Camera steered mechanical weed control in sugar beet,maize and soybean

In sugar beet, maize and soybean, weeds are usually controlled by herbicides uniformly applied across the whole field. Due to restrictions in herbicide use and negative side effects, mechanical weeding plays a major role in integrated weed management (IWM). In 2015 and 2016, eight field experiments were conducted to test the efficacy of an OEM Claas 3-D stereo camera^® in combination with an Einböck Row-Guard^® hoe for controlling weeds. Ducks-foot blades in the inter-row were combined with four different mechanical intra-row weeding elements in sugar beet, maize and soybean and a band sprayer in sugar beet. Average weed densities in the untreated control plots were from 12 to 153 plants m^?2 with Chenopodium album, Polygonum convolvulus, Thlapsi arvense being the most abundant weed species. Camera steered hoeing resulted in 78% weed control efficacy compared to 65% using machine hoeing with manual guidance. Mechanical intra-row elements controlled up to 79% of the weeds in the crop rows. Those elements did not cause significant crop damage except for the treatment with a rotary harrow in maize in 2016. Weed control efficacy was highest in the herbicide treatments with almost 100% followed by herbicide band-applications combined with inter-row hoeing. Mechanical weed control treatments increased white sugar yield by 39%, maize biomass yield by 43% and soybean grain yield by 58% compared to the untreated control in both years. However, yield increase was again higher with chemical weed control. In conclusion, camera guided weed hoeing has improved efficacy and selectivity of mechanical weed control in sugar beet, maize and soybean.     

Monitoring rare or elusive large mammals using effort-corrected voluntary observers

Populations of rare or elusive large mammals are difficult to monitor, because they usually are secretive, solitary, occur at low densities, and have large home ranges. The global trend of generally decreasing large carnivore populations necessitates new, feasible, reliable, and cost-effective monitoring methods. We evaluate an index method developed for monitoring populations of moose (Alces alces) based on voluntarily and systematically collected observations from hunters, corrected for effort, for use in monitoring populations of large carnivores in Sweden. For our evaluation, we used independent estimates of minimum brown bear (Ursus arctos) densities from DNA-based scat surveys and brown bear distribution from mandatory reports from successful bear hunters. We verified that the index correctly reflected bear distribution. We also found strong linear relationships between the indices and the independent density estimates for bears at the scale of local management units (about 1000-2000 km²) in all three regional study areas (adjusted R² = 0.88-0.60). Our results suggest that systematic, effort-corrected reports of observed animals can be an alternative and accurate monitoring method for the conservation and management of large mammals occurring over large areas when large numbers of willing volunteers are available (effort >30,000 h).     

Remote sensing and forest inventories in Nordic countries – roadmap for the future

The Nordic countries have long traditions in forest inventory and remote sensing (RS). In sample-based national forest inventories (NFIs), utilization of aerial photographs started during the 1960s, satellite images during the 1980s, laser scanning during the 2000s, and photogrammetric point clouds during the 2010s. In forest management inventories (FMI), utilization of aerial photos started during the 1940s and laser scanning during the 2000s. However, so far, RS has mostly been used for map production and research rather than for estimation of regional parameters or inference on their accuracy. In recent years, the RS technology has been developing very fast. At the same time, the needs for information are constantly increasing. New technologies have created possibilities for cost-efficient production of accurate, large area forest data sets, which also will change the way forest inventories are done in the future. In this study, we analyse the state-of-the-art both in the NFIs and FMIs in the Nordic countries. We identify the benefits and drawbacks of different RS materials and data acquisition approaches with different user perspectives. Based on the analysis, we identify the needs for further development and emerging research questions. We also discuss alternatives for ownership of the data and cost-sharing between different actors in the field.     

The Tolerance Index and Translocation Factor were Used to Identify the Barley Genotypes with High Arsenic Stress Tolerance

Ninety-four barley genotypes were used to investigate the genotypic differences in arsenic (As) uptake and translocation and their relationships with As tolerance index (TI) and translocation factor (TF). Two As treatments (300 µM and 500 µM) were applied in the initial screening and the confirmatory experiments, respectively. The results showed significant (p < 0.05) differences in tissue biomass, shoot height, root length, As TI and TF among genotypes. Based on As TI, 11 barley genotypes were selected and divided into 3 groups, i.e. tolerant, mildly tolerant and sensitive. There was more As uptake in the roots of the As tolerant genotypes, while the As sensitive genotypes contained more As in shoots, which was further proved by the greater TF. Significantly negative correlation was observed between shoot and root As concentration. The results showed that As tolerant genotypes are able to restrict the upward movement of As, thus developing their tolerance.     

The effect of cobalt stress on growth and physiological traits and its association with cobalt accumulation in barley genotypes differing in cobalt tolerance

Cobalt (Co) is beneficial for legume plants and not an essential element for most plants. There is no sufficient information about the effect of Co stress on barley growth. The current experiment was carried out to investigate the effects of different Co levels (25, 50, 75, and 100 µM) on growth and physiological traits of three barley genotypes (B325, J36, and B340) differing in Co tolerance. The results showed that Co stress inhibited plant growth, decreased chlorophyll content and photosynthetic rate, and enhanced oxidative stress. However, the effects differed among genotypes, with B325 and B340 being the most and the least affected, respectively. Co stress caused decrease and increase of manganese (Mn) and phosphorus (P) concentrations in both roots and shoots, respectively; iron (Fe) concentration had little change in shoots and a significant decrease in roots. The current results showed a close association of Co tolerance and its accumulation in plant tissues.     

