JournalTOCs

Nutrient Cycling in Agroecosystems
Journal Prestige (SJR): 0.895

Citation Impact (citeScore): 2
Number of Followers: 1

This is an Open Access Journal

Open Access journal
ISSN (Print) 1385-1314 - ISSN (Online) 1573-0867
Published by Springer-Verlag

[2468 journals]

On-farm use of recycled liquid ammonium sulphate in Southwest Germany
using a participatory approach
- Abstract: Abstract For political and environmental reasons, there is an urgent need for alternatives to energy-intensive synthetic fertilizers. One solution is the targeted recycling of nutrients within agriculture. In this study, liquid ammonium sulphate (LAS) as a recycling product derived from digestate treatment was compared to calcium ammonium nitrate, manure and original digestates in an on-farm experiment using a participatory approach. Based on regular meetings with the farmers involved, a flexible experimental design was developed which integrated the fertilization legislation and the farmers’ operational structures already in place, such as crop rotation, available application techniques and manure management demands. The aim was to achieve both implementation practicability and acceptance of the study results by the farmers. Results from the year 2020 showed that LAS applied with three-jet nozzles in barley and wheat had significantly lower yields than the other fertilizers. Applied with a slurry tanker trailing shoe applicator in 2021, LAS had comparable yields to the other fertilizers in maize (51.2 t ha−1) and comparable yields to digestate in rapeseed (4.4 t ha−1). Application techniques that minimize environmental impacts and lower the LAS pH could potentially increase the effectiveness of the fertilizer. We recommend that farmers use this fertilizer not as a single solution but as a mineral compensatory fertilizer in addition to organic fertilizers following local fertilizer legislation. In this case, LAS could potentially substitute calcium ammonium nitrate (CAN).
  PubDate: 2023-12-02
Marginal increase in nitrate leaching under grass–clover leys by
slurry and mineral fertilizer
- Abstract: Abstract On dairy farms, fertilization of grass-clover swards ensures stable grass yields but may increase the potential for nitrate leaching on light-textured soils. The aim of this study was to quantify the N use efficiency and nitrate leaching under fertilized grass-clover leys. The study was conducted over 2 years at two sites, with increasing applications of mineral fertilizer (0–480 kg available N ha−1) alone or in combination with a basic application of cattle slurry. For plots fertilized with mineral N, the N soil surface balance was independent of the application rate and in the same range as for unfertilized plots (− 11 to 51 kg N ha−1). However, when plots were fertilized with slurry N (+ mineral N), the surplus was substantially increased owing to the fraction of organic N applied in slurry (95–100 kg N ha−1) and higher biological N2 fixation inputs (55–228 kg N ha−1). The type of fertilizer had no effect on nitrate leaching across the full range of application rates. Nitrate leaching increased quadratically as a function of application rate, with a range of 3–117 kg N ha−1 (0.33–17 mg l−1 in soil solution sampled with suction cups) in the first year and less in the second year, when clover proportion was lower due to the self-regulatory nature of grass-clover mixtures. Importantly, the rate of marginal leaching increased with fertilization level: below 150 kg N ha−1 there was no additional leaching from fertilization and at 200 kg N ha−1 around 5% of additional fertilizer-N was leached. This is less than generally found for arable crops and thus even in intensive dairy systems, grass-clover leys are an environmentally favorable crop.
  PubDate: 2023-11-16
Adjusting nitrogen fertilization to spatial variations in growth
conditions in silvopastoral systems for improved nitrogen use efficiency
- Abstract: Abstract Grass swards in silvopastoral systems have a lower herbage production near trees than open grassland. This is related to a lower nitrogen (N) uptake in an area close to the tree lines. The N use efficiency for the whole field can then be improved when N input is spatially adjusted and the overall amount reduced. We performed a 2-year field experiment to gain insights into this idea for making savings on N inputs by studying the response of the grass sward to fertilizer N input in relation to the distance from trees. We hypothesized an interaction between N input rate and position to the tree line on grassland herbage production and N uptake and, accordingly, N use efficiency. The field trial was carried out in a silvopastoral system in Germany consisting of the factors year (2019 and 2020), position (2.5, 6.5 and 24.5 m distances to tree line), annual N application rate (0, 15 and 30 g N m−2) and harvest date (four harvests per year). We found significant interactions between position × N rate for all target variables, and usually also in interactions with the harvest date or year. The N application close to trees at a distance < 6.5 m had in most cases no significant influence on herbage production but significantly increased herbage production by up to 35% at positions further away. Omitting the N fertilization in a corridor of 6.5 m near the trees would contribute directly to the saving of fertilizer N without a negative trade-off in herbage production.
