PlantyOrganic: Design and results 2012

Increasingly strict legislation about fertilizer inputs and developing organic regulations are a strong stimulation to optimize the internal nutrient dynamics of organic arable farms. In the project “PlantyOrganic” , initialized by Biowad and realized at SPNA location Kollumerwaard, a challenging arable system is developed and tested: 100% internal nitrogen supply without input of nutrients from outside. In this report the design of the rotation and fertilizer scheme is presented and discussed, and the starting conditions in spring 2012 are documented. The NDICEA nitrogen model is used to explore the nitrogen dynamics. It is concluded that a 100% farm-own nitrogen supply can be achieved with good production levels. The 2012 results gave no reason to reconsider the rotation and fertilizer design, but since this was the first year of this experiment none of the crops had the precrop as foreseen in the design and the fertilizer used was only partly cut-and-carry fertilizer

PlantyOrganic: Results 2013

2013 was the second year of the "PlantyOrganic" system development in practice. The six-year rotation is laid out and measurements took place at soil and crop. With the exception of the potatoes in 2013 all crops had the pre-crop as foreseen in the design. The fertilizers used were completely produced in the own system, as foreseen in the system design. The amounts of nitrogen applied were about 45 % higher than in the design. Soil nitrogen is measured and used as input in the nitrogen model NDICEA. There was a sufficient match between measured and calculated level of soil mineral nitrogen. The crops performed well, with a high yield in carrots and oats, and a disappointing yield in wheat. In wheat nitrogen was limiting for the yield, we do not yet have a satisfactory explanation. In cauliflower a lack of nitrogen ijn the last phase of the growth had a negative effect on the quality and the crop could not be sold. All plots went green into the winter. Until now no research has been done on the availability of phosphate and potassium. Because there is no supply of these minerals from outside the system, the balance is negative. In time the circle could be closed by means of regional re-use of minerals, for example by the application of household waste compost. PlantyOrganic can become a very good research location for research on the mobilisation of phosphate (and potassium) in circumstances of low supply and/or low chemically analysed availability

Comparative effects of the herbicides dicamba, 2,4-D and paraquat on non-green potato tuber calli

The effects of the herbicides 1,1'-dimethyl-4,4'-bipyridylium dichloride (paraquat), 3,6-dichloro-2-metoxybenzoic acid (dicamba) and 2,4-dichlorophenoxyacetic acid (2,4-D) on cell growth of non-green potato tuber calli are described. We attempted to relate the effects with toxicity, in particular the enzymes committed to the cellular antioxidant system. Cell cultures were exposed to the herbicides for a period of 4 weeks. Cellular integrity on the basis of fluorescein release was strongly affected by 2,4-D, followed by dicamba, and was not affected by paraquat. However, the three herbicides decreased the energy charge, with paraquat and 2,4-D being very efficient. Paraquat induced catalase (CAT) activity at low concentrations (1 [mu]M), whereas at higher concentrations, inhibition was observed. Dicamba and 2,4-D stimulated CAT as a function of concentration. Superoxide dismutase (SOD) activity was strongly stimulated by paraquat, whereas dicamba and 2,4-D were efficient only at higher concentrations. Glutathione reductase (GR) activity was induced by all the herbicides, suggesting that glutathione and glutathione-dependent enzymes are putatively involved in the detoxification of these herbicides. Paraquat slightly inhibited glutathione S-transferase (GST), whereas 2,4-D and dicamba promoted significant activation. These results indicate that the detoxifying mechanisms for 2,4-D and dicamba may be different from the mechanisms of paraquat detoxification. However, the main cause of cell death induced by paraquat and 2,4-D is putatively related with the cell energy charge decrease.http://www.sciencedirect.com/science/article/B7GJ7-4SBRTGG-2/1/57bc6e71553b233694cdc5be53c9bf6