scholarly journals Are Optical Tools Suitable to Manage Phosphate and Potassium Fertigation in Tomato Crops?

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1006A-1006 ◽  
Author(s):  
Paolo Sambo ◽  
Giorgio Gianquinto ◽  
Valente Forte
Keyword(s):  
Phosphorus Deficiency ◽  
Green Light ◽  
Fertilizer Application ◽  
Nitrogen And Phosphorus ◽  
Tomato Crop ◽  
Simple Index ◽  
First Results ◽  
Crop Cycle ◽  
Phosphorus And Potassium ◽  
N Management

Several experiments on multispectral radiometer showed its suitability in driving nitrogen fertigation in tomato crop. Nir-Green light ratio describes crop nitrogen status well, highlighting element deficiency or excess, which is a great help to farmers in choosing timing and intensity of fertilizer application. The scientific literature reports several studies about nitrogen management only, but not phosphorus and potassium. Because of the advantage obtained with N, it would be desirable to also adapt it to phosphorus and potassium management. For this purpose, a preliminary trial was carried out on the omato cultivar Brigade grown in pots in a greenhouse. Four nutrient solution were supplied. Three were lacking in N, P, or K—the last had all elements needed for a balanced growth. Radiometer readings were taken once a week during the crop cycle, around noon. First results were encouraging. After some data elaboration, it appeared evident that, in some cases, it was possible to set the fertigation treatments apart by only having a look at the single wavelengths measured by the instrument. Through the Nir/green index, used in N management, phosphorus deficiency was identified as well. Potassium trend line was completely different from those of nitrogen and phosphorus, and very similar to that of the control. The utilization of the radiometer in handling potassium fertigation in tomato appeared somewhat difficult. Its application might be desirable, instead, for phosphorus fertigation in addition to nitrogen. The 560 and 710 nm wavelengths might be the especially more useful for this purpose, although a simple index or a combination of some simple indices able to identify phosphorous deficiency/excess and to screen them from those induced by nitrogen are needed.

scholarly journals THE RESPONSE OF SUGARCANE TO FERTILIZERS I. THE ARECIBO CYCLE, 1944-1950

1969 ◽  
Vol 36 (3) ◽  
pp. 203-229
Author(s):  
George Samuels ◽  
Pablo Landrau, Jr.
Keyword(s):  
Dry Weight ◽  
Fertilizer Application ◽  
Phosphate Fertilizers ◽  
Nitrogen And Phosphorus ◽  
Yearly Variation ◽  
Rainfall Variations ◽  
The Mean ◽  
Phosphorus And Potassium ◽  
High Yields ◽  
Percent Nitrogen

A variety-fertilizer experiment using four varieties at seven fertilizer levels was carried on for a plant sugarcane and four ratoons. The major results were: 1. Nitrogen gave the highest yield increases in hundredweights of 96° available sugar per acre. 2. Phosphate fertilizers did not increase the yields of sugar. 3. Potassium fertilizers did increase the yields of sugar per acre. 4. The application of nitrogen and phosphorus did not influence sucrose concentrations in the cane. The omission of potassium did decrease the sucrose content of the cane significantly. 5. Variety P.R. 903 gave the highest yields of sugar per acre as compared with P.O.J. 2878, M. 275, and M. 317. The yields of M. 317 and P.O.J. 2878 were about equal, and M. 275 gave the lowest yields. 6. The varieties maintained their relative yielding power when tested at various fertilizer levels. Except for the no-fertilizer level, P.R. 903 maintained its significant lead in yield at all levels of fertilizer application. There was no significant interaction between varieties and fertilizers. 7. The reductions in yields from the omission of a fertilizer element for the mean of five crops were 33, 3, and 9 percent for nitrogen, phosphorus, and potassium, respectively. 8. Analysis of leaf samples revealed that corrections must be made for rainfall to prevent a yearly variation in the data. When corrected for rainfall variations, values of 1.40 percent nitrogen (dry weight of the leaf) or below were associated with low cane yields, and values of 1.60 percent or over with high yields. For phosphorus, values above 0.17 percent phosphorus in the leaf at a cane age of 3 months may be regarded as indicating no appreciable need for phosphate fertilizers. Potassium values of 1.70 percent potassium in the leaf or less indicate a need for potash, and 1.90 percent or greater, none.