  PubDate: 2023-11-08
Multi-experiment assessment of soil nitrous oxide emissions in sugarcane
- Abstract: Abstract Soil nitrous oxide (N2O) fluxes comprise a significant part of the greenhouse gas emissions of agricultural products but are spatially and temporally variable, due to complex interactions between climate, soil and management variables. This study aimed to identify the main factors that affect N2O emissions under sugarcane, using a multi-site database from field experiments. Greenhouse gas fluxes, soil, climate, and management data were obtained from 13 field trials spanning the 2011–2017 period. We conducted exploratory, descriptive and inferential data analyses in experiments with varying fertiliser and stillage (vinasse) type and rate, and crop residue rates. The most relevant period of high N2O fluxes was the first 46 days after fertiliser application. The results indicate a strong positive correlation of cumulative N2O with nitrogen (N) fertiliser rate, soil fungi community (18S rRNA gene), soil ammonium (NH4+) and nitrate (NO3−); and a moderate negative correlation with amoA genes of ammonia-oxidising archaea (AOA) and soil organic matter content. The regression analysis revealed that easily routinely measured climate and management-related variables explained over 50% of the variation in cumulative N2O emissions, and that additional soil chemical and physical parameters improved the regression fit with an R2 = 0.65. Cross-wavelet analysis indicated significant correlations of N2O fluxes with rainfall and air temperature up to 64 days, associated with temporal lags of 2 to 4 days in some experiments, and presenting a good environmental control over fluxes in general. The nitrogen fertiliser mean emission factors ranged from 0.03 to 1.17% of N applied, with urea and ammonium nitrate plus vinasse producing high emissions, while ammonium sulphate, ammonium nitrate without vinasse, calcium nitrate, and mitigation alternatives (nitrification inhibitors and timing of vinasse application) producing low N2O-EFs. Measurements from multiple sites spanning several cropping seasons were useful for exploring the influence of environmental and management-related variables on soil N2O emissions in sugarcane production, providing support for global warming mitigation strategies, nitrogen management policies, and increased agricultural input efficiency.
  PubDate: 2023-10-21
Nitrogen fertilizer replacement values of organic amendments:
determination and prediction
- Abstract: Abstract The nitrogen fertilizer replacement value (NFRV) quantifies the value of organic amendments as a nitrogen (N) fertilizer, and is commonly defined as the extent to which organic fertilizer N can replace mineral fertilizer N. NFRVs can be calculated by comparing the crop N uptake from equal N application rates of mineral and organic fertilizer, or by comparing the N rates of both fertilizers needed to obtain equal crop N uptake. Currently, NFRVs are mainly known for animal manure, whereas other organic waste products may become available as fertilizer products in the future. In this study, a pot experiment with spring wheat was performed to (1) assess NFRVs of a range of organic amendments; (2) compare NFRVs based on equal N application with NFRVs based on equal N uptake; and (3) assess which product characteristics explain observed variation. Observed NFRVs varied between 6.2 and 78.8%, with the lowest value for raw food waste and the highest for fishmeal. NFRVs were overestimated when calculated based on equal N application rate (with on average 6.9% point), and more so at high N application rate (9.0% point). NFRVs should therefore be calculated based on equal N uptake from organic and mineral fertilizers. Nitrogen concentration of the organic fertilizer provided the best explanation of variation observed in NFRVs (R2 = 0.86). These findings give valuable insights into the large variation in value of organic waste streams as organic fertilizer and can support decisions on sustainable N application rates, to increase crop N uptake and reduce N losses to the environment.
