scholarly journals Defoliation percentage in two soybean cultivars at different growth stages

Author(s):  
Cláudio A. da S. Glier ◽  
José B. Duarte Júnior ◽  
Gabriel M. Fachin ◽  
Antonio C. T. da Costa ◽  
Vandeir F. Guimarães ◽  
...  

ABSTRACT The objective of this study was to evaluate the agronomic variables due to the effects of different levels of defoliation in the phenological phases of two soybean cultivars. The experiment was conducted during the 2011/2012 season, in a randomized block design with three replicates, in a 2 x 4 x 5 factorial scheme. Two cultivars were exposed to defoliations of 0, 25, 50, 75 and 100% at the stages of V4, V9, R3 and R5. The cultivar 'NK 7059RR' showed less sensitivity to defoliation than the cultivar 'IN 4990RG'. 25% defoliation levels reduced the yield of the cultivar 'IN 4990RG', while levels of 75 and 100% reduce the number of grains per pod in both cultivars. The defoliation performed in the V4 stage lead to lower grain yield than defoliation in V9. The most sensitive stages to defoliation are R3 and R5, where there is a greater reduction in the production potential of soybeans.

2020 ◽  
Vol 8 (3) ◽  
pp. 63
Author(s):  
Priscila Pereira Sacramento ◽  
Letícia Cunha da Hungria ◽  
Jamil Chaar El-Husny ◽  
Luis De Souza Freitas

The aim of this study was to evaluate the influence of planting density and cultivar of soybean on yield components in the southeast Amazon. The experiment was carried out in an Oxisol, with a randomized block design in a 2 x 4 factorial scheme. The treatments were two soybean cultivars (BRS 9090 RR and BRS 8990 RR) and four planting densities (13, 15, 18 and 20 plants m-1), with three replications. First pod insertion height (IFP), plant height (H), number of pods per plant (NPP), grain yield (Y) and weight of 100 grains (W100) were evaluated. The insertion height of the first pod showed a tendency of increase with the increment of plants per linear meter for cultivar BRS 8990 RR, different of the behavior observed for the cultivar BRS 9090 RR, which only showed difference when the density of 300.000 plants ha-1 was tested. For plant height, among soybean cultivars, there was only difference in D400, with BRS 8990 RR showing a maximum height of 83.3 cm, 21% higher than BRS 9090 RR. When evaluated under D350, BRS 8990 RR showed an increase of 13% in the number of pods compared to BRS 9090 RR. Both cultivars showed linear behavior for the grain yield, increasing according the plant population, with the highest grain yield obtained under the density of 400.000 plants ha-1 (4527.3 kg ha-1). The weight of 100 grains was not influenced by any variation factor.


2019 ◽  
Vol 11 (6) ◽  
pp. 407
Author(s):  
T. Schneider ◽  
M. A. Rizzardi ◽  
A. P. Rockenbach ◽  
S. T. Peruzzo

Soybean cultivars without tolerance can suffer injury from exposure to tank herbicide residues. This study aimed at assessing the potential effects of the broad spectrum herbicide dicamba on sensitive soybean during its vegetative and reproductive stages. The trial was performed in a randomized complete block design with four replications. Six rates (1.4, 2.8, 5.6, 11.2, 16.8 and 28.0 g ae ha-1) of dicamba were applied at two soybean growth stages (V3 and R2). The soybeans were planted in Passo Fundo, Rio Grande do Sul state in 2015/16 agricultural year. The dicamba induced symptoms of soybean phytotoxicity showed a steady rise at all the assessment times. The soybean decreased in height as the subdose of the herbicide increased. Dicamba was observed to negatively affect the number of nodes alone, during the V3 and R2 stages. The grain yield was adversely affected at the 28.0 g ae ha-1 subdose, in the V3 application stage, and in response to the 16.8 and 28.0 g ae ha-1 subdoses in the R2 stage.


2018 ◽  
Vol 36 (0) ◽  
Author(s):  
L.H.S. ZOBIOLE ◽  
F.H. KRENCHINSKI ◽  
G.R. PEREIRA ◽  
P.E. RAMPAZZO ◽  
R.S. RUBIN ◽  
...  

