http://dx.doi.org/10.15361/1984-5529.2016v44n4p549-556
549
Accumulation of nutrients and growth in castor bean plants
Acúmulo de nutrientes e crescimento em plantas de mamona
Altino Junior Mendes de OLIVEIRA1; Carlos Henrique de OLIVEIRA1; Enilson de Barros SILVA2; Evander Alves FERREIRA3; Gustavo Antônio Mendes PEREIRA3; Daniel Valadão SILVA4
1 Engenheiros Agrônomos, Universidade Federal dos Vales do Jequitinhonha e Mucuri, [email protected], [email protected]
2 Doutor, Universidade Federal dos Vales do Jequitinhonha e Mucuri, [email protected];
3 Autor para correspondência - Doutor, Universidade Federal de Viçosa, departamento de fitotecnia, laboratório de herbicida no solo, Avenida Peter Henry Rolfs, s/n - Campus Universitário, Viçosa - MG, 36570-900, [email protected]
4 Doutor, Universidade Federal Rural do Semi-Árido, [email protected] Recebido em: 11-02-2014; Aceito em: 21-07-2016 Abstract
Information about nutrient uptake and accumulation by different crops during development stages allows iden- tifying periods of higher demand and an adequate fertilization management. An experiment under field condi- tions was carried out in order to evaluate macro and micronutrient accumulation in castor bean leaf tissue, as well as to identify nutrient uptake critical stages of this crop. Treatments were consisted of evaluation periods with samples collected every ten days until 160 days after emergence of crop. Castor bean plants showed higher macronutrient accumulation in descending order: N > K > Ca > S > Mg > P and the following micronutri- ents Fe > Mn > Zn > B > Cu > Mo. The highest accumulation rates of N, P and K nutrients occur from 20 to 110 days after emergence (DAE) with the highest N uptake from 30 to 40 DAE, remaining high until approximately 110 DAE. Regarding potassium, the highest uptake occurs between 40 and 50 DAE, with high uptake rates until approximately 110 DAE. The highest phosphorus uptake was between 80 and 90 DAE. The majority of macro and micronutrients were accumulated in leaves during most part of evaluation cycle.
Additional keywords: growth analysis; nutrient accumulation rate; nutrient partitioning; Ricinus communis L.
Resumo
O conhecimento da absorção e do acúmulo de nutrientes por culturas, nas diferentes fases de desenvolvi- mento, permite identificar períodos de maior exigência e adequar o melhor manejo da adubação. Um experi- mento de campo foi realizado para avaliar o acúmulo de macro e micronutrientes nos tecidos vegetais da cul- tura da mamona, bem como identificar as fases críticas de absorção de nutrientes por parte dessa cultura. Os tratamentos foram constituídos das épocas de avaliação, com as coletas realizadas a cada dez dias e finaliza- das aos 160 dias após a emergência da cultura. As plantas de mamona apresentaram maior acúmulo de ma- cronutrientes em ordem decrescente: N > K > Ca > S > Mg > P, e os seguintes micronutrientes: Fe > Mn > Zn >
> B > Cu > Mo. As maiores taxas de acúmulo dos nutrientes N, P e K ocorrem dos 20 aos 110 dias após a emergência (DAE), sendo que a maior taxa de absorção de N ocorreu dos 30 aos 40 DAE, permanecendo alta até aproximadamente 110 DAE. Com relação ao potássio, o pico de absorção desse nutriente está entre 40 e 50 DAE, com taxas de absorção relativamente elevadas até, aproximadamente, 100 DAE, e o maior pico de absorção de fósforo localizou-se entre 80 e 90 DAE. A maior parte dos macros e micronutrientes avaliados encontra-se acumulada nas folhas da cultura durante a maior parte do ciclo de avaliação.
Palavras-chave adicionais: análise de crescimento; partição de nutrientes; Ricinus communis L.; taxa de acú- mulo de nutrientes;
Introduction
Castor bean (Ricinus communis L.) is an oilseed species widely cultivated throughout Brazil with great economic and social importance. The pur- pose of this species production is the oil extraction from its seeds. In the past years, there have been increased studies on castor bean management prac- tices, mainly due to the Brazilian Federal Government regulation on the biodiesel percentage use in diesel oil (Gondim et al., 2006, Fanan et al., 2009).
