Suchergebnisse

To obtain quality seedlings of yerba mate and productive plants with a high standard raw-material, it is necessary the adequate nutrition for the seedlings in the nurseries. Fertilization management is one of the key factors that contribute to the better quality of seedlings, survival, and growth after planting in the field. Therefore, this work hypothesizes that controlled nutrient-release fertilizer can be used as base fertilizers in the production of yerba mate seedlings. Thus, the objective of this work was to evaluate the growth and quality of Ilex paraguariensis seedlings subjected to doses of controlled-release fertilizer, in order to define the most suitable dose for this stage of the crop. For all the analyzed variables a significant treatment effect was observed, indicating a positive response of the species to fertilization. Increasing doses of controlled-release fertilizer provided increments in height, collar diameter, height and collar diameter ratio, leaves number, leaf area, shoot, root and total dry mass, shoot and root dry mass ratio, height and shoot dry mass ratio and Dickson quality index, compared to unfertilized yerba mate seedlings. Controlled release fertilization promotes the growth and quality of yerba mate seedlings. Doses from 6 g L-1 of Basacote® Mini 6M fertilizer (13-6-16 + 1.4) can be used in the base fertilization of the seedlings.
Keywords: Basacote. Base Fertilizer. Dickson Quality Index. Ilex paraguariensis A.St.-Hil. Morphological Attributes.
Resumo
Para a obtenção de mudas de erva-mate de qualidade e plantas produtivas com alto padrão de matéria-prima é de suma importância a nutrição adequada das mudas nos viveiros. O manejo da adubação é um dos principais fatores que contribuem para a maior qualidade das mudas, sobrevivência e crescimento após o plantio no campo. Fertilizantes de liberação controlada de nutrientes podem ser utilizados como adubação de base na produção de mudas de erva-mate. O objetivo foi avaliar o crescimento e a qualidade de mudas de Ilex paraguariensis submetidas a doses de fertilizante de liberação controlada, de forma a definir a dose mais indicada para essa fase da cultura. Para todas as variáveis analisadas foi verificado efeito significativo do tratamento, indicando resposta positiva da espécie à adubação. Doses crescentes de fertilizante de liberação controlada proporcionaram aumentos na altura, diâmetro do coleto, relação altura e diâmetro do coleto, número de folhas, área foliar, massa seca da parte aérea, radicular e total, relação massa seca parte área e radicular, relação altura e massa seca parte aérea e índice de qualidade de Dickson, em comparação com as mudas de erva-mate não fertilizadas. Adubação de liberação controlada favorece o crescimento e a qualidade das mudas de erva-mate. Doses a partir de 6 g L-1 de fertilizante Basacote® Mini 6M (13-6-16 + 1,4) podem ser utilizadas na adubação de base das mudas.
Palavras-chave: Basacote. Adubação de base. Índice de Qualidade de Dickson. Ilex paraguariensis A.St.-Hil. Atributos morfofisiológicos.