ABSTRACT: The goal of this study was to compare the efficacy of different weed management through a burndown application followed by sequential applications of herbicides to control Conyza spp. Thus, four field experiments were conducted, two in the western region of Paraná state (E1 and E2), one in Jataí, Goiás state (E3) and another one in Ibirubá, Rio Grande do Sul state (E4). Conyza spp. in this area had a height ranging between 25 and 60 cm. Treatments were arranged in a randomized block design with four replications. The primary herbicide treatments were 2,4-D + glyphosate + diclosulam, chlorimuron-ethyl + glyphosate + 2,4-D, and four doses of diclosulam + halauxifen-methyl + glyphosate. These treatments were applied singly or in sequential applications, made 10 days before the application of ammonium glufosinate, paraquat or saflufenacil. In all experiments, results showed efficient (90%) control of treatments containing diclosulam + halauxifen-methyl in combination with glyphosate on day 35 DAA, regardless of sequential applications. Applications of 2,4-D + glyphosate + diclosulam or chlorimuron-ethyl + glyphosate + 2,4-D were not effective against Conyza spp. at E1 and E2 locations, possibly due to the greater weed size (50 to 60 cm) at these sites. However, the same treatments were effective at E3 and E4 locations, where weeds were smaller. Diclosulam + halauxifen-methyl + glyphosate associated with ammonium glufosinate, paraquat or saflufenacil in sequential applications, proved to be an important tool to manage Conyza spp. at different growth stages.


2017 ◽  
Vol 3 (9) ◽  
pp. 110
Author(s):  
Aruna KT

The pot experiment was carried out during September 2015 to January 2016 at instructional farm, College of Agricultural Engineering, UAS Raichur under rain shelter to study the effect of different water regimes, (i.e. T1:100, T2:90, T3:80, T4:70, T5:60 and T6:50) per cent of water application with available moisture holding capacity on grain yield and water use efficiency. Completely Randomized block design with four replications was used in this study. The results showed that there was significant difference between the yield and (WUE) under different levels of irrigation. The total irrigation water applied were (i.e., 211.98, 243.02, 225.78, 155.09, 135.51 and 105.62 mm/plant) under different water regime treatments (100, 90, 80, 70, 60 and 50 %) of available moisture holding capacity (AMHC) respectively. Grain yield productions under different treatments were 106.25, 171.25, 127.50, 75, 55 and 40.75 g/plant/pot at 100, 90, 80, 70, 60 and 50 per cent of AMHC respectively. The results showed that water use efficiency (WUE) at different treatments were 0.50, 0.70, 0.56, 0.48, 0.41 and 0.39 g/mm for (100, 90, 80, 70, 60 and 50 %) per cent of AMHC respectively. Therefore, the 90 % of AMHC treatment (T2) is recommended for groundnut irrigation for water saving. The comparison of actual crop coefficient that obtained by water balance technic in experiment and crop coefficient (Kc) values of groundnut for different crop growth stages were selected based on the values suggested by FAO (Allen et al., 1998) are similar in the treatment of 90 % (T2) of the AMHC. Furthermore, the result showed that the treatment of 90 per cent of Available moisture holding capacity (T2) seemed to be better adapted to product a high crop yield with acceptable yield coupling with water use efficiency in this region.


Author(s):  
Gilmar Seidel ◽  
Caroline Wesp ◽  
Jana Koefender ◽  
Diego Pascoal Golle ◽  
André Schoffel ◽  
...  

