Groundwater pollution with nitrate is a big challenge for drinking water abstraction in regions with intensive agricultural land-use, specifically with high livestock densities on sandy soils in humid climates. Karst aquifers with high water flow velocities are extremely vulnerable to this problem. To cope with this situation, a field trial with an installation of ceramic suction cups under a randomised block design with a typical north-German cropping sequence of silage maize–winter wheat–winter barley was established in a karst water protection zone. Over three years, reduced nitrogen (N) application rates and N type (mineral or combined organic + mineral fertilisation) were tested for their effects on crop yields and leachate water quality below the root zone. Results showed no significant reductions in crop yields with 10/20% reduced N rates for cereals/maize and only slight reductions in cereal protein content. Nitrate concentration from adapted N rates was significantly lower in treatments with an application of organic fertilisers (−7.74 mg NO3-N l−1) with greatest potential after cultivation of maize; in only mineral fertilised plots the effect was smaller (−3.80 mg NO3-N l−1). Cumulative leaching losses were positively correlated with post-harvest soil mineral nitrogen content but even in unfertilised control plots losses >50 kg N ha−1 were observed in some crop-years. Reduced N rates led to decreased leaching losses of 14% (6.3 kg N ha−1 a−1) with mineral and 29% (20.1 kg N ha−1 a−1) with organic + mineral fertilisation on average overall cops and years. The presented study revealed the general potential of adapted fertilisation strategies with moderately reduced N applications (−10/−20%) to increase leachate water quality without affecting significantly crop yields. However, regionally typical after-effects from yearlong high N surpluses in livestock intensive farming systems are a limiting factor.

Today, the demand for soybean for feed industry and food production in Germany is met by imports from South and North America. Soybean cultivation in Germany, although challenging, will be of interest in the future due to an increasing demand for non-genetically modified (NGM) soybeans. To meet this rising demand for NGM soybeans and to increase resource use efficiency there is a need to reduce soybean harvest losses arising from harvesting with combine harvester. The height of the first pod can be a major factor affecting harvest losses, especially when it is not possible to maintain a sufficiently low cutting height. From 2011 to 2013, six soybean varieties were cultivated using two cropping systems (conventional 'CON' and organic 'ORG') at the Osnabrück University of Applied Sciences in a randomized block design with four replications to investigate the effect of first pod height and plant length on harvest losses and the effect of the cropping system on these parameters. Before harvesting with an experimental harvester, 1.5 m 2 per plot were harvested manually as a reference. First pod height, number of pods per plant and plant length were determined on 10 plants per plot. Over the three years of the study, the first pod height (10.4 cm) and plant length (81.4 cm) were on average higher under conventional conditions compared to organic cultivation (7.3 cm; 60.9 cm). On average, lower harvest losses (25.6% vs. 39.2%) and higher grain yields (20.8 dt ha −1 vs. 16.9 dt ha −1) were also observed under conventional cultivation. Varieties differed significantly in grain yield, first pod height and plant length. A high first pod height was related to a longer plant length and lower harvest losses at both sites. However, a high first pod height and a high plant length did not lead to higher grain yields on any of the plots. These results indicate that harvest efficiency can be improved by choosing varieties with long plant lengths if it is not possible to maintain a low cutting height when harvesting with a combine harvester.