelen en suikerbieten. Voor borium, koper, kobalt, magnesium, mangaan en zink is de plantbeschikbaarheid in de bodem en de opname door het gewas bepaald. Bij gelijke aanvoer aan stikstof, fosfaat en kalium met de verschillende producten waren er weinig verschillen in gewasopbrengst en in plantbeschikbaarheid en gewasopname van de micronutriënten. Gemiddelde waarden voor plantbeschikbaarheid in de bodem en voor gehalten in geoogste aardappelen en suikerbieten worden gegeven

Empower Innovations in Routine Soil Testing

Conventional soil tests are commonly used to assess single soil characteristics. Thus, many different tests are needed for a full soil fertility/soil quality assessment, which is laborious and expensive. New broad-spectrum soil tests offer the potential to assess many soil characteristics quickly, but often face challenges with calibration, validation, and acceptance in practice. Here, we describe the results of a 20 year research program aimed at overcoming the aforementioned challenges. A three-step approach was applied: (1) selecting and establishing two contrasting rapid broad-spectrum soil tests, (2) relating the results of these new tests to the results of conventional soil tests for a wide variety of soils, and (3) validating the results of the new soil tests through field trials and communicating the results. We selected Near Infrared Spectroscopy (NIRS) and multi-nutrient 0.01 M CaCl2 extraction (1:10 soil to solution ratio; w/v) as broad-spectrum techniques. NIRS was extensively calibrated and validated for the physical, chemical, and biological characteristics of soil. The CaCl2 extraction technique was extensively calibrated and validated for ‘plant available’ nutrients, often in combination with the results of NIRS. The results indicate that the accuracy of NIRS determinations is high for SOM, clay, SOC, ECEC, Ca-CEC, N-total, sand, and inorganic-C (R2 ≥ 0.95) and good for pH, Mg-CEC, and S-total (R2 ≥ 0.90). The combination of the CaCl2 extraction technique and NIRS gave results that related well (R2 > 0.80) to the results of conventional soil tests for P, K, Mg, Na, Mn, Cu, Co, and pH. In conclusion, the three-step approach has revolutionized soil testing in The Netherlands. These two broad-spectrum soil tests have improved soil testing; have contributed to increased insights into the physical, chemical, and biological characteristics of soil; and have thereby led to more sustainable soil management and cropping systems

Microbial catabolic diversity in and beyond the rhizosphere of plant species and plant genotypes

Microorganisms in the rhizosphere drive important ecosystem processes such as nutrient cycling and organic matter decomposition. Microbial activity in the rhizosphere is a function of both rhizodeposition and the soil's inherent microbial community. In this study, we investigated plant species and genotype effects on microbial functioning in the rhizosphere and compared it to the corresponding bulk soil. We investigated the rhizospheres and bulk soils from eight natural grassland species (four grasses and four forbs) in a long-term biodiversity experiment and genotypes of two crop species (Solanum tuberosum and Brassica juncea) in a short term experiment. Soil microbial functioning was assessed by determining microbial catabolic diversity, which is the microbial response to addition of several carbon-rich substrates. Substrate-induced respiration was higher in the rhizosphere than in the bulk soil for all plant species and genotypes, except for the grasses Agrostis capillaris, Anthoxanthum odoratum and Holcus lanatus, which yielded similar microbial activities in the two soil zones. Microbial catabolic profiles in the rhizospheres of Rumex acetosa, Leucanthemum vulgare and Plantago lanceolata were most distinct from each other and from the other grassland species. The bulk soil's microbial community catabolic profile was also species dependent. For S. tuberosum we found a genotype effect on the microbial catabolic profile in the rhizsophere but not in the bulk soil. For Brassica juncea no such genotype effects were found in the rhizosphere or bulk soil. This is a first step to link microbial rhizosphere activities to soil functioning in natural and agricultural ecosystems.</p

Microbial catabolic diversity in and beyond the rhizosphere of plant species and plant genotypes