FACTOR PRODUCTIVITY TRENDS IN A RICE–WHEAT CROPPING SYSTEM UNDER LONG-TERM USE OF CHEMICAL FERTILIZERS

1998 ◽  
Vol 34 (1) ◽  
pp. 1-18 ◽  
Author(s):  
R. L. YADAV
Keyword(s):  
Organic Carbon ◽  
Cropping System ◽  
Fertilizer Application ◽  
Factor Productivity ◽  
Nitrogen And Phosphorus ◽  
Available Nitrogen ◽  
Phosphorus And Potassium ◽  
Partial Factor Productivity ◽  
Partial Factor

A long-term fertilizer experiment was conducted on the rice–wheat cropping system at four locations in India. Trends in partial factor productivity of applied nitrogen, benefit : cost ratio of fertilizer application, grain yield, changes in soil organic carbon, and available nitrogen (N), phosphorus (P) and potassium (K) were studied in control (N0P0K0), N (N120P0K0), NP (N120P80K0), NK (N120P0K40) and NPK (N120P80K40) fertilizer treatments. On average at all locations, continuous rice–wheat cropping for 16 years decreased the yield of rice by 57% in unfertilized plots and by 32% in plots receiving nitrogen and phosphorus fertilizers. Over the same period wheat yields only declined in unfertilized plots by 18%; in plots receiving nitrogen, phosphorus and potassium yields increased by 18% and they increased by 33.6% in plots receiving nitrogen and phosphorus fertilizer. Partial factor productivity of applied nitrogen (the ratio of output value to the cost of a specific input) exhibited similar trends. Profit from fertilizer application, however, increased over the 16-year cycle by 130% in rice and by 262% in wheat in the treatment given nitrogen and phosphorus fertilizers. The long-term rice–wheat cropping system became depleted in soil organic carbon and available nitrogen and phosphorus at two locations but increased in organic carbon, available nitrogen and potassium at the third location. The available phosphorus and potassium content of the soil also increased at the fourth location.

scholarly journals FEATURES OF BASIC NUTRIENT CONSUMPTION BY LINSEED FLAXIN THE CONTEXT OF FERTILIZER APPLICATION

2021 ◽  
pp. 32-37
Author(s):  
P.Yu. Latartsev ◽  
◽  
O.I. Antonova ◽  
Keyword(s):  
Crop Yields ◽  
Fertilizer Application ◽  
Average Content ◽  
Nitrogen Application ◽  
Total Removal ◽  
Nitrogen And Phosphorus ◽  
Nutrient Consumption ◽  
Phosphorus Containing ◽  
Phosphorus And Potassium ◽  
Nitrogen Phosphorus

The study of the content and removal of nitrogen, phosphorus and potassium by linseed flax plants of the oilseed variety Severniy showed that more nitrogen and phosphorus accumulated in seeds, and potassium -in straw. The average content levels in seeds were as follow-ing: N -4.79%, P2O5 -0.79%, K2O -1.05% as compared to respective levels in straw: 0.64%, 0.1% and 1.73%. When applying fertilizers, the content of all nutrients in the straw decreases, and in the seeds it mainly remains at the con-trol level. Due to the higher crop yields in all fertilized vari-ants, the removal of phosphorus and potassium exceeds the control; and nitrogen removal –in the variants with a higher rate of nitrogen application. With seeds, an average of 87-87.8% of nitrogen and phosphorus and 37.3% of potassium from the total removal is removed from the field. Increased rate of nitrogen application contributes to greater consumption of not only nitrogen but also phosphorus and potassium. The rates of nitrogen application in the experi-ments do not compensate for its yield removal with seeds; that requires increased nitrogen application against the background of phosphorus-containing fertilizers.

