Institute for Agricultural Ecology

Freising, Germany

Institute for Agricultural Ecology

Freising, Germany
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Capriel P.,Josef Raps Str. 3 | Capriel P.,Institute for Agricultural Ecology
European Journal of Soil Science | Year: 2013

In the last 60years traditional agriculture in industrialized European countries, which had initially been dependent on available natural resources, has shifted towards a massive intensification of nutrient turnover because of cheap energy and low-cost synthetic fertilizers. At the same time farm structure has undergone profound changes, resulting in an increase in the number of specialized farms to the detriment of traditional non-specialized ones. All these trends have had a significant impact on agricultural management. The intensification of agricultural management together with climate change could affect the quantity and quality of soil organic matter (SOM). That could imply decreasing soil fertility, reduced harvest yields, increasing nutrient losses and additional greenhouse gas emission. In order to measure the long-term development of SOM in agricultural soils a monitoring programme was initiated in Bavaria in 1986. The measurements are based on 92 representative plots located on cropland and 21 plots located on managed permanent grassland. Between 1986 and 2007 the monitoring plots have been sampled four times. The monitoring results suggest a decrease of soil organic carbon content, total nitrogen content and C:N ratio in cropland as well as in grassland in Bavaria between 1986 and 2007. Crops and organic fertilizers are together with the initial SOM content the main causes of the observed changes in SOM quantity and quality. A climatic effect could be neither proved nor excluded. The results in Bavaria are consistent with the reported changes in organic carbon of agricultural soils in Austria, Belgium, France, the Netherlands and England. In Bavaria we should expect declining SOM stocks, particularly soil organic carbon, in agricultural soils if the supply of organic matter remains constant or even decreases. © 2013 The Author. Journal compilation © 2013 British Society of Soil Science.

Gronle A.,Thunen Institute of Organic Farming | Lux G.,FH Dresden | Bohm H.,Thunen Institute of Organic Farming | Schmidtke K.,FH Dresden | And 5 more authors.
Soil and Tillage Research | Year: 2015

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. © 2014 Elsevier B.V.

Urbatzka P.,Institute for Agricultural Ecology | Grass R.,University of Kassel | Haase T.,University of Kassel | Schuler C.,University of Kassel | And 2 more authors.
Journal fur Kulturpflanzen | Year: 2011

In contrast to the common spring pea (SP), little is known about the capacity of winter peas (WP) for symbiotic N 2 fixation in pure and mixed stands. Therefore, seven WP genotypes and one semi-leafless SP in pure stands and two mixtures with cereals (25% (Mix1) or 50% (Mix2) of the pea pure stand sowing density) were examined in field experiments on two sites. The amount of fixed N 2 at flowering and at mature harvest was assessed applying the extended total-N-difference method. At flowering and at grain harvest the N 2 fixation for the five frost-resistant WP genotypes (52 and 85 kg ha -1, respectively) was generally higher than for SP (17 and 42 kg ha -1, respectively). This was traced back to the earlier N 2 fixation of WP and a usually higher above-ground biomass (144 and 75 kg ha -1, respectively) and presumably higher below-ground biomass as compared with SP. Furthermore, average inorganic N in soil at mature harvest in pure stands was higher under WP (69 kg ha -1) than under SP (36 kg ha -1), while for any other treatment similar values on a lower level were estimated. Results show that WP may better contribute to the N supply within crop rotations than SP.

Urbatzka P.,Institute for Agricultural Ecology | Grass R.,University of Kassel | Haase T.,University of Kassel | Schuler C.,University of Kassel | And 2 more authors.
Organic Agriculture | Year: 2011

High grain yields are difficult to achieve for common spring pea (SP), mainly as a result of its relatively low competitiveness and yield instability. In field experiments, seven different genotypes of winter pea (WP) were analysed for their yield performance and yield stability in comparison to one SP in pure and mixed stands (two replacement designs with cereal) at two experimental sites in four and two growing seasons, respectively. Additionally, in a selection of treatments, parameters of grain quality were analysed. Two of the seven genotypes cannot be recommended for cropping in climates where there are frequent incidences of frost in winter, due to their poor winter hardiness. The pea grain yield of the highest-yielding WP grown in mixed stands (overall mean of 2.4 t DM ha-1) was higher than in a pure stand, with 1.8 and 1.9 t DM ha-1 for WP and SP, respectively. Moreover, the concentration of valuable substances (crude protein, amino acids) in WP was comparable to SP, but the concentration of unfavourable secondary compounds (tannin, trypsin inhibitor activity) was significantly higher. WP showed higher yield stability than SP, and negligible weed infestation was observed for WP, but not for SP. Hence, using WP-cereal mixtures provides an alternative to cropping SP, but awareness of the potential constraint to its use as feedstuff for monogastrics is required. © 2011 Springer Science & Business Media BV.

Geischeder R.,TU Munich | Brandhuber R.,Institute for Agricultural Ecology | Demmel M.,Institute for Agriculture Engineering and Animal Husbandry
American Society of Agricultural and Biological Engineers Annual International Meeting 2011, ASABE 2011 | Year: 2011

The use of heavy machinery is increasing in agriculture today, therefore the risk of subsoil compaction rises. In the literature antithetic statements about different undercarriages concepts can be found. Therefore a field experiment was designed in order to study the effects of the same contact area pressure under a rubber belt, a large tire two times and a small tire four times. Vertical soil pressure was measured at four depths by installing soil pressure sensors. To determine soil deformation 600 undisturbed soil samples were taken out of two depths (0.15-0.20 m and 0.38-0.43 m) additional a cone penetrometer was used. The investigation shows considerable deformations in a depth of 20 cm. The maximum effect in the depth was detected by the wheel load 51.5 kN (two times). The rubber belt (113 kN) shows high pressure peaks only in 20 cm depth but it is not the same effect as four times 23.5 kN of wheel. Through the high tension by the rubber belt, the weight can be better firm up. The considerably established differences between track and tire argue for an unequal distribution of pressure under the tire with a high concentration in the centre of the contact area. The soil properties detected the problem driving under wet conditions over loosen soil in spring. Every treatment will easily compacting the topsoil. In this case, there was no differentiation between the undercarriages. Under terms of this field trail no effects detected in subsoil were detected.

Kohler B.,Institute for Animal Nutrition and Feed Management | Diepolder M.,Institute for Agricultural Ecology | Ostertag J.,Institute for Animal Nutrition and Feed Management | Thurner S.,Institute for Agricultural Engineering and Animal Husbandry | Spiekers H.,Institute for Animal Nutrition and Feed Management
Agricultural and Food Science | Year: 2013

An efficient feed management is important for a sustainable and economic agricultural production. One of the main points for improving the efficiency is the reduction of feed losses. In the present investigation the dry matter (DM) losses of grass, lucerne and maize silages in farm scaled bunker silos were analysed. The method of determining DM losses was the total-in versus total-out DM mass flow of the silos, including the determination of DM content and other silage parameters via manual sampling. The results taken from 48 silos showed on average for all investigated crops 9-12% of DM losses. Density and feed out rate showed a negative correlation to DM losses in maize silages. According to the applied method for determining DM losses on farm scale, a guideline of 8% can be suggested for maximum DM losses in bunker silos for grass and maize silages. The described method seems to be applicable for improving the feed management by using largely automated measurements on the harvest and feeding side.

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