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Cover crop use in organic rice cropping systems efficiently manages the two most limiting factors in organic agriculture - weed competition and nutrient availability. Nonetheless, cover crop biomasses on soil surfaces under the anaerobic conditions in flooded rice systems produce organic acids (mainly acetic acid) that cause early phytotoxicity to rice seedling coleoptile and roots. This study evaluated the dose-response of acetic acid on germination rates and post-germination growth traits (coleoptile, first leaf, and roots). Under controlled conditions, the seeds of three rice varieties (Sant’Andrea, Salvo, and Selenio) were immersed in acetic acid concentrations (0, 9, 18, 36, 54, and 72 ppm) for eight days. Germination results suggest that acetic acid likely scarred var. Salvo, based on a 15% faster germination rate compared to untreated controls. Across all varieties, increased acetic acid concentrations never slowed germination. During post-germination growth stages, root phytotoxicity was always more evident than shoot phytotoxicity, although the responses varied among the varieties. Root length damage appeared first at acetic acid concentrations of 36 ppm in var. Sant’Andrea and Selenio, and at 54 ppm in var. Salvo. Root length measurements provided explicit and speedy information on varietal tolerance to acetic acid and, consequently to cover crop fermentation and suggested that direct observation of root damage in paddy fields is valuable for prompt water management decisions, such as flooding interruption. Further development of this method may lead to more complete varietal screening and identification of related genetic traits responsible for tolerance. Highlights- Based on genotype, increasing acetic acid levels in flooding waters can speed rice germination.- Roots are more sensitive than shoots to acetic acid phytotoxicity during very early germination.- Early root length impairments provide information on tolerance to acetic acid phytotoxicity.- A slower germination rate may induce higher tolerance to green mulching.

Agriculture contributes to over 20% of global anthropogenic GHG emissions and irrigated paddy fields account for 5–10% of CH4 emissions. Main organic input providing methanogenesis substrate is straw. We hypothesized that removing rice straw can mitigate CH4 emissions, and that replacing its carbon (C) input with raw or solid digestate can be a valuable alternative both for crop, soil and emission responses. A mesocosm study was setup to follow crop growth, changes in soil pore water chemistry (dissolved Fe(II) and dissolved Organic C), and CH4 emissions over one cropping season on soil treated with the combination of two straw managements (removal or incorporation) and three fertilizations (mineral, raw digestate, solid digestate). Soils not receiving straw on average emitted 38 % less than soils after straw incorporation, while the two organic fertilizers did not increase emissions with respect to mineral N application. Furthermore, straw incorporation induced a yield depression independently from the fertilization strategy, probably as a result of N immobilization, especially in early stages. This was evidenced by early SPAD observations and flag leaf length, and both grain and straw final production. Moreover, the two organic fertilizers were not fully able to sustain crop N requirements with respect to the mineral fertilizer. Straw management was therefore decisive for determining both rice yield and CH4 emissions, while the impact of fertilization treatments was crucial only for crop productivity.

Nitrogen (N) fertilisation is the main agronomic practice that affects rice yield and quality; similarly, its mismanagement can affect both economic and environmental aspects of crop production. Therefore, it is highly important to direct N fertilisation during the critical growth stages of rice development using vegetation indices (VIs). To this end, a two-year experiment was conducted in 2014 and 2015 in Castello d’Agogna (PV), northwest Italy. The study had three aims: i) establish the best N fertilisation management in temperate rice cropping systems, in terms of total N supply and splitting, to maximise crop yield and N apparent recovery (AR); ii) evaluate the capability of crop N status indicators (CNSIs) measured at panicle initiation stage (PI) to determine grain yield; iii) derive Nfertiliser_rate_at_PI = f(CNSI) from a field trial to attain specific yield goals. Results obtained for Centauro variety suggested that to maximise yield while avoiding AR reduction, a low dose of about 50 kg N ha−1 should be supplied during early growth, then increased at PI. In addition, the final topdressing fertilisation can compensate for any previous stage supply deficiency and can be determined from VI measurements. Findings also identified the normalised difference red edge (NDRE) index as the best VI to determine rice N status in specific agro-environmental conditions. SPAD and NDVI values measured with Rapid Scan can be used to determine N fertilisation at PI, although such measurements require correction through Sufficiency Indices (SIs) calculated as the ratio between VI measurements and VI values of a well-N fertilised plot. The trial also demonstrated that plots supplied with N amounts of 140 kg N ha−1 (pre-sowing and tillering stages combined) can serve as reference plots for SI calculation that allows to consider the effect of weather and soil variability on VI measurements. A notable exception to this finding was NDVI measured with GreenSeeker, which showed limited ability to assess rice N status under study environmental conditions. Indeed, both VI and the derived SI were influenced by seasonal and soil fertility conditions. Finally, a specific statistical method to derive calibration functions for variable rate application fertiliser spreaders from a suitable experiment was defined. These functions will establish the N amount to be supplied at PI related to the CNSI measure. For each CNSI, a specific slope of the calibration function is determined while the intercept is varied depending on the grain yield goal. The higher the acceptable reduction relative to the maximum obtainable yield, the lower the N supply required at PI.