Effects of Age at Harvest and Fertilizer Application on the Yield, Available Carbohydrates and Hydrocyanic Acid Content of Cassava (Manihot palmata Pohl)

1977 ◽  
Vol 88 (3) ◽  
pp. 679-681
Author(s):  
G. O. Obigbesan ◽  
A. O. Ketiku ◽  
A. A. Fayemi
Keyword(s):  
Acid Content ◽  
Fertilizer Application ◽  
Hydrocyanic Acid ◽  
Nitrogen And Phosphorus ◽  
Growing Seasons ◽  
Significant Yield ◽  
Phosphorus And Potassium ◽  
Nitrogen Phosphorus

SUMMARYExperiments were carried out over two growing seasons to find out the effects of fertilizer application and age at harvest on the yield, available carbohydrates and hydrocyanic acid content of Manihot palmata.Fertilizers were applied at the following rates: 0–0–0; 45–45–0; 45–45–45; 45–45–67, and 45–45–90 kg/ha of nitrogen, phosphorus and potassium respectively. Harvests were at 9 and 15 months after planting. Application of nitrogen and phosphorus resulted in significant yield increases. Fertilizer application had no significant effect on the hydrocyanic acid content of the tubers. Harvesting at 15 months gave more than double the tuber yields and a higher percentage of hydrocyanic acid than harvesting at 9 months. It is, therefore, desirable to use efficient methods of processing the tubers harvested at 15 months to obtain safe products for industrial and nutritional uses.

Effects of Nitrogen, Phosphorus and Potassium on Flowering and Yield of Soybeans in Nigeria

1965 ◽  
Vol 1 (3) ◽  
pp. 185-188
Author(s):  
G. P. Tewari
Keyword(s):  
Fertilizer Application ◽  
Residual Effects ◽  
First Year ◽  
Flower Initiation ◽  
Forming Process ◽  
Nitrogen And Phosphorus ◽  
Cropping Season ◽  
Second Year ◽  
Phosphorus And Potassium ◽  
Cropping Seasons

SummaryA NPK factorial experiment was conducted during two successive cropping seasons to study direct and residual effects of various treatments on the flower initiation and yield of soybeans. Plants were slower to reach the maximum flowering stage in the year of fertilizer application than in the following year. During the first year potassium in association with phosphorus delayed the flower forming process, whereas potassium alone hastened flowering in the second year unless associated with a high dosage of nitrogen. All the treatments gave far greater yields in the first season, suggesting that fertilizers should be applied during every cropping season. Nitrogen and phosphorus at 20 pounds of N2 and P2O5, per acre gave the biggest yields, but potassium failed to show any response. The residual responses to potassium and phosphorus during the second year were significant but not to nitrogen.

scholarly journals Performance of Cassava (Manihot esculenta Crantz) Varieties under Different Soil Amendments

2019 ◽  
pp. 1-7
Author(s):  
Kwadwo Gyasi Santo ◽  
Joseph Sarkodie-Addo
Keyword(s):  
Starch Content ◽  
Block Design ◽  
Organic Fertilizer ◽  
Poultry Manure ◽  
Fertilizer Application ◽  
Nitrogen And Phosphorus ◽  
Manihot Esculenta Crantz ◽  
Combined Application ◽  
Phosphorus And Potassium ◽  
Nitrogen Phosphorus

