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- ItemAgricultural water balance in the polder Scheidgraben (Brandenburg)(Berlin ; Heidelberg : Springer, 2022) Drastig, Katrin; Schmidtke, Lea; Jacobs, Helen; Recker, MartinA predicted increase in water demand for irrigated agriculture in the wake of climate change, and the threat of more extensive periods of drought, poses a challenge to the availability of groundwater resources in Germany. In this study, water availability and water withdrawal for agricultural irrigation are calculated for the polder Scheidgraben (Brandenburg). The agricultural water demand in the Scheidgraben polder is modeled using the AgroHyd Farmmodel. Climate data, soil data, plant-specific data and operating data of all farms in the polder are used as a data basis. In the dry years 2018 and 2019, more than 20% of the potentially available water in the Scheidgraben polder was used for irrigation. The use of water resources by agricultural water withdrawals in the area may increasingly be a problem in the future. In some regions of Brandenburg, region-specific calculations for water management are necessary due to a wide range of conflicts and thus steadily increasing challenges for water authorities.
- ItemCase Study of Effects of Mineral N Fertilization Amounts on Water Productivity in Rainfed Winter Rapeseed Cultivation on a Sandy Soil in Brandenburg (Germany) over Three Years(Basel : MDPI, 2021) Drastig, Katrin; Kreidenweis, Ulrich; Meyer-Aurich, Andreas; Ammon, Christian; Prochnow, AnnetteDetailed knowledge about farm management practices and related hydrological processes on water productivity is required to substantially increase the productivity of precipitation water use in agriculture. With this in mind, the effect of the nitrogen (N) fertilization level on water productivity of winter oilseed rape (Brassica napus L.) was analyzed using a modeling approach and field measurements. In this first study of interception loss and water productivity in winter oilseed rape, the crop was cultivated in a field experiment on a sandy soil in Brandenburg (Germany) under five nitrogen fertilization treatments with 0, 60, 120, 180, and 240 kg mineral N ha−1 a−1. Based on data from three vegetation periods the water flows and the mass-based water productivity of seeds were calculated on a daily basis with the AgroHyd Farmmodel modeling software. As recommended from the recently developed guidelines of the FAO on water use in agriculture, the method water productivity was applied and uncertainties associated with the calculations were assessed. Economic profit-based water productivity (WPprofit) was calculated considering the costs of fertilization and the optimal level of N fertilization, which was determined based on a quadratic crop yield response function. Mean water productivity of seeds varied from 1.16 kg m−3 for the unfertilized control sample to 2.00 kg m−3 under the highest fertilization rate. N fertilization had a clearly positive effect on WPprofit. However, fertilizer application rates above 120 kg N ha−1 a−1 led to only marginal increases in yields. Water productivity of seeds under the highest fertilization rate was only insignificantly higher than under medium application rates. The optimum N level for the maximal WPprofit identified here was higher with 216 kg N ha−1 a−1. The conclusion is that further research is needed to investigate the interaction between fertilization and other farm management practices.
- ItemThe Effect of Best Crop Practices in the Pig and Poultry Production on Water Productivity in a Southern Brazilian Watershed(Basel : MDPI, 2020) Carra, Sofia Helena Zanella; Palhares, Julio Cesar Pascale; Drastig, Katrin; Schneider, Vania ElisabeteThis study analyzes the relation between Brazilian broiler and pig production and water productivity using recently developed reference guidelines on water footprinting for livestock production systems and supply chains. Different rainfed crop arrangements, in different scenarios and producer regions in Brazil, were assessed. Water productivity of broiler feed consumption ranged from 0.63 to 1.38 kg per m3 water input to rainfed summer maize (safra) and from 1.20 to 2.21 kg per m3 water input to winter maize (safrinha) while it ranged from 0.28 to 0.95 kg per m3 water input to rainfed soy. For pig feed consumption, rainfed maize ranged from 0.68 to 1.49 kg per m3 water input (safra) and from 1.30 to 2.38 kg per m3 water input (safrinha) while it ranged from 0.30 to 1.03 kg per m3 water input to rainfed soy. A potential amount of water saving of 0.0336 km3 year−1 and 0.0202 km3 year−1 could be attained for producing broiler and pig feed, respectively, depending on the crop rotation and producer region. The results showed that the evapotranspiration of animal feed production represents more than 99% of the total water consumption for broiler and pig production in the study area. The implementation of best crop practices resulted in higher water productivity values of chicken and pork meat and also improved the rainfall water-saving in comparison to conventional agriculture. Hence, the water productivity of the animal production chain in tropical regions demands a close relation to agriculture in order to attain a better understanding and improvement of rainfall water productivity for animal feed production.
- ItemStudy of Water Productivity of Industrial Hemp under Hot and Dry Conditions in Brandenburg (Germany) in the Year 2018(Basel : MDPI, 2020) Drastig, Katrin; Flemming, Inken; Gusovius, Hans-Jörg; Herppich, Werner B.Hemp (Cannabis sativa L.) is a high-yielding multi-purpose crop, but its hydrological functioning is poorly understood. Studies on the interception processes in hemp have been lacking so far. This study contributes to the understanding of the influences of evaporation of intercepted water and other hydrological fluxes within plants of two cultivars, “Santhica 27” and “Ivory”, on the water productivity. To determine water productivity and evaporation from interception, field measurements were conducted on plants of both cultivars at different stages of development. Precipitation (P), throughfall (TF), transpiration (T), and volumetric water content (VWC) were measured along with leaf area index (LAI) and yield of selected plant components. For the entire vegetation period, the cumulative P of 44 mm was converted into 13 mm TF (30%). The inferred evaporation of intercepted water (I) was high at 31 mm (71%). For the assessment water fluxes, the evaporation of intercepted water must be considered in the decision-making process. Besides the LAI, the plant architecture and the meteorological conditions during the cropping cycle seem to be the main factors determining I in the case of plants of both cultivars. Water productivity (WPDM) of the whole plant varied between 3.07 kg m−3 for Ivory and 3.49 for Santhica 27. In the case of bast yield, WPDM was 0.39 kg m-3 for Santhica 27 and 0.45 kg m−3 for Ivory. After the propagation of the uncertainties, the bandwidth of the WPDM of the whole plant was between 0.42 kg m−3 and 2.57 kg m−3. For bast fiber a bandwidth of the WP between 0.06 kg m−3 and 0.33 kg m−3 was calculated. The results show furthermore that even with a precise examination of water productivity, a high bandwidth of local values is revealed on different cultivars. However, generic WP values for fiber crops are not attainable.