scholarly journals UROCHLOA GRASS GROWTH AS A FUNCTION OF NITROGEN AND PHOSPHORUS FERTILIZATION

2021 ◽  
Vol 39 (4) ◽  
pp. 492-504
Author(s):  
Maurício Luiz de Mello Vieira LEITE ◽  
Leandro Ricardo Rodrigues de LUCENA ◽  
Raul Caco Alves BEZERRA ◽  
Mirna Clarissa Rodrigues de ALMEIDA ◽  
Vicente José Laamon Pinto SIMÕES

The urochloa grass (Urochloa mosambicensis) is a perennial grass, C4 plant, with a high photosynthetic rate and CO2 fixation, persistent to water deficit, adapted to a wide diversity of soils and hot climate regions. Thus, the objective was to evaluate the urochloa grass growth and define the best models to estimate plant height as a function of nitrogen and phosphate fertilization. The experimental design was completely randomized, in the 2 x 2 factorial design (presence and absence of nitrogen presence and absence of phosphorus), with four replications. Was used a dose of nitrogen and phosphorus equivalent to 100 kg.ha-1 of N and 150 kg.ha-1 of P2O5, respectively. The following models were used: linear, power, gamma andlogistic to estimate plant height as a function of the following explanatory variables: days after planting, nitrogen and phosphorus doses. The criteria used to determine the best model(s) were as follows: higher adjusted coefficient of determination, lower Akaike information criterion, lower sum of square of residuals and high Willmott index. The plant height in the absence of nitrogen and phosphorus and when applied 100 kg.ha-1 of N and 150 kg.ha-1 of P2O5 was estimated more accurately by the Gamma model with high power of explanation. The adoption of the Gamma model allows to estimate the U.  mosambicensis plant height, in a non-destructive manner, with high precision, speed and low cost, depending of age plant and nitrogen and phosphate fertilization.

Author(s):  
S. Brocks ◽  
G. Bareth

Crop-Surface-Models (CSMs) are a useful tool for monitoring in-field crop growth variability, thus enabling precision agriculture which is necessary for achieving higher agricultural yields. This contribution provides a first assessment on the suitability of using consumer-grade smart cameras as sensors for the stereoscopic creation of crop-surface models using oblique imagery acquired from ground-based positions. An application that automates image acquisition and transmission was developed. Automated image acquisition took place throughout the growing period of barley in 2013. For three dates where both automated image acquisition and manual measurements of plant height were available, CSMs were generated using a combination of AgiSoft PhotoScan and Esri ArcGIS. The coefficient of determination <i>R</i><sup>2</sup> between the average of the manually measured plant heights per plots and the average height of the developed crop surface models was 0.61 (<i>n</i> = 24). The overall correlation between the manually measured heights and the CSM-derived heights is 0.78. The average per plot of the manually measured plant heights in the timeframe covered by the generated CSMs range from 19 to 95 cm, while the average plant height per plot of the generated CSMs range from 2.1 to 69 cm. These first results show that the presented approach is feasible.


2019 ◽  
pp. 1967-1974
Author(s):  
Carime Moraes ◽  
Roberta Mendes dos Santos ◽  
Everlon Cid Rigobelo

Maize is the most important crop cultivated worldwide. It needs a significant amount of nitrogen and phosphorus fertilization to maintain high yields. However, the high cost of fertilization makes production more expensive and damages the environment. The present study used Azospirillum brasilense and Bacillus subtilis bacteria in an attempt to supply nitrogen and phosphorus fertilization to a maize crop. The experiment was carried out with maize plants under greenhouse conditions with a factorial scheme (4 x 2 x 2), where the first factor corresponded to bacterial inoculation: (a) control (no inoculation); (b) A. brasilense inoculation (AZ); (c) B. subtilis inoculation (BS) and (d) inoculation with a mixture of (AZ+BS), the second factor corresponded to the presence or absence of rock phosphate fertilization and the third factor corresponded to the presence or absence of top-dressed nitrogen fertilizer. Evaluated plant parameters were height, shoot dry matter (SDM), root dry matter (RDM), and soil parameters were total colony forming units of bacteria (CFU), nitrogen, soluble phosphorus and microbial biomass carbon (MBC). Although some parameters were improved with mineral fertilization in general, the findings showed that there were many adverse effects with the use of rock phosphate fertilization and A. brasilense inoculation. When both were applied together in treatments, there was reduction in plant height, microbial biomass carbon and total number of bacteria compared to treatments without rock phosphate fertilization. These results strongly suggest that rock phosphate harms the ability of A. brasilense to promote plant growth and demonstrate the necessity of new studies to verify whether this negative effect occurs under field conditions and could reduce yields in maize crop production.


