13 research outputs found

    Optimising Exogenous Organic Matter use in cropping systems of a francilian region : evolution of soil organic carbon stocks and substitution of mineral fertiliser

    No full text
    L’utilisation des Produits RĂ©siduaires Organiques (PRO) par l’agriculture peut permettre de substituer une partie des engrais minĂ©raux et augmenter les niveaux de matiĂšre organique des sols. Elle peut Ă©galement gĂ©nĂ©rer des pollutions azotĂ©es via la lixiviation de nitrate ou des Ă©missions gazeuses. Mieux connaitre le devenir du carbone (C) et de l’azote (N) aprĂšs applications de PRO sur les sols agricoles contribue Ă  amĂ©liorer les bĂ©nĂ©fices de cette pratique et Ă  en limiter les impacts environnementaux. Cette thĂšse a pour objectif: (i) de prĂ©dire les dynamiques du C et du N en cas d’applications de PRO sur les sols agricoles, (ii) d’étudier les effets de scenarios d’apports de PRO sur les stocks de carbone dans les sols, la substitution des engrais azotĂ©s et les pollutions azotĂ©es dans le contexte du territoire de la Plaine de Versailles, en prenant en compte la diversitĂ© des sols, de leurs teneurs en C et des successions culturales, (iii) d’amĂ©liorer ces bĂ©nĂ©fices Ă  l’échelon du territoire via une distribution optimale des PRO. Le modĂšle CERES-EGC a Ă©tĂ© utilisĂ© pour simuler les effets de 13 ans d’apports de PRO sur les dynamiques de C et de N dans le systĂšme sol-plante-atmosphĂšre de l’expĂ©rimentation QualiAgro, situĂ©e au cƓur du territoire d’étude. Le sous-modĂšle NCSOIL a Ă©tĂ© paramĂ©trĂ© Ă  partir de cinĂ©tiques de minĂ©ralisation de C et N mesurĂ©es en conditions contrĂŽlĂ©es de laboratoire. Le transfert de ces paramĂštres dans CERES-EGC a permis de simuler correctement les Ă©volution des stocks de carbone dans les sols, les rendements et les prĂ©lĂšvements de N par les cultures ainsi que l’évolution des stocks de N minĂ©ral dans les sols. Les dynamiques de minĂ©ralisation de C et N des 18 PRO disponibles sur le territoire ont Ă©tĂ© dĂ©terminĂ©es. NCSOIL a Ă©tĂ© paramĂ©trĂ© Ă  partir des caractĂ©ristiques analytiques et des rĂ©sultats de fractions biochimiques des PRO. Les types de sol du territoire n’ont pas impactĂ© significativement le paramĂ©trage. Les PRO ont Ă©tĂ© classĂ©s selon 4 types : (1) composts stables, (2) composts moins matures restant plus rĂ©actifs et les fumiers stables, (3) des fumiers trĂšs rĂ©actifs correspondant Ă  des fumiers de chevaux, (4) des PRO trĂšs rĂ©actifs tels que des boues et des fientes pouvant plutĂŽt ĂȘtre utilisĂ©s comme fertilisants. De nombreux scenarios d’apport de PRO, contraints par les flux de phosphore et de N apportĂ©s, ont Ă©tĂ© simulĂ©s sur 20 ans dans tous les contextes de sols, successions culturales et teneurs en C organique des sols du territoire. Le type de sol a impactĂ© le plus le stockage de C et les lixiviations de nitrate tandis que les successions culturales Ă©taient prĂ©pondĂ©rantes sur la substitution des engrais. Des composts ont permis de stocker 1.1 t C ha- 1 an-1 allant jusqu’63% du C apportĂ©. Des substitutions de 74 kg N ha-1 an-1 ont Ă©tĂ© atteintes avec une boue mais aussi un compost en prenant en compte la substitution des engrais liĂ©e aux augmentations de matiĂšre organique dans les sols. La substitution des engrais a pu atteindre plus de 90% du N apportĂ© par les PRO, ceci Ă©tant liĂ© aux arriĂšres-effets sur le stockage de matiĂšre organique dans les sols et dĂ©pendant des hypothĂšses de calcul de la substitution des engrais azotĂ©s. Un modĂšle d’optimisation a Ă©tĂ© dĂ©veloppĂ© pour sĂ©lectionner les scenarios d’apports de PRO pour chaque ilot du territoire (sol x succession de culture x teneur en C organique initiale x surface) tenant compte de la disponibilitĂ© des PRO et avec pour objectif de maximiser le stockage de C ou les substitutions en