Developing novel farming systems: effective use of nutrients from cover crops in intensive organic farming

On-farm nitrogen fixation is a driving force in organic agriculture. The efficiency with which this nitrogen is used can be increased by using alfalfa or grass-clover crops directly as fertilizer on other fields: cut-and-carry fertilizers. In two crops in two years, the use of several types of alfalfa and grass-clover as fertilizer is compared with the use of poultry manure and slurry. The nitrogen use efficiency at crop level is comparable or better for the cut-and-carry fertilizers as compared to the animal manures. The relative P and K content of these fertilizers comes closer to the crop demand than that of the poultry manure. Crop yields are comparable or better when using the alfalfa or grass-clover as fertilizer. It is concluded that the cut-and-carry fertilizers are a serious alternative for manure as part of an overall farm soil fertility strategy

Can changes in soil properties in organic banana production suppress fusarium wilt?

Organic agriculture promotes disease suppression through healthy soils by increasing biological activity and diversity through the application of organic fertilizers and increasing organic inputs. Fusarium wilt of bananas (Fusarium oxysporum f. sp. cubense) (Foc), also known as Panama disease, has been a devastating disease throughout the world. So far, no fungicides or cultural measures have been found that control Foc sufficiently. The aim of this research was to assess whether organic-based farming systems were more resilient than inorganic farming systems to soil borne diseases, in particular Fusarium wilts. A survey was conducted comparing five organic and five conventional banana plantations at paired sites in north Queensland, Australia. Soil samples were collected and analysed for chemical, physical and biological soil health indicators. Disease development of F. oxysporum f. sp. lycopersici in tomatoes and Foc in bananas were studied in pot trials to pursue clues for identifying Fusarium suppressive soil traits. Organic soils from the survey showed higher microbial activity and lower disease symptom expression (both with tomatoes and bananas) than conventional soils. In the survey, nematode diversity and soil sulphate content were recurring indicators in all experiments showing close correlations to pathogen growth, disease expression and plant health. Organic soils were lower in plant-parasitic nematodes and sulphate sulphur levels and higher in nematode diversity, labile soil C and microbial indicators. Soil conduciveness or suppression of Foc appeared to be largely governed by competition for carbon. Measurement of soil microbial enzyme activity, nematode community structure and diversity and possibly sulphate sulphur seem to provide a relatively reliable indicator for general disease suppression. Differences between organic and conventional agriculture cannot be related to single management practices, but may be linked to synergies among system components

Minder en anders bemesten : voordelen van maaimeststoffen voor de teelt van najaarsspinazie : resultaten veldproef bij Joost van Strien in Ens

In 2009 heeft het Louis Bolk Instituut onderzoek verricht naar het gebruik van versgemaaide en ingekuilde maaimeststoffen voor de bemesting van najaarspinazie op het biodynamische bedrijf van Joost van Strien in de Noord Oost Polder. Vers gemaaide grasklaver, luzerne, en ingekuilde luzerne werden vergeleken met het gebruik van kippenmest. Uit het onderzoek blijkt dat door gebruik van het systeem dat op het bedrijf van Joost van Strien is ontwikkeld, doelgericht gebruik kan worden gemaakt van meerjarige vlinderbloemige gewassen. Hierdoor worden zowel het bodemleven en bodemkwaliteit bevorderd terwijl de afhankelijkheid van biologische akkerbouw van externe dierlijke meststoffen sterk wordt verminderd door het sluiten van interne nutriëntenkringlopen

Lucerne (Medicago sativa) or grass-clover as cut-and-carry fertilizers in organic agriculture

Onfarm nitrogen fixation is a driving force in organic agriculture. The efficiency with which this nitrogen is used can be increased by using lucerne (Medicago sativa) or grassclover directly as sources of fertilizer on arable land: cutandcarry fertilizers. In two arable crops, the use of lucerne and grassclover as fertilizers was compared with the use of poultry manure and slurry. The nitrogenuse efficiency at crop level was comparable or better for the cutandcarry fertilizers as compared to the animal manures. The relative P and K content of these fertilizers came closer to the crop demand than that of the poultry manure. Crop yields were comparable or better when using lucerne or grassclover as fertilizer. It is concluded that cutandcarry fertilizers are a serious alternative for manure as part of an overall farm soil fertility strategy