In Brazil, corn planted area increased by 30%. Therefore, there was also an increase in the incidence of pathogens in the crop. The objective of this work was to evaluate the influence of fungicide applications on corn crops in the different growth stages for the control of the diseases and its effect on the occurrence of mycotoxins in the grain. The experiment was carried out in the 2017/2018 summer crop, in the municipality of Cruz Alta, state of Rio Grande do Sul/BR. This study used P 1630 hybrid, in a randomized block design with eight treatments (control, V8, PT, V4 + V8, V4 + V8 + PT, V8 + PT, V8 + PT + 15, PT + 15) and three replicates. The fungicide fluxapiroxade + pyraclostrobin + epoxiconazole at the dose of 1.0 L/ha-1 was used. The diseases that affected the crop were the white spot and helmintosporiosis, therefore, reducing the incidence of diseases. Also the highest yields were obtained where the applications started at the phenological stage V4 and V8. The levels of mycotoxins detected in this work remained within the limits of the legislation, with a significant reduction in the accumulation of fumonisin and aflatoxin with fungicide applications.


Author(s):  
Cleber M. Guimarães ◽  
Luís F. Stone ◽  
Ana C. de L. Silva

ABSTRACT To achieve an accurate phenotyping for drought tolerance, it is important to control water stress levels and timing. This study aimed to determine water use by upland rice plants during periods of irrigation withholding and its relationship with grain yield in order to increase the efficiency of this phenotyping. Two experiments were carried out in a randomized block design in which six water treatments (irrigation withholding for periods of 2, 4, 6, 8, 10 and 12 days) were compared, with four replicates. In the first experiment, treatments were applied at the R3 stage (panicle exsertion) and, in the second, at the R5 stage (beginning of grain filling). The amount of water evapotranspired was determined by the difference between the soil water storage at the beginning and at the end of irrigation withholding periods, from the surface to 80-cm depth. Evapotranspiration of upland rice from R3 stage was higher compared to that observed from R5 stage, when subjected to similar irrigation withholding periods in both growth stages. Rice grain yield is more sensitive to irrigation withholding imposed from R5 stage than from R3 stage.


Author(s):  
Mohd. Zakir Hussain ◽  
Ashok Kumar Kumar ◽  
Devendra Mandal ◽  
Rajeev Singh ◽  
R. K. Sohane

A field experiment was conducted during Kharif season at Crop Research Farm of Tirhut College of Agriculture, Dholi in 2017 to observe the effect of different levels of potassium on yield and economics of Kharif maize. The experiment was laid out in Randomized block design with four replications and nine treatments at a different level of potassium (0, 30, 60, 90, 120 and 150 kg ha-1) in which three treatments T7, T8 and T9 were along with 5 tons of FYM. There were no marked effect of different treatments on the number of cob plant-1, length of cob, the girth of cob and test weight. However, the number of grains cob-1 was found significantly higher in treatment T9 (T4 + 5 t FYM ha-1). Grain yield, stover yield and stone yield were significantly influenced by different treatments. The maximum grain yield (63.19 q ha-1), stover yield (101.61 q ha-1) and stone yield  (14.61 q ha-1) were recorded under treatment T9 (T4 + 5 t FYM ha-1). Economics of different  treatments indicated  that by higher grain yield, treatment T9 (T4 + 5 t FYM ha-1) exhibited maximum gross returns, net returns and B:C ratio of Rs 90,046 ha-1, Rs 47,987 ha-1 and 1.14, respectively.


Author(s):  
S. Salma Santhosh ◽  
T. Chitdeshwari ◽  
D. Jegadeeswari ◽  
C. Kavitha

