Direct Nitrous Oxide Emissions From Tropical And Sub-Tropical Agricultural Systems : A Review and Modelling of Emission Factors

We acknowledge the financial support from the CGIAR Research Programs on Climate Change, Agriculture and Food Security (CCAFS). Grant ref. n. P25.Peer reviewedPublisher PD

Results from the Fertilizer demonstration experiment with maize at IOP Farm in Iringa, Tanzania in 2019

In 2019, an experiment was run at the IOP farm in Tanzania. Five nutrient management treatments were combined in a full factorial setup with two tillage options. The lowest maize yield was obtained under conventional tillage without fertilizer application, and the highest maize yield with reduced tillage and the highest NPK fertilizer level combined with micronutrients. This highest NKP fertilizer level targeted 70% of water-limited yield. Furthermore, it was shown that P and K were used more efficient under reduced tillage compared to conventional tillage, while there was no difference in N use efficiency between the two tillage options. In addition, a number of field visits was organized. From the six villages surrounding the farm a total of 120 farmers made at least 4 visits to the experiment once in every month between February and June. That brings the number of farmers that learned from the 2018 trial to 480+

Re-assessing Nitrous Oxide Emissions from Croplands Across Mainland China

Reliable quantification of nitrous oxide emission is a key to assessing efficiency of use and environmental impacts of N fertilizers in crop production. In this study, N2O emission and yield were quantified with a database of 853 field measurements in 104 reported studies and a regression model was fitted to the associated environmental attributes and management practices from China’s croplands. The fitted emission model explained 48% of the variance in N2O emissions as a function of fertilizer rate, crop type, temperature, soil clay content, and the interaction between N rate and fertilizer type. With all other variables fixed, N2O emissions were lower with rice than with legumes and then other upland crops, lower with organic fertilizers than with mineral fertilizers. We used the subset of the dataset for rice - covering a full range of different typical water regimes, and estimated emissions from China’s rice cultivation to be 31.1 Gg N2O-N per year. The fitted yield model explained 35% of the variance in crop yield as a function of fertilizer rate, temperature, crop type, and soil clay content. Finally, the empirical models for N2O emission and crop yield were coupled to explore the optimum N rates (N rate with minimum N2O emission per unit yield) for combinations of crop and fertilizer types. Consequently, the optimum N application rate ranged between 100 kg N ha−1 and 190 kg N ha−1 respectively with organic and mineral fertilizers, and different crop types. This study therefore improved on existing empirical methods to estimate N2O emissions from China’s croplands and suggests how N rate may be optimized for different crops, fertilizers and site conditions

D1940: Results from the Fertilizer demonstration experiment with maize at IOP Farm in Iringa, Tanzania in 2018

In 2018, an experiment was run at the IOP farm in Tanzania. Four nutrient management treatments were combined factorial with two tillage options. The results show that the lowest maize yield was obtained under conventional tillage without fertilizer application, and the highest with reduced tillage and NPK fertilizer to target 70% of water-limited yield and the addition of micronutrients. A number of field visits was organized, and from the six villages surrounding the farm, hence a total of 120 farmers made at least 4 visits to the farm, one every month between February and June. That brings the number of farmers that learned from the 2018 trial to 480+. In addition, the Tanzania Uhuru Torch made a stop at the Trial, to recognize the importance of the training tool for the farmers. During this festive day a large array of different stakeholders visited the farm, such as village leaders, region and district level leaders and young and older farmers

Results from the fertilizer demonstration experiment with maize at Farm for the Future Tanzania in Iringa, in 2020

In 2020, an experiment was run for the third consecutive season at the Farm for the Future Tanzania Ltd. (FFF), which is part of Ilula Orphan Program’s (IOP) Farm, Ilula, Iringa Region, in Tanzania. The FFF farm is training farmers in 16 villages with a focus on dissemination activities at regional and national levels. The purpose of the experiment is to test and demonstrate crop fertilization strategies that combine high maize yields with high nutrient use efficiency (NUE) and low greenhouse gas (GHG) emissions. Five nutrient management treatments were combined in a full factorial setup with two tillage options. Highest yields were obtained with reduced tillage combined with NPK fertilizer to target 70% of waterlimited yield (Yw) and micro-nutrients (Mg, S, Zn combined), and with half NPK fertilizer and half composted manure. The lowest maize yields were obtained from both the treatment without fertilizer application and the fertilizer treatment with only P and K applied at reduced and conventional tillage. Results showed no significant differences in both agronomic N use efficiency (N-AE, additional grain yield per kg N applied when correcting for the P and K applied) and fertilizer use efficiency (additional grain yield per kg N applied when including yield effects from P and K) between reduced and conventional tillage. N-AE obtained in the experiment of 34.0 kg yield/kg N was much higher compared to the current average N-AE in sub-Saharan Africa of 14.3 kg yield/kg N. When targeting 70% of Yw for maize, this improved N-AE value could result in 58% reduction in GHG emission per hectare (ha) from fertilizer application (direct and indirect emissions). Despite the cancellation of the farmers field days, due to the Covid19 pandemic, ten young farmers still took part in the experimental setup and trial planting

