O objetivo do trabalho foi avaliar o impacto de intervenções nutricionais no valor da pegada hídrica do produto leite bovino. O cálculo da pegada hídrica considerou as águas verde, azul e cinza, consumidas no sistema de produção e no beneficiamento do produto. Para determinação dos consumos de água no sistema de produção foram selecionados dois grupos experimentais, cada um contendo sete vacas em lactação. As dietas fornecidas a cada grupo continha os mesmos ingredientes. Porém, na composição do concentrado havia diferentes percentuais proteicos. O concentrado fornecido ao Grupo 1, continha 20% de proteína bruta, e o concentrado fornecido ao Grupo 2, tinha seu teor de proteico ajustado de acordo com a produção de leite do grupo, ao longo da lactação. O ajuste do teor de proteína da dieta as necessidades dos animais promoveu a redução dos consumos das águas verde, azul e cinza e da pegada hídrica do produto leite. A pegada hídrica do Grupo 1 com base no nitrato foi de 503,79 L kg-1 de FPCM (86,1% água verde, 13,4% água azul e 0,43% água cinza) e a do Grupo 2 foi de 452,59 L kg-1 de FPCM (85,3% água verde, 14,3% água azul e 0,45% água cinza). Com base no fósforo, a pegada total do Grupo 1 foi igual a 518,43 L kg-1 de FPCM (83,7% água verde, 13,1% água azul e 3,2% água cinza) e a do Grupo 2 foi de 465,16 L kg-1 de FPCM (83% água verde, 13,9 % água azul e 3,1% água cinza). Entre as três águas, a verde foi a que apresentou maior consumo, atestando a importância da eficiência hídrica na agricultura para os produtos de origem animal. A prática de irrigação das pastagens representou o maior consumo de água azul. O Grupo 2 apresentou melhor eficiência de uso de nutrientes, mas em ambos os grupos as entradas foram maiores que as saídas. O balanço do Grupo 1 foi de 962,7 kg de N, 95,2 kg de P e 545,1 kg de K e do Grupo 2, 869,4 kg de N, 57,8 kg de P, 601,9 kg de K. A captação de água de chuva por cisterna foi avaliada como uma tecnologia hídrica. Essa demonstrou ter impacto positivo na redução do volume de água captado de fonte natural, mas a análise financeira da tecnologia se mostrou inviável para a condição produtiva do estudo. A utilização de intervenções nutricionais que promovam o melhor aproveitamento dos nutrientes pelos animais demonstrou ser uma prática que também contribui para melhoria da eficiência hídrica do sistema de produção e dos produtos de origem animal. Estudos que relacionam o cálculo da pegada hídrica com os aspectos produtivos da pecuária promoverão impactos positivos na conservação dos recursos hídricos e no desempenho dos sistemas de produção. / The aim of the study was to evaluate the impact of nutritional interventions on the dairy milk water footprint. Water footprint calculation considered the green, blue and gray water consumed in the production system and in the dairy unit. To determine the water consumption in the production system was selected two experimental groups with seven lactating cows each. The diets provided to each group contained the same feeds. However, concentrate had different crude protein contents. The concentrate feed Group 1 contained 20% of crude protein, and the concentrate feed Group 2 had its protein content adjusted according to the milk production of the group. The adjustment of the protein content promoted a lower consumption of green, blue and gray water and the reduction of water footprint value. The water footprint based on nitrate in the Group 1 was 503.79 L kg-1 of FPCM (86.1% green water, 13.4% blue water, and 0.43% gray water) and in the Group 2 was 452.59 L kg-1 FPCM (85.3% green water, 14.3% blue water, and 0.45% gray water). Water footprint based on phosphorus was 518.43 L kg-1 of FPCM to Group 1 (83.7% green water, 13.1% blue water, and 3.2% gray water) and to Group 2 was 465.16 L kg-1 of FPCM (83% green water, 13.9% blue water, and 3.1% gray water). Green was the highest volume consumed. This shows the relation between agriculture water efficiency and the water footprint of animal products. Irrigation represented the highest consumption of blue water. The nutrient use efficiency was better to Group 2, but in both groups the inputs were higher than the outputs. The nutrient balance for Group 1 was 962.7 kg N, 95.2 kg P and 545.1 kg K and for Group 2, 869.4 kg N, 57.8 kg P, 601.9 kg of K. Rainwater harvesting in a cistern was evaluated as a water technology. It had a positive impact on reducing the withdraw from ground source, but the economic analysis of the cistern was unfeasible for the productive condition. The use of nutritional interventions for lactating cows promoted better nutrient utilization and has proved to be a management that contributes to the increase of water efficiency in the production system and to animal products. Studies that relate the water footprint with productive aspects of livestock will promote positive impacts on the water conservation and on the performance of production systems.