An adequate nutrient supply in each crop development stage is essential for growth at all stages (Ritchie et al., 2003). To optimize the use of each species to fertilization, knowledge about the development stages with higher nutritional require- ments is necessary. It is possible to obtain this infor- mation through studies defined as "nutrient uptake rate", in which the absorbed amounts of nutrients concerning to age and/or physiological stage of a crop are determined. Thus, the determination of nutri- ent uptake and accumulation in plant development
550
stages are important aiming at identifying periods when elements are most required during crop and its distribution on different plant structures, enabling appropriate management fertilization.
Another important aspect regarding the study on nutrient uptake and accumulation is the better use of fertilizers and the fraction of nutrients supplied by soil (Prezotti, 2001). The chemical composition and the accumulation of nutrients in leaves and fruits are essential information about nutritional requirements of a plant. Posteriorly, this information will support nutri- ent recommendations to be provided to plants through fertilization (Laviola & Dias, 2008).
Therefore, this study aimed at determining macro and micronutrient accumulation in castor bean leaf tissues (cv. Guarani), as well as identifying the stage of the greatest nutrient uptake of this crop.
Material and methods
The experiment was conducted in field condi- tions of Universidade Federal dos Vales do Jequitin- honha and Mucuri, Diamantina-MG, from September 2011 to February 2012 in quartzarenic neosol (RQo), with clay texture and slope of 2%. The soil chemical analyzes shows: pH (water) of 5.4; organic matter content of 1 dag kg-1; P, K and Ca of 1.4; 10 and 0.5 mg dm-3, respectively; Mg, Al, H+Al and CTCefective
of 0.2; 0.4; 4.4 and 1.7 cmolc dm-3, respectively. A total of 2 t ha-1 of dolomitic limestone was applied and basic and top dressed fertilization was carried out as recommended by the State of Minas Gerais for castor bean crop (CFSEMG, 1999). An amount of 90 kg ha-1 of P2O5 using simple superphosphate (18% of P2O5) as source was provided for planting as well as 60 kg ha-1 of K2O as potassium chloride (58% of K2O). At 40 days after emergence (DAE), a total of 40 kg ha-1 of N, using ammonium sulfate (20% of N) was applied.
Castor bean plant density (cv. Guarani) was 2 plants per m and spacing of 1 m between rows, as recommended by the State of Minas Gerais for this crop (CFSEMG, 1999). Desired plant densities were kept through thinning at 7 DAE of plants.
The experimental design was a randomized block with four replications. The treatments consisted of sixteen evaluation periods with three plants col- lected per sample every 10 days after planting, until the end of crop cycle at 160 days. Each plot consisted of four rows with 6 m length, with spacing of 1.0 m (CFSEMG, 1999). The two central rows were consid- ered as the floor area excluding 1 m at each end.
The macro and micronutrient contents for stems and leaves of castor bean plants were deter- mined. Plant was divided into leaves, stems, fruits and seeds for dry matter accumulation rate.
The collected plant material was washed in distilled water and dried in an oven with forced air at 65° C, until constant weight to determine shoot dry mass on an electronic scale. After drying, it was grinding in mill with fine sieve (40 mesh), aiming at homogenizing the
material. Then, macro and micronutrient contents were assessed (Malavolta et al., 1997).
Results were shown as plots where macro and micronutrient accumulation in leaves and stem of castor bean plant were represented, as well as the mass accumulation of dry mass in leaves, stems, fruits and seeds of crop during the evaluation cycle. The relative growth rate was also calculated according to equation 1 and nitrogen, phosphorus and potassium uptake rates according to equation 2. In order to represent the total accumulation of main nutrients, plots of macro and micronutrients accumulation were made considering 160 days after emergence.
TC =P2 - P1
T2 - T1 (1)
Wherein: P1 and P2 are total dry mass (TDM) of two successive samples. T1 and T2 are the time intervals in days between the two samples.
TA =TR1 - T1
TR2 - T2 (2)
Wherein: TR1 and TR2 are nutrient content of two successive samples. T1 and T2 are the time intervals in days between the two samples.