Author(s):  
Manal A. Asker

A field experiment was conducted to study the effect of nitrogen(0,200 and 300 kgNha-1) and phosphorus (0,60,and 180 kgPha-1) fertilization and their combination on yield and some growth parameters of sudangrass(Sorghum Sudanese). (Number of leaves per plant, plant height, number of heads per plant, weight of 1000 seeds, ,yields of seeds , dry weight of shoots and protein content in seeds)were measure . Results indicated that nitrogen and phosphate application and their combination had significant effects on all growth parameters and yield of Sudangrass . The combination treatment of 300kgNha-1 plus 180 kgPha-1) gave higher yield (71.86 gm.plant-1) and protein content in seeds( 5.79 %) and other growth parameters.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Supakorn Harnsoongnoen ◽  
Nuananong Jaroensuk

AbstractThe water displacement and flotation are two of the most accurate and rapid methods for grading and assessing freshness of agricultural products based on density determination. However, these techniques are still not suitable for use in agricultural inspections of products such as eggs that absorb water which can be considered intrusive or destructive and can affect the result of measurements. Here we present a novel proposal for a method of non-destructive, non-invasive, low cost, simple and real—time monitoring of the grading and freshness assessment of eggs based on density detection using machine vision and a weighing sensor. This is the first proposal that divides egg freshness into intervals through density measurements. The machine vision system was developed for the measurement of external physical characteristics (length and breadth) of eggs for evaluating their volume. The weighing system was developed for the measurement of the weight of the egg. Egg weight and volume were used to calculate density for grading and egg freshness assessment. The proposed system could measure the weight, volume and density with an accuracy of 99.88%, 98.26% and 99.02%, respectively. The results showed that the weight and freshness of eggs stored at room temperature decreased with storage time. The relationship between density and percentage of freshness was linear for the all sizes of eggs, the coefficient of determination (R2) of 0.9982, 0.9999, 0.9996, 0.9996 and 0.9994 for classified egg size classified 0, 1, 2, 3 and 4, respectively. This study shows that egg freshness can be determined through density without using water to test for water displacement or egg flotation which has future potential as a measuring system important for the poultry industry.


Sensors ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 256
Author(s):  
Pengfei Han ◽  
Han Mei ◽  
Di Liu ◽  
Ning Zeng ◽  
Xiao Tang ◽  
...  

Pollutant gases, such as CO, NO2, O3, and SO2 affect human health, and low-cost sensors are an important complement to regulatory-grade instruments in pollutant monitoring. Previous studies focused on one or several species, while comprehensive assessments of multiple sensors remain limited. We conducted a 12-month field evaluation of four Alphasense sensors in Beijing and used single linear regression (SLR), multiple linear regression (MLR), random forest regressor (RFR), and neural network (long short-term memory (LSTM)) methods to calibrate and validate the measurements with nearby reference measurements from national monitoring stations. For performances, CO > O3 > NO2 > SO2 for the coefficient of determination (R2) and root mean square error (RMSE). The MLR did not increase the R2 after considering the temperature and relative humidity influences compared with the SLR (with R2 remaining at approximately 0.6 for O3 and 0.4 for NO2). However, the RFR and LSTM models significantly increased the O3, NO2, and SO2 performances, with the R2 increasing from 0.3–0.5 to >0.7 for O3 and NO2, and the RMSE decreasing from 20.4 to 13.2 ppb for NO2. For the SLR, there were relatively larger biases, while the LSTMs maintained a close mean relative bias of approximately zero (e.g., <5% for O3 and NO2), indicating that these sensors combined with the LSTMs are suitable for hot spot detection. We highlight that the performance of LSTM is better than that of random forest and linear methods. This study assessed four electrochemical air quality sensors and different calibration models, and the methodology and results can benefit assessments of other low-cost sensors.


