999 resultados para nitrogen fertilization
Resumo:
A field experiment with pineapple (Smooth Cayenne) was carried out on an Ultisol located in the city of Agudos (22º30'S; 49º03'W), in the state of São Paulo, Brazil, with the objective of investigating the effects of rates and sources of potassium fertilizer on plant growth and fruit yield. The experiment was a complete factorial design (4x3) with four rates (0, 175, 350, and 700 kg ha-1 of K2O) and three combinations of K sources (100% KCl, 100% K2SO4, and 40% K2SO4 + 60% KCl). Plant growth and fruit yield were evaluated. Biomass accumulation of pineapple plants was impaired by chlorine added with potassium chloride. Fruit yield increased with potassium fertilization. At high rates of K application, fertilization with K2SO4 showed better results than with KCl. Detrimental effects of KCl were associated with excess of chlorine.
Resumo:
A field experiment was carried out on an Ultisol located at the city of Agudos (22º30'S; 49º03'W), in the state of São Paulo, Brazil, in order to determine the effects of rates and sources of potassium fertilizer on nutritional status of 'Smooth Cayenne' pineapple and on some soil chemical properties. The experiment was a complete factorial design with four rates (0, 175, 350, and 700 kg ha-1 of K2O) and three combinations of K sources (100% KCl, 100% K2SO4 and 40% K2SO4 + 60% KCl). Soil samples were taken from the depths 0-20 cm, 20-40 cm and 40-60 cm at planting and 14 months after. Nutritional status of pineapple plants was assessed by means of tissue analysis. Soil K availability increased with application of K fertilizer, regardless of K sources. Soil chlorine and Cl concentration in pineapple leaves increased with application of KCl or K2SO4+KCl. Plant uptake of potassium was shaped by soil K availability and by the application rates of K fertilizer, independently of K sources.
Resumo:
The objective of this work was to evaluate the alterations in carbon and nitrogen mineralization due to different soil tillage systems and groundcover species for intercropped orange trees. The experiment was established in an Ultisol soil (Typic Paleudults) originated from Caiuá sandstone in northwestern of the state of Paraná, Brazil, in an area previously cultivated with pasture (Brachiaria humidicola). Two soil tillage systems were evaluated: conventional tillage (CT) in the entire area and strip tillage (ST) with a 2-m width, each with different groundcover vegetation management systems. The citrus cultivar utilized was the 'Pera' orange (Citrus sinensis) grafted onto a 'Rangpur' lime rootstock. The soil samples were collected at a 0-15-cm depth after five years of experiment development. Samples were collected from under the tree canopy and from the inter-row space after the following treatments: (1) CT and annual cover crop with the leguminous Calopogonium mucunoides; (2) CT and perennial cover crop with the leguminous peanut Arachis pintoi; (3) CT and evergreen cover crop with Bahiagrass Paspalum notatum; (4) CT and cover crop with spontaneous B. humidicola grass vegetation; and (5) ST and maintenance of the remaining grass (pasture) of B. humidicola. The soil tillage systems and different groundcover vegetation influenced the C and N mineralization, both under the tree canopy and in the inter-row space. The cultivation of B. humidicola under strip tillage provided higher potential mineralization than the other treatments in the inter-row space. Strip tillage increased the C and N mineralization compared to conventional tillage. The grass cultivation increased the C and N mineralization when compared to the others treatments cultivated in the inter-row space.