Results and discussions
Until about 100 DAE, corresponding with the early of bean formation, castor bean plants showed increased tendency to dry mass accumulation in leaves, and, from 100 to 120 DAE a great production of leaves was observed. From this moment plant began to accumulate higher amount of dry mass in stem. It is important to emphasize that, at 60 DAE castor bean plants entered in the reproductive stage and at 70 DAE began the dry mass accumulation in fruit and posteriorly in seeds. From that period, there was a higher dry mass accumulation in fruit and seeds compared to the other parts of evaluated plants (Figure 1).
Therefore, it was found that dry mass was most represented by reproductive structures (fruit and seeds), followed by stem and at last by leaves (repro- ductive structures > stems > leaves); in this case due to reproductive structures are composed of rachis, racemes and inflorescences partially developed (Figure 1). Similar results were found by Nascimento et al. (2006) when studying the development of two castor bean hybrids.
It should be noted that there was a strong de- crease in accumulated dry mass percentage in leaves from the early of reproductive stage, which occurred approximately between 60 and 70 DAE, due to the change of the main drain from leaves to reproductive structures (Figure 1).
This fact was also observed in other plant
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species, according to the reports of Rodrigues (1992), in C. benghalensis; Pedrinho Júnior et al. (2003), in R. brasiliensis, H. suaveolens and Alternanthera tenella; Bianco et al. (2004), in Rottboellia exaltata;
and Carvalho et al. (2007), in B. plantaginea.
By evaluating nitrogen accumulation in castor bean plants, it was found that until approximately 150 DAE stem had the highest amount of nitrogen (Figure
2A). However, from 150 DAE there was greater accumulation of this nutrient in leaves. Different results were found by Nascimento et al. (2006), which noted that among the analyzed bean castor plant parts, except the reproductive structures, leaves stood out regarding N accumulation during crop cycle.
Figure 1 - Dry mass accumulation of leaves, stem, fruit and seeds of castor bean plants at different evaluation periods.
Regarding phosphorus, the steam showed the highest accumulation of this nutrient until 90 DAE.
From this period, phosphorus showed higher ten- dency to accumulate in leaves (Figure 2B).
The highest accumulation of potassium was observed until 80 DAE, and after this evaluation period, the nutrient accumulated in larger amounts in leaves (Figure 2C). K is related to the activity of over 60 enzymes, with leaf turgidity, being essential for internal transport of sugars and electrochemical bal- ance of plant. Under potassium deficiency, there is a reduction in photosynthetic activity of leaves (Santos et al., 2010), increased root respiration, carbon ori- entation to roots increasing root-shoot ratio, nitrate uptake is reduced and on the other hand, Na, Ca and Mg uptake increase (Taiz & Zeiger, 2013).
In studies on castor bean fertilization, Canecchio Filho et al. (1963) evaluated the influence of NPK increasing doses in crop and found that N application provided gains of 134 kg ha-1. The appli- cation of 75 and 150 kg ha-1 of P2O5 also provided, respectively, 1,138 and 1,518 kg ha-1 against 305 kg ha-1 of the control. Another important aspect mentioned by the authors is the significant effect of P
and N in reducing time for flowering and harvesting of the first clusters, while K acted in the opposite direction.
Sulfur and calcium showed higher accumula- tion in castor bean leaves during all evaluation periods (Figure 2D and 2E).
Regarding magnesium, it was observed that this nutrient initially, i.e., until approximately 60 DAE accumulated in greater quantities in stem, considering that from 80 to 100 DAE, this relationship reversed, with higher magnesium accumulation in leaves and again from 100 to 150 DAE, stem accumulated higher proportion of magnesium. However, from 150 days, most of this nutrient was in leaves (Figure 2F).
By evaluating the micronutrient accumulation in castor bean plants, it was found that copper had higher tendency to accumulate in plant stem of this species until 110 DAE. After this period, this micronu- trient was found in greater quantities in leaves of crop (Figure 3A). Manganese, zinc and boron were found mainly in castor bean leaves during all evaluation periods (Figura 3B, 3C and 3E).
0 200 400 600 800 1.000 1.200 1.400 1.600
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160
Emergence
Vegetative stage Reproductive stage
-
1
)
Days after emergence and phenological stages
Seed Fruit Leaf Stem
Dry mass (kg ha-1)
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A B
C D
E F
Figure 2 - Macronutrients accumulation in leaves and castor bean stem at different evaluation periods:
A) Nitrogen; B) phosphorus; C) Potassium; D) sulfur; E) Calcium; F) Magnesium.