engrais azotĂ©s ou de minimiser la lixiviation de nitrate au niveau du territoire. En apportant prĂ©fĂ©rentiellement les PRO les plus stables sur les sols Ă  fort potentiel de stockage de C (fortes teneurs en argile et calcaire), jusqu’à 0.47 t C ha-1 an- 1 pourrait ĂȘtre stockĂ©. En appliquant prĂ©fĂ©rentiellement les PRO fertilisants sur les successions Ă  maĂŻs, et les PRO amendants sur les successions Ă  colza jusqu’à 53 kg N ha-1 an-1 de N de synthĂšse pourrait ĂȘtre Ă©conomisĂ©s.The use of Exogenous Organic Matter (EOM) in agriculture could be an efficient way to substitute mineral fertilisation and increase soil organic matter (SOM) enhancing soil fertility and storing carbon (C). It could also cause nitrogen (N) pollutions such as nitrate leaching and gas emissions. Better understanding of C and N fate after EOM applications on cropped soils would allow improving these benefits while limiting environmental impacts. This thesis aims at: (i) predicting EOM impacts when applied on cropped soils, (ii) studying the effects of various scenarios of EOM applications in terms of C storage, synthetic N saving and N pollutions in the context of the Plain of Versailles region (221 kmÂČ) and taking into account soil diversity, crop successions and soil organic C contents, (ii) studying the potential for improving these benefits at the regional scale with an optimal distribution of EOM. The CERES-EGC crop model was used to simulate the effects of repeated applications of EOM over 13 years on both soil C and N dynamics in the soil-crop-water-air system of the long-term field experiment QualiAgro located within the region. The sub-model NCSOIL was parameterised from C and N mineralisation kinetics of EOM measured in laboratory conditions. When transposing the parameters into the CERES-EGC model, C storage at the field scale was well simulated, together with crop N uptake and yields, as well as soil mineral N contents. The kinetics of C and N mineralisation of the 18 EOM available in the region were used along with EOM biochemical fractionations for parameterising the NCSOIL model. The soil type did not significantly change EOM parameters. Four groups of EOM were distinguished based on their C and N dynamics: (i) stable composts, (2) more reactive and less mature composts and stable manures, (3) manures with reactive OM corresponding to horse manures and (4) very reactive EOM as sludges, litters that should be used as fertilisers. Numerous scenarios of EOM applications, constrained on the phosphorus and N quantities they bring (and limiting the input in trace elements), were simulated for 20 years in all regional contexts of soil, crop successions and soil organic C contents. The soil type was the main factor controlling C storage and N leaching while it was crop successions for N saving. Some composts allowed C storage up to 1.1 t C ha-1 yr -1 reaching 63% of C applied. N saving of 74 kg N ha-1 yr -1 were possible with a dried sewage sludge and a compost. N substitution could reach more than 90% of N applied with EOM, these high percentages being related with the indirect effect of EOM on soil OM and the hypothesis made for N substitution An optimisation model was developed to select EOM application scenario for each crop plot (soil x crop succession x initial soil OC content x area) accounting for EOM availability in the region with the objectives of maximising C storage or synthetic N saving or minimising N leaching at the regional scale. Applying preferentially the most stable EOM on soils with the highest potential for C storage i.e. with the highest calcareous and clay contents, up to 0.47 t C ha-1 yr-1 could be stored. Applying preferentially fertilising EOM on crop succession with maize and amending EOM on succession with rapeseed, up to 53 kg N ha-1 yr -1 could be saved