Aims: To evaluate the effect of various sources and levels of calcium fertilisation in improving the growth and SPAD index of hybrid tomato at different growth stages. Study Design: Factorial randomized block design (FRBD) with three replications. Place and Duration of Study: A field experiment was conducted in the farmer’s field at Devarayapuram village, Thondamuthur block, Coimbatore from January to April, 2021. Methodology: A field experiment was conducted with hybrid tomato (Solanum lycopersiucm L) Shivam by using various organic and inorganic calcium sources viz., calcium sulphate, calcium nitrate, calcium silicate, poultry manure and pressmud applied at different levels (0, 20, 40, 60, 80 kg Ca ha-1) in a factorial randomized block design with three replications. The growth parameters such as plant height, root length, lateral root length, root volume and SPAD index were recorded as per standard protocols at different plant growth stages. Results: A linear increase in the plant growth, root traits and SPAD index of hybrid tomato was noted by the addition of organic and inorganic sources of calcium and the highest values were observed with the application of 80 kg Ca ha-1. Higher plant height (93.8 cm), root length (16.8 cm), lateral root length (13.3 g cc-1) and SPAD index (62.0) was registered with poultry manure applied at 80 kg Ca ha-1 which was followed by pressmud applied at the same level. Skipping of calcium in the fertiliser schedule registered the lowest growth response of hybrid tomato at all the growth stages. Conclusion: Inorganic Ca fertiliser sources though improved the growth, root traits and SPAD index of hybrid tomato at different growth stages, and it was comparatively lesser than the organic sources such as poultry manure and pressmud as calcium sources. The order of better growth performance was: Poultry manure > Pressmud > Ca silicate > Ca Nitrate > Ca sulphate. The lowest values of all the growth attributes were noted with NPK control. It was concluded that application of poultry manure at 80 kg Ca ha-1 would be effective in improving the growth, root traits and SPAD index of hybrid tomato.


2020 ◽  
Vol 15 (2) ◽  
pp. 86-90
Author(s):  
Mohana Rao Puli ◽  
P.R.K. Prasad

A Doctoral Research was conducted for two consecutive years (2011-2012 and 2012-2013) on fine texture soils of agricultural college farm, Bapatla to find out the residual effect of different sources of nutrients applied to preceding rice on P content in maize at different growth stages. The experiment was laidout in a Randomized Block Design in Kharif season with four treatments. The treatments consisted of M1 (RDF - Control), M2 (10t FYM ha-1 + RDF), M3 (1.5t vermicompost ha-1 + RDF), M4 (Green manuring + RDF). During the immediate Rabi, the experiment was laid out in a split-plot design without disturbing the soil for succeeding maize with the four treatments given to Kharif rice as main plot treatments and each of these divided into five sub-plots to receive five levels of fertilizer NPK application viz., N1 - 75%NPK, N2 - 100% NPK, N3 - 125% NPK, N4 - 150% NPK and N5 - 175% NPK for succeeding maize. Data collected on P content in maize at different growth stages was significantly increased with the application of 100% NPK in combination with FYM @10t ha-1 to preceding rice crop, irrespective of the NPK levels applied to succeeding maize crop. However, it was on par with that of green manuring together with 100% NPK during both the years of the study.


2020 ◽  
Vol 50 ◽  
Author(s):  
Inara Alves Martins ◽  
Silvino Guimarães Moreira ◽  
Adriano Teodoro Bruzi ◽  
Guilherme Vieira Pimentel ◽  
Paulo Eduardo Ribeiro Marchiori

ABSTRACT The herbicide lactofen has been used by producers in many conditions, in order to increase the soybean yield. This study aimed to evaluate the influence of lactofen and the phytohormone kinetin on the morpho-agronomic traits, carbohydrate partitioning and yield, in soybean cultivars. Three experiments were carried out in the field, in addition to one experiment in a greenhouse. A randomized block design, with four replications, was used. The treatments were: lactofen [144 g ha-1 of active ingredient (a.i.)], lactofen + kinetin (144 g ha-1 of a.i. + 0.5 g ha-1), kinetin (0.5 g ha-1), manual cutting of apical buds and control. In the subplots, six soybean cultivars (M 6410 IPRO, M 5917 IPRO, NS 7670 RR, NS 6909 IPRO, BMX Lança IPRO and Produza IPRO) were used. In the field, the plant lodging index, plant height, number of nodes and branches, pods and grains per plant, mass of 100 grains and grain yield were evaluated. In the greenhouse, the starch, reducing sugars, sucrose and total sugars in the leaves, stems and roots of three soybean cultivars were quantified. The application of lactofen in the V6 stage influenced the morpho-agronomic traits of the cultivars in the field and increased the soybean yield by 312 kg ha-1, considering all the cultivars. The phytohormone did not influence the morpho-agronomic traits neither the grain yield. The treatments did not induce modification in the partitioning of carbohydrates destined to the roots.


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