scholarly journals Evaluation of the correlation between SPAD readings and absolute chlorophyll content of maize under different nitrogen supply conditions

2019 ◽  
pp. 121-126
Author(s):  
Attila Simkó ◽  
Szilvia Veres

Currently, one of the most important objectives of agriculture is to maintain the principles of the sustainability. The use of precision technologies in agriculture belongs to this topic. The use of precision technologies is increasingly widespread in the cultivation of various agricultural crops, including maize. Sensing is an important part of these techniques. In our experiment we compared two methods: measuring relative chlorophyll content and the method of determine the extractable chlorophylls. The experimental plant was maize (Zea mays L.) and the measurements were performed at an early development stage (V8) of three genotypes. Three levels of nitrogen (0; 80; 160 kg ha-1) were applied during the experiment. The relative chlorophyll content was measured by SPAD-502 (Minolta, Japan) and a handheld GreenSeeker (Trimble, USA) device. The extractable total chlorophyll content decreased in parallel with the increased nitrogen level. The obtained SPAD values were diversified furthermore the NDVI values have not been changed for the effect of different nitrogen fertilization. In the early stages of development of maize, these parameters need to be complemented with other measurements to provide reliable information about the crops nitrogen status.

Author(s):  
Dinkar J. Gaikwad ◽  
Apurba Pal ◽  
Subhasis Mondal

Aims: Arsenic (As) contamination in rice is at alarming level as majority of rice growing regions in India are As contaminated. Present investigation is designed to study the better understanding of the physiological and biochemical mechanisms in the amount of chlorophyll change and antioxidative enzymes activity under arsenic stress on rice variety IET-4786 (Shatabdi). Study Design: Completely Randomized Design. Place and Duration of Study: The experiment was carried out in the departmental laboratory of Plant Physiology, Bidhan Chandra Krishi Viswavidyalaya (BCKV), Mohanpur, Nadia,West Bengal during the year 2017-18. Methodology: Two classes of inorganic arsenic- As(V) in the form of Sodium arsenate (Na2HAsO4.7H2O, M. W. = 321.01) and As(III) in the form of Sodium arsenite (NaAsO2, M.W. =129.91) were added to the modified Hoagland nutrient solution@ 2.5, 5.0, 7.5, 10.0, 12.5,15.0 mg L-1concentration. After 20 days of treatment, rice seedlings under arsenate/arsenite treatments were analyzed for change in total chlorophyll content and antioxidative enzymes activity such as superoxide dismutase (SOD: EC 1.15.1.1), catalase (CAT: EC 1.11.1.6), ascorbate peroxidase (APX: EC1.11.1.11) and peroxidase (POD: EC 1.11.1.7). Results: A noticeable decrease in total chlorophyll content was observed with arsenic treatments as compared to control. Various antioxidative enzymes showed significant variable response upon exposure to As(III) and As(V). SOD activities increased at low arsenic exposure up to 7.5 mg L-1 but decreased with further increase in arsenic treatments.  APX and POD activities were increased with increase in arsenic concentrations while CAT activity displayed decreasing trend. Conclusion: The results are suggestive of differential metabolism of As(III) and As(V) in rice and could exert harmfulness in the early development stage of rice at inappropriate concentrations.


2021 ◽  
Vol 13 (7) ◽  
pp. 1
Author(s):  
Thiago C. V. Stacciarini ◽  
Aurélio R. Neto ◽  
José M. Alves ◽  
Marina G. Marques

In Brazil, sugarcane (Saccharum spp.) is considered one of the most economically important crops. Nitrogen (N) is one of the most required elements in sugarcane cultivation. Nevertheless, the information about the soil and foliar applications of this nutrient in crops are discrepant. Therefore, the importance of this study is evident. Given the above, this study aimed to evaluate the soil-applied and foliar N fertilization of sugarcane. The experiment was conducted at the Araporã Bioenergia S.A. power plant, located at Fazenda Santa Rita, in the municipality of Itumbiara-GO. The 5 × 5 factorial design was adopted, with four repetitions, including five doses of soil-applied ammonium nitrate and five doses of foliar Amidic N polymer. The nutrient extraction, the experiment’s initial and final total chlorophyll content, the biometric indexes and the industrial quality indexes were analyzed for sugarcane. The ammonium nitrate doses caused differences in fiber, sacarose content, total recoverable sugar, sugar cane Brix, magnesium, and zinc, which was statistically different for the foliar polymer doses. There was no increment of the production variables with the increase of the nitrogen supply in the soil. On the other hand, the levels of zinc and magnesium in the leaves increased 12% and 27%, respectively, reflecting the importance of this fertilization in sugarcane cultivation.


