Investigation of the soil properties that affect Olsen P critical values in different soil types and impact on P fertiliser recommendations

Optimization of phosphorus (P) fertiliser use is desired to ensure more sustainable use of fertiliser, economic food production and reduction of eutrophication of water bodies. Presently, the Olsen P values on which fertiliser recommendations are based to achieve optimum yield are frequently the same for all soils. The aim of this study was to identify the properties of different soils that affect their critical Olsen P values in order to develop better, soil specific P fertiliser recommendations. A pot experiment using 10 soils with low available P with different P additions was carried out to investigate the impact of wide-ranging soil properties on the relationship between P addition, resultant Olsen P values and yield response of ryegrass to Olsen P values. The relationship between added P and Olsen P varied greatly between the individual soils. These relationships were affected by pH, manganese oxide, crystalline aluminium oxide and amorphous iron oxide contents of the soil. Different soils had widely varying critical Olsen P values for ryegrass. However, these could not be related to the measured soil properties. Fertiliser recommendations and critical values for optimum yield of ryegrass based on the Olsen P test should be soil specific. The complexity and lack of clarity over which combination of soil properties governs critical Olsen P values calls for further investigation with more soil types and additional soil property measurements to elucidate the different factors controlling critical Olsen P values in different soils

Cultures intemédiaires, légumineuses et fertilisation organique

Le présent travail, réalisé en collaboration entre l’Earth & Life Institute de l’Université catholique de Louvain et l’IRBAB asbl entre 2014 et 2018, concerne la gestion de l’interculture céréale-betterave par l’implantation de cultures intermédiaires comprenant des légumineuses et la fertilisation par des engrais de ferme. L’objectif de l’expérimentation est multiple : · Évaluer l’intérêt des engrais de ferme avant implantation d’un couvert avec légumineuses ; · Comparer différentes espèces de légumineuses en condition de semis tardif ; · Mesurer le potentiel en termes de piégeage d’azote des différents couverts (CIPAN) ; · Comparer l’impact des différentes modalités, dont la destruction tardive des CIPAN (+ destr. précoce de moutarde), sur les biomasses et teneurs des couverts et sur les reliquats azotés

An overview of fertilizer-P recommendations in Europe: soil testing, calibration and fertilizer recommendations

The procedure for applying phosphorus (P) fertilizer to soil can be divided into three consecutive steps: (i) Measurement of soil-P availability, (ii) calibration of the soil-P fertility level and (iii) estimation of the recommended P dose. Information on each of these steps was obtained for 18 European countries and regions with the aim of comparing P fertilizer recommendation systems at the European scale. We collected information on P fertilizer recommendations through conventional or grey literature, and personal contacts with researchers, laboratories and advisory services. We found much variation between countries for each of the three steps: There are more than 10 soil-P tests currently in use, apparent contradictions in the interpretation of soil-P test values and more than 3-fold differences in the P fertilizer recommendations for similar soil-crop situations. This last result was confirmed by conducting a simple experimental inter-laboratory comparison. Moreover, soil properties (pH, clay content) and crop species characteristics (P responsiveness) are used in some countries in the calibration and recommendation steps, but in different ways. However, there are also common characteristics: soil-P availability is determined in all countries by extraction with chemical reagents and the calibration of the soil-P test values, and the fertilizer recommendations are based on the results from empirical field trials. Moreover, the fertilizer recommendations are nearly all based on the amount of P exported in the crops. As long as rational scientific and theoretical backgrounds are lacking, there is no point in trying to synchronize the different chemical methods used. We therefore call for a mechanistic approach in which the processes involved in plant P nutrition are truly reproduced by a single standard method or simulated by sorption-desorption models

Détermination des coefficients d’équivalence azotée d’engrais de ferme en culture de printemps

Améliorer les conseils de fertilisation azotée en précisant les coefficients d’équivalence engrais azoté (CEN) du fumier et du lisier de bovin appliqués au printemps en culture de maïs ensilage Mettre en évidence les fertilisations azotées du maïs ensilage optimales permettant de garantir des reliquats d’automne conformes avec les objectifs de qualité de l’eau (Directive-cadre Eau en Wallonie

An overview of fertilizer-P recommendations in Europe: soil testing, calibration and fertilizer recommendations

The procedure for applying phosphorus (P) fertilizer to soil can be divided into three consecutive steps: (i) Measurement of soil-P availability, (ii) calibration of the soil-P fertility level and (iii) estimation of the recommended P dose. Information on each of these steps was obtained for 18 European countries and regions with the aim of comparing P fertilizer recommendation systems at the European scale. We collected information on P fertilizer recommendations through conventional or grey literature, and personal contacts with researchers, laboratories and advisory services. We found much variation between countries for each of the three steps: There are more than 10 soil-P tests currently in use, apparent contradictions in the interpretation of soil-P test values and more than 3-fold differences in the P fertilizer recommendations for similar soil-crop situations. This last result was confirmed by conducting a simple experimental inter-laboratory comparison. Moreover, soil properties (pH, clay content) and crop species characteristics (P responsiveness) are used in some countries in the calibration and recommendation steps, but in different ways. However, there are also common characteristics: soil-P availability is determined in all countries by extraction with chemical reagents and the calibration of the soil-P test values, and the fertilizer recommendations are based on the results from empirical field trials. Moreover, the fertilizer recommendations are nearly all based on the amount of P exported in the crops. As long as rational scientific and theoretical backgrounds are lacking, there is no point in trying to synchronize the different chemical methods used. We therefore call for a mechanistic approach in which the processes involved in plant P nutrition are truly reproduced by a single standard method or simulated by sorption-desorption models

A participative network of organic and conventional crop farms in the Seine Basin (France) for evaluating nitrate leaching and yield performance

International audienceIn the Seine Basin, characterized by intensive arable crops, most surface and groundwater is contaminated by nitrate (NO3-). A collaborative study was set up, involving a network of volunteer farmers, to investigate NO3- leaching with ceramic cups (90 cm deep) on whole crop rotations of organic (OF) and conventional (CF) commercial farms in the Seine Basin. A total of eight CF and six OF systems were studied (63 fields) in five different soil and climate conditions, taking into account a wide diversity of practices (including low or no exogenous N inputs, systematic catch-crop implementation, and no tillage) and use of different exogenous organic matter (EOM) such as biogas residue; slurry; poultry manure; and cow and horse manure. Over the 2 years, OF cropping systems (including alfalfa) led to a lower average sub-root concentration (37 +/- 9 mg NO3- l(-1)) than CF systems (48 +/- 19 mg NO3- l(-1), +/- standard deviation between farms). The water inflows calculated ranged from 86 to 190 mm depending on the year for the 4-month drainage period. The amounts of N leached were on average 23%lower in OF (12.5 +/- 2.9 kg N ha(-1) yr(-1)) than in CF systems (16.2 +/- 6.3 kg N ha(-1)yr(-1)). Concerning farming practices, the main impacting factors were the use of EOM in fall, the lack of catch crops before spring, and the proportion of legumes in the rotation. Overall, this wide collaborative network highlights good and innovative practices by CF and OF farmers attempting to decrease NO3- in groundwater