  PubDate: 2023-10-13
Soil respiration under different N fertilization and irrigation regimes in
Bengaluru, S-India
- Abstract: Abstract Rapid urbanization in many countries of the Global South has led to intensification of urban and peri-urban agriculture (UPA) whose effects on the soils’ physical, chemical, and microbial properties have been hardly studied. We therefore investigated the effects of different intensity levels, exemplified by three rates of mineral nitrogen (N) addition and irrigation on CO2 emissions in typical crops during the wet (Kharif) and dry (Rabi) season on a Nitisol in Bengaluru, S-India. Respiration data were collected from 2017 to 2021 in two two-factorial split-plot experiments conducted under rainfed and irrigated conditions. Test crops were maize (Zea mays L.), finger millet (Eleusine coracana Gaertn.), and lablab (Lablab purpureus L. Sweet) under rainfed and irrigated conditions, as well as the vegetables cabbage (Brassica oleracea var. capitata), eggplant (Solanum melongena L.), and tomato (Solanum lycopersicum L.) or chili (Capsicum annuum L.). Carbon dioxide (CO2) emissions were determined using a Los Gatos Research (LGR) multi-gas analyzer whereby under our study conditions CH4, NH3 and N2O were negligible. Measurements were conducted from 7:00 am to 11:30 am and repeated from 12:30 pm to 6:00 pm. Irrespective of irrigation, season, crops and N fertilizer level, CO2 emission rates during afternoon hours were significantly higher (2–128%) than during morning hours. In the irrigated field diurnal emission differences between afternoon and morning hours ranged from 0.04 to 1.61 kg CO2-C ha−1 h−1 while in the rainfed field they averaged 0.20–1.78 kg CO2-C ha−1 h−1. Irrespective of crops, in the rainfed field CO2 emissions in high N plots were 56.4% larger than in low N plots whereas in the irrigated field they were only 12.1% larger. The results of a linear mixed model analysis indicated that N fertilization enhanced CO2 emissions whereby these effects were highest in rainfed crops. Soil moisture enhanced emissions in rainfed crops but decreased them under irrigation where crop-specific CO2 emissions within a season were independent of N application. Soil temperature at 5 cm depth enhanced CO2 emissions in both fields. Overall, higher N and soil temperature enhanced CO2 fluxes whereas effects of soil moisture depended on irrigation.
  PubDate: 2023-09-15
Fertilization strategies to reduce yield-scaled N2O emissions based on the
use of biochar and biochar-based fertilizers
- Abstract: Abstract Novel fertilization strategies, such as the use of biochar-based fertilizers (BBFs) and the co-application of biochar with mineral fertilizers, have shown promising results for mitigating nitrous oxide (N2O) emissions and reducing N losses in agroecosystems. Two greenhouse experiments were performed with radish to evaluate: (1) the mitigation of yield-scaled N2O emissions using BBFs, produced at either 400 or 800 °C and enriched with urea, compared to the co-application of raw biochars with urea; and (2) the N2O mitigation potential of low rates of raw biochars, equivalent to those used with BBFs fertilization, co-applied with low and high N rates (90 and 180 kg N ha−1). BBF produced at 800 °C reduced yield-scaled N2O emissions by 32% as compared to the urea treatment, and by 60%, as compared to the combination of raw biochar with urea. This reduction was attributed to the slow rate of N release in BBF. On the contrary, the co-application of low rates of biochar with urea increased yield-scaled N2O emissions as compared to the fertilization with urea alone. Low rates of biochar (1.4–3.1 t ha−1) reduced yield-scaled N2O emissions only with a high rate of N fertilization. High-pyrolysis-temperature biochar, co-applied with synthetic fertilizer, or used to produce BBFs, demonstrated lower yield-scaled N2O emissions than biochar produced at a lower pyrolysis temperature. This study showed that BBFs are a promising fertilization strategy as compared to the co-application of biochar with synthetic fertilizers.