    Optimisation de l'insertion des Produits Résiduaires Organiques dans les systÚmes de cultures d'un territoire francilien : évolution des stocks de carbone organique et substitution des engrais minéraux

    No full text
    The use of Exogenous Organic Matter (EOM) in agriculture could be an efficient way to substitute mineral fertilisation and increase soil organic matter (SOM) enhancing soil fertility and storing carbon (C). It could also cause nitrogen (N) pollutions such as nitrate leaching and gas emissions. Better understanding of C and N fate after EOM applications on cropped soils would allow improving these benefits while limiting environmental impacts. This thesis aims at: (i) predicting EOM impacts when applied on cropped soils, (ii) studying the effects of various scenarios of EOM applications in terms of C storage, synthetic N saving and N pollutions in the context of the Plain of Versailles region (221 kmÂČ) and taking into account soil diversity, crop successions and soil organic C contents, (ii) studying the potential for improving these benefits at the regional scale with an optimal distribution of EOM. The CERES-EGC crop model was used to simulate the effects of repeated applications of EOM over 13 years on both soil C and N dynamics in the soil-crop-water-air system of the long-term field experiment QualiAgro located within the region. The sub-model NCSOIL was parameterised from C and N mineralisation kinetics of EOM measured in laboratory conditions. When transposing the parameters into the CERES-EGC model, C storage at the field scale was well simulated, together with crop N uptake and yields, as well as soil mineral N contents. The kinetics of C and N mineralisation of the 18 EOM available in the region were used along with EOM biochemical fractionations for parameterising the NCSOIL model. The soil type did not significantly change EOM parameters. Four groups of EOM were distinguished based on their C and N dynamics: (i) stable composts, (2) more reactive and less mature composts and stable manures, (3) manures with reactive OM corresponding to horse manures and (4) very reactive EOM as sludges, litters that should be used as fertilisers. Numerous scenarios of EOM applications, constrained on the phosphorus and N quantities they bring (and limiting the input in trace elements), were simulated for 20 years in all regional contexts of soil, crop successions and soil organic C contents. The soil type was the main factor controlling C storage and N leaching while it was crop successions for N saving. Some composts allowed C storage up to 1.1 t C ha-1 yr -1 reaching 63% of C applied. N saving of 74 kg N ha-1 yr -1 were possible with a dried sewage sludge and a compost. N substitution could reach more than 90% of N applied with EOM, these high percentages being related with the indirect effect of EOM on soil OM and the hypothesis made for N substitution An optimisation model was developed to select EOM application scenario for each crop plot (soil x crop succession x initial soil OC content x area) accounting for EOM availability in the region with the objectives of maximising C storage or synthetic N saving or minimising N leaching at the regional scale. Applying preferentially the most stable EOM on soils with the highest potential for C storage i.e. with the highest calcareous and clay contents, up to 0.47 t C ha-1 yr-1 could be stored. Applying preferentially fertilising EOM on crop succession with maize and amending EOM on succession with rapeseed, up to 53 kg N ha-1 yr -1 could be saved.L’utilisation des Produits RĂ©siduaires Organiques (PRO) par l’agriculture peut permettre de substituer une partie des engrais minĂ©raux et augmenter les niveaux de matiĂšre organique des sols. Elle peut Ă©galement gĂ©nĂ©rer des pollutions azotĂ©es via la lixiviation