Effects of the Polish Rootstocks P2 and P22 on Vigour,Yield and Fruit Characteristics of the Apple Cultivar ‘Gravenstein’

Abstract

The performance of the Polish rootstocks P2 and P22 under Norwegian growing conditions was evaluated over 10 years (1983–92). Tree vigour of the apple cultivar ‘Gravenstein’ on P2 and P22 was 64 and 16% of that on M9, respectively. Trees on P2 had the highest yield efficiency, but less total yield per tree than M9. Owing to very dwarfing growth, trees on P22 failed to establish a sufficient canopy and produced significantly smaller apples. P2 and P22 affected apple soluble solids in a favourable way, but did not influence fruit acidity.     

Treasuring crop wild relative diversity: analysis of success from the seed collecting phase of the ‘Adapting Agriculture to Climate Change’ project

The seed collecting phase of the ‘Adapting Agriculture to Climate Change’ project was, to the best of our knowledge, the most comprehensive crop wild relatives (CWR) collecting and conservation mission to-date and provides priceless genetic diversity for ongoing and future crop breeding efforts. The seed collecting started in 2013 and was concluded in 2019, it was carried out in 22 countries in Africa, Asia, the Americas and Europe, involving CWR taxa of 28 different crop genepools. 3002 target seed accessions of 242 taxa were collected and are currently stored long-term in the countries of collection and, in most of the cases, backed up at the Millennium Seed Bank (UK). Considering also non-target species, 3854 seed accessions were collected. For the genepools of bambara groundnut (Vigna subterranea (L.) Verdc.), barley (Hordeum L.), grass pea (Lathyrus sativus L.), sorghum (Sorghum bicolor (L.) Moench), and wheat (Triticum L.), the collecting phase was highly successful in terms of diversity of both, species and populations. Despite the overall success of the project, in our analysis we discovered several issues that were encountered in the seed collecting. In particular, comparing the initial collecting targets with the seed accessions effectively collected it emerges that: (1) some important crop genepools were characterized by a low collecting success (e.g. banana/plantain (Musa L.), potato (Solanum tuberosum L.), rice (Oryza L.), (2) genepool 1 (the most important for breeding efforts) of some crop genepools was under-collected (e.g. eggplant (Solanum L.) and sorghum), (3) some important centres of plant biodiversity (especially the Indian Subcontinent) were underrepresented in the seed collecting. This analysis can guide further collecting missions in order to fill gaps in the long-term conservation of CWR of great importance for crop improvement.

     

Soil heterogeneity at the field scale: a challenge for precision crop protection

Crop protection seldom takes into account soil heterogeneity at the field scale. Yet, variable site characteristics affect the incidence of pests as well as the efficacy and fate of pesticides in soil. This article reviews crucial starting points for incorporating soil information into precision crop protection (PCP). At present, the lack of adequate field maps is a major drawback. Conventional soil analyses are too expensive to capture soil heterogeneity at the field scale with the required spatial resolution. Therefore, we discuss alternative procedures exemplified by our own results concerning (i) minimally and non-invasive sensor techniques for the estimation of soil properties, (ii) the evidence of soil heterogeneity with respect to PCP, and (iii) current possibilities for incorporation of high resolution soil information into crop protection decisions. Soil organic carbon (SOC) and soil texture are extremely interesting for PCP. Their determination with minimally invasive techniques requires the sampling of soils, because the sensors must be used in the laboratory. However, this technique delivers precise information at low cost. We accurately determined SOC in the near-infrared. In the mid-infrared, texture and lime content were also exactly quantified. Non-invasive sensors require less effort. The airborne HyMap sensor was suitable for the detection of variability in SOC at high resolution, thus promising further progress regarding SOC data acquisition from bare soil. The apparent electrical conductivity as measured by an EM38 sensor was shown to be a suitable proxy for soil texture and layering. A survey of arable fields near Bonn (Germany) revealed widespread within-field heterogeneity of texture-related ECa, SOC and other characteristics. Maps of herbicide sorption and application rate were derived from sensor data, showing that optimal herbicide dosage is strongly governed by soil variability. A phytoassay with isoproturon confirmed the reliability of spatially varied herbicide application rates. Mapping areas with an enhanced leaching risk within fields allows them to be kept free of pesticides with related regulatory restrictions. We conclude that the use of information on soil heterogeneity within the concept of PCP is beneficial, both economically and ecologically.     

Markers of Borna disease virus infection in cats with staggering disease

Borna disease virus (BDV) is a RNA-virus causing neurological disorders in a wide range of mammals. In cats, BDV infection may cause staggering disease. Presently, staggering disease is a tentative clinical diagnosis, only confirmed at necropsy. In this study, cats with staggering disease were investigated to study markers of BDV infection aiming for improvement of current diagnostics. Nineteen cats fulfilled the inclusion criteria based on neurological signs and pathological findings. In 17/19 cats, BDV infection markers (BDV-specific antibodies and/or BDV-RNA) were found, and antibodies in serum (13/16, 81%) were the most common marker. BDV-RNA was found in 11/19 cats (58%). In a reference population without neurological signs, 4/25 cats were seropositive (16%). The clinical history and neurological signs in combination with presence of BDV infection markers, where serology and rRT-PCR on blood can be helpful tools, improve the diagnostic accuracy in the living cat.