Intensive swine operations produce large amounts of manure that must be dealt with responsibly. Liquid swine manure (LSM) collected in storage units is applied to cropland as a nutrient source. Maximizing crop utilization of the nitrogen (N) added in manure is important to achieve economic and environmental benefits. The objectives of this research were to evaluate the effect of 1) adding a nitrification inhibitor and 2) using supplemental phosphorus (P) and sulfur (S) fertilizers as means of enhancing crop recovery of LSM-N.<p>Field experiments were conducted at two long-term manure management sites in Saskatchewan; 1) Dixon (Black Chernozem) and 2) Melfort (Dark Grey Luvisol). At the Dixon site, plant and soil samples were collected throughout the 2005 and 2006 growing season, and ammonium-N (NH4+-N) and nitrate-N (NO3--N) concentration in soil, and total N content in plant were measured. Plant root simulator (PRSTM) probes were used to measure NH4+-N and NO3--N supply rates at the Dixon site to determine the effectiveness of a nitrification inhibitor dicyandiamide (DCD) added to LSM. Crop recovery of N applied through LSM application was assessed by measuring seed and straw yield and total N content. The effect of adding supplemental P fertilizer at 6.5 kg P ha-1 to swine manure amended soil on N recovery was also evaluated at the Dixon site. At the S deficient Melfort site, the effect of supplemental S fertilizer added at 40 kg S ha-1 as ammonium sulfate and elemental S was evaluated.<p>The addition of DCD (0.275 mL kg-1) to LSM in 2005 and 2006 at Dixon did not significantly affect the proportion of LSM-N recovered or the seed yield. However, measurements of available NH4+-N and NO3--N concentrations and supply rates at the beginning of the growing season in 2005 indicated that the nitrification inhibitor was effective in keeping more of the LSM-N in the NH4+ form for approximately 14 days after LSM application. <p> The addition of supplemental P fertilizer to plots fertilized with LSM at the Dixon site, generally did not produce any significant increase in crop N recovery or seed yield. However, increase in crop N recovery and seed yield in 100 kg N ha-1 urea treatments indicates that there was insufficient P available in the soils to maximize crop N recovery and seed yield. It appears that LSM is able to provide sufficient amounts of available P when applied annually at rates of 37,000 L ha-1 or higher. <p>At the Melfort site, the addition of supplemental S fertilizer did not significantly affect crop N recovery or seed yield in LSM treatments. Annual applications of the low rate of LSM of 37,000 L ha-1 supplied sufficient amounts of N and S to maximize seed yield and crop N recovery. However, large significant increases in seed yield and crop N recovery with supplemental S fertilizers were observed in the 80 kg N ha-1 urea treatment.<p>The use of a nitrification inhibitor added to LSM was effective at maintaining N in NH4+ form longer; however there was no significant effect on final yield, grain N or %N recovery. This may be due to the low N loss potential on prairies. Supplemental S and P fertilizer may be required with liquid swine manure. Supplemental commercial fertilizers with LSM are dependant on: the crop nutrient requirements, soil nutrient status and manure nutrient composition.

Intensive swine operations produce large amounts of manure that must be dealt with responsibly. Liquid swine manure (LSM) collected in storage units is applied to cropland as a nutrient source. Maximizing crop utilization of the nitrogen (N) added in manure is important to achieve economic and environmental benefits. The objectives of this research were to evaluate the effect of 1) adding a nitrification inhibitor and 2) using supplemental phosphorus (P) and sulfur (S) fertilizers as means of enhancing crop recovery of LSM-N.<p>Field experiments were conducted at two long-term manure management sites in Saskatchewan; 1) Dixon (Black Chernozem) and 2) Melfort (Dark Grey Luvisol). At the Dixon site, plant and soil samples were collected throughout the 2005 and 2006 growing season, and ammonium-N (NH4+-N) and nitrate-N (NO3--N) concentration in soil, and total N content in plant were measured. Plant root simulator (PRSTM) probes were used to measure NH4+-N and NO3--N supply rates at the Dixon site to determine the effectiveness of a nitrification inhibitor dicyandiamide (DCD) added to LSM. Crop recovery of N applied through LSM application was assessed by measuring seed and straw yield and total N content. The effect of adding supplemental P fertilizer at 6.5 kg P ha-1 to swine manure amended soil on N recovery was also evaluated at the Dixon site. At the S deficient Melfort site, the effect of supplemental S fertilizer added at 40 kg S ha-1 as ammonium sulfate and elemental S was evaluated.