de nitrate ou des Ă©missions gazeuses. Mieux connaitre le devenir du carbone (C) et de l’azote (N) aprĂšs applications de PRO sur les sols agricoles contribue Ă  amĂ©liorer les bĂ©nĂ©fices de cette pratique et Ă  en limiter les impacts environnementaux. Cette thĂšse a pour objectif: (i) de prĂ©dire les dynamiques du C et du N en cas d’applications de PRO sur les sols agricoles, (ii) d’étudier les effets de scenarios d’apports de PRO sur les stocks de carbone dans les sols, la substitution des engrais azotĂ©s et les pollutions azotĂ©es dans le contexte du territoire de la Plaine de Versailles, en prenant en compte la diversitĂ© des sols, de leurs teneurs en C et des successions culturales, (iii) d’amĂ©liorer ces bĂ©nĂ©fices Ă  l’échelon du territoire via une distribution optimale des PRO. Le modĂšle CERES-EGC a Ă©tĂ© utilisĂ© pour simuler les effets de 13 ans d’apports de PRO sur les dynamiques de C et de N dans le systĂšme sol-plante-atmosphĂšre de l’expĂ©rimentation QualiAgro, situĂ©e au cƓur du territoire d’étude. Le sous-modĂšle NCSOIL a Ă©tĂ© paramĂ©trĂ© Ă  partir de cinĂ©tiques de minĂ©ralisation de C et N mesurĂ©es en conditions contrĂŽlĂ©es de laboratoire. Le transfert de ces paramĂštres dans CERES-EGC a permis de simuler correctement les Ă©volution des stocks de carbone dans les sols, les rendements et les prĂ©lĂšvements de N par les cultures ainsi que l’évolution des stocks de N minĂ©ral dans les sols. Les dynamiques de minĂ©ralisation de C et N des 18 PRO disponibles sur le territoire ont Ă©tĂ© dĂ©terminĂ©es. NCSOIL a Ă©tĂ© paramĂ©trĂ© Ă  partir des caractĂ©ristiques analytiques et des rĂ©sultats de fractions biochimiques des PRO. Les types de sol du territoire n’ont pas impactĂ© significativement le paramĂ©trage. Les PRO ont Ă©tĂ© classĂ©s selon 4 types : (1) composts stables, (2) composts moins matures restant plus rĂ©actifs et les fumiers stables, (3) des fumiers trĂšs rĂ©actifs correspondant Ă  des fumiers de chevaux, (4) des PRO trĂšs rĂ©actifs tels que des boues et des fientes pouvant plutĂŽt ĂȘtre utilisĂ©s comme fertilisants. De nombreux scenarios d’apport de PRO, contraints par les flux de phosphore et de N apportĂ©s, ont Ă©tĂ© simulĂ©s sur 20 ans dans tous les contextes de sols, successions culturales et teneurs en C organique des sols du territoire. Le type de sol a impactĂ© le plus le stockage de C et les lixiviations de nitrate tandis que les successions culturales Ă©taient prĂ©pondĂ©rantes sur la substitution des engrais. Des composts ont permis de stocker 1.1 t C ha- 1 an-1 allant jusqu’63% du C apportĂ©. Des substitutions de 74 kg N ha-1 an-1 ont Ă©tĂ© atteintes avec une boue mais aussi un compost en prenant en compte la substitution des engrais liĂ©e aux augmentations de matiĂšre organique dans les sols. La substitution des engrais a pu atteindre plus de 90% du N apportĂ© par les PRO, ceci Ă©tant liĂ© aux arriĂšres-effets sur le stockage de matiĂšre organique dans les sols et dĂ©pendant des hypothĂšses de calcul de la substitution des engrais azotĂ©s. Un modĂšle d’optimisation a Ă©tĂ© dĂ©veloppĂ© pour sĂ©lectionner les scenarios d’apports de PRO pour chaque ilot du territoire (sol x succession de culture x teneur en C organique initiale x surface) tenant compte de la disponibilitĂ© des PRO et avec pour objectif de maximiser le stockage de C ou les substitutions en engrais azotĂ©s ou de minimiser la lixiviation de nitrate au niveau du territoire. En apportant prĂ©fĂ©rentiellement les PRO les plus stables sur les sols Ă  fort potentiel de stockage de C (fortes teneurs en argile et calcaire), jusqu’à 0.47 t C ha-1 an- 1 pourrait ĂȘtre stockĂ©. En appliquant prĂ©fĂ©rentiellement les PRO fertilisants sur les successions Ă  maĂŻs, et les PRO amendants sur les successions Ă  colza jusqu’à 53 kg N ha-1 an-1 de N de synthĂšse pourrait ĂȘtre Ă©conomisĂ©s