Microorganisms in the rhizosphere drive important ecosystem processes such as nutrient cycling and organic matter decomposition. Microbial activity in the rhizosphere is a function of both rhizodeposition and the soil's inherent microbial community. In this study, we investigated plant species and genotype effects on microbial functioning in the rhizosphere and compared it to the corresponding bulk soil. We investigated the rhizospheres and bulk soils from eight natural grassland species (four grasses and four forbs) in a long-term biodiversity experiment and genotypes of two crop species (Solanum tuberosum and Brassica juncea) in a short term experiment. Soil microbial functioning was assessed by determining microbial catabolic diversity, which is the microbial response to addition of several carbon-rich substrates. Substrate-induced respiration was higher in the rhizosphere than in the bulk soil for all plant species and genotypes, except for the grasses Agrostis capillaris, Anthoxanthum odoratum and Holcus lanatus, which yielded similar microbial activities in the two soil zones. Microbial catabolic profiles in the rhizospheres of Rumex acetosa, Leucanthemum vulgare and Plantago lanceolata were most distinct from each other and from the other grassland species. The bulk soil's microbial community catabolic profile was also species dependent. For S. tuberosum we found a genotype effect on the microbial catabolic profile in the rhizsophere but not in the bulk soil. For Brassica juncea no such genotype effects were found in the rhizosphere or bulk soil. This is a first step to link microbial rhizosphere activities to soil functioning in natural and agricultural ecosystems.</p

Sturen op bodemweerbaarheid door toediening van organische materialen : TKI-AF-15261

Tien zeer uiteenlopende organische producten zijn onderzocht op hun vermogen om ziektewering van een bodem te verhogen. In potproeven werd aangetoond dat een aantal van deze producten de ziektewering van zandgrond tegen Rhizoctonia solani en Meloidogyne hapla konden stimuleren. Vervolgens zijn de organische producten onder praktijkomstandigheden in de teelt van aardappel en suikerbiet getoetst. Bij een dosering van de producten conform de bemestingsadviezen waren de opbrengsten van de gewassen vergelijkbaar met een kunstmest bemeste controle en werd afhankelijk van de samenstelling van de producten tot 160, 50 en 200 kg/ha aan N, P en K bemesting bespaard (bij aardappel). De producten hadden onder veldomstandigheden een geringe invloed op de ziektewerende eigenschappen van de grond: Pythium ziektewering was in enkele gevallen verhoogd, maar er was geen meetbare verhoging van ziektewering tegen Rhizoctonia en Meloidogyne. Daarnaast zijn diverse (biologische) bodemparameters bepaald

Data underlying the publication: Chitin- and keratin-rich soil amendments suppress Rhizoctonia solani disease via changes to the soil microbial community

Microbial and chemical-physical data from soil samples treated with ten organic products were selected to assess their potential to enhance disease suppression in soil. After the products were amended into two different arable soils, pot experiments were performed to assess soil suppressiveness against the fungal pathogen Rhizoctonia solani. In addition, several soil characteristics were analyzed, as well as the bacterial and fungal community composition and how microorganisms interact within these communities, to better understand the effect of the organic amendments on creating disease suppressive soils

Chitin- and Keratin-Rich Soil Amendments Suppress Rhizoctonia solani Disease via Changes to the Soil Microbial Community

Enhancing soil suppressiveness against plant pathogens or pests is a promising alternative strategy to chemical pesticides. Organic amendments have been shown to reduce crop diseases and pests, with chitin products the most efficient against fungal pathogens. To study which characteristics of organic products are correlated with disease suppression, an experiment was designed in which 10 types of organic amendments with different physicochemical properties were tested against the soilborne pathogen Rhizoctonia solani in sugar beet seedlings. Organic amendments rich in keratin or chitin reduced Rhizoctonia solani disease symptoms in sugar beet plants. The bacterial and fungal microbial communities in amended soils were distinct from the microbial communities in nonamended soil, as well as those in soils that received other nonsuppressive treatments. The Rhizoctonia-suppressive amended soils were rich in saprophytic bacteria and fungi that are known for their keratinolytic and chitinolytic properties (i.e., Oxalobacteraceae and Mortierellaceae). The microbial community in keratin- and chitin-amended soils was associated with higher zinc, copper, and selenium, respectively.IMPORTANCE Our results highlight the importance of soil microorganisms in plant disease suppression and the possibility to steer soil microbial community composition by applying organic amendments to the soil