<p>The addition of DCD (0.275 mL kg-1) to LSM in 2005 and 2006 at Dixon did not significantly affect the proportion of LSM-N recovered or the seed yield. However, measurements of available NH4+-N and NO3--N concentrations and supply rates at the beginning of the growing season in 2005 indicated that the nitrification inhibitor was effective in keeping more of the LSM-N in the NH4+ form for approximately 14 days after LSM application. <p> The addition of supplemental P fertilizer to plots fertilized with LSM at the Dixon site, generally did not produce any significant increase in crop N recovery or seed yield. However, increase in crop N recovery and seed yield in 100 kg N ha-1 urea treatments indicates that there was insufficient P available in the soils to maximize crop N recovery and seed yield. It appears that LSM is able to provide sufficient amounts of available P when applied annually at rates of 37,000 L ha-1 or higher. <p>At the Melfort site, the addition of supplemental S fertilizer did not significantly affect crop N recovery or seed yield in LSM treatments. Annual applications of the low rate of LSM of 37,000 L ha-1 supplied sufficient amounts of N and S to maximize seed yield and crop N recovery. However, large significant increases in seed yield and crop N recovery with supplemental S fertilizers were observed in the 80 kg N ha-1 urea treatment.<p>The use of a nitrification inhibitor added to LSM was effective at maintaining N in NH4+ form longer; however there was no significant effect on final yield, grain N or %N recovery. This may be due to the low N loss potential on prairies. Supplemental S and P fertilizer may be required with liquid swine manure. Supplemental commercial fertilizers with LSM are dependant on: the crop nutrient requirements, soil nutrient status and manure nutrient composition.

Minimal studies have evaluated nitrification and subsequent denitrification for soils where rice is produced in the delayedlood system. Laboratory and field experiments were conducted at USDA-ARS and the Delta Research and Extension Center in Stoneville, MS to quantify the nitrification potential of southern USA soils, and evaluate nitrogen amendments aimed to reduce nitrification rates on clay soils. The Sharkey clay soil at Stoneville, MS was one of the soils with the greatest nitrification potential. Dicyandiamide (DCD) increased the number of days that half the total recovered inorganic–N was in the ammonium–N form (half-life) by approximately 3old and 18% when compared to non-amended urea in the laboratory and field, respectively. Results suggested that nitrapyrin was not an effective nitrification inhibitor in southern soil. Coated urea (43%N) applied 12 days before flood establishment (dbf) was most successful at reducing nitrification resulting in yield comparable to urea applied one dbf.

Made available in DSpace on 2016-12-08T15:50:04Z (GMT). No. of bitstreams: 1 PGMS14DA020.pdf: 1241701 bytes, checksum: 696adecfb227383e0ee8edb226ce8b1e (MD5) Previous issue date: 2014-01-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Practices of soil management and use of animal manure as a source of fertilizer affect emissions of greenhouse gases (GHG), which contribute to global warming. The main greenhouse gases produced in agriculture, in addition to carbon dioxide, are nitrous oxide (N2O) and methane (CH4), being issued mainly by the use of animal manure and rice cultivation, respectively. Therefore, three studies were conducted to evaluate the effect of management practices on emissions of N2O and CH4. In study I, the soil was a Humic Dystrudept and the effect of conventional tillage (CT) and no tillage (NT) with and without the application of liquid swine manure systems (DLS) was evaluated. In study II, under the same soil type, the effect of addition of nitrification inhibitor dicyandiamide (DCD) to liquid swine manure (DLS) on the mitigation of greenhouse gases was evaluated. In study III, the soil was a Typic Albaqualf, the effect of continuous and intermittent flooding systems in emissions of CH4 and N2O emissions during the rice cultivation systems were evaluated. Air samples were collected in static chambers and concentration of N2O and CH4 determined by gas chromatography. Approximately 2/3 of the annual N2O emission occurred during the first 90 days after application of DLS. At the end of about a year, the emission factor for N2O in treatments with and without the application of DLS ranged 1-5% of the N applied. The N2O emissions were controlled mainly by the availability of nitrate, total soil porosity filled with water, soil temperature and microbial activity (CO2 flux). The use of DCD with manure reduced approximately 60% of cumulative N2O emissions from NT. The soil revolving on CT may have reduced the efficiency of the inhibitor on N2O emissions, suggesting the need for increased dose of DCD in this soil management. The DCD, delays the onset of nitrate in the soil after application of DLS, reducing N losses and pollution potential of manure. On the Study III, it was found that intermittent irrigation with 60% saturated soil reduced emissions of CH4 about 90% compared to continuous flooding. This system can represent a promising practice in mitigating N2O and CH4 emissions without reducing productivity in rice / Práticas de manejo do solo