2014 ◽  
Vol 18 (6) ◽  
pp. 2191-2200 ◽  
Author(s):  
S. T. Harrington ◽  
J. R. Harrington

Abstract. The objective of this research was to investigate the relationship between water and sediment discharge on the transport of nutrients: nitrogen and phosphorus. Water discharge, suspended sediment concentration and dissolved and particulate forms of nitrogen and phosphorus were monitored on the 105 km2 River Owenabue catchment in Ireland. Water discharge was found to have an influence on both particulate and dissolved nutrient transport, but more so for particulate nutrients. The particulate portion of N and P in collected samples was found to be 24 and 39%, respectively. Increased particulate nitrogen concentrations were found at the onset of high discharge events, but did not correlate well to discharge. High concentrations of phosphorus were associated with increased discharge rates and the coefficient of determination (r2) between most forms of phosphorus and both discharge and suspended sediment concentrations were observed to be greater than 0.5. The mean TN yield is 4004 kg km−2 yr−1 for the full 29-month monitoring period with a mean PN yield of 982 kg km−2 yr−1, 25% of the TN yield with the contribution to the yield of PN and PP estimated to be 25 and 53% respectively. These yields represent a PN and PP contribution to the suspended sediment load of 5.6 and 0.28% respectively for the monitoring period. While total nitrogen and total phosphorus levels were similar to other European catchments, levels of bio-available phosphorus were elevated indicating a potential risk of eutrophication within the river.


2008 ◽  
Vol 3 (1) ◽  
Author(s):  
V. Lina Cardoso ◽  
C. Esperanza Ramírez ◽  
E. Violeta Escalante

There are problems associated with sludge management in small treatment plants (&lt;10 L/s) located in rural communities, due to costly conventional technology for sludge stabilization. Many of these plants have only sludge drying beds. Mexican Institute of Water Technology has proposed developing suitable low-cost technologies, one of which is vermicomposting a biodegradation system using earthworms of the species Eisenia foetida (earthworm) which stabilize sludge and reduce its pathogenicity. The objective of this work is to present two case studies where vermicomposting technology has been applied in Mexico. The first study corresponds to a plant where 4.8 m3/month of sludge are produced; for these wastes, a vermicomposting system was built and installed. The second study is a treatment plant where 9 m3/month of sludge are produced; experimental tests were conducted with sludge and water hyacinth and a vermicomposting system was designed. The vermicomposts were analyzed using parameters defined by Mexican standards. In regards to stabilization, TVS was reduced by 38% and the microbiological quality of the vermicompost was Class A and B, with a reduction in fecal coliforms and Helminth eggs according to NOM-004-SEMARNAT-2002. A CRETI (Corrosivity, Reactivity, Explosivity, Toxicity and Ignitability) analysis (NOM-052-SEMARNAT-2005) was used to show that the process reduced the concentration of releasable sulfides. The agronomic quality of the vermicompost exhibited a high content of organic matter comparable to many organic manures and high content of nutrients such as nitrogen and phosphorus. It is concluded that it is possible to improve the conditions of sewage sludge management in small plants of rural communities with a minimum investment (less than $10,000.00 USD) and with a requirement of a minimum area of 60 to 70 m2 for a production of less than 9 m3/month of dehydrated sludge (80% humidity).


2021 ◽  
Vol 11 (21) ◽  
pp. 10454
Author(s):  
Antonella Maria Loconsole ◽  
Vito Vincenzo Francione ◽  
Vincenza Portosi ◽  
Onofrio Losito ◽  
Michele Catalano ◽  
...  

A water-in-diesel microwave sensor based on a substrate integrated waveguide (SIW) microwave applicator is designed and characterized in this study. The interaction between the microwave electromagnetic field and the diesel fuel contaminated with small concentrations of water is obtained via suitable radiating slots placed on the top of an SIW waveguiding structure. The SIW applicator working frequency is chosen by observing the behavior of the complex dielectric permittivity of the fuel–water blend based on a preliminary wide band investigation. The performances of the SIW microwave sensor are evaluated in terms of scattering parameter modulus |S21| as a function of the water concentration in ppm. The best sensitivity Δ|S21|Δρ=1.42 mdB/ppm is obtained at a frequency of f=9.76 GHz, with a coefficient of determination R2=0.94. The sensor is low-cost, low profile and ensures a good sensitivity for constant and real-time monitoring.


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