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Cereals and home-grown grain legumes are main feedstuffs for monogastric animals. Thus, knowledge on variations of their crude nutrient and amino acid composition is of great interest in animal nutrition. Genetic and environmental factors are known to be able to affect the nutrient composition of crops. Thus, the aim of the study was to analyse a selection of grains of organic cereal and grain legume species for their crude nutrient and amino acid contents and to determine the effect of variety and environmental conditions on the variations. Furthermore, the use of equations to predict amino acid contents from the crude protein content of cereals and grain legumes was tested. The contents of the crude nutrients and 18 amino acids of 835 samples of ten different cereal and grain legume species were analysed. Selected nutrients were subjected to correlation analyses. Furthermore, generalised linear models with multiple comparisons were conducted to assess the effect of species as well as of variety, harvest site and harvest year on the analysed ingredients. The contents of all crude nutrients and amino acids varied depending on the species and the considered nutrient. The lowest variation coefficients (1.3–2.6% in cereals and 3.1, 3.5 and 6.8% in field peas, field beans and blue lupins, respectively) were observed for the contents of nitrogen-free extracts. The crude protein contents varied widely, specifically in winter rye (coefficient of variation: CV = 17.4%). However, compared to table values, the cereals and grain legumes of the present study tended to contain low amounts of crude protein and high amounts of starch. Due to the wide variations, there is no distinct consistency between table values and the results of this study. High negative correlations between starch and crude protein contents were observed in eight species. Furthermore, the amino acid profile of cereals and grain legumes varied depending on the crude protein contents. Higher crude protein contents were often related to lower contents of several essential amino acids in favour of glutamine/glutamic acid, proline and phenylalanine in cereals as well as of arginine in grain legumes. Furthermore, variety, harvest site and harvest year affected the contents of the analysed ingredients depending on the species. However, the environmental factors had a greater influence than the variety. The observed variations must be regarded in diet formulation. Equations can be used to estimate the amino acid contents of cereals and grain legumes from their crude protein content. However, additional analysis results are needed to improve the predictability with equations.

The cultivation of weak weed competitive pea sole crops after reduced ploughing depth may result in weed problems in organic farming. Intercropping peas and cereals is one option to manage weed problems. However, little evidence exists on the weed suppressive ability of pea-cereal intercrops after differing ploughing depths. The effect of crop stand (pea sole crop, pea-oat intercrop and oat sole crop) and ploughing depth (10–12 vs. 25–27 cm) on the annual weed infestation, PAR transmission and weed nitrogen as well as water supply was investigated in field experiments in Northern Germany. In order to determine causes for the differing weed suppressive ability in pea and oat sole or intercrops, a pot experiment and a bioassay were conducted complementary to the field experiments. Crop stand and ploughing depth did not interact with regard to weed infestation. The weed suppressive ability increased from pea sole crops to oat sole crops, whereas shallow ploughing resulted in a significantly higher weed infestation than deep ploughing. While crop-weed competition for light was not essential for the differing weed suppressive ability, competition for water and nitrogen were detected to be key factors. As root exudates of the examined oat cultivar showed a growth inhibiting potential, allelopathy may also contribute to the weed suppression in oat sole and pea-oat intercrops. Results from this study indicate that pea-oat intercropping is not able to compensate for the higher annual weed infestation after shallow ploughing. Nevertheless, owing to their good weed suppressive ability, intercrops with cereals are of particular suitability for the cultivation of weak weed suppressive semi-leafless peas in reduced tilled soils in organic farming.