e utilização de dejetos animais como fonte de fertilizantes afetam as emissões de gases de efeito estufa (GEE), as quais agravam o aquecimento global. Os principais gases de efeito estufa produzidos na agricultura, além do gás carbônico, são o óxido nitroso (N2O) e metano (CH4), sendo emitidos principalmente pela utilização de dejetos animais e no cultivo do arroz irrigado, respectivamente. Diante disso, três estudos foram conduzidos com o objetivo de avaliar o efeito de práticas de manejo nas emissões de N2O e CH4. No estudo I, em um Cambissolo Húmico, avaliou-se o efeito dos sistemas de preparo convencional (PC) e plantio direto (PD) com e sem a aplicação de dejeto líquido de suínos (DLS). No estudo II, em um Cambissolo Húmico, foi avaliado o efeito da adição do inibidor de nitrificação dicianodiamida (DCD) a dejetos suínos na mitigação dos gases. No estudo III, em um Planossolo Háplico, foi avaliado o efeito dos sistemas de alagamento contínuo e intermitente nas emissões de CH4 e N2O durante o cultivo de arroz. Amostras de ar foram coletadas em câmaras estáticas e a concentração de N2O e CH4 foi determinada por cromatografia gasosa. Aproximadamente 2/3 da emissão anual de N2O ocorreu durante os primeiros 90 dias após a aplicação do DLS. Ao final de aproximadamente um ano o fator de emissão de N2O nos tratamentos com e sem a aplicação de DLS variou de 1 a 5% do N aplicado. As emissões de N2O foram controladas principalmente pela disponibilidade de nitrato, porosidade total do solo preenchida por água, temperatura do solo e atividade microbiana (fluxo de CO2). A utilização de DCD junto aos dejetos reduziu aproximadamente 60% das emissões acumuladas de N2O no PD. O 10 revolvimento do solo no PC pode ter reduzido a eficiência do inibidor nas emissões de N2O, sugerindo a necessidade de maior dose de DCD neste sistema de manejo do solo. A DCD, ao retardar o aparecimento de nitrato no solo após a aplicação de DLS, reduz as perdas de N e o potencial poluidor dos dejetos. Com relação ao estudo III, verificou-se que o sistema de irrigação intermitente com 60% de saturação do solo reduziu as emissões de CH4 em cerca de 90% em relação ao sistema de alagamento contínuo. Esse sistema pode ser uma prática promissora na mitigação das emissões de N2O e CH4, sem redução de produtividade na cultura do arroz

The expansion of livestock husbandry and biogas production in large parts of northwestern Germany during the last two decades increased the amount of accruing manure, as well as the demand for maize as fodder crop and substrate for biogas plants. To overcome phosphorus deficiency symptoms during early growth of maize, farmers commonly apply mineral starter fertilizers containing ammonium-nitrogen and phosphorus on top of the usual manure applications required to meet crop nutrient demand. This practice typically leads to overfertilization of N and P and the excess nutrients are then prone to be lost into the environment. Recent developments of agricultural machinery allow for the injection of slurry bands into the soil prior to maize planting. Due to high concentrations of ammonium and phosphorus in the manure band, chemical transformation and translocation of these nutrients is reduced. When the bands are placed near the seeds, even the radicles can access the applied nutrients. Hence, application of mineral starter fertilizers might be obviated. Earlier investigations showed insufficient knowledge of nutrient transformations in manure bands and their consequences on crop growth. To resolve these problems a research project at the University of Applied Sciences Osnabrück was conducted in close cooperation with the local agricultural extension services, machinery producers and farmers. In a series of field trials, broadcasting of liquid manure was compared to injection with and without a nitrification inhibitor in three consecutive growing seasons (2013 to 2015). The trials were conducted in a split-plot design, where all liquid manure treatments were divided in subplots with and without a mineral starter fertilizer. Biomass samplings at eight leaves stage and harvest gave insight into the performance of the treatments. Compared to broadcast application with starter fertilizer, manure injection showed slightly retarded early growth in some trials. However, yields and nitrogen uptake at harvest were similar. When a nitrification inhibitor was added to the injected manure, early growth was not retarded, yields were alike broadcast and injection treatments, but nitrogen uptake was higher in all seasons (on average ~7%). To further investigate nitrogen dynamics and crop growth, another field trial was conducted on a sandy soil close to Osnabrück in 2014 and 2015. Manure injection with and without a nitrification inhibitor was compared to broadcast application with mineral starter fertilizer and an unfertilized control treatment. Plant samplings were taken at regular intervals. Major precipitation events in May and June 2014 led to significant nitrate leaching, especially in the broadcast treatment. Manure injection delayed the nitrification