  PubDate: 2023-09-09
  DOI: 10.1007/s10705-023-10313-w
Plant and soil N of different winter cover crops as green manure for
subsequent organic white cabbage
- Abstract: Abstract Leguminous cover crops used as green manures can reduce fertilizer inputs by supplying nitrogen (N) via mineralization of incorporated N-rich biomass derived from biological N2 fixation. In a multi-year trial at three locations in Germany, the effects of leguminous, non-leguminous and mixed green manure crops on the yield of the subsequent cash crop white cabbage (Brassica oleracea convar. capitata var. alba) were investigated. The winter cover crop treatments were forage rye (Secale cereale L.), a mixture of forage rye with winter Hungarian vetch (Vicia pannonica Crantz), sole-cropped winter Hungarian vetch, winter pea (Pisum sativum L.), and winter faba bean (Vicia faba L.) with bare soil as a control. Sole-cropped legumes showed higher marketable cabbage head yields (head weight > 1.0 kg) compared to the other cover crop treatments, with 25.5, 25.9 and 28.1 Mg ha− 1 for vetch, pea and faba bean, respectively. The aboveground biomass of the legume winter cover crop treatments had higher N offtakes with 185, 177 and 159 kg N ha− 1 for vetch, pea and faba bean, respectively, with significantly lower carbon (C)/N ratios compared to rye and rye with vetch. The constant C/N ratio of the aboveground biomass of leguminous cover crops throughout the growing period indicates that the optimum incorporation date to achieve high N mineralization rates is less time dependent in leguminous compared to non-leguminous cover crops. The results of the present study show that leguminous winter cover crops do not reduce the soil N availability for a succeeding high N demanding cabbage crop resulting in yields comparable to agricultural practice without winter cover crops.
  PubDate: 2023-08-13
  DOI: 10.1007/s10705-023-10306-9
Soils potentially vulnerable to phosphorus losses: speciation of inorganic
and organic phosphorus and estimation of leaching losses
- Abstract: Abstract Eutrophication is an important threat to aquatic ecosystems world-wide, and reliable identification of areas vulnerable to phosphorus (P) losses from diffuse sources is essential for high efficiency of mitigation measures. In this three-step study we investigated (i) relationships between the agronomic (Olsen-P and P-AL) and environmental soil P tests (P-CaCl2) with molecular techniques (31P NMR and XANES) followed by (ii) rainfall simulation experiment on topsoil lysimeters and (iii) comparison to long-term field measurements of water quality. Soil samples were collected from seven sites indicated to be vulnerable to nutrient losses due to underlying geology. High P release correlated to standard agronomic P tests (Olsen P, r = 0.67; and P-AL, r = 0.74) and low P sorption capacity (r = − 0.5). High content of iron-bound P compounds indicated more labile P and higher release of dissolved P (r = 0.67). The leaching experiment showed that three out of four soils with high initial soil P status had both higher P leaching concentrations before fertilization (0.83–7.7 mg P l−1) compared to soil with low initial soil P status (0.007–0.23 mg P l−1), and higher increase in P concentrations after fertilization. Higher soil P sorption capacity reduced P leaching losses. Finally, long-term monitoring data show no significant trends in P losses in a field with low initial P content and moderate P fertilization rates whereas high and over time increasing P losses were recorded in a field with high initial soil P content and repetitively high P fertilization rates.
  PubDate: 2023-07-31
  DOI: 10.1007/s10705-023-10298-6
Sustainable growth of organic farming in the EU requires a rethink of
nutrient supply
- Abstract: Abstract The European Commission recently set a target of increasing the area of organic agriculture to 25% by 2030. To achieve this, it is imperative to understand current nutrient use patterns and identify sustainable nutrient supply opportunities. To that end, this study assessed the sustainability of the current nutrient origin and supply of 71 arable organic farms in 8 European regions. Deficient nutrient supply was found on 24%, 66%, and 56% of farms for nitrogen, phosphorus, and potassium, respectively. On average, we show a moderate surplus for nitrogen (28 kg ha−1), while phosphorus and potassium balances were close to zero (− 1 and 2 kg ha−1, respectively). Large variation between countries and farm types shows a divide between more intensive systems relying on external inputs, and less intensive systems facing nutrient deficits and lower outputs. We show, for the first time, the extent of current use of external input types, where conventional manures supplied 17–26% of external nutrients and inputs from non-agricultural origin supplied 31–41%. A large proportion of nutrient sources within the last group are materials derived from urban wastes. The sustainable expansion of the organic sector will require increased use of locally available recycled fertilizers from urban wastes, and acceptance of such sources by organic farmers is shown to be high, provided they are considered safe.