In containerized nursery-crop production, conventional phosphorus (P) fertilization amounts are reported to be in excess of plant needs which has resulted in poor P use efficiency (PUE) and subsequent P leaching from containers. Phosphorus leaching can be reduced and PUE improved without affecting plant growth by reducing P fertilization. The objective of this study was to identify the lowest controlled-release fertilizer (CRF)-P content and subsequent pour-through-extracted substrate pore-water P (PWP) concentration that produces maximal shoot growth of two common container-grown nursery crop species, Hydrangea macrophylla 'PIIHM-II' (hydrangea) and Ilex crenata 'Helleri' (holly), in a pine bark substrate. Hydrangea and holly liners were potted into 3.8-L containers containing a pine bark substrate and grown simultaneously in two different Virginia ecoregions, Middle Atlantic Coastal Plain (MACP) and Ridge and Valley (RV). Plants were fertilized with one of five CRF formulations, each containing equal nitrogen (N) and potassium (K) and 0.4%, 0.9%, 1.3%, 1.7% or 2.6% (control) P to supply containers with 0.1, 0.2, 0.3, 0.4 or 0.6 g P, respectively. In both ecoregions, hydrangea shoot dry weight (SDW) and growth index [i.e., (widest width + perpendicular width + height) divided by 3, GI] values were maximal in plants fertilized with 0.3 to 0.4 g P or the control. The lowest CRF-P rate needed for maximal SDW and GI of holly was 0.2 g P at the RV site and 0.4 g P at the MACP site. Mean PWP concentrations that corresponded with highest SDW were as low as 0.8 and 1.2 mg L-1 for hydrangea and holly, respectively. Results from this research suggest hydrangea requires approximately half the P rate supplied by recommended rates of conventional CRFs. Since the growth response of holly to CRF-P rate at the MACP site was inconsistent with results observed at the RV site and findings in scientific literature, further research is needed to determine the minimum required CRF-P rate for this taxon. ; Virginia Agricultural Experiment Station; Clean Water3 of the National Institute of Food and Agriculture, U.S. Department of Agriculture [SCRI 2014-51181-22372]; Virginia Nursery and Landscape Association; Horticultural Research Institute, Virginia Agricultural Council; Hatch Program ; The authors thank Julie Brindley, Velva Groover, and Anna Birnbaum for technical assistance, as well as Saunders Brothers Nursery and Bailey Nursery for donating plants for this research. Funding was provided by the Virginia Agricultural Experiment Station, the Hatch Program and Clean Water3(SCRI 2014-51181-22372) of the National Institute of Food and Agriculture, U.S. Department of Agriculture, the Horticultural Research Institute, Virginia Agricultural Council, and the Virginia Nursery and Landscape Association. ; Public domain authored by a U.S. government employee

Conventional methods of pesticide application in agricultural field and fate of the pesticides in the environment and human health -- Methods for determination of pesticides and fate of pesticides in the fields -- Chemistry and toxicology behind insecticides and herbicides -- Controlled Release Pesticides as a route to Sustainable Crop production -- Manufacturing of slow- and controlled-release Pesticides -- Characteristics and types of slow/ controlled release of pesticides -- Advanced Controlled Nanopesticide Delivery Systems for Managing Insect Pests -- Polymer Formulations for Pesticide Release -- Molecularly Imprinted Sensors for Detecting Controlled Release of Pesticides -- Controlled Release Herbicides and Allelopathy as Sustainable Alternatives in Crop Production -- Controlled release of plant hormones for modifying crop yield

Urea is the main solid N fertilizer used worldwide. Among its advantages are the high nutrient content, ease of handling and application, and low cost. Urea is subject to high losses through NH3 volatilization if surface-applied on soils. Therefore, ammonium nitrate is the preferred N source, especially in the ratoon cycles. Urea treated with the urease inhibitor NBPT and controlled-release fertilizers are options to replace ammonium nitrate. Controlled-release urea (CRU) is produced by coating the urea granules with resin or synthetic polymers so that the urea in the nucleus is not in contact with soil moisture. This study aimed to test CRU in sugarcane ratoons compared with ammonium nitrate (AN) and urea treated with urease inhibitor (UR-NBPT) at three rates: 60, 120 and 180 kg ha–1. Efficiency was also compared with two control treatments, the N control and the NPK control. Two field experiments were established and conducted in 2020 and 2021 in Sao Paulo state, Brazil. Sugarcane yield was evaluated in both experiments. N losses as NH3 volatilized were measured in the first experiment. All sources were equally efficient in promoting increases in sugarcane ratoon yield in both experiments. The relative yield obtained with N fertilizers and the control without N showed yield increases in the first experiment of 40, 54 and 68% for 60, 120 and 180 kg N ha–1 as AN, respectively; 29, 61 and 61% for 60, 120 and 180 kg N ha–1 as
urea-NBPT, respectively; and 32, 62 and 67% for 60, 120 and 180 kg N ha–1 as CRU, respectively. Yields were higher in the second experiment, but increases in yield were lower compared to the first. Increases of 7, 10 and 16% for AN in three doses, 5, 12, 15% for UR-NBPT and 7, 9 and 14% for CRU were observed, respectively. N losses as NH3 volatilized were relatively low; CRU fertilizer showed good protection against NH3 losses by volatilization, protecting urea for about 30 days. This protection, however, did not affect yield. NH3 losses reached 13% of the N applied in the treatment with urea (about 16 kg N ha–1), 11% for Urea-NBPT (about 13 kg N ha–1) and 9% for CRU (about 11 kg N ha–1). Analyzing the results of both experiments CRU did not show an advantage in efficiency compared to AN and Urea-NBPT.