Organic Wastes Amended with Sorbents Reduce N2O Emissions from Sugarcane Cropping

Nutrient-rich organic wastes and soil ameliorants can benefit crop performance and soil health but can also prevent crop nutrient sufficiency or increase greenhouse gas emissions. We hypothesised that nitrogen (N)-rich agricultural waste (poultry litter) amended with sorbents (bentonite clay or biochar) or compost (high C/N ratio) attenuates the concentration of inorganic nitrogen (N) in soil and reduces emissions of nitrous oxide (N2O). We tested this hypothesis with a field experiment conducted on a commercial sugarcane farm, using in vitro incubations. Treatments received 160 kg N ha−1, either from mineral fertiliser or poultry litter, with additional N (2–60 kg N ha−1) supplied by the sorbents and compost. Crop yield was similar in all N treatments, indicating N sufficiency, with the poultry litter + biochar treatment statistically matching the yield of the no-N control. Confirming our hypothesis, mineral N fertiliser resulted in the highest concentrations of soil inorganic N, followed by poultry litter and the amended poultry formulations. Reflecting the soil inorganic N concentrations, the average N2O emission factors ranked as per the following: mineral fertiliser 8.02% > poultry litter 6.77% > poultry litter + compost 6.75% > poultry litter + bentonite 5.5% > poultry litter + biochar 3.4%. All emission factors exceeded the IPCC Tier 1 default for managed soils (1%) and the Australian Government default for sugarcane soil (1.25%). Our findings reinforce concerns that current default emissions factors underestimate N2O emissions. The laboratory incubations broadly matched the field N2O emissions, indicating that in vitro testing is a cost-effective first step to guide the blending of organic wastes in a way that ensures N sufficiency for crops but minimises N losses. We conclude that suitable sorbent-waste formulations that attenuate N release will advance N efficiency and the circular nutrient economy

Organic Wastes Amended with Sorbents Reduce N2O Emissions from Sugarcane Cropping

Nutrient-rich organic wastes and soil ameliorants can benefit crop performance and soil health but can also prevent crop nutrient sufficiency or increase greenhouse gas emissions. We hypothesised that nitrogen (N)-rich agricultural waste (poultry litter) amended with sorbents (bentonite clay or biochar) or compost (high C/N ratio) attenuates the concentration of inorganic nitrogen (N) in soil and reduces emissions of nitrous oxide (N2O). We tested this hypothesis with a field experiment conducted on a commercial sugarcane farm, using in vitro incubations. Treatments received 160 kg N ha−1, either from mineral fertiliser or poultry litter, with additional N (2–60 kg N ha−1) supplied by the sorbents and compost. Crop yield was similar in all N treatments, indicating N sufficiency, with the poultry litter + biochar treatment statistically matching the yield of the no-N control. Confirming our hypothesis, mineral N fertiliser resulted in the highest concentrations of soil inorganic N, followed by poultry litter and the amended poultry formulations. Reflecting the soil inorganic N concentrations, the average N2O emission factors ranked as per the following: mineral fertiliser 8.02% > poultry litter 6.77% > poultry litter + compost 6.75% > poultry litter + bentonite 5.5% > poultry litter + biochar 3.4%. All emission factors exceeded the IPCC Tier 1 default for managed soils (1%) and the Australian Government default for sugarcane soil (1.25%). Our findings reinforce concerns that current default emissions factors underestimate N2O emissions. The laboratory incubations broadly matched the field N2O emissions, indicating that in vitro testing is a cost-effective first step to guide the blending of organic wastes in a way that ensures N sufficiency for crops but minimises N losses. We conclude that suitable sorbent-waste formulations that attenuate N release will advance N efficiency and the circular nutrient economy