  PubDate: 2023-07-14
  DOI: 10.1007/s10705-023-10297-7
N2O emission factors for cattle urine: effect of patch characteristics and
environmental drivers
- Abstract: Abstract Urine patches from grazing cattle are hotspots of nitrous oxide (N2O) emissions. The default IPCC emission factor for urine patches (EFurine) is 0.77% for wet climates and 0.32% for dry climates. However, literature reports a considerable range of cattle urine EF values and urine characteristics used in experimental studies, revealing contrary results on the effects of urine patch characteristics and seasonal pattern. Therefore, we examined N2O emissions and corresponding EFurine values in relation to urine patch characteristics (urine N concentration, urine volume, patch area, urine composition) and environmental drivers (precipitation, water filled pore space, soil temperature). Ten artificial urine application experiments were performed from July 2020 to June 2022 on a pasture located in Eastern Switzerland. Urine N concentration, patch area, volume and urine N composition showed no significant effects on the EFurine value (p > 0.05). EFurine varied, however, strongly over time (0.17–2.05%). A large part of the variation could be predicted either by cumulative precipitation 20 days after urine application using a second order polynomial model (Adj. R2 = 0.60) or average WFPS 30 days after urine application using a linear model (Adj. R2 = 0.45). The derived precipitation model was used to simulate EFurine weekly over the last 20 years showing no significant differences between the seasons of a year. The resulting overall average EFurine was 0.67%. More field studies are needed across sites/regions differing in climate and soil properties to implement a country-specific EF3 for Switzerland and to improve the quantification of N2O emissions at the national scales.
  PubDate: 2023-07-10
  DOI: 10.1007/s10705-023-10290-0
Identifying the circularization opportunities for organic wastes generated
in a Mediterranean region
- Abstract: Abstract Understanding the extent and characteristics of biomass resources is important for managing it effectively within the bioeconomy and leveraging biomass towards the highest value uses or those which are most appropriate. To this end, a large regional study was conducted to characterize the main physicochemical characteristics of common biomasses and identify potential limitations to use or opportunities for. Valencia is fourth most populous autonomous region of Spain, having a large importance for the European vegetable and citrus product markets, among others. Across 164 municipalities, 625 samples were characterized for contents of organic matter, total nitrogen, total phosphorus, pH, electrical conductivity, and polyphenol contents, and 224 samples were characterized for metal and metalloid contents. The different biomass types included in the study were expert-classified into a total of 54 biomass subcategories. Overall, nutrient contents were the parameter most associated with waste type, while electrical conductivity had the highest variability within groups. Considering all the samples, nutrient contents were sufficient to reach established minimums for marking as an EU-labelled fertilizing product in 479/625 cases, and pertinent limits on heavy metal contents were exceeded in 20/224 cases. The highest polyphenol contents were found in the pomegranate and citric wastes, which were substantially higher than in the organic wastes from olive oil and wine production. Machine learning techniques (k-means and hierarchical clustering analysis) applied to the datasets showed that biomasses were best classified into two groups based on pH, electrical conductivity, organic matter, and N, P, and Na contents, and three groups based on metal and metalloid contents. The summary data are presented in appendices for regional and European nutrient budgeting and modelling use. Based on the analyzed properties, the most appropriate uses can be identified, whether for transformation in biological processes, energy generation, recovery of critical elements, or extraction of high value compounds.
  PubDate: 2023-07-07
  DOI: 10.1007/s10705-023-10292-y
Canola productivity and carbon footprint under different cropping systems
in eastern Canada
- Abstract: Abstract Diversified crop rotation with an appropriate sequence may be a promising strategy for increasing crop productivity while reducing greenhouse gas emissions (GHGs) and lowering carbon (C) footprint for more sustainable agricultural systems. The objectives of this study were to (i) assess the agronomic performance and C footprint of canola (Brassica napus L.) production in different cropping systems, and (ii) better understand how canola could be adapted to existing cropping systems in eastern Canada. A four-year canola-based phase rotation study, including maize (Zea mays L.), wheat (Triticum aestivum L.), and soybean (Glycine max L.), started in 2011 and continued for two cycles in Ottawa, ON; Montreal, QC; and Canning, NS. It was found that, compared to continuous monoculture (canola, maize or wheat), diversified cropping systems increased crop yields by an average of 32% and reduced the C footprint of all rotations by 33%, except under severe heat and drought conditions. The effect of rotation on yield and C footprint of canola production varied significantly among site-years. At Ottawa, the canola following soybean (SC) had 12% higher canola yield than monoculture canola (CC), 5 and 8% higher canola yield than canola following wheat (WC) or maize (MC). At Montreal, canola yield ranked as MC > SC > WC > CC. At Canning, the highest canola yield was in WC (21%) and SC (13%). Overall, most SC rotations had the lowest C footprint, and CC cropping had the highest C footprint, with only a few exceptions. Regardless of the cropping system, canola required more N input and was high in oil and protein in the harvested product, and produced the highest C footprint, while soybean had the lowest C footprint at all three sites. Our findings indicate that a diversified cropping system with canola production following soybean significantly improved canola yield while lowering the C footprint. However, profitable and sustainable canola production in eastern Canada is threatened by climate change-induced drought and heat stress.