2013 ◽  
pp. 159-162
Author(s):  
Péter Ragán

Nitrogen fertilisation is a critical point of maize production. Five hybrids of different maturity dates were examined in a field experiment, three treatments (different application dates) and three basic fertiliser doses (0, 60, 120 kg ha-1 N) were used. At the 6-leaf-stage of maize, each fertilisation level of the 2nd and 3rd treatment was given 30 kg N ha-1 fertiliser active ingredient in addition to the basic fertiliser doses with the exception of the control plots and further 30 kg N ha-1 fertiliser was applied at the 12-leaf-stage. The final fertiliser doses were 0, 90 and 150 kg N ha-1 in the second treatment and 0, 120 and 180 kg N ha-1 in the 3rd treatment. The whole amount of the basic fertiliser (ammonium nitrate) was applied in the spring, one month before sowing. The relative chlorophyll content of the maize leaves was measured, with a Minolta SPAD-502 measurement device. The measurements were carried out at the 6-leaf growth stage (V6) of maize on the youngest fully developed leaf of the 6th, 7th and 8th plants from the second row of each plot. There were significant differences in the SPAD-readings measured at the V6 phenophase of maize between the hybrids (p<0.001) and the fertiliser treatments (p<0.05). The regression analysis did not show any correlation between the SPAD-values and fertilisation. The highest significant SPAD-reading and yield were obtained by applying 120 kg ha-1 N. As a result of the regression analysis performed on yield, it can be concluded that the correlation between fertilisation and yield in the 1st and 2nd treatment was moderately close (r=0.439, r=0.480) and it was close in the 3rd treatment (r=0.513). The correlation between the SPAD-readings and yield was the closes in the 2nd treatment (r=0.639), while the SPAD-value had a 40.9% influence on yield (p<0.001).


2016 ◽  
Vol 15 (3) ◽  
pp. 398 ◽  
Author(s):  
RAFAEL CADORE ◽  
ANTÔNIO PAULINO DA COSTA NETTO ◽  
EDÉSIO FIALHO DOS REIS ◽  
VILMAR ANTONIO RAGAGNIN ◽  
DOUGLAS SIQUEIRA FREITAS ◽  
...  

RESUMO - Microrganismos do gênero Azospirillum possuem o potencial de melhorar o desenvolvimento e a produção da cultura do milho. Porém as respostas dos híbridos de milho não são iguais frente à inoculação com estes microrganismos, devido a possível especificidade na interação entre genótipo e microrganismo e os diferentes manejos adotados. Desta forma, objetivou-se com este trabalho avaliar o desenvolvimento e a produtividade de dez híbridos a fim de indicar entre esses híbridos os mais responsivos quando submetidos à inoculação de Azospirillum brasilense e a diferentes doses de nitrogênio em cobertura. Vários caracteres agronômicos foram avaliados como: altura de plantas, altura de inserção da espiga, diâmetro de colmo, teor de clorofila total, tamanho de espiga, número de fileiras da espiga, números de grãos por fileira, massa de 100 grãos e produtividade de grãos. Além dos caracteres agronômicos avaliou-se a atividade da enzima redutase do nitrato em duas diferentes épocas (V4 - V6 e VT). Os híbridos mais produtivos foram o Biogene 7046, Dekalb 310 VT PRO™ e Agroeste 1596 VT PRO™. O incremento das doses de nitrogênio aumentou o diâmetro do colmo, teor de clorofila total, comprimento da espiga, grãos por fileira e a produção de grãos.Palavras-chave: adubação nitrogenada; bactérias diazotróficas; safrinha.MAIZE HYBRIDS INOCULATED WITH Azospirillum brasilense UNDER DIFFERENT DOSES OF NITROGENABSTRACT – Microorganisms of the genus Azospirillum have the potential to improve the development and production of maize. However, the response of corn hybrids is not equal under inoculation with these microorganisms due to the specificity in the interaction between genotype and microorganism and the use of different managements. Thus, the objective of this work was to evaluate the development and productivity of ten hybrids to indicate the most responsive when subjected to inoculation with Azospirillum brasilense and different doses of nitrogen fertilization. Several agronomic characters were evaluate as plant height, ear insertion height, stem diameter, total chlorophyll content, ear size, number of rows grains per ear, number of grains per row, mass of 100 grains and grain yield. In addition to the agronomic traits the activity of the enzyme nitrate reductase was evaluated in two different seasons (V4 - V6 and VT). The most productive hybrids were Biogene 7046, Dekalb 310 VT PRO ™ and Agroeste 1596 VT PRO ™.The increment of nitrogen increased stem diameter, total chlorophyll content, ear length, grains per row and grain production.Keywords: dizotrofic bacterias; nitrogen fertilization; second harvest.


Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 492
Author(s):  
Meriem Riache ◽  
Pedro Revilla ◽  
Oula Maafi ◽  
Rosa Ana Malvar ◽  
Abderahmane Djemel

Drought and low nitrogen are major stresses for maize (Zea mays L.), and maize populations from the Sahara Desert are potential sources of stress tolerance. The objectives were to assess the tolerance and varietal and heterosis effects of Algerian populations under no-nitrogen fertilization and water stress. A diallel among six Algerian maize population was evaluated under drought (300 mm irrigation) vs. control (600 mm) and no-nitrogen fertilization vs. 120 kh ha−1 N fertilization. Genotypes showed significant differences and genetic effects for water- and nitrogen-stress tolerance. We propose a reciprocal recurrent selection to take advantage of additive and non-additive effects, using AOR and IGS, since they showed good performance in optimum and stress conditions, for improving yield heterosis for AOR × IGS. Negative effects are not expected on plant height, anthesis–silking interval or early vigor. These populations and BAH could be sources of inbred lines tolerant to drought and no-nitrogen fertilization. There was no relationship between origin and genetic group and stress tolerance per se or as parents of tolerant crosses. These populations and crosses could be used as base material among Algerian populations, for breeding programs focusing on tolerance to water or nitrogen stress.


Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1354
Author(s):  
Sergio E. Medina-Cuéllar ◽  
Deli N. Tirado-González ◽  
Marcos Portillo-Vázquez ◽  
Sergio Orozco-Cirilo ◽  
Marco A. López-Santiago ◽  
...  

Utilization of maize stover to the production of meat and milk and saving the grains for human consumption would be one strategy for the optimal usage of resources. Variance and tendency analyses were applied to find the optimal nitrogen (N) fertilization dose (0, 100, 145, 190, 240, and 290 kg/ha) for forage (F), stover (S), cob (C), and grain (G) yields, as well as the optimal grain-to-forage, cob-to-forage, and cob-to-stover ratios (G:F, C:F, and C:S, respectively). The study was performed in central Mexico (20.691389° N and −101.259722° W, 1740 m a.m.s.l.; Cwa (Köppen), 699 mm annual precipitation; alluvial soils). N-190 and N-240 improved the individual yields and ratios the most. Linear and quadratic models for CDM, GDM, and G:F ratio had coefficients of determination (R2) of 0.20–0.46 (p < 0.03). Cubic showed R2 = 0.30–0.72 (p < 0.02), and the best models were for CDM, GDM, and the G:F, C:F, and C:S DM ratios (R2 = 0.60–0.72; p < 0.0002). Neither SHB nor SDM negatively correlated with CDM or GDM (r = 0.23–0.48; p < 0.0001). Excess of N had negative effects on forage, stover, cobs, and grains yields, but optimal N fertilization increased the proportion of the G:F, C:F, and C:S ratios, as well as the SHB and SDM yields, without negative effects on grain production.


2021 ◽  
Vol 184 ◽  
pp. 106088
Author(s):  
Jing Zhang ◽  
Haiqing Tian ◽  
Di Wang ◽  
Haijun Li ◽  
Abdul Mounem Mouazen

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1211
Author(s):  
Barbara Frąszczak ◽  
Monika Kula-Maximenko

The spectrum of light significantly influences the growth of plants cultivated in closed systems. Five lettuce cultivars with different leaf colours were grown under white light (W, 170 μmol m−2 s−1) and under white light with the addition of red (W + R) or blue light (W + B) (230 μmol m−2 s−1). The plants were grown until they reached the seedling phase (30 days). Each cultivar reacted differently to the light spectrum applied. The red-leaved cultivar exhibited the strongest plasticity in response to the spectrum. The blue light stimulated the growth of the leaf surface in all the plants. The red light negatively influenced the length of leaves in the cultivars, but it positively affected their number in red and dark-green lettuce. It also increased the relative chlorophyll content and fresh weight gain in the cultivars containing anthocyanins. When the cultivars were grown under white light, they had longer leaves and higher value of the leaf shape index. The light-green cultivars had a greater fresh weight. Both the addition of blue and red light significantly increased the relative chlorophyll content in the dark-green cultivar. The spectrum enhanced with blue light had positive influence on most of the parameters under analysis in butter lettuce cultivars. These cultivars were also characterised by the highest absorbance of blue light.


Sign in / Sign up

Export Citation Format

Share Document