Resumo:
Työssä selvitetään kompostointilaitoksen lopputuotteen erilaisia käyttömahdollisuuksia. Yleisten käyttökohteiden pohjalta on luotu malli Vapo Oy Biotech:n toimittaman Himangan kompostointilaitoksen kompostin hyödyntämiselle. Laitos sijaitsee Himangan kunnassa Keski- Pohjanmaalla. Laitoksella kompostoidaan pääasiassa Himangan ja ympäröivien kuntien jätevesilietteitä turkiseläinlantaa. Jätehuolto Suomessa ja koko EU:n alueella elää voimakasta muutoskautta. Orgaanisten jätteiden vienti kaatopaikoille pyritään tulevaisuudessa lopettamaan kokonaan, mikä on lisännyt niiden käsittelyä mm. kompostoimalla. Kompostoinnin lopputuotteena saadaan ravinteikasta, humuspitoista ainesta. Kompostoinnin yhtenä tavoitteena on tuottaa hyötykäyttöön soveltuvaa tuotetta, joten käyttökohteen löytäminen kompostille on laitoksen toiminnan kannalta erittäin tärkeää. Kompostin käyttömahdollisuuksiin vaikuttavat lainsäädäntö, kompostin ominaisuudet sekä paikalliset olosuhteet. Käyttökohteet on työssä jaettu ei-energiakäyttöön ja energiakäyttöön. Ei-energiakäyttöön kuuluvat maanparannuskäyttö, lannoitekäyttö, käyttö kasvualustassa, maisemointi ja julkinen rakentaminen sekä joitakin erityissovelluksia. Energiakäytön puolella on tarkasteltu kompostin soveltuvuutta erilaisille polttotekniikoille sekä vertailtu kompostia muihin kiinteisiin polttoaineisiin. Kompostien soveltuvuutta eri kohteisiin on arvioitu kompostin analyysi- ja kasvatuskoetulosten pohjalta. Kompostin ei-energiakaytössa on saatu eri tutkimuksissa lupaavia tuloksia. Kompostin on todettu soveltuvan erittäin hyvin mm. perunanviljelyyn, viljan ja nurmikasvien viljelyyn ja erilaisiin maisemointikohteisiin sekä kotipuutarhakäyttöön. Kompostin käyttöä polttoaineena ei ole vielä kokeiltu missään. Kompostin polton suurimmat ongelmat ovat korkea tuhka-, rikki- ja typpipitoisuus sekä epätasainen laatu.
Resumo:
Tutkimuksen tarkoituksena oli selvittää typenoksidien vähennysmahdollisuudet Stora Enson Varkauden tehtaiden sellutehtaalla ja voimalaitoksella. Tutkimuksessa käsiteltiin tehdasalueen suurimpia typenoksidien päästölähteitä: soodakattilaa, meesauunia, kuorikattilaa, öljykattilaa ja muovi-alumiinijakeen kaasutuslaitosta. Tutkimuksessa selvitettiin typenoksidipäästöjen syntymekanismit ja erilaisiin polttotekniikoihin soveltuvat typenoksidien vähennystekniikat. Varkauden tehtaiden typenoksidien vuosipäästö vuonna 2001 oli 836 tonnia. Kansallinen lainsäädäntö, kansainväliset sopimukset sekä paras käytettävissä oleva tekniikka (BAT) huomioiden selvitettiin kuhunkin kohteeseen parhaiten soveltuvat ratkaisut. Tutkimuksen perusteella laadittiin toimenpideohjelma, joka määrittelee suositeltavan toteutusjärjestyksen typenoksidien vähennystoimenpiteille. Toimenpideohjelman tärkeimpinä kriteereinä pidettiin vuonna 2004 tulevan uuden ympäristöluvan arvioituja luparajoja sekä toimenpiteiden kustannustehokkuutta. Toteutusjärjestyksessä ensimmäiseksi valittiin koeajojakson järjestäminen ajon optimoimiseksi kiertopetikattilalla ja toiseksi meesauunin ajon optimointi jatkuvatoimisen NOx-analysaattorin avulla. Seuraaviksi toimenpiteiksi ehdotettiin vertikaali-ilmajärjestelmän käyttöönottoa soodakattilalla sekä SNCR-järjestelmän asennusta kuorikattilalle. Saavutettava NOx-vähennys tulisi olemaan 10 – 45 % ja hinta 30 – 3573 EUR vähennettyä NOx-tonnia kohti. Tutkimuksen osana Ilmatieteen laitoksella teetetyn typenoksidien leviämisselvityksen mukaan Stora Enson tehtaiden NOx-päästöjen vaikutus Varkauden ilmanlaatuun on hyvin pieni. Suurin osa NOx-päästöistä aiheutuu liikenteestä.