  PubDate: 2023-06-28
  DOI: 10.1007/s10705-023-10294-w
Potassium and magnesium uptake and fertiliser use efficiency by oil palm
at contrasting sites in Sumatra, Indonesia
- Abstract: Abstract The accuracy of fertiliser recommendations can be improved by knowledge of use efficiency of applied nutrients. The aim of this work was to determine the efficiency with which mature oil palm (Elaeis guineensis Jacq.) recovers and uses fertiliser K and Mg under different environmental conditions in Sumatra, Indonesia. The work was carried out in seven factorial fertiliser trials (NPKMg) at sites with contrasting soils, slope and rainfall (1500–3500 mm annual average). We recorded the palms’ fresh fruit bunch yield (weekly), vegetative growth and nutrient content (annually), and soil properties (once during the study) over three years. Nutrient content of the above-ground palm components was calculated by multiplying concentration by biomass. Palm responses to K and Mg application were analysed at non-limiting values of the other nutrients. Fresh fruit bunch yield was significantly increased by application of K in five of the seven sites (by 4.8–11.9 t ha−1) and by Mg in two of the seven sites (by 7.2–12.3 t ha−1). Application of these fertilisers also significantly increased growth and nutrient content in most situations. Nutrient use efficiency declined with increasing yield and nutrient uptake. In the five sites with most positive yield responses to K, agronomic efficiency of K and Mg differed between sites due to differences in recovery efficiency. Recovery efficiency was correlated positively to soil K, Mg and silt content and rainfall, and negatively to slope and soil moisture deficit. In contrast, physiological efficiency of K and Mg use was similar across sites, despite differences in palm age and planting density. It thus appeared that physiological efficiency was determined by genotype and that variation in agronomic efficiency was mostly a result of differences in recovery efficiency.
  PubDate: 2023-06-21
  DOI: 10.1007/s10705-023-10289-7
Cereal yields in Ethiopia relate to soil properties and N and P
fertilizers
- Abstract: Abstract There is an urgent need to increase cereal yields in the Ethiopian Highlands to ensure national food security. A major crop response-to-fertilizer program was set up in 2017–2019 as part of the CASCAPE project in the Ethiopian Highlands. It covered 33 experiments on maize, teff and wheat in five reference soil groups (Nitisols, Luvisols, Vertisols, Leptosols and Andosols). Five levels of multi-nutrient fertilizer (50–300 kg NPSZnB ha− 1 and 100 kg urea ha− 1) were applied. At the lower fertilizer level, average yields were 5500, 1500 and 3300 kg ha− 1 for maize, teff and wheat, respectively. At the highest rate, yields were 7900, 2100 and 5000 kg ha− 1. Maize and wheat yields were strongly correlated to the reference soil groups, but not to rainfall differences. Wheat yields were also positively correlated to soil organic carbon levels, underpinning the need to apply integrated soil fertility management. Comparing NPSZnB fertilizers with NPS and DAP fertilizers revealed a lack of statistically significant advantage for the fertilizers including Zn and B. As B was present in fine-granular form in the fertilizer bags, being prone to segregation, firm conclusions on the need for this micronutrient cannot be drawn. The use of ‘recommendation windows’ is suggested to group results into concrete packages at district levels and below, preferably combined with soil maps since soil types were correlated with maize and wheat yields. The windows could then be the starting point to develop ‘last mile’ fertilizer use policies, relevant to farmers and the way they manage their fields in the landscape.
