An organic vegetable crop rotation aimed at self-sufficiency in nitrogen

The paper describes the organic vegetable crop rotation. The ideas behind the design of the crop rotation, the use of green manures and catch crops, and how information on crop root growth has been used to try to design a crop rotation with a high NUE and minimal N leaching losses. The results from the first years of the rotation, in terms of yield and N uptake of the crops and of the content of inorganic N in the soil are presented

Combining agronomic and breeding approaches for improved nutrient use efficiency

There is a strong need to improve agricultural nutrient use efficiency (NUE), but NUE is complex, and not even well defined. The abstract and presentation deal with how NUE is determined by the combination of Genetic, Environmental and Management factors (GxExM), and how genetics as well as crop management must be combined in order to achieve improved overall NUE

Brassicas in sustainable production and organic farming

Brassica plant species show some characteristics in their use of plant nutrients which make them different from most other crops. These characteristics often make brassicas difficult to grow in low-input systems with limited nutrient availability, but at the same time they also make some brassica species valuable tools for reducing nitrate leaching losses and improving N management in farming systems. The paper presents experimental results on brassica crops as main crops and cover crops

Comparing conventional and improved organic vegetable rotations, yields and nitrogen husbandry

During 2005 to 2009 three approaches to organic vegetable rotations were compared to a conventional rotation in an interdisciplinary project. The organic rotations differed in their reliance on animal manure vs. cover crops and intercrops, but the rotation of main vegetable and cereal crops were identical in the four rotations. One organic rotation (O1) relied on import of manure for supply of nutrients, in another (O2) cover crops were used to replace most of the manure import, and in (O3) also intercrops were grown to improve natural pest regulation. The yearly import of nitrogen were on average 149, 94, 28, and 28 kg N.ha-1 in C, O1, O2, and O3 respectively. On average the yield in the O1 system was 83% of the yield in the conventional system. In the O2 rotation the yield was the same, though the nutrient import was much lower, whereas the intercrops in O3 reduced the yield to 70% of the conventional fotation. The effect on single crops varied with organic yields ranging from 60% (onion) to almost 100% (carrots, oats) of conventional yields. Crop root growth varied strongly among crops with rooting depths of less than 0.4 m (onions) to more than 2 m (cabbage, rye, fodder radish catch crop). Root growth was unaffected by cropping system, but the inclusion of deep rooted catch crops and green manures in O2 and O3 increased the total root exploitation of the soil strongly. Thus, while the O1 and O2 systems had almost identical yields and N uptake there were large differences in their effects on soil N; e.g. the subsoil (1-2.5 m) N content was on average 18 kg N.ha-1 in the O2 compared 61 and 53 kg N.ha-1 in the C and O1 respectively, indicating strongly reduced N leaching losses in O2

Modelling root distribution and nitrogen uptake

Plant soil and atmosphere models are commonly used to predict crop yield and environmental consequence. Such models often include complex modelling modules for water movement, soil organic matter turnover and, above ground plant growth. However, the root modelling in these models are often very simple, partly due to a limited access to experimental data. We present a two-dimensional model for root growth and proliferation. The model focuses on annual crops, and attempt to model root growth of the crops and its significance for N uptake from different parts of the soil volume

Beregning af kvælstoftilførsel i sædskiftet

Grønsagsproduktion er mange steder i Europa en vigtig kilde til kvælstofudvaskning. For at forebygge dette, er det vigtigt at kunne beregne tilgængelighed og udvaskning af kvælstof i grønsagssædskifter. En ny computermodel - EU-rotate – kan hjælpe til med at optimere kvælstoftilførsel og sædskifteplanlægning

Økologisk grønsagssædskifte uden kvælstofimport

Artiklen viser resultaterne fra de første 6 år af et økologisk grønsagssædskifte. I sædskiftet dyrkes porrer, hvidkål, løg, gulerødder og ærter, foruden byg og grøngødning. Sædskiftet er et 6-marks skifte, der er gennemført uden import af gødning. Forsyningen af afgrøderne med kvælstof er sikret ved udnyttelse af efterafgrøder og grøngødning samt ved udnyttelse af afgrøder med dyb rodvækst. Resultaterne viser, at vi har kunnet opnå høje udbytter af grønsagerne i sædskiftet, selv af de meget krævende grønsagsarter som hvidkål og porre. En af de vigtigste faktorer har været at holde markerne bevoksede i efteråret, det har klart reduceret nitratindholdet i jorden i efteråret og dermed risikoen for udvaskning, og samtidig klart øget kvælstofindholdet i jorden næste forår hvor afgrøderne kan bruge det. Resultaterne viste også, at grøngødning, der undersås i korn og derefter gror igennem efteråret, har givet en god virkning, næsten lige så stor en virkning som grøngødning der gror et helt år på marken

Model analysis of environmental relations in a vegetable rotation experiment

In a chapter which will be part of the final report from the Subproject 7 of the QLIF project (http://www.qlif.org/), the nitrogen relations of organic and conventional vegetable rotations are analysed using the EU-rotate simulation model. Measured data from the VegQure project are used, where a vegetable based rotation grown either conventionally, or organically using two different set of strategies (manure import v.s. cover crops and green manure)

RoCo 2011-2013: Rødder og kompost, økologisk dyrkning med begrænset tilgængelighed af næringsstoffer

Folder med beskrivelse af RoCo projektet. De vigtigste emner i projektet er 1) undersøgelse af sortsvariation i rodvækst og næringsstofudnyttelse i sorter af vårhvede, salat og løg, 2) udvikling af komposttyper på basis af byaffald, 3) test og demonstration af kompost og hvedesorter, 4) udvikling af bagemetoder der tillader bagning med mel med lavere proteininghold og 5) undersøgelse af holdninger og barierrer for recirkulering af byaffaldskilder som gødning til økologisk jordbrug

Rodvækst og sorter til økologi

Den tidlige rodvækst er vigtig for afgrødernes etablering i en økologisk dyrket jord med begrænset næringsstoftilgængelighed. Vi har studeret forskelle i tidlig rodvækst imellem sorter af vårhvede, og fundet betydelige forskelle både i samlet rodvækst, og i røddernes fordeling i jorden