Studies were carried out at Offinso in the Ashanti Region of Ghana to assess root quality of cassava grown with application of poultry manure and NPK 15-15-15 and NPK 23-10-10 fertilizers. The experimental design was a 2 x 6 factorial, arranged in a Randomized Complete Block Design (RCBD) with three replications. The treatments consisted of two cassava varieties in combination with five inorganic and/or organic fertilizer formulations and a control with no fertilizer. The parameters measured were starch content, poundability, nitrogen, phosphorus and potassium contents of cassava roots. The data collected were subjected to analysis of variance using the Genstat Statistical package. The results of the study indicated that Bankyehemaa produced higher starch content (29.86%) than the Nkabom variety. Fertilizer application increased starch content with the combined application of poultry manure and NPK 23-10-10 treatment recording the highest treatment effect (30.40%). Both the organic and inorganic fertilizers applied increased starch content of cassava roots. Poundability was not also affected by both variety and fertilizer application. However, roots treated with NPK 15-15-15 only and poultry manure alone were very poundable (3.0). Variety significantly affected only nitrogen and phosphorus contents of cassava roots. Bankyehemaa had higher content (0.72%) of nitrogen than Nkabom, while Nkabom recorded higher content (1.05%) of phosphorus than Bankyehemaa. Generally, application of fertilizer significantly affected root contents of nitrogen, phosphorus and potassium. However, potassium and phosphorus contents were reduced by the organic fertilizer (poultry manure). The NPK 15-15-15 treatment produced higher potassium (9.37%) and phosphorus (1.36%) contents of roots than the other treatments. The highest nitrogen content of roots (0.78%) was observed in the combined application of poultry manure and NPK 23-10-10 treatment.

New Results on Electroluminescence from Porous Silicon

1992 ◽  
Vol 283 ◽  
Author(s):  
Peter Steiner ◽  
Frank Kozlowski ◽  
Hermann Sandmaier ◽  
Walter Lang
Keyword(s):  
Porous Silicon ◽  
Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Uv Light ◽  
Green Light ◽  
Light Emitting ◽  
Porous Region ◽  
First Results

ABSTRACTFirst results on light emitting diodes in porous silicon were reported in 1991. They showed a quantum efficiency of 10-7 to 10-5 and an orange spectrum. Over the last year some progress was achieved:- By applying UV-light during the etching blue and green light emitting diodes in porous silicon are fabricated.- When a p/n junction is realized within the porous region, a quantum efficiency of 10-4 is obtained.

scholarly journals N Management of European Grasslands: Can the Exchange of Gaseous N Species Be Influenced at the Operational Level?

2001 ◽  
Vol 1 ◽  
pp. 652-657 ◽  
Author(s):  
P. Calanca ◽  
A. Neftel ◽  
J. Fuhrer
Keyword(s):  
Late Summer ◽  
Fertilizer Application ◽  
Effective Control ◽  
Management Options ◽  
Total N ◽  
Model Calculations ◽  
Weather Forecasts ◽  
Grassland Ecosystems ◽  
Order Of Magnitude ◽  
N Management

Grassland ecosystems can be regarded as biochemical reactors in which large amounts of organic nitrogen (N) are converted into inorganic N, and vice versa. If managed in a sustainable manner, grasslands should operate in a quasi steady state, characterized by an almost perfect balance between total N input and output. As a consequence, the exchange of gaseous N species (NH3, NO, NO2, N2O, and N2) between grasslands and the atmosphere is very small compared to the total N turnover. In this study, the effects of two management options (mowing and fertilization) on production and emission of nitrous oxide (N2O) from a grass/clover crop were examined on the basis of observations and model results referring to an experiment carried out on the Swiss Plateau in late summer of 2000. It was found that production and emission of N2O induced by mowing were of the same order of magnitude as those brought about by fertilization, suggesting a possible transfer of N from clover to the soil after defoliation. Emissions were strongly modulated by precipitation on time scales ranging from 1 day to 1 week. This indicates that effective control of N2O emissions through management on a day-to-day basis requires reliable medium-range weather forecasts. Model calculations were not able to reproduce essential characteristics of the emissions. The model slightly overestimated the background emissions, but severely underestimated the emission peaks following fertilizer application, and largely failed to reproduce emission induced by mowing. Shortfalls in the model used for this study were found in relation to the description of soil-water fluxes, soil organic matter, and the physiology of clover.