  PubDate: 2023-06-21
  DOI: 10.1007/s10705-023-10291-z
Challenges and opportunities for nutrient circularity: an innovation
platform approach
- Abstract: Abstract To reduce nutrient losses from the food system, it is necessary to improve biomass management and foster change. Such a change is often hindered by a lack of stakeholder interaction. Therefore, a qualitative case study and a practical application of the innovation platform approach in the Dutch-German border region Rhine-Waal were carried out to determine challenges and opportunities in the agro-food-waste system towards circular nutrient management in a nutrient-saturated and intensive animal production-dominated localized area. Twenty-one actors participated in a half-day workshop. A bottom-up approach was chosen as it increases trust between stakeholders and supports the acceptance of research processes. This study identified opportunities and challenges perceived by stakeholders participating in the innovation platform approach to facilitate a transition towards local circular nutrient management. We observed that challenges and opportunities exist at three levels: the individual actor’s level, the system level and the interconnection of the system with its wider environment. With a variety of stakeholders from animal and crop production to the food processing industry being present in the study area, the current demand and supply of biomass is very diverse. This diversity has been identified as a distinct opportunity for the establishment of a biomass exchange network in the area. However, information on demand and supply of nutrients between actors is currently scattered and information sharing hindered by the lack of direct monetary benefits. The lessons learned using the innovation platform approach are a first step towards improving nutrient circularity at a localized scale in nutrient-saturated areas.
  PubDate: 2023-06-05
  DOI: 10.1007/s10705-023-10285-x
Lysimeter deep N fertilizer placement reduced leaching and improved N use
efficiency
- Abstract: Abstract Deep fertilization has been tested widely for nitrogen (N) use efficiency but there is little evidence of its impact on N leaching and the interplay between climate factors and crop N use. In this study, we tested the effect of three fertilizer N placements on leaching, crop growth, and greenhouse gas (GHG) emissions in a lysimeter experiment over three consecutive years with spring-sown cereals (S1, S2, and S3). Leaching was additionally monitored in an 11-month fallow period (F1) preceding S1 and a 15-month fallow period (F2) following S3. In addition to a control with no N fertilizer (Control), 100 kg N ha−1 year−1 of ammonium nitrate was placed at 0.2 m (Deep), 0.07 m (Shallow), or halved between 0.07 m and 0.2 m (Mixed). Deep reduced leachate amount in each cropping period, with significant reductions (p < 0.05) in the drought year (S2) and cumulatively for S1-S3. Overall, Deep reduced leaching by 22, 25 and 34% compared to Shallow, Mixed and Control, respectively. Deep and Mixed reduced N leaching across S1-S3 compared with Shallow, but Deep further reduced N loads by 15% compared to Mixed and was significantly lowest (p < 0.05) among the fertilized treatments in S1 and S2. In S3, Deep increased grain yields by 28 and 22% compared to Shallow and Mixed, respectively, while nearly doubling the agronomic efficiency of N (AEN) and the recovery efficiency of N (REN). Deep N placement is a promising mitigation practice that should be further investigated.
  PubDate: 2023-05-14
  DOI: 10.1007/s10705-023-10286-w
Indigenous nutrient supply, weeding and fertilisation strategies influence
on-farm N, P and K use efficiency in lowland rice
- Abstract: Abstract Enhancing use efficiency of applied fertiliser increases farmers’ returns on fertiliser investment through reducing nutrient inputs and improving yields. We investigated on-farm how indigenous nutrient supply and management practices affected N, P, and K uptake, agronomic efficiency and recovery efficiency of fertiliser, and physiological efficiency of nutrients taken up, under irrigated lowland rice conditions in Uganda. Treatments included recommended agronomic practices (RAP) without fertilisation, farmers’ practice (FP), farmers’ selected intensification practice (FIP), and RAP with NPK fertilisation (RAP + NPK). Indigenous N, P, and K supply varied greatly among farmers’ fields. N, P, and K uptake were significantly higher under RAP + NPK than under RAP, FP, and FIP; however, physiological efficiency (PE; kg grain kg−1 nutrient uptake) was significantly lower under RAP + NPK by 19% (N), and 12% (P/K), due to a larger effect of NPK application on uptake than on yield, leading to higher tissue concentrations. Indigenous available N reduced apparent N recovery, and agronomic and physiological N efficiencies independent of treatment. Also, P and K PEs decreased with increasing indigenous supply. Delaying weeding beyond recommended time, in interaction with indigenous N supply, decreased agronomic N efficiency, but increased PE of N. Interaction between P rate and timing reduced its PE; K rate and weeding time interaction reduced its PE. The decrease in efficiencies at high indigenous supply and delayed weeding indicates a need for site-specific fertilisation strategies based on naturally available nutrient levels and proper weeding. Weeding and fertilisation timing directly affect nutrient use efficiency, and therefore, fertiliser use efficiency in rice production systems.