Resumo:
Guava response to liming and fertilization can be monitored by tissue testing. Tissue nutrient signature is often diagnosed against nutrient concentration standards. However, this approach has been criticized for not considering nutrient interactions and to generate numerical biases as a result of data redundancy, scale dependency and non-normal distribution. Techniques of compositional data analysis can control those biases by balancing groups of nutrients, such as those involved in liming and fertilization. The sequentially arranged and orthonormal isometric log ratios (ilr) or balances avoid numerical bias inherent to compositional data. The objectives were to relate tissue nutrient balances with the production of "Paluma" guava orchards differentially limed and fertilized, and to adjust the current patterns of nutrient balance with the range of more productive guava trees. It was conducted one experiment of 7-yr of liming and three experiments of 3-yr with N, P and K trials in 'Paluma' orchards on an Oxisol. Plant N, P, K, Ca and Mg were monitored yearly. It was selected the [N, P, K | Ca, Mg], [N, P | K], [N | P] and [Ca | Mg] balances to set apart the effects of liming (Ca-Mg) and fertilizers (N-K) on macronutrient balances. Liming largely influenced nutrient balances of guava in the Oxisol while fertilization was less influential. The large range of guava yields and nutrient balances allowed defining balance ranges and comparing them with the critical ranges of nutrient concentration values currently used in Brazil and combined into ilr coordinates.
Resumo:
Biofilters degrade only a small fraction of the natural organic matter (NOM) contained in seawater which is the leading cause of biofouling in downstream processes. This work studies the effects of chemical additions on NOM biodegradation by biofilters. In this work, biofiltration of seawater with an empty bed contact time (EBCT) of 6 min and a hydraulic loading rate of 10 m h-1 reduces the biological oxygen demand (BOD7) by 8%, the dissolved organic carbon (DOC) by 6% and the UV absorbance at 254 nm (A254) by 7%. Different amounts of ammonium chloride are added to the seawater (up to twice the total dissolved nitrogen in untreated seawater) to study its possible effect on the removal of NOM by a pilot-scale biofilter. Seawater is amended with different amounts of easily biodegradable dissolved organic carbon (BDOC) supplied as sodium acetate (up to twice the DOC) for the same purpose. The results of this work reveal that the ammonium chloride additions do not significantly affect NOM removal and the sodium acetate is completely consumed by the biofiltration process. For both types of chemical additions, the BOD7, DOC and A254 in the outlet stream of the biofilter are similar to the values for the untreated control. These results indicate that this biofilter easily removes the BDOC from the seawater when the EBCT is not above 6 min. Furthermore, nitrogen does not limit the NOM biodegradation in seawater under these experimental conditions.
Resumo:
This study was carried out to evaluate the yield, total N content in leaves and must composition of grapes from the Cabernet Sauvignon variety subjected to the application of urea and organic compost. Cabernet Sauvignon grapevines in Rosário do Sul, RS, Brazil, in 2008, 2009 and 2010 were subjected to annual application of 40 kg N ha-1 in the form of organic compost and urea, and compared to unfertilized grapevines. In the 2008/09, 2009/10 and 2010/11 crop seasons, leaves were collected for analysis of total N content. At maturation of the grapes, the yield and quality attributes of the must were evaluated. The application of N sources, especially organic compost, increased the N content in the whole leaf at full flowering. Application of organic compost and urea has little effect on grape yield and does not affect the total nutrient content in the must, nor the enological attributes.