of slurry ammonium and consequently the translocation out of the root zone. Thus, plants in injection treatments could accumulate more nitrogen in their biomass and showed less nitrogen deficiency symptoms. This led to increased yield (+16.5%) and nitrogen uptake (+9.6%) for injection treatment with nitrification inhibitor compared to broadcast treatment. In 2015, low temperatures impaired seminal root growth and phosphorus availability. The mineral starter fertilizer in the broadcast treatment led to better early growth than injected slurry. When a nitrification inhibitor was added to the injected manure, less P deficiency symptoms were observed, and the crop growth was only slightly retarded. Due to the high compensation potential of silage maize, these differences were equalized until harvest. Nevertheless, the mean apparent nitrogen recovery efficiency of both seasons was higher in injection treatments with and without nitrification inhibitor, compared to broadcast with mineral starter fertilizer (48%, 56% and 43%, respectively). To ease the handling of field trial series by decreasing the number of tissue samplings, the use of a handheld sensor was tested during vegetative growth of maize. In the series of field trials with the local extension service, the derived vegetation index showed significant correlations to biomass and nitrogen uptake at eight leaves stage. Measurements of the vegetative growth observed during the nitrogen dynamics trial showed that the sensor needs sufficient leaf area to deliver precise data, but also tends to saturate when maize tassels evolve. The best estimates were found between six and ten leaves. Thus, the sensor can be a valuable tool to reduce numbers of tissue samples and, thus, time and effort needed in fertilization trials. Altogether, these results should encourage farmers to obviate mineral starter fertilizers by using manure injection when cropping maize on sandy soils. The advantages that come along with manure injection based on the present research indicate higher shares of manure nutrients find their way into the plants due to delayed biochemical transformations. These nutrients are consequently not lost into the environment. Nitrification inhibitors have shown a positive effect on crop performance and led to a further reduction of nitrogen losses. However, further knowledge of their decomposition with special regard to the ecological impact of their compounds and metabolites need to be thoroughly evaluated.

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.

Irish agriculture is becoming increasingly regulated, with restrictions on fertiliser application rates and stocking rates to reduce nitrate (NO₀⁻) leaching losses. However these regulations have been, to date, based on minimal field research. The purpose of this study was to determine the actual leaching losses of nitrate from Irish dairy pasture at a range of stocking rates, and to investigate the effectiveness of the nitrification inhibitor DCD at reducing nitrate leaching losses where these are deemed excessive. In grazed pastures, a major source of leached nitrate is the urine patch, where a high rate of N is applied in one application. This trial recorded the losses from urine and non-urine areas of pasture separately. Nitrate leaching losses from three soils were recorded using lysimeters at Johnstown Castle, Co. Wexford, over two years. Total nitrate losses were higher from the freely drained Clonakilty and Elton soils than from the heavy Rathangan soil. Mean nitrate losses from urine patches ranged from 16 - 233 kg nitrate-N / ha⁻¹, and were reduced by up to 53% when DCD was applied. DCD also reduced peak and mean nitrate-N concentrations in many cases. In addition, DCD halved the nitrous oxide (N₂O) emission factor on the Rathangan soil, caused increases in pasture N content, and increased herbage yield in some treatments. The distribution of urine patches under dairy grazing was recorded using GPS at Kilworth, Co. Cork. Cows were also found to deposit 0.359 urine patches per grazing hour. A model was produced to predict field-scale nitrate leaching losses from dairy pasture at a range of stocking rates. At 2.94 cows per hectare, the highest stocking rate, annual field N loss was below 34 kg nitrate-N ha⁻¹, mean drainage N concentrations were below 5.65 mg nitrate-N L⁻¹ (the EU drinking water guideline value), and the worst-case-scenario autumn peak concentration did not exceed 21.55 mg nitrate-N L⁻¹ (above the EU Maximum Allowable Concentration (MAC) but below the World Health Organisation (WHO) drinking water limit). DCD reduced total annual field N loss by 21% (a conservative estimate), and also reduced mean and peak nitrate concentrations. Provided fertiliser application rates are at or below 291 kg N ha⁻¹, and based on current legislative values for drinking water quality, this trial does not support any blanket restrictions on the stocking rate of Irish dairy farms. However where particularly high water quality is required, DCD shows potential as a useful tool to achieve low nitrate concentrations.