Results from the fertilizer demonstration experiment with maize at Farm for the Future Tanzania in Iringa, in 2021: Final narrative report

In 2021, an experiment was run for the fourth consecutive season at the Farm for the Future Tanzania Ltd (FFF) which is part of Ilula Orphan Program (IOP)’s Farm, Ilula, Iringa Region, in Tanzania. The FFF farm, is training farmers in 16 villages, with a focus on dissemination activities at regional, as well as national level. The purpose of the experiment is to experimentally test and demonstrate low-emission crop fertilisation strategies that combine high maize yields with high nutrient use efficiency and low emissions. Four nutrient management treatments were combined in a full factorial setup with two tillage options. Lowest yields were obtained with no fertilizer addition (control treatment) under conventional tillage and reduced tillage (1-2 t/ha), while the treatments with fertilizer addition consistently showed very high yields (close to 10 t/ha). Root number and root length were larger for reduced tillage compared to conventional tillage at the control treatment, but this difference was not significant. Root penetration resistance was significantly higher at conventional tillage compared to reduced tillage for the control treatment. Around 100 pupils from primary as well as secondary school made two field visits to the trial. Also, a farmers field day was organized, and from the sixteen villages surrounding the farm, a total of about 400 farmers attended the planting session and the field day

Coupling GIS and LCA for biodiversity assessments of land use

Geospatial details about land use are necessary to assess its potential impacts on biodiversity. Geographic information systems (GIS) are adept at modeling land use in a spatially explicit manner, while life cycle assessment (LCA) does not conventionally utilize geospatial information. This study presents a proof-of-concept approach for coupling GIS and LCA for biodiversity assessments of land use and applies it to a case study of ethanol production from agricultural crops in California. GIS modeling was used to generate crop production scenarios for corn and sugar beets that met a range of ethanol production targets. The selected study area was a four-county region in the southern San Joaquin Valley of California, USA. The resulting land use maps were translated into maps of habitat types. From these maps, vectors were created that contained the total areas for each habitat type in the study region. These habitat compositions are treated as elementary input flows and used to calculate different biodiversity impact indicators in a second paper (Geyer et al., submitted). Ten ethanol production scenarios were developed with GIS modeling. Current land use is added as baseline scenario. The parcels selected for corn and sugar beet production were generally in different locations. Moreover, corn and sugar beets are classified as different habitat types. Consequently, the scenarios differed in both the habitat types converted and in the habitat types expanded. Importantly, land use increased nonlinearly with increasing ethanol production targets. The GIS modeling for this study used spatial data that are commonly available in most developed countries and only required functions that are provided in virtually any commercial or open-source GIS software package. This study has demonstrated that GIS-based inventory modeling of land use allows important refinements in LCA theory and practice. Using GIS, land use can be modeled as a geospatial and nonlinear function of output. For each spatially explicit process, land use can be expressed within the conventional structure of LCA methodology as a set of elementary input flows of habitat types

De Novo Mutations in FOXJ1 Result in a Motile Ciliopathy with Hydrocephalus and Randomization of Left/Right Body Asymmetry

Hydrocephalus is one of the most prevalent form of developmental central nervous system (CNS) malformations. Cerebrospinal fluid (CSF) flow depends on both heartbeat and body movement. Furthermore, it has been shown that CSF flow within and across brain ventricles depends on cilia motility of the ependymal cells lining the brain ventricles, which play a crucial role to maintain patency of the narrow sites of CSF passage during brain formation in mice. Using whole-exome and whole-genome sequencing, we identified an autosomal-dominant cause of a distinct motile ciliopathy related to defective ciliogenesis of the ependymal cilia in six individuals. Heterozygous de novo mutations in FOXJ1, which encodes a well-known member of the forkhead transcription factors important for ciliogenesis of motile cilia, cause a motile ciliopathy that is characterized by hydrocephalus internus, chronic destructive airway disease, and randomization of left/right body asymmetry. Mutant respiratory epithelial cells are unable to generate a fluid flow and exhibit a reduced number of cilia per cell, as documented by high-speed video microscopy (HVMA), transmission electron microscopy (TEM), and immunofluorescence analysis (IF). TEM and IF demonstrate mislocalized basal bodies. In line with this finding, the focal adhesion protein PTK2 displays aberrant localization in the cytoplasm of the mutant respiratory epithelial cells