Search results for "yield"
showing 10 items of 1338 documents
Exploiting Palladium-Catalyzed Cross-Coupling for the Synthesis of 2-Aryl-Substituted 1-Aminocyclopropylphosphonates
2015
A series of 2-aryl-substituted 1-aminocyclopropylphosphonates containing an additional remote phosphonate group have been synthesized starting from readily accessible dimethyl (1 R *,2 R *)-2-(4-bromophenyl)-1-formamidocyclopropylphosphonate using cross-coupling methodology. Different types of palladium-catalyzed reactions for carbon–carbon and carbon–phosphorus bond formation were realized. In each case the optimum conditions were found to obtain the desired products in high yield in both small- and large-scale experiments.
ChemInform Abstract: Synthesis of 3-Triazenopyrroles.
2010
Abstract The 3-triazenopyrroles, a new class of pyrrole derivatives, were synthesized in quantitative yield by coupling 3-diazopyrroles with secondary amines.
Unexpected high robustness of electrochemical cross-coupling for a broad range of current density
2017
Solvent effect enables electrosynthesis of organic compounds with strong variation of electric current at constant efficacy.
L-Band vegetation optical depth for crop phenology monitoring and crop yield assessment
2018
Vegetation Optical Depth (VOD) at L-band is highly sensitive to the water content and above-ground biomass of vegetation. Hence, it has great potential for monitoring crop phenology and for providing crop yield forecasts. Recently, the Multi-Temporal Dual Channel Algorithm (MT -DCA) has been proposed to retrieve L-band VOD from Soil Moisture Active Passive (SMAP) measurements. In previous research, SMAP VOD has been compared to crop phenology and has been used to derive crop yield estimates. Here, we review and expand these initial research studies. In particular, we quantify the capability of VOD to detect different crop stages, and test different VOD metrics (i.e., maximum, range and inte…
Nitrogen Use Efficiency and Nitrogen Fertilizer Recovery of Durum Wheat Genotypes as Affected by Interspecific Competition
2010
A better understanding of the genotype response to N fertilization under weed competition is necessary to identify varieties that exhibit high N use effi ciency even when weeds compete for available N. Such varieties may be more suitable for low input or organic systems. Th is study assessed the variations in nitrogen use effi ciency (NUE) (and its components) and the recovery of 15 N-labeled fertilizer in three durum wheat (Triticum durum Desf.) genotypes (one landrace and two varieties that diff er in terms of plant growth, grain yield potential, and adaptability to stressful environments) grown in the presence or absence of interspecifi c competition and varying soil N availability (0 or…
Potential predictability of crop impacting climate variables for East Africa and application to sorghum in the Mt Kenya area
2013
In Southern countries with rural low income populations, the vulnerability of rainfed agriculture to rainfall variability requires effective solutions to mitigate the effects of climatic hazards on crops. Predicting the characteristics of rainy seasons some time before they start should help the establishment of agricultural adaptation strategies to rainfall hazards. This is the objective of the present study, focused on East Africa (Kenya and northern Tanzania), and divided in three parts:- Define and document intra-seasonal descriptors (ISD) that will be considered in the predictability study. A new methodological approach has been developed in order to define the onset date (ORS) and the…
Vertical distribution of crop load and fruit quality within vase- and Y-shaped canopies of 'Elegant Lady' peach
2005
Canopy shape and depth may influence crop uniformity of peach trees at harvest. To test this hypothesis we examined yield distribution and fruit quality changes at different canopy levels of peach trees trained to delayed vase (DV) and perpendicular Y (Y). Trees of both training forms were divided vertically into six or seven 50-cm-deep layers and fruit was harvested at commercial ripening from each layer separately. Regardless of training form, number of fruit and yield per layer were highest in the central part of the canopy, but more evenly distributed among canopy layers in Y trees. In DV trees, fruit weight decreased linearly from top to bottom, whereas it remained constant along the t…
Use of NOAA-AVHRR NDVI data for environmental monitoring and crop forecasting in the Sahel. Preliminary results
1992
Abstract Several studies have shown that the NDVI calculated from NOAA-AVHRR data is related to annual rainfall and primary productivity in Sahelian areas. Such correlations, however, are affected by several environmental factors and have been tested only with data accumulated during rainy seasons, which is not ideal for the prediction of crop yield. In the present study a methodology of NOAA AVHRR data processing is presented which utilizes NDVI computed only in the first part of some rainy seasons and statistically takes into account the geographical variability in land resources and atmospheric conditions. From the first results of the application of the methodology in Niger, its potenti…
Yield development of flax varieties and lines within variable environment in Latvia
2015
Flax is the multiple purpose crop cultivated in temperate region. Seeds of oil flax recently became important constituent for many industrial applications, such as pharmacy, medicine, food production <em>etc.</em> and have high prospective for use in Latvia. Understanding the underlying processes that limit seed yield in flax is major with respect to enhancing the breeding of flax for yield improvements. The aim of study was evaluated 29 flax varieties and lines (including 20 Latvian origins) plasticity of seed yield production in changeable environmental conditions. The experiment was carried out in the Agricultural Scientific Centre of Latgale on field trials over the period 2…
Relationship between N-cycling communities and ecosystem functioning in a 50-year-old fertilization experiment.
2009
The relative importance of size and composition of microbial communities in ecosystem functioning is poorly understood. Here, we investigated how community composition and size of selected functional guilds in the nitrogen cycle correlated with agroecosystem functioning, which was defined as microbial process rates, total crop yield and nitrogen content in the crop. Soil was sampled from a 50-year fertilizer trial and the treatments comprised unfertilized bare fallow, unfertilized with crop, and plots with crop fertilized with calcium nitrate, ammonium sulfate, solid cattle manure or sewage sludge. The size of the functional guilds and the total bacterial community were greatly affected by …