scholarly journals BALANÇO DA FERTIRRIGAÇÃO EM MELOEIRO “PELE-DE-SAPO”

Irriga ◽  
2007 ◽  
Vol 12 (1) ◽  
pp. 63-72 ◽  
Author(s):  
Manoel Januário da Silva Júnior ◽  
José Francismar de Medeiros ◽  
Fábio Henrique Tavares de Oliveira ◽  
Indalécio Dutra
Keyword(s):  
Soil Nitrogen ◽  
Cucumis Melo ◽  
Nutrient Balance ◽  
Rio Grande ◽  
Critical Periods ◽  
Management Efficiency ◽  
Crop Cycle ◽  
Phosphorus And Potassium ◽  
Cucumis Melo L ◽  
Nitrogen Phosphorus

BALANÇO DA FERTIRRIGAÇÃO EM MELOEIRO “PELE-DE-SAPO”  Manoel Januário da Silva Júnior1; José Francismar de Medeiros2; Fábio Henrique Tavares de Oliveira3; Indalécio Dutra21Departamento de Engenharia Rural, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, SP, [email protected] de Ciências Ambientais, Universidade Federal Rural do Semi-Árido, Mossoró 3Departamento de Solos e Engenharia Rural, CCA, Universidade Federal da Paraiba, Areia, PB,  1 RESUMO O melão produzido no estado do Rio Grande do Norte é cultivado sob irrigação, sendo uma das culturas em que mais se pratica a fertirrigação. A fertirrigação tem se mostrado como a técnica mais adequada para parcelar a dose dos nutrientes em várias aplicações durante o ciclo da cultura. Entretanto, ainda não se conhece a eficiência dessa técnica. O objetivo deste trabalho foi avaliar o balanço dos nutrientes no sistema solo-planta, aplicados através da fertirrigação identificando os períodos críticos para o manejo da fertirrigação. Os tratamentos foram: doses de nitrogênio (83, 119 e 156 kgN ha-1) e doses de potássio (190, 271 e 352 kg K2O ha-1) aplicadas via fertirrigação e o experimento foi montado em blocos aleatorizados com três repetições. Coletou-se solo e planta aos 22, 33, 43, 54 e 69 dias após a semeadura e determinaram-se os teores de N, P e K na planta e no solo. O aumento da dose de nitrogênio provocou aumento das perdas desse nutriente e, quando se aumentou a dose de potássio houve acúmulo no solo. As maiores perdas de nitrogênio, fósforo e potássio ocorreram no período de maior exigência nutricional da cultura. UNITERMOS: Cucumis melo L., manejo da fertirrigação, índices de eficiência  SILVA JÚNIOR, M. J. da; MEDEIROS, J. F. de; OLIVEIRA, F. H. T. de; DUTRA, I. BALANCE OF FERTIGATION IN “PELE-DE-SAPO” MELON PLANTS  2 ABSTRACT Melon production in Rio Grandedo Norte state (Brazil) is grown under irrigation and it is one of the crops where fertigation is more used. The importance of fertigation technique is attributed to nutrient dose fractioning into several applications during crop cycle. Therefore, the efficiency of this technique is not known yet. This study aimed to evaluate nutrient balance applied through fertigation in a soil-plant system to identify critical periods for fertigation management. The treatments consisted of nitrogen doses (83, 119, and 156 kgN ha-1) and potassium doses (190, 271, and 352 kg K2O ha-1) applied via fertigation and the experimental design was randomized blocks with three replications. Soil and plants were sampled at 22, 33, 43, 54 and 69 days after seeding to determine plant and soil contents of N, P and K. The increase in nitrogen dose raised soil nitrogen losses, but the increase in potassium dose caused accumulation in the soil. Higher losses of nitrogen, phosphorus and potassium occurred in the crop higher nutritional demand stage. KEYWORDS: Cucumis melo L., fertigation management, efficiency indices

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