Accumulation of magnesium
0 2 4 6 8 10 12 14 16
10 30 50 70 90 110 130 150
Days after emergence Magnesium (kg ha-1)
Steam Leaves Accumulation of calcium
0 2 4 6 8 10 12 14 16 18
10 30 50 70 90 110 130 150
Days after emergence Calcium (Kg ha-1)
Stem Leaves
Accumulation of sulfur
0 2 4 6 8 10 12
10 30 50 70 90 110 130 150
Days after emergence Sulfur (kg ha-1)
Stem Leaves Accumulation of potassium
0 10 20 30 40 50 60 70 80 90
10 30 50 70 90 110 130 150
Days after emergence Potassium (kg ha-1)
Stem Leaves
Accumulation of phosphorus
0 1 2 3 4 5 6
10 30 50 70 90 110 130 150
Days after emergence Phosphorus (kg ha-1)
Stem Leaves Accumulation of nitrogen
0 50 100 150 200 250 300 350
10 30 50 70 90 110 130 150
Days after emergence Nitrogen (kg ha-1)
Stem Leaves
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A B
C D
E
Figure 3. Micronutrient accumulation in leaves and castor bean stem at different evaluation periods.
A) Copper; B) Manganese; C) Zinc; D) Iron; E) boron.
Iron showed tendency to balanced accumu- lation in leaves and steams of evaluated species (Figure 3D).
The culture of castor bean had the highest
growth rate at 120 DAE, corresponding to the repro- ductive stage, between 110 and 130 DAE, reaching maximum at 120 DAE (Figure 4). This stage corre- sponds to dry mass accumulation in seeds.
Accumulation of manganese
0 50 100 150 200 250 300 350 400
10 30 50 70 90 110 130 150
Days after emergence Manganese (g ha-1)
Stem Leaves Accumulation of copper
0 20 40 60 80 100 120 140
10 30 50 70 90 110 130 150
Days after emergence Copper (g ha-1)
Stem Leaves
Accumulation of boron
0.00000 0.00020 0.00040 0.00060 0.00080 0.00100 0.00120 0.00140
10 30 50 70 90 110 130 150
Days after emergence Boron (g ha-1)
Stem Leaves
Accumulation of iron
0 100 200 300 400 500 600 700 800 900
10 30 50 70 90 110 130 150
Days after emergence Iron (g ha-1)
Stem Leaves Accumulation of zinc
0 5 0 10 0 15 0 20 0 25 0 30 0 35 0
1 0
3 0
5 0
7 0
9
0 11
0 13 0
15 Days after emergence 0
Zinc (g ha-1)
Stem Leaves s
554
ŷ=0.76+5.84e[-0.5((x-123.10)/13.10)2] R2=0.96 Figure 4 - Relative growth rate of castor bean plants at different evaluation periods.
The higher nitrogen uptake rate was from 20 to 40 DAE, with the greatest potassium uptake rate just after nitrogen uptake peak, i.e. from 40 to 60 DAE. It is important to consider that the potassium uptake rate remains high until approximately 120 DAE (Figure 5), indicating that at the production stage there are increased K requirement. This nutrient plays
an important role in fruit formation, acting in transport of assimilates in the phloem (Marschner, 2011). The biomass increase in fruit is accompanied necessarily by K accumulation. Furthermore, this is a required nutrient in the activation of several enzymes essential for the synthesis of organic compounds, including starch (Marenco & Lopes, 2009, Marschner, 2011).
Nitrogen - ŷ=0.73+5.38e[-0.5((x-96.27)/22.08)2] R2=0.89 Phosphorus - ŷ=0.023+0.144e[-0.5((x-100.97)/10.83)2] R2=0.81
Potassium - ŷ=0.22+1.07e[-0.5((x-92.91)/20.69)2] R2=0.77
Figure 5 - Uptake rate of nitrogen, phosphorus and potassium in castor bean plants at different periods of evaluation.
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150160
Initial growth Vegetative stage Reproductive stage
Days after emergence/Development stages of crop
g day-1
Nitrogen Phosphorus Potassium 0
1 2 3 4 5 6 7
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160
Initial growth Vegetative stage Reproductive stage Dry mass (g day-1)
Days after emergence/Development stages of crop
555
It was observed that the period of highest phosphorus uptake was between 60 and 80 DAE (Figure 5).