Root zone temperature alters storage root formation and growth of sweetpotato

Large mounds amended with plant residues are a common cultivation method for sweetpotato (Ipomoea batatas) in the western parts of the Papua New Guinea highlands, with a suggested benefit of elevated root zone temperature (RZT) from decomposition. This study aimed to evaluate whether RZT affects the formation and growth of sweetpotato storage roots. Experiments evaluated the effects of a constant elevated RZT on the Beauregard cultivar and of a short-term increase in RZT on the Beauregard and Northern Star cultivars. Plants were grown in 18-L pots divided into a control compartment (constant RZT at 20 degrees C) and a treated compartment (RZT at 30, 40 or 50 degrees C). Constant elevated RZT was maintained until harvest, while short-term increase in RZT occurred in weeks 2 and 3 only. Constant elevated RZT did not affect the total number of storage roots, but RZT of 30 degrees C and above reduced the dry-biomass of storage roots. The short-term increase in RZT did not alter the total number or dry-biomass of storage roots in Beauregard, while both of these attributes were reduced at RZT of 40 degrees C or above in Northern Star. Elevated RZT inhibited dry-biomass accumulation of storage root, with a more pronounced impact at constant elevated RZT. These results demonstrate that any benefits of the mound culture on sweetpotato yield production do not arise through the influence of temperature elevation

Estimation of the surface coseismic deformation zone width along active faults based on global data

Η εκδήλωση επιφανειακών διαρρήξεων και μετατοπίσεων κατά μήκος των ρηγμάτων, κατά τη διάρκεια ισχυρού σεισμού, έχει σαν αποτέλεσμα την ενίσχυση των καταστροφών λόγω επιβάρυνσης που προκαλούν επιπλέον των σεισμικών δονήσεων και οι εδαφικές παραμορφώσεις. Το μέγεθος των σεισμικών μετατοπίσεων μπορεί να εκτιμηθεί με βάση υπάρχουσες εμπειρικές σχέσεις που συνδέουν το μέγεθος του σεισμού με το μήκος του ρήγματος και την σεισμική μετατόπιση. Ένα θέμα μεγάλου ενδιαφέροντος για την αντισεισμική προστασία και τον αστικό σχεδιασμό, αφορά το πλάτος της ζώνης μέσα στο οποίο θα εκδηλωθούν οι επιφανειακές διαρρήξεις κατά μήκος του ρήγματος που ανέδρασε. Στον Ελληνικό Αντισεισμικό Κανονισμό αναφέρεται η απαγόρευση δόμησης πάνω σε ενεργά ρήγματα, χωρίς όμως να καθορίζεται το πλάτος της ζώνης απαγόρευσης. Σε κανονισμούς άλλων χωρών διευκρινίζεται ότι αυτό, σε περίπτωση απλών κατασκευών θα είναι 25m εκατέρωθεν του ενεργού ρήγματος. Σκοπός της παρούσας διπλωματικής εργασίας είναι να διερευνήσει την επίδραση του μήκους και του είδους ενός ρήγματος στο πλάτος της ζώνης μέσα στο οποίο εκδηλώνονται οι εδαφικές σεισμικές διαρρήξεις. Για την εκτίμηση του μελετήθηκαν ορισμένοι μεγάλοι σεισμοί σε διάφορες χώρες της γης, με βάση τους οποίους εξάγονται τα πρώτα συμπεράσματα. Η παρούσα διπλωματική εργασία αποτελεί μια αρχική προσπάθεια καταγραφής και συστηματικοποίησης τέτοιου είδους πληροφοριών στην Ελλάδα, και θεωρούμε ότι θα πρέπει να επεκταθεί με την συστηματική καταγραφή όσο το δυνατόν περισσότερων σεισμών για τους οποίους υπάρχουν διαθέσιμα τα κατάλληλα στοιχεία αξιολόγησης. Στο πλαίσιο της διπλωματικής εργασίας έγινε συλλογή, επεξεργασία και αξιολόγηση των πληροφοριών που αφορούσαν την εκδήλωση επιφανειακών διαρρήξεων, τεκτονικής προέλευσης, κατά τη διάρκεια ισχυρών σεισμών. Σημειώνεται ότι επειδή λεπτομερή δεδομένα μεγεθών στο θέμα αυτό είναι περιορισμένα, ελήφθησαν υπόψη και χάρτες, σχέδια ή φωτογραφίες υπαίθρου για την αξιολόγηση του πλάτους της ζώνης συνσεισμικής παραμόρφωσης.The occurrence of surface rupturing and displacement along the faults, during strong earthquakes, result on the elevated destruction due to additional ground deformation. The magnitude of the coseismic displacement can be estimated on the basis of existed empirical relationships between the earthquake magnitude, the length of the fault and the seismic displacement. An interest topic for the antiseismic protection and urban design is the estimation of the width of the surface coseismic deformation zone along an active fault. According to the Greek Antiseismic Code, construction on the active faults is prohibited, although the width of the zone is not considered. In seismic regulations of other countries, this zone has a width of 25m in each side of the concerned active fault. The purpose of this thesis was to investigate the influence of the fault type and length on the width of the zone, inside of which the seismic surface ruptures are formed. For this estimation, a number of strong earthquakes in global scale were studied and the preliminary results were provided. This work is a first attempt, in Greece, to record and evaluate such a kind of information, considering that a systematic research must be conrinued in this domain This work was based on the collection, processing and evaluation of the information concerning the surface rupruring, of tectonic origin, during strong earthquakes. It is noticed that due to the limited detailed data, relevant maps, designs and field photographs were taken in consideration, for the estimation of the deformation zone width.Χρήστος Α. ΠαπαγεωργίουΓιασουμής Α. Μιχαή