Many excellent results are obtained in agricultural and forestry research projects, but their practical adoption is often limited. The aim of the European project VALERIE is to increase the transfer and application of innovations produced by research in agriculture and forestry, by facilitating their integration into management practices. The project is still ongoing and the results illustrated in this paper are still temporary and subject to being improved. Here we present the methodology used in VALERIE to extract and summarise knowledge for innovation from research documents with the aim of making it available to final users through ask-Valerie.eu; we also report on current progress. The tasks associated with extracting and summarising knowledge are centred on: i) an ontology; ii) a document base; and iii) a system (ask-Valerie.eu) that allows users to effectively search the document base. An ontology defines a set of concepts and the relations between them. The VALERIE ontology is built by experts in the agricultural and forestry domain and contains 6169 concepts (21st October 2016). The document base is the collection of documents in which the system searches. The VALERIE document base includes scientific and practical documents derived from various sources, written in any of a number of languages. All documents contained in the document base are annotated using the ontology: each term (a word or a short phrase) in the document that matches a concept in the VALERIE-ontology is linked to that concept. Annotation is an automated process that takes place whenever a document is added to the document base. The document base contains 4278 documents (October 2016). Among them, there are 201 minifactsheets written by members of the VALERIE project, each describing an innovation with: a short description of the innovation, a list of correlated projects, and some links to scientific and practical documents. ask-Valerie.eu searches documents and fragments of text from the document base that address the user’s query. ask-Valerie.eu mimics the dialogue between a practitioner and an expert and achieves this functionality by: i) supporting the practitioner in articulating the question (it completes terms that the user starts to type and suggests other possibly relevant terms); ii) expanding the query using synonyms; iii) extracting and ranking text fragments from the documents.

Organic farming has become increasingly important in recent decades as the consumer has grown its focus on the food and environmental benefits of the technique. However, when compared to conventional farming systems, organic farm system are known to yield less. Presented in this paper are the results from two organic cropping systems following six years of organic management. Fertilisation management differentiated the two systems; one was fertilised with green manure and commercial organic fertilisers, while the other was fertilised with dairy manure. A conventional cropping system, managed with mineral fertiliser as typical in the southern Piemonte region (Italy), served as the bussiness as usual crop management. The first hypothesis tested related to crop yield variation during the initial phase of organic management; we expected a sharp reduction in the early phase, then minor reductions later on. The second hypothesis tested related to soil fertility variation; we expected enhanced soil fertility under organic management. Overall, the organic system produced less, relative to the conventional system in interaction with year effect. Yield reduction seemed related to the lower soil nutrient availability of organic fertilisers that provided nutrients consequent to mineralisation. Therefore, summer crops are well-suited to manure-fertilised organic farms as mineralisation happens at higher temperatures, as opposed to winter wheat, which is largely reduced in such systems. Commercial organic fertilisers can, however, limit this effect through their high nutrient availability in the winter and early spring Also shown was that soil quality, defined as a general decrease in soil organic carbon (SOC) over time in the three analysed arable systems, can be mitigated by manure additions. Green manuring can maintain SOC and increase total N in soil, only if introduced for a sufficient number of years during crop rotation. Finally, soil fertility and Potential Mineralisable N in the different systems demonstrated that organic systems managed with commercial organic nitrogen fertilisers and green manure do not improve soil quality, compared to systems managed with mineral fertilisers.