O objetivo do trabalho foi avaliar o impacto de intervenções nutricionais no valor da pegada hídrica do produto leite bovino. O cálculo da pegada hídrica considerou as águas verde, azul e cinza, consumidas no sistema de produção e no beneficiamento do produto. Para determinação dos consumos de água no sistema de produção foram selecionados dois grupos experimentais, cada um contendo sete vacas em lactação. As dietas fornecidas a cada grupo continha os mesmos ingredientes. Porém, na composição do concentrado havia diferentes percentuais proteicos. O concentrado fornecido ao Grupo 1, continha 20% de proteína bruta, e o concentrado fornecido ao Grupo 2, tinha seu teor de proteico ajustado de acordo com a produção de leite do grupo, ao longo da lactação. O ajuste do teor de proteína da dieta as necessidades dos animais promoveu a redução dos consumos das águas verde, azul e cinza e da pegada hídrica do produto leite. A pegada hídrica do Grupo 1 com base no nitrato foi de 503,79 L kg-1 de FPCM (86,1% água verde, 13,4% água azul e 0,43% água cinza) e a do Grupo 2 foi de 452,59 L kg-1 de FPCM (85,3% água verde, 14,3% água azul e 0,45% água cinza). Com base no fósforo, a pegada total do Grupo 1 foi igual a 518,43 L kg-1 de FPCM (83,7% água verde, 13,1% água azul e 3,2% água cinza) e a do Grupo 2 foi de 465,16 L kg-1 de FPCM (83% água verde, 13,9 % água azul e 3,1% água cinza). Entre as três águas, a verde foi a que apresentou maior consumo, atestando a importância da eficiência hídrica na agricultura para os produtos de origem animal. A prática de irrigação das pastagens representou o maior consumo de água azul. O Grupo 2 apresentou melhor eficiência de uso de nutrientes, mas em ambos os grupos as entradas foram maiores que as saídas. O balanço do Grupo 1 foi de 962,7 kg de N, 95,2 kg de P e 545,1 kg de K e do Grupo 2, 869,4 kg de N, 57,8 kg de P, 601,9 kg de K. A captação de água de chuva por cisterna foi avaliada como uma tecnologia hídrica. Essa demonstrou ter impacto positivo na redução do volume de água captado de fonte natural, mas a análise financeira da tecnologia se mostrou inviável para a condição produtiva do estudo. A utilização de intervenções nutricionais que promovam o melhor aproveitamento dos nutrientes pelos animais demonstrou ser uma prática que também contribui para melhoria da eficiência hídrica do sistema de produção e dos produtos de origem animal. Estudos que relacionam o cálculo da pegada hídrica com os aspectos produtivos da pecuária promoverão impactos positivos na conservação dos recursos hídricos e no desempenho dos sistemas de produção. / The aim of the study was to evaluate the impact of nutritional interventions on the dairy milk water footprint. Water footprint calculation considered the green, blue and gray water consumed in the production system and in the dairy unit. To determine the water consumption in the production system was selected two experimental groups with seven lactating cows each. The diets provided to each group contained the same feeds. However, concentrate had different crude protein contents. The concentrate feed Group 1 contained 20% of crude protein, and the concentrate feed Group 2 had its protein content adjusted according to the milk production of the group. The adjustment of the protein content promoted a lower consumption of green, blue and gray water and the reduction of water footprint value. The water footprint based on nitrate in the Group 1 was 503.79 L kg-1 of FPCM (86.1% green water, 13.4% blue water, and 0.43% gray water) and in the Group 2 was 452.59 L kg-1 FPCM (85.3% green water, 14.3% blue water, and 0.45% gray water). Water footprint based on phosphorus was 518.43 L kg-1 of FPCM to Group 1 (83.7% green water, 13.1% blue water, and 3.2% gray water) and to Group 2 was 465.16 L kg-1 of FPCM (83% green water, 13.9% blue water, and 3.1% gray water). Green was the highest volume consumed. This shows the relation between agriculture water efficiency and the water footprint of animal products. Irrigation represented the highest consumption of blue water. The nutrient use efficiency was better to Group 2, but in both groups the inputs were higher than the outputs. The nutrient balance for Group 1 was 962.7 kg N, 95.2 kg P and 545.1 kg K and for Group 2, 869.4 kg N, 57.8 kg P, 601.9 kg of K. Rainwater harvesting in a cistern was evaluated as a water technology. It had a positive impact on reducing the withdraw from ground source, but the economic analysis of the cistern was unfeasible for the productive condition. The use of nutritional interventions for lactating cows promoted better nutrient utilization and has proved to be a management that contributes to the increase of water efficiency in the production system and to animal products. Studies that relate the water footprint with productive aspects of livestock will promote positive impacts on the water conservation and on the performance of production systems.