    Apport des images satellitaires de trÚs haute résolution spatiale PLEIADES à la caractérisation des cultures et des opérations culturales en début de saison

    No full text
    This study is part of several projects aiming at spatially monitoring the effects of exogenous organic matter apply on soil organic carbon sequestration, and necessitating for this purpose the gathering of spatial data about cropping systems. The aim of this study was to assess the contribution of very high spatial resolution (VHR) PlĂ©iades images to both early season crop identification and mapping and changes in bare soil surface characteristics due to cultural operations. The study region covering 4000 ha including 2100 ha-croplands is located west of the peri-urban territory of the Versailles plain and the Alluets plateau (Yvelines, France). About 100 cropped fields were observed on the ground synchronously with two PlĂ©iades images of 3 and 24 April 2013 and one SPOT4 image of 2 April 2013. The GIS structuring of these field data was used for delimitating both training and test zones for the support vector machine classifier with polynomial function kernel (pSVM). For the single date-images, the pSVM was computed on the 4 spectral bands while for the bitemporal PlĂ©iades image, it relied on the 8 spectral bands and the two NDVI bands. For the single-date classifications of crops, the overall accuracy reached 87% for the SPOT4 image of 2 April (6 classes), 79% for the Pleiades image of 3 April (6 classes) and 82% for that of 24 April (7 classes). For the bi-temporal PlĂ©iades image, the overall accuracy was about 80% (7 classes), winter crops, grasslands and fallows being very well detected while confusions occured between spring barley at initial stages (2-3 leaves) and bare soils prepared for other spring crops. At the earlier date (2-3 April), the PlĂ©iades image very well discriminated cultural operations (>77%, user’s or producer’s accuracies) as well as fallows and grasslands, and brought unique information about within-field spatial heterogeneity of crop development stages, while winter cereals and rapeseed were better discriminated by the SPOT4 image winter cereals (>70%, user’s or producer’s accuracies). Pleiades images therefore bring information complementary to multispectral images with high spatial resolution.Cette Ă©tude s'inscrit dans des programmes de recherche visant Ă  surveiller spatialement l’effet des apports de produits rĂ©siduaires organiques sur les stocks de carbone des sols, et nĂ©cessitant pour cela le recueil de donnĂ©es spatialisĂ©es sur les systĂšmes de culture. L'objectif de cette Ă©tude est celui d'Ă©valuer, au niveau d'organisation spatiale des parcelles culturales, l'apport des images satellitaires de TrĂšs Haute RĂ©solution Spatiale (THRS) PlĂ©iades Ă  l'identification des cultures Ă  des stades de dĂ©veloppement prĂ©coce d’une part, Ă  la dĂ©tection des changements d'Ă©tat de surface des sols nus liĂ©s aux opĂ©rations culturales, d’autre part. La rĂ©gion d’étude, vaste d’environ 4000 ha, dont 2100 ha de surface agricole utile, est situĂ©e Ă  l’ouest du territoire pĂ©riurbain francilien de la Plaine de Versailles et du Plateau des Alluets (PVPA) (Yvelines). Environ 100 parcelles culturales ont fait l’objet d’observations de terrain synchrones des prises de vue des deux images PlĂ©iades acquises les 3 et 24 avril 2013 et d’une image SPOT4 acquise le 2 avril 2013. La structuration gĂ©omatique de ces donnĂ©es acquises sur le terrain a servi Ă  dĂ©limiter des zones susceptibles de servir Ă  l’entraĂźnement ou la validation des rĂ©sultats de classification assistĂ©e par machine Ă  support de vecteurs Ă  noyau polynomial (pSVM). La classification pSVM a Ă©tĂ© mise en Ɠuvre sur les 4 bandes spectrales assorties du