Maize-bean intercropping is currently gaining popularity among farmers in Germany, although there is hardly any data available on the yield potential under moderate maritime climate conditions in comparison to pure maize cultivation as well as on the choice of the bean cultivar. To assess the agronomic potential of maize-bean intercropping for organic farming, field-experiments over two growing seasons were conducted in Northern Germany (53°46′N, 10°30′E). A split-plot design with two sowing times of the beans as main-plot-factor and different bean species and cultivars (Phaseolus vulgaris, cv.: Cobra, Eva, Tarbais, P. coccineus, cv.: Preisgewinner, Weise Riesen, Vicia faba cv.: Isabell) as subplot-factor was applied. In both years, the average intercropping yield (11 t ha−1 in 2011 and 14 t ha−1 in 2012) of the two sowing dates was comparable to that of maize-control, except for Maize-Eva in 2011. The highest intercropping yields in 2011 were shown by cv. Tarbais and Preisgewinner with bean shares ranging from 34% to 39%. By contrast, the late-sown beans in 2012 had a share of 6–12% only, reflecting the overall higher maize yield level. Compared to maize control, the intercropping with Tarbais and Preisgewinner, which achieved the highest leaf mass scores, led to a significant improvement in crude protein yield by 36% and 18% in 2011, respectively. Earlier ripening bean cultivars (e.g. cv. Eva and Cobra) tend to lose their leaves before harvest. So cultivars with a longer growth period (e.g. cv. Tarbais), similar to maize, should be used to achieve high bean and crude protein yields. Our results demonstrate the importance of cultivar choice for achieving high bean yields that have the potential to improve feed quality. Tarbais and Preisgewinner were the most suitable cultivars for maize-bean intercropping, as they achieved the highest bean yields and improved the crude protein yield in 2011. Even though further optimization is indispensable, we have shown that maize-bean intercropping can fit into organic farming systems under moderate maritime climate.

The nitrogen supply plays an important role in achieving quality characteristics in organic potato farming. Different defoliation systems of ryegrass–clover may influence the amount of fixed nitrogen available to the tubers. In a field experiment, the effect of different defoliation systems (cutting, mulching and a combination of them) of the pre-crop ryegrass–clover on selected quality attributes of organically grown potatoes, destined for processing into French fries (cv. Agria) or crisps (cv. Marlen), were conducted in two consecutive years (2003 and 2004). Parameters studied included compounds related to the sensory properties of potato food (tuber dry matter, starch, reducing sugars) as well as nutritional quality (nitrogen, minerals). Selected agronomic parameters such as total tuber yields and tuber size distribution were also compared. Furthermore, the influence of additional slurry fertilisation and 4 months of storage on these parameters were investigated. Total yields and portion of tuber yield 50–60 mm were significantly affected by the pure mulching variant in 2003. In 2003, the starch concentration at harvest, as well as after storage, was above the required minimum of 22% (cv. Marlen) and 19% (cv. Agria), while in 2004, this was slightly beneath these values. In 2004, a significant increase of starch concentration by the pure cutting variant was observed. In both years, mulched ryegrass–clover caused a decrease in tuber DM contents of 2.10 and 3.54%, respectively, compared to the cutting systems. Fertilisation significantly decreased DM and starch concentration. In 2004, the reducing sugar concentration of tubers of cv. Marlen from the pure cutting system was with 2.1 g kg−1 FM above the required maximum of 1.5 g kg−1 for crisps. In addition, storage led to a three to fivefold increase of reducing sugars concentrations in the tubers in this year. After slurry fertilisation, 8.8% higher N contents and up to 36% higher K concentrations were measured. Mulching of the pre-crop combined with slurry application led to an up to 61% higher tuber K concentration compared to the cutting system. The results indicate that different defoliation systems of the pre-crop ryegrass–clover and slurry fertilisation had only minor effects on internal tuber quality attributes. Quality parameters were more affected by the prevailing weather conditions in combination with the genotype of different potato cultivars.

