Nitrogen use efficiency and nutrient partitioning in maize as affected by blends of controlled-release and conventional urea

ABSTRACT

Blends of controlled-release urea (CRU) and conventional urea can be an alternative to conventional fertilization to improve nitrogen use efficiency (NUE) and reduce costs when applied as a single application to agricultural crops. Different indexes of NUE, grain yield, nutrient uptake and partitioning in maize (Zea mays L.) were investigated in field experiments. The treatments consisted of a single rate of 180 kg N ha^?1 with different proportions of polymer-sulfur coated urea (PSCU) and conventional urea (U) applied incorporated at sowing (0.05 m below and 0.1 m to the side of the seed row) at two tropical sites (Site 1, Typic Haplustox; Site 2, Rhodic Haplustox) in Brazil. A control treatment (without urea-N) and a treatment with conventional urea management (UCM: 20% of urea-N applied as basal fertilizer and 80% of N applied as top dressing) were also included. This study demonstrates that blends of PSCU and U are efficient in supplying N throughout the maize cycle at a Typic Haplustox site when applied in a single application incorporated at sowing, resulting in high yields and adequate macronutrient uptake. PSCU improved NUE index compared to U and UCM. There was not response for N fertilization in the Rhodic Haplustox site.     

Effect of Equilibrium Solution Ionic Strength on the Adsorption of Zn,Cu, Cd,Pb, As,and P on Aluminum Mining By-Product

Adsorption onto powdered activated carbon (PAC) is a promising option to remove organic micro-pollutants (OMP) from drinking water sources or wastewater. Since this treatment option requires continuous PAC dosing, sufficient contact time and subsequent separation of the PAC, the integration into existing process chains is challenging. In the present investigation, the pre-loading of a deep bed filter with PAC used as fixed bed adsorber was investigated. The retention and distribution of an exemplary PAC in a pumice rapid filter were determined. Gravimetry combined with combustion of the PAC at 550 °C was applied to differentiate between PAC and filter material residues and revealed comparably high PAC immobilization in the upper third of the pumice filter. Comparative adsorption experiments in batch with suspended PAC and continuous filtration tests with immobilized PAC showed advantageous results for immobilized PAC with regard to the removal of OMP and the sum parameters dissolved organic carbon and UV light absorption at 254 nm wavelength. The results indicate that a conventional rapid filter together with PAC can be effectively utilized as fixed bed adsorption filter.     

Influence of Land Use on the Physical Properties of Chernozems in the Forest-Steppe Zone of Western Siberia

Eurasian Soil Science - The land use type and agricultural practices significantly affect the aggregate state and many physical properties of soils. In this study, we provide a comparative...     

Geno-phenotypic diversity in a natural population of Hancornia speciosa Gomes: implications for conservation and improvement

Genetic Resources and Crop Evolution - Hancornia speciosa Gomes is native tree to South America, and its fruits are a source of income for communities and the food industry. The reduction of...     

Aeration strategy for controlling grain storage based on simulation and on real data acquisition

In this work a new control strategy for grain aeration systems was proposed. This strategy was implemented in a software package called AERO and relates four conditions which depend on real time data acquisition and on the process simulation. The main advantage of AERO controller is that it can be used in different geographic regions, during different seasons and with different aeration systems, automatically adjusting its set points. The objectives of AERO controller are to equalize the temperatures inside the bin, to cool the grain mass whenever is possible and to maintain the moisture content under safe conditions. The results showed that the proposed strategy is efficient to achieve these objectives. Moreover, significant energy saving has been achieved with the AERO controller.     

Planting mahogany in canopy gaps created by commercial harvesting

Attempts at natural forest management of mahogany (Swietenia macrophylla King) have so far met with limited success, whilst many plantations are beset by the shoot borer Hypsipyla spp. In this paper we present preliminary results of an approach to enrichment planting that aims to balance economic returns (rapid growth and good silvicultural form) with intervention costs and changes to forest structure. Mahogany seedlings were planted in gaps created by selective timber harvesting and that ranged in vertical projected area from 91 to 542 m² (mean = 257 m²). Seedlings grew within the matrix of gap regrowth, with limited control of competing vegetation. Sixty-one percent of seedlings had survived by 4.4 years (equivalent to an annual mortality rate of 10.5% year⁻¹), and had reached a mean height of 4.5 m. Stocking levels of mahogany were similar to that of naturally regenerated commercial species in unplanted gaps of the same age, but mahogany seedlings were significantly taller. The incidence of shoot borer attack on mahogany stems was relatively low (54.7%), but, more importantly, most damaged stems (58%) responded by producing a single replacement leader. The cost of the proposed methodology (US$ 94 per gap over 4.4 years) was low compared to the high value of mahogany timber relative to other species in the forest. The implications of planting mahogany in gaps for forest management and the potential benefits to conservation of the species are considered.     