NDVI pour les images monodates, et pour les 8 bandes spectrales assorties de 2 bandes NDVI pour l’image bi-temporelle PlĂ©iades. Pour les classifications monodates des cultures, la prĂ©cision totale atteint 87% pour l’image SPOT4 du 2 avril (6 classes), 79% pour l’image PlĂ©iades du 3 avril (6 classes) et 85% pour celle du 24 avril (7 classes). Pour la classification bitemporelle (7 classes), la prĂ©cision totale est de prĂšs de 80%, avec des cultures d’hiver trĂšs bien discriminĂ©es tandis que les confusions opĂšrent entre l’orge de printemps aux stades 2-3 feuilles et les sols nus prĂ©parĂ©s pour les autres cultures de printemps. A la date la plus prĂ©coce (2-3 avril), l’image PlĂ©iades discrimine bien les opĂ©rations culturales (prĂ©cisions utilisateur et producteur >77%), les jachĂšres et les prairies et renseigne sur l’hĂ©tĂ©rogĂ©nĂ©itĂ© spatiale des stades de dĂ©veloppement des cultures, tandis que les cĂ©rĂ©ales d’hiver et le colza sont mieux dĂ©tectĂ©s sur l’image SPOT4 (prĂ©cisions utilisateur et producteur >70%). Les images PlĂ©iades apportent donc des informations complĂ©mentaires Ă  celles des images multispectrales de haute rĂ©solution spatiale.Cette Ă©tude s'inscrit dans des programmes de recherche visant Ă  surveiller spatialement l’effet des apports de produits rĂ©siduaires organiques sur les stocks de carbone des sols, et nĂ©cessitant pour cela le recueil de donnĂ©es spatialisĂ©es sur les systĂšmes de culture. L'objectif de cette Ă©tude est celui d'Ă©valuer, au niveau d'organisation spatiale des parcelles culturales, l'apport des images satellitaires de TrĂšs Haute RĂ©solution Spatiale (THRS) PlĂ©iades Ă  l'identification des cultures Ă  des stades de dĂ©veloppement prĂ©coce d’une part, Ă  la dĂ©tection des changements d'Ă©tat de surface des sols nus liĂ©s aux opĂ©rations culturales, d’autre part. La rĂ©gion d’étude, vaste d’environ 4000 ha, dont 2100 ha de surface agricole utile, est situĂ©e Ă  l’ouest du territoire pĂ©riurbain francilien de la Plaine de Versailles et du Plateau des Alluets (PVPA) (Yvelines). Environ 100 parcelles culturales ont fait l’objet d’observations de terrain synchrones des prises de vue des deux images PlĂ©iades acquises les 3 et 24 avril 2013 et d’une image SPOT4 acquise le 2 avril 2013. La structuration gĂ©omatique de ces donnĂ©es acquises sur le terrain a servi Ă  dĂ©limiter des zones susceptibles de servir Ă  l’entraĂźnement ou la validation des rĂ©sultats de classification assistĂ©e par machine Ă  support de vecteurs Ă  noyau polynomial (pSVM). La classification pSVM a Ă©tĂ© mise en Ɠuvre sur les 4 bandes spectrales assorties du NDVI pour les images monodates, et pour les 8 bandes spectrales assorties de 2 bandes NDVI pour l’image bi-temporelle PlĂ©iades. Pour les classifications monodates des cultures, la prĂ©cision totale atteint 87% pour l’image SPOT4 du 2 avril (6 classes), 79% pour l’image PlĂ©iades du 3 avril (6 classes) et 85% pour celle du 24 avril (7 classes). Pour la classification bitemporelle (7 classes), la prĂ©cision totale est de prĂšs de 80%, avec des cultures d’hiver trĂšs bien discriminĂ©es tandis que les confusions opĂšrent entre l’orge de printemps aux stades 2-3 feuilles et les sols nus prĂ©parĂ©s pour les autres cultures de printemps. A la date la plus prĂ©coce (2-3 avril), l’image PlĂ©iades discrimine bien les opĂ©rations culturales (prĂ©cisions utilisateur et producteur >77%), les jachĂšres et les prairies et renseigne sur l’hĂ©tĂ©rogĂ©nĂ©itĂ© spatiale des stades de dĂ©veloppement des cultures, tandis que les cĂ©rĂ©ales d’hiver et le colza sont mieux dĂ©tectĂ©s sur l’image SPOT4 (prĂ©cisions utilisateur et producteur >70%). Les images PlĂ©iades apportent donc des informations complĂ©mentaires Ă  celles des images multispectrales de haute rĂ©solution spatiale