Selection for root morphological traits improves the growth of grafted bell pepper

Plant breeding programs seldom explicitly consider root traits in selecting high-performance lines. With increased emphasis on resource use efficiency in horticulture, there is a need to identify root traits that are linked to nutrient capture. Grafting could provide a basis for identifying beneficial root traits to be included in breeding programs. Research was conducted to investigate the relationship between root traits and biomass of bell pepper (Capsicum annuum) using a standard commercial cultivar ('Warlock') as a scion over 11 rootstocks of wild pepper (Capsicum chinense), while self-grafted 'Warlock' was used as a control. After 5 weeks of growth in rhizoboxes, the plants were harvested to determine the biomass and root traits (total length, surface area, volume and average diameter). Effect of rootstocks resulted in above-ground biomass differences of -12 to +65% relative to the control, indicating that some rootstocks of the wild accessions were able to exploit more soil resources for a greater above-ground growth. Analysis of root images indicated that eight accessions produced significantly larger root surface area and volume, with a larger biomass allocation to shoots compared with the control. Shoot biomass was significantly correlated with root length (r2=0.484), root surface area (r2=0.424) and root volume (r2=0.355). These correlations showed that some rootstocks are capable of producing larger above-ground biomass with a relatively smaller photosynthate investment in root growth. These results indicate that the selection of wild accessions as rootstock has the potential to improve the root system of bell pepper for a greater above-ground biomass

Free light fraction carbon and nitrogen, a physically uncomplexed soil organic matter distribution within subtropical grass and leucaena-grass pastures

Quantifying the size and turnover of physically uncomplexed soil organic matter (SOM) is crucial for the understanding of nutrient cycling and storage of soil organic carbon (SOC). However, the C and nitrogen (N) dynamics of SOM fractions in leucaena (Leucaena leucocephala)-grass pastures remains unclear. We assessed the potential of leucaena to sequester labile, free light fraction (fLF) C and N in soil by estimating the origin, quantity and vertical distribution of physically unprotected SOM. The soil from a chronosequence of seasonally grazed leucaena stands (0-40 years) was sampled to a depth of 0.2m and soil and fLF were analysed for organic C, N and delta C-13 and delta N-15. On average, the fLF formed 20% of SOC and 14% of total N stocks in the upper 0.1m of soil from leucaena rows and showed a peak of fLF-C and fLF-N stocks in the 22-year-stand. The fLF delta C-13 and fLF delta N-15 values indicated that leucaena produced 37% of fLF-C and 28% of fLF-N in the upper 0.1m of soil from leucaena rows. Irrespective of pasture type or soil depth, the majority of fLF-C originated from the accompanying C-4 pasture-grass species. This study suggests that fLF-C and fLF-N, the labile SOM, can form a significant portion of total SOM, especially in leucaena-grass pastures

Zika discourse in the Americas: A multilingual topic analysis of Twitter.

This work examines Twitter discussion surrounding the 2015 outbreak of Zika, a virus that is most often mild but has been associated with serious birth defects and neurological syndromes. We introduce and analyze a collection of 3.9 million tweets mentioning Zika geolocated to North and South America, where the virus is most prevalent. Using a multilingual topic model, we automatically identify and extract the key topics of discussion across the dataset in English, Spanish, and Portuguese. We examine the variation in Twitter activity across time and location, finding that rises in activity tend to follow to major events, and geographic rates of Zika-related discussion are moderately correlated with Zika incidence (ρ = .398)