2020, Herppich, Werner B., Gusovius, Hans-Jörg, Flemming, Inken, Drastig, Katrin

Hemp currently regains certain importance as fiber, oil and medical crop not least because of its modest requirements of biocides, fertilizer and water. During recent years, crops were exposed to a combination of drought and heat, even in northern Central-Europe. Dynamic responses of photosynthesis and stomatal conductance to these stresses and their persistent effects had been studied, if at all, in controlled environment experiments. Comprehensive field studies on diurnal and long-term net photosynthesis and gas exchange, and yield properties of hemp during a drought prone, high-temperature season in northern Central-Europe are obviously missing. Thus, in whole season field trails, the essential actual physiological (rates of net photosynthesis and transpiration, stomatal conductance, water use efficiencies, ambient and internal CO2 concentrations) and the yield performance of modern high-yielding multi-purpose hemp cultivars, ‘Ivory’ and ‘Santhica 27’, were evaluated under extreme environmental conditions and highly limited soil water supply. This provides comprehensive information on the usability of these cultivars under potential future harsh production conditions. Plants of both cultivars differentially cope with the prevailing climatic and soil water conditions. While ‘Ivory’ plants developed high rates of CO2 gain and established large leaf area per plant in the mid-season, those of ‘Santhica 27’ utilized lower CO2 uptake rates at lower leaf area per plant most time. This and the higher germination success of ‘Santhica 27’ resulted in nearly twice the yield compared to ‘Ivory’. Although stomatal control of CO2 gain was pronounced in both cultivars, higher stomatal limitations in ‘Ivory’ plants resulted in higher overall intrinsic water use efficiency. Cultivation of both hemp cultivars with only basic irrigation during seed germination was successful and without large effects on yield and quality. This was valid even under extremely hot and dry climatic conditions in northern Central Europe.

2020, Carra, Sofia Helena Zanella, Palhares, Julio Cesar Pascale, Drastig, Katrin, Schneider, Vania Elisabete

This 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.

2017-2-1, Peth, Denise, Drastig, Katrin, Prochnow, Annette

The German wine sector has encountered new challenges in water management recently. To manage water resources responsibly, it is necessary to understand the relationship between the input of water and the output of wine, in terms of quantity and quality. The objectives of this study are to examine water use at the farm scale at three German wineries in Rhenish Hesse, and to develop and apply, for the first time, a quality-based indicator. Water use is analyzed in terms of wine production and wine-making over three years. After the spatial and temporal boundaries of the wineries and the water flows are defined, the farm water productivity indicator is calculated to assess water use at the winery scale. Farm water productivity is calculated using the AgroHyd Farmmodel modeling software. Average productivity on a quantity basis is 3.91 L wine per m3 of water. Productivity on a quality basis is 329.24 Oechsle per m3 of water. Water input from transpiration for wine production accounts for 99.4%-99.7% of total water input in the wineries, and, because irrigation is not used, precipitation is the sole source of transpired water. Future studies should use both quality-based and mass-based indicators of productivity. © 2017 by the authors.

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.

2021, Drastig, Katrin, Kreidenweis, Ulrich, Meyer-Aurich, Andreas, Ammon, Christian, Prochnow, Annette

Detailed 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.