Winter peas (Pisum sativum L.) are a promising alternative to spring peas in organic farming. Intercroppingwinter peas and cereals may be a beneficial way to improve lodging resistance in normal-leafed andweed suppression in semi-leafless winter peas. At the same time, there is an increasing interest in areduction in tillage intensity, e.g. shallow ploughing. A normal-leafed, coloured-flowered (cv. E.F.B. 33)and a semi-leafless, white-flowered winter pea (cv. James) were cultivated as sole crops or in intercropswith triticale (Triticosecale Wittmarck) on a loam soil under Northern German conditions during twoseasons (2009/2010, 2010/2011) and compared for winter survival, lodging resistance, yield performance,grain quality and succeeding winter wheat yield. The two ploughing depths were short-term shallowploughing to 10–12 cm and continuous deep ploughing to 25–27 cm. Intercropping did not improvewinter survival, which depended on pre-winter development. Owing to the low lodging resistance ofnormal-leafed winter pea E.F.B. 33, sole cropping is not advisable. Intercropping normal-leafed winterpea E.F.B. 33 and triticale resulted in a better yield performance (2.54–3.39 t d.m. ha−1) than the semi-leafless winter pea James sole (0.97–1.79 t d.m. ha−1) or intercrops (2.05–2.86 t d.m. ha−1). E.F.B. 33 hadsignificantly higher grain crude protein, crude fibre and macronutrient contents, whereas the crude fat,starch and sugar content as well as the energetic feed value were higher in James. Wheat yields afterE.F.B. 33 sole and intercrops were higher than after the corresponding James sole or intercrops. Thebiomass production, yield performance and the energetic feed value of winter pea sole and intercropswere comparable between ploughing depths or higher after shallow ploughing. Thus, E.F.B. 33-triticaleintercrops provided better results than James sole or intercrops, except for the energetic feed value, andshallow ploughing was a good alternative to deep ploughing for the cultivation of winter peas.

The effect of ploughing depth and mechanical soil loading on the performance of pea sole crops, oat sole crops and pea–oat intercrops was investigated in field experiments under organic farming conditions at two sites in Germany in 2009 and 2010. The two ploughing depths were short-term shallow ploughing to a soil depth of 7–10 cm and deep ploughing to 25–30 cm. Wheel loads of 26 and 45 kN, which correspond to typical rear wheel loads of field machinery used during sowing operations, were compared to an uncompacted control. Shallow ploughing resulted in a greater penetration resistance in the 14–28 cm soil layer compared to deep ploughing. An increase in mechanical soil loading intensity increased the bulk density and decreased the air capacity in the 10–15 cm soil layer, whereas the penetration resistance was not affected. The annual weed infestation in pea sole crops was higher after shallow than after deep ploughing at both sites. Pea–oat intercrops compensated for the higher weed infestation after shallow ploughing at one site due to their excellent weed suppressive ability. Dependent on oat productivity, pea–oat intercrops produced comparable or higher grain and protein yields than pea sole crops. Intercropped pea yield components and grain protein yields were significantly lower than those of sole cropped peas. The ploughing depth did not affect pea grain yields in either year and oat yields in 2009. Due to a better emergence, the grain and protein yield of sole and intercropped oats were significantly higher after shallow ploughing in 2010. Mechanical soil loading did not have any effect on the yield performance of pea sole crops, oat sole crops and pea–oat intercrops in 2009. In 2010, mechanical soil loading of 26 kN and 45 kN decreased the pea grain yield by 12.1% and 20.8% respectively, regardless of sole or intercropped. Neither the grain yield nor the grain quality of sole and intercropped oats was affected by the mechanical soil loading in 2010. Grain and crude protein yields of total crop stands decreased with increasing mechanical soil loading after deep ploughing, whereas no significant differences were revealed after shallow ploughing. The present study confirms the positive qualities of pea–oat intercrops with regard to weed suppression and plant performance. Shallow ploughing mitigates the risk of a decrease in crop performance caused by heavy field traffic and provides an alternative to deep ploughing even in low weed competitive organically farmed grain legumes.

A mixed cropping system of rapeseed and 10 % turnip rape as trap crop was compared with oilseed rape in pure stand to demonstrate the reduction of infestation by insect pests. Furthermore the application of bio-pesticides like pyrethrum/rape oil (Spruzit® Neu), spinosad (SpinTor), diatomeen earth (SiO~2~) /sunflower-oil and rock powder/water was tested. Oilseed rape showed a higher infestation by stem weevils (Ceutorhynchus spp.) in the mixed cropping system compared to rapeseed in pure stand. The reduction of the pollen beetle (Meligethes aeneus) on the rapeseed buds resulted from higher attractiveness of turnip rape as a consequence of advanced growth. The faster development of turnip rape seems to be the important key of successful pollen beetle regulation. The application of pyrethrum and spinosad against Ceutorhynchus spp. had no effect, spinosad was the only agent that caused a reduction of the pollen beetle.