Stikstofbemesting: klaar voor de toekomst? Minder afhankelijk worden van dierlijke mest

Aanscherping van fosfaatnormen en strengere normen voor gebruik van bio-mest vormen een uitdaging voor de bedrijfsvoering. Biodynamisch akkerbouwer Joost van Strien speelt hierop in, in samenwerking met het Louis Bolk Instituut. Centraal staat dan het sluiten van kringlopen, door gebruik van vlinderbloemige maaimeststoffe

Benefits of Vetch and Rye Cover Crops to Sweet Corn under No-Tillage

Leguminous cover crops (CCs) may reduce N fertilizer requirements by fixing N biologically and storing leftover N-fertilizer applied in the previous year. The objective of this study was to determine the contribution of CCs [rye (Secale cereal L.) and hairy vetch (Vicia villosa Roth)] on plant N nutrition and weed suppression to the following sweet corn (Zea mays L.). The CCs were planted in the fall of 2003 and 2005, and sweet corn was planted in spring of 2004 and 2006. The experiment contained N rates and CC treatments. In 2004, two CC treatments were tested: none and a CC mixture consisting of 67% rye and 33% hairy vetch. In 2006 the experiment contained five CC treatments (100% rye; 100% vetch; 67% rye and 33% vetch; 33% rye and 67% vetch; and none). Nitrogen rates of 0, 67, and 133 kg ha(-1) were split-applied at emergence, V3-4, and V9-10 growth stages. Two additional plots under non-CC treatment received N rates of 200 or 267 kg ha(-1) to develop a N response curve. Sweet corn growth, N-accumulation, and yield were increased when CCs were presented for low-fertilizer inputs. The N contribution of CC to the sweet corn ranged between 35 and 75 kg ha(-1). Yield response to N-fertilizer application was fitted in a cubic model with optimum yield of 22 Mg ha(-1) attained with 230 kg N ha(-1). Rye reduced weed biomass by 25% and 36% compared with non-CC and vetch. In conclusion, the potential CC yield benefits to sweet corn were greatest at lowest supplemental N rate

Benefits of Vetch and Rye Cover Crops to Sweet Corn under No-Tillage

Leguminous cover crops (CCs) may reduce N fertilizer requirements by fixing N biologically and storing leftover N-fertilizer applied in the previous year. The objective of this study was to determine the contribution of CCs [rye (Secale cereal L.) and hairy vetch (Vicia villosa Roth)] on plant N nutrition and weed suppression to the following sweet corn (Zea mays L.). The CCs were planted in the fall of 2003 and 2005, and sweet corn was planted in spring of 2004 and 2006. The experiment contained N rates and CC treatments. In 2004, two CC treatments were tested: none and a CC mixture consisting of 67% rye and 33% hairy vetch. In 2006 the experiment contained five CC treatments (100% rye; 100% vetch; 67% rye and 33% vetch; 33% rye and 67% vetch; and none). Nitrogen rates of 0, 67, and 133 kg ha(-1) were split-applied at emergence, V3-4, and V9-10 growth stages. Two additional plots under non-CC treatment received N rates of 200 or 267 kg ha(-1) to develop a N response curve. Sweet corn growth, N-accumulation, and yield were increased when CCs were presented for low-fertilizer inputs. The N contribution of CC to the sweet corn ranged between 35 and 75 kg ha(-1). Yield response to N-fertilizer application was fitted in a cubic model with optimum yield of 22 Mg ha(-1) attained with 230 kg N ha(-1). Rye reduced weed biomass by 25% and 36% compared with non-CC and vetch. In conclusion, the potential CC yield benefits to sweet corn were greatest at lowest supplemental N rate