Resumo:
Tämän työn tarkoituksena oli löytää keinoja erään leijukerroskattilan typenoksidipäästöjen vähentämiseksi. Koska päästöt olivat jo alunperin alhaiset leijukerrostekniikan ja hybridin SNCR/SCR –typenpoistolaitteiston ansiosta, päätettiin päästöjä lähteä vähentämään parantamalla ammoniakkiruiskutuksen säätöä. Alkuperäinen ammoniakkiruiskutuksen säätö oli liian hidas, jotta satunnaisten häiriöiden aiheuttamat typenoksidipiikit olisi pystytty poistamaan. Ammoniakkiruiskutusta parannettiin lisäämällä jokaiseen ammoniakkilinjaan mäntäpumput, joiden avulla ammoniakkia voidaan syöttää sinne, missä sitä eniten tarvitaan. Ammoniakkiruiskutuksen säätöön kehitettiin uusi sumeaan logiikkaan perustuva säätäjä. Myös muita kehittyneitä säätömenetelmiä kuten neuroverkkoa hyödynnettiin säätäjän kehityksessä. Ammoniakkiruiskutuksen säätäjää testattiin menestyksekkäästi Ruotsissa Brista Kraftin Märstassa sijaitsevalla voimalaitoksella
Resumo:
The aim of this study was to evaluate the response to phosphorus (P) and potassium (K) fertilization and to establish the critical levels of P and K in the soil and in the plant tissue in pear trees. Two experiments were conducted in São Joaquim (SC), Brazil. In experiment 1, the plants received annually the application of increasing rates of phosphate fertilizer (0, 40, 80, 120 and 160 kg P2O5 ha-1), while in experiment 2, increasing rates of potassium fertilizer (0, 40, 80, 120 and 160 kg K2O ha-1) were applied annually. In the two experiments, soil was collected annually from the 0-10, 10-20 and 0-20 cm layers, and the available P (experiment 1) and exchangeable K (experiment 2) content was analyzed. Whole leaves were collected annually, which were subjected to analysis of total P (experiment 1) and total K (experiment 2) content. The number and weight of the fruits per plant and fruit yield were evaluated. Application of P on the soil planted with pear trees increased the nutrient content in the soil and, in most crop seasons, in the whole leaf, but it did not affect the yield components and fruit yield. The application of K on the soil with pear trees increased the nutrient content in the soil and, in most of the crop seasons, in the whole leaf, but the potassium content in the whole leaf decreased in the crop season with greater fruit yield. The yield components and fruit yield were not affected by K fertilization.
Resumo:
Growth experiments showed that adenine and hypoxanthine can be used as nitrogen sources by several strains of K. pneumoniae under aerobic conditions. The assimilation of all nitrogens from these purines indicates that the catabolic pathway is complete and proceeds past allantoin. Here we identify the genetic system responsible for the oxidation of hypoxanthine to allantoin in K. pneumoniae. The hpx cluster consists of seven genes, for which an organization in four transcriptional units, hpxDE, hpxR, hpxO and hpxPQT, is proposed. The proteins involved in the oxidation of hypoxanthine (HpxDE) or uric acid (HpxO) did not display any similarity to other reported enzymes known to catalyze these reactions, but instead are similar to oxygenases acting on aromatic compounds. Expression of the hpx system is activated by nitrogen limitation and by the presence of specific substrates, with hpxDE and hpxPQT controlled by both signals. Nitrogen control of hpxPQT transcription, which depends on 54, is mediated by the Ntr system. In contrast, neither NtrC nor NAC is involved in the nitrogen control of hpxDE, which is dependent on 70 for transcription. Activation of these operons by the specific substrates is also mediated by different effectors and regulatory proteins. Induction of hpxPQT requires uric acid formation, whereas expression of hpxDE is induced by the presence of hypoxanthine through the regulatory protein HpxR. This LysR-type regulator binds to a TCTGC-N4-GCAAA site in the intergenic hpxD-hpxR region. When bound to this site for hpxDE activation, HpxR negatively controls its own transcription.