    Early-season mapping of crops and cultural operations using very high spatial resolution Pléiades images

    No full text
    The aim of this study was to assess the contribution of very high spatial resolution (VHSR) PlĂ©iades images to both early season crop identification and the mapping of bare soil surface characteristics due to cultural operations. The study region covering 21 km2 is located west of the peri-urban territory of the Versailles plain and the Alluets plateau (Yvelines, France). About 100 cropped fields were observed on the ground synchronously with two PlĂ©iades images of 3 and 24 April 2013 and one SPOT4 image of 2 April 2013. The GIS structuring of these field data along with vector information about field boundaries was used for delimitating both training and test zones for the support vector machine classifier with polynomial function kernel (pSVM). The pSVM was computed on the spectral bands and NDVI for both single-date PlĂ©iades and the bi-temporal PlĂ©iades pair. For the single-date classifications of crops, the overall per-pixel accuracy reached 87% for the SPOT4 image of 2 April (6 classes), 79% for the PlĂ©iades image of 3 April (6 classes) and 82% for that of 24 April (7 classes). At the earlier date (2–3 April), the PlĂ©iades image very well discriminated cultural operations (>77%, user’s or producer’s accuracies) as well as fallows and grasslands, while winter cereals and rapeseed were better discriminated by the SPOT4 image winter cereals (>70%, user’s or producer’s accuracies). As PlĂ©iades images revealed within-field spatial variations of early phenological stages of winter cereals that could be critical for adjusting management of zones with delayed development during the growing season, they brought information complementary to multispectral images with high spatial resolution. For the bi-temporal PlĂ©iades image, the overall per-pixel accuracy was about 80% (7 classes), winter crops, grasslands and fallows being very well detected while confusions occurred between spring barley at initial stages (2–3 leaves) and bare soils prepared for other spring crops. Using an additional validation field set covering ∌1/3 of the study area croplands, the crop map resulting from the bi-temporal PlĂ©iades pair achieved correct crop prediction for about 89.7% of the validation fields when considering composite classes for winter cereals and for spring crops. Early-season PlĂ©iades images therefore show a considerable potential for anticipating regional crop patterns and detecting soil tillage operations in sprin

    Contribution of VSHR Pléiades images to the assessment of agricultural systems over a peri-urban region near Paris, France

    No full text
    Contribution of VSHR Pléiades images to the assessment of agricultural systems over a peri-urban region near Paris, France. Pléiades Day

    Modelling the long-term effect of urban waste compost applications on carbon and nitrogen dynamics in temperate cropland

    No full text
    The recycling in agriculture of Exogenous Organic Matter (EOM) issued from organic waste treatment is a promising way to restore soil organic matter (SOM) content in intensively managed soils. EOM applications to crop fields may also be used as substitute to synthetic fertilisers. The CERES-EGC mechanistic model was used to simulate the effects of repeated applications of urban waste composts and manure over 13 years on both soil carbon (C) and nitrogen (N) dynamics in the soil–crop–water–air system of the long-term field experiment QualiAgro. Several EOMs were considered: a farmyard manure, FYM; a municipal solid waste compost, MSW; a bio-waste compost, BIO; a co-compost of green waste and sewage sludge, GWS. Each EOM application brought the equivalent of 220–400 kg N ha−1. The sub-model NCSOIL was parameterised from C and N mineralisation kinetics of EOMs measured during incubations of soil–EOM mixtures in controlled conditions. The simulation correctly reproduced the experimental kinetics. When transposing these parameters into the CERES-EGC model, C storage at the field scale was well simulated, together with crop N uptake and yields, as well as soil mineral N contents despite a slight overestimation. The GWS compost generated the highest C storage over the 13 y-period and MSW the lowest with 65% and 36% of the Exogenous Organic Carbon (EOC) applied incorporated into the soil organic C, respectively. The GWS and MSW had the highest potential of N loss because of high mineral N content and a high potential of N mineralisation, respectively in contrast to FYM and BIO. MSW had also the highest apparent N use efficiency (48.8%) thanks to a high potential of mineralisation (76.3% of organic N applied). The achieved CERES-EGC parameterisation offers promising prospects for predicting the effects of a larger panel of EOMs, and for further using this soil–plant–water–atmosphere model to manage EOM application practices at the regional scale in compliance with crop production and environmental aims

    Simulation with the NCSOIL model of carbon and nitrogen dynamics in a loamy soil after various compost applications

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    INRA Unités EGC et PESSAC, Veolia EnvironnementSimulation with the NCSOIL model of carbon and nitrogen dynamics in a loamy soil after various compost applications. 15. International Conferences of RAMIRAN (Network on R ecycling of Agricultural, Municipal and Industrial Residues in Agriculture
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