In a castor bean experiment, Canecchio Filho
& Freire (1958) evaluated the influence of NPK fertili- zation in crop and found that N application was extremely positive, providing yield increase of 31%
(additional of 815 kg ha-1 compared to control). These same authors also found that P addition provided gain of 25%, corresponding to yield increase of 358 kg ha-1. In 1959, these authors evaluated the spacing influ- ence and NPK fertilization on castor bean crop in three successive harvests. They found that there was no influence of N, because in the treatments with or without nutrient, the first crop accounted for 64%. In the treatments with no K and in those with doses of 30 and 60 kg ha-1 of K2O the first harvest repre- sented, respectively, 67%, 62% and 63%; with no P and with doses of 60 and 120 kg ha-1 of P2O5, 66%, 65% and 62%, respectively.
By comparing the relative growth rate of crop with uptake rate of nitrogen, phosphorus and potas- sium, it has been found that these do not coincide, as the largest uptake peak prior to the highest peak of crop growth (Figures 4 and 5). However, in the largest uptake rate, plant enters in the reproductive process.
In general, the maximum daily accumulation of nutri- ents coincided with the initial fruiting period of both species, as also observed by Fayad et al. (2002) in tomato plants. During this period, there is the estab- lishment of a driving force of nutrients and assimi- lates, due to increased metabolic activity, associated to hormonal activity and cell division and growth (Taiz
& Zeiger, 2013). The absorption of nutrients is differ- ent according to the crop development stage, increasing in flowering, in the formation and growth of fruits or organ to be harvested, so in addition to the amount of absorbed nutrients, it should also be con- sidered its concentration in different development stages (Haag, et al., 1981; Malavolta et al., 1997).
The absorption, transport and use efficiencies indicate plant ability to extract nutrients from culture, to convert the absorbed nutrient in dry mass and to redistribute and to reuse mineral elements (Rozane et al., 2007). From 30 to 80 DAE, where the peaks of highest nitrogen, phosphorus and potassium uptake rate are, crop is possibly highly competitive with weeds for nutrients, considering that from 100 to 130 DAE, period associated with the highest growth rate of crop, is also related to higher competitive capacity for light (Vasconcelos et al., 2012).
The most absorbed nutrients by castor bean crop in descending order were N > K > Ca > S > Mg >
P, with the amounts of 295.0; 110.0; 15.0; 1.0; 8.0 and 7.0 kg ha-1, respectively. This study showed dif- ference in nutrient accumulation in castor bean plants compared to other crops from the same family jatropha (Jatropha curcas L.), cassava, rubber, all representatives of Euphorbiaceae family, as well as castor bean. Regarding cassava crop, Lorenzi et al.
(1981) found that in two cultivars the most accumu- lated macronutrients in plant total dry mass were:
N > K > Ca > Mg > P > S. Regarding rubber plant, Viegas et al. (1992) found that the accumulation of nutrients per hectare in the dry mass of leaves was described by N > K > Ca > P > S > Mg. On the other hand, Laviola & Dias (2008) observed that the amount of nutrients absorbed by jatropha plants described a certain order by N > Ca > K > Mg > P > S in leaves and N > K > Ca > P > Mg > S in fruits.
Regarding micronutrients, the following order was observed Fe > Mg > Zn > Cu > B, in castor bean plants, and the amount accumulated in leaves and steam was 780.0; 305.0; 301.0; 118.0 g ha-1, respec- tively.
Conclusions
Castor bean accumulated macronutrients in descending order of quantity: N > K > Ca > S > Mg > P and the following micronutrients: Fe > Mn > Zn > B >
> Cu > Mo. The highest N and K uptake peaks was on vegetative stage from 50 DAE and P in the repro- ductive stage at 90 DAE, however, culture shows slow growth rate with a peak close to 120 DAE, when there was also greater accumulation of most macro and micronutrients.
Acknowledgments
The authors thank to Coordenação de Aper- feiçoamento e Pessoal de Nível Superior (CAPES) and Fundação de Amparo a Pesquisa do Estado de Minas Gerais (FAPEMIG) for the financial support and scholarships.
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