Maize is the dominant crop in northwestern Germany and is mostly cultivated on sandy soils. Additionally, due to intensive livestock husbandry and biogas production, large amounts of liquid manures are produced. The current farm practice leads to high N and P surpluses at field level accompanied by environmental pollution, like nitrate leaching, eutrophication of non-agricultural ecosystems, and N2O emissions. The accruing liquid manures are often used for maize fertilization. Thereby, slurries are mainly broadcast applied using trailing hose applicators followed by incorporation into the topsoil. In addition, a mineral N P starter fertilizer (MSF) is band-applied below the seed-corn at planting to overcome the limited nutrient availability during the early growth stages. Using a slurry injection technique below the maize row before planting might serve a substitute for MSF. Addition of a nitrification inhibitor (NI) into the slurry before injection seems to be an option to further decrease N losses. The objectives of this thesis were to compare the current and novel fertilizing strategies with a special focus on soil mineral nitrogen (SMN) dynamics and plant P, zinc (Zn) and manganese (Mn) status. For both issues the effect of adding a NI into the slurry was investigated. To characterize the SMN dynamics after slurry injection an appropriate soil sampling strategy had to be developed. Therefore, three consecutive field trials were conducted. The first testing of the new soil sampling approach was implemented in an existing experiment where the slurry was injected at a depth of 12 cm (upper rim) below the soil surface. The soil profile (75 cm wide) centered below the maize row was sampled using a grid-like approach to a depth of 90 cm. Around the injection zone, soil monoliths (SM) were sampled using a purpose-built soil shovel. Below the SMs and in the interrow space (15 and 30 cm distance to the row) a standardized auger procedure was used. The second experiment aimed to improve the sampling strategy with focus on sample homogenization quality and necessary sample sizes per pooled sample. In the third experiment this improved sampling strategy was validated. Results from the first testing of the sampling procedure showed that the strategy is suitable, although some problems occurred. Especially the high spread in values among the replications caused high coefficients of variation (CV; mostly 40 – 60%). The improvement trial revealed that for the SM, which contains the slurry band, an intensive homogenization is required. In addition, suitable sample sizes (twelve auger samples and six soil monolith samples per pooled sample) have to be collected to obtain reliable SMN values. Following this enhanced sampling strategy in the final validation trial, the spread in values was considerably reduced and resulted in CV values of mostly < 20%. The method can be adapted to other fertilizer placement strategies and further row crops. To compare both fertilizing strategies with respect to the spatial and temporal SMN dynamics as well as to the plant nutrient status two field trials were conducted using pig slurry on sandy soils in 2014 and 2015. Four treatments were tested: unfertilized control, broadcast application + MSF, injection, and injection + NI. Soil samples were taken using the new sampling strategy at several dates during the growing season. Plant samples were simultaneously collected to evaluate the plant P, Zn, and Mn status at different growth stages. In 2014, all fertilized N was displaced from the top soil layer of the broadcast treatment until the 6-leaf stage due to heavy rainfall, while N displacement was significantly smaller after slurry injection. The lateral movement of injected slurry N was negligible. In 2015, almost no displacement of fertilized N out of the top soil layer occurred independently of treatments, due to distinctly lower rainfall. The release of slurry N was delayed following broadcast application and large SMN concentrations were detected in the injection zones until the 10-leaf stage. The addition of a NI resulted in significantly increased NH4-N shares in the injection zone throughout the early growth stages (+ 46% in 2014 and + 12% in 2015 at 6-leaf stage). Thus, in 2014 SMN displacement was delayed, and in 2015 increased SMN concentrations were found around the slurry band, most probably due to lower N losses via denitrification. Furthermore, NI addition significantly increased the nutrient uptake by maize during early growth in both years. With P deficiency due to cold weather conditions in 2015, broadcast application showed higher P uptake until the 6-leaf stage (36 – 58%), while it was lower at the 8- (32%) and 10- (19%) leaf stages compared to slurry injection (+ NI). Zn availability was enhanced during early growth after slurry injection (+ NI) and Zn as well as Mn uptake were higher at harvest. Furthermore, dry matter yields were higher (2014) or equal (2015) compared to broadcast application. The P balances were decreased by 10 – 14 kg P ha-1, while Zn and Mn balances were excessive independent of treatments. The field trials showed that after slurry injection, especially when combined with a NI, the applied nitrogen is located in a soil zone with better spatial availability for plant roots compared to broadcast application. Furthermore, the MSF can be substituted without affecting early growth of maize. In conclusion, slurry injection leads to equal (or even higher) yields and enables farmers in northwestern Germany to reduce the P and N surpluses. This would support several goals concerning sustainable land use: Lower pollution of ground and surface waters, reduced emission of NH3, more efficient use of the limited rock P reserves, and less need of transporting organic manures out of regions with intensive animal husbandry and/or biogas production. However, slurry injection enhances the risk of N2O emissions, which contributes to climate change. Thus, for a final evaluation of the environmental impact a life cycle assessment would be worthwhile.