  PubDate: 2023-04-28
  DOI: 10.1007/s10705-023-10275-z
Fate and cost effectiveness of soil carbon sequestered using supplementary
nutrients applied to crop residues under field conditions
- Abstract: Abstract Changes in carbon (C) and nitrogen (N) associated with fine fraction (FF) soil organic matter (SOM) were determined to a depth of 1.80 m at a field site that was managed with supplementary nutrients (2007–2012) to sequester soil C from crop residues. Soil C and N stocks were monitored for a further 3 years (to 2015) with supplementary nutrients maintained, and then for 5 years after they were ceased (2015–2020). The increase in FF-C established in the first phase of nutrient addition (9.6 Mg C ha−1) was maintained during the ongoing 3 year period of nutrient addition (9.8 Mg C ha−1) but declined to 3.0 Mg C ha−1 during the subsequent 5 years when nutrient addition ceased. The decline in FF-C stocks was attributed to both less formation of FF-C without the supplementary nutrients applied, and to nutrient mining as insufficient N was being applied to both treatments to fully satisfy the N removed in crops. The addition of supplementary nutrients to the residue influenced crop yield in some years, and seed protein in most years, but the responses were crop and season dependant and there was no overall difference in the amount of C in crop biomass returned to the soil. An economic analysis using long-term fertiliser and grain prices suggested that the strategy to sequester more C in FF-SOM through nutrient addition to residue was essentially cost neutral. Better tailoring of nutrient inputs to achieve the required stoichiometric ratios in SOM, and an assumed payment for the sequestered C (AU$40 Mg−1 CO2 equivalent) provided a reliable economic benefit during the period of nutrient addition. However the economic benefit was lost when nutrient addition ceased, and would reduce if fertiliser prices increased or the C price declined. Our results confirm that addition of supplementary nutrients to C-rich crop residues is an effective means to sequester soil C that can persist for several years even after nutrient addition ceases. However, ongoing nutrient inputs in excess of crop removal are required to ensure long-term sequestration of the C from crop residue.
  PubDate: 2023-04-21
  DOI: 10.1007/s10705-023-10272-2
Greenlandic glacial rock flour improves crop yield in organic agricultural
production
- Abstract: Abstract The application of mechanically crushed silicate minerals to agricultural soils has been proposed as a method for both improving crop yields and sequestering inorganic carbon through enhanced mineral weathering. In Greenland, large quantities of finely grained glacial rock flour (GRF) are naturally produced by glacial erosion of bedrock and deposited in easily accessible lacustrine and marine deposits, without the need for energy-intensive grinding. To determine if this material can improve crop yields, we applied 10 and 50 t GRF ha−1 to a sandy, organic agricultural field in Denmark. Two field trials were carried out to test the first-year yield response to GRF in both maize and potatoes, residual effects on potato yields in the year after application, and second and third-year residual effects on spring wheat. Reference-K treatments were included for comparison to determine if the beneficial effects of GRF were primarily due to its K content (3.5% K2O). This alternative source of silicate minerals improved crop yields in the year of application. Though there was no improvement in yield with the reference-K treatments, for each additional ton of GRF applied, maize dry yield increased by 59 kg ha−1 and potato tuber yield by an additional 90 kg ha−1. No residual effects on crop yields were observed in the following years, but we suspect that benefits might persist over multiple seasons at sites with lower initial fertility. The increase in yields achieved with GRF could offset some of the costs of applying silicate minerals as a CO2 sequestration scheme.
  PubDate: 2023-03-21
  DOI: 10.1007/s10705-023-10274-0