A new lupene triterpenetriol and anticholinesterase activity of Salvia sclareoides

A new lupene triterpenetriol was isolated from the acetone extract of the aerial parts of Salvia sclareoides and characterised as (1beta,3beta)-lup-20(29)-ene-1,3,30-triol (1). In addition, nepetidin (2), nepeticin (3), lupendiol (4), (1beta,11alpha)-dihydroxy-lup-20(29)-en-3-one (5), ursolic acid (6), sumaresinolic acid (7) and hederagenin (8), were identified in this Salvia sp. To the best of our knowledge, the compounds 2 and 7 are new constituents in Salvia spp. The acetone, ethanol, butanol and water extracts of the plant were screened for the in vitro inhibitory activity of acetylcholinesterase (AChE) and butyrilcholinesterase (BChE), enzymes which play a role in the Alzheimer disease. All extracts inhibited acetylcholinesterase activity at 10 microg/ml, a remarkable activity since the standard drug rivastigmine does not inhibit acetylcholinesterase at the same concentration. Regarding the butyrilcholinesterase, the acetone extract at 1000 microg/ml was able to inhibit completely the enzyme activity and the butanol and ethanol extracts, at this concentration, produced a potent inhibition of BchE.     

Is single-step genomic REML with the algorithm for proven and young more computationally efficient when less generations of data are present?

Efficient computing techniques allow the estimation of variance components for virtually any traditional dataset. When genomic information is available, variance components can be estimated using genomic REML (GREML). If only a portion of the animals have genotypes, single-step GREML (ssGREML) is the method of choice. The genomic relationship matrix (G) used in both cases is dense, limiting computations depending on the number of genotyped animals. The algorithm for proven and young (APY) can be used to create a sparse inverse of G (GAPY~-1) with close to linear memory and computing requirements. In ssGREML, the inverse of the realized relationship matrix (H⁻¹) also includes the inverse of the pedigree relationship matrix, which can be dense with a long pedigree, but sparser with short. The main purpose of this study was to investigate whether costs of ssGREML can be reduced using APY with truncated pedigree and phenotypes. We also investigated the impact of truncation on variance components estimation when different numbers of core animals are used in APY. Simulations included 150K animals from 10 generations, with selection. Phenotypes (h² = 0.3) were available for all animals in generations 1–9. A total of 30K animals in generations 8 and 9, and 15K validation animals in generation 10 were genotyped for 52,890 SNP. Average information REML and ssGREML with G⁻¹ and GAPY~-1 using 1K, 5K, 9K, and 14K core animals were compared. Variance components are impacted when the core group in APY represents the number of eigenvalues explaining a small fraction of the total variation in G. The most time-consuming operation was the inversion of G, with more than 50% of the total time. Next, numerical factorization consumed nearly 30% of the total computing time. On average, a 7% decrease in the computing time for ordering was observed by removing each generation of data. APY can be successfully applied to create the inverse of the genomic relationship matrix used in ssGREML for estimating variance components. To ensure reliable variance component estimation, it is important to use a core size that corresponds to the number of largest eigenvalues explaining around 98% of total variation in G. When APY is used, pedigrees can be truncated to increase the sparsity of H and slightly reduce computing time for ordering and symbolic factorization, with no impact on the estimates.     

A nontoxic derivative of Bothrops jararaca venom suitable to generate antibodies against the native venom.

Bothrops jararaca venom was toxoided by stepwise iodination with cold iodine, and doses up to 30 LD50 were non-lethal by i.p. route (BICALHO et al., 1990). Groups of mice injected chronically with the native, or the iodinated venom, have been subjected to histological examination. In the native group, in the spleen, around the white pulp, an acellular, amorphous eosinophilic substance, metachromatic to Methyl Violet, PAS positive, and dichroic to Congo Red under polarized light, was present. Strong congestion in the liver, kidneys and lungs was found. The salivary glands were replenished with an amorphous substance in the serosal acini. The groups injected with the iodinated venom only show discrete alterations, more akin to the control group. The anavenin was immunogenic. Antibody generation in mice and rabbits was detected by ELISA. In mice, active protection against challenge with native venom was presented. The iodinated venom generated a rabbit antiserum with strong lines in gel immunoprecipitation against the lethal venom. A minimum neutralization titer of 2.3 mg ml-1 against the native venom was attained in the first cycle (28 days) of immunization. After 3 cycles (100 days), the protection rose to 5.1 mg ml-1.