Journal of Plant Physiology & Pathology ISSN: 2329-955X

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Research Article, J Plant Physiol Pathol Vol: 7 Issue: 3

Evaluation of Biofertilizer Associated to the Organic Compound Bokashi for the Culture of Lactuca sativa L: A Original Study

*Corresponding Authors:
Luciana Teixeira De Paula
Department of Agronomy School, University Center North Paulista (Unorp-Sao Jose do Rio Preto-SP)
Brazil
Tel:+5517981666537
E-mail: [email protected]

Received: July 11, 2019 Accepted:August 20, 2019 Published:August 26, 2019

Citation: Paula LTD, Pacheco CH, Esteves TJ, Ikefuti CV (2019) Evaluation of Biofertilizer Associated to the Organic Compound Bokashi for the Culture of Lactuca sativa L: A Original Study. J Plant Physiol Pathol 7:3.

Abstract

Organic fertilizers still have little potential in agriculture. They are considered easy to prepare and their composition contains accessible and low-cost materials, being excellent tools for the treatment in natural ecosystems, as they maintain the balance of biodiversity. The objective of this work was to evaluate the effects of the use of liquid biofertilizer associated with organic bokashi on lettuce production (Lactuca sativa L.). Based on the results obtained, it was possible to evaluate that the lettuce grown in soil treated with the organic compound bokashi and with the liquid biofertilizer presented better quality in all the criteria evaluated by this work in relation to the control, but only the treatment with bokashi results was higher.

Keywords: Organic fertilizers; Biofertilizer liquid; Bokashi organic compound

Introduction

To meet the aspirations of a highly consumer society, it was necessary to generate a system of agricultural production on a large scale, aiming at a high agricultural productivity, which led to an increase in the use of agrochemicals in conventional agriculture. Many environmental impacts have been caused by this production model, which has been damaging the health of consumers and workers dealing with chemical fertilizers and agrochemicals [1]. It can be considered, then, that conventional agriculture has negative points that are borne by society as a whole [2].

Nowadays, there is a growing awareness of society regarding the problems caused by pesticides and the misuse of natural resources, which were mistakenly seen as inexhaustible. However, there is a challenging path to be achieved in improving productivity and profitability using a model that seeks sustainable production development [2,3].

In organic agriculture we seek to substitute agrochemicals for non-aggressive inputs to the environment, giving preference to the residues produced in the property or region, easy to handle and allowed by a certification system, such as dung and organic compounds, green fertilizers and liquid biofertilizers, among others [4]. Organic farming has proven to be an alternative pathway for the harmonious survival of humans with their planet.

The insertion of organic products in the market demands standardization restricted to organic agriculture, so that it protects farmers and consumers. Organic standards restrict the use of inputs and dictate a range of practices to be followed [4]. Federal Law 10,831, dated December 23, 2003 regulates the organic production system, discussing disciplinary rules for the production, classification, processing, packaging, distribution, identification and certification of the quality of organic products, whether of animal or vegetable origin [5].

Organic fertilizers still have little potential to be exploited by farmers. They are easy to prepare because the materials used in their composition are usually found inside the property, or are low-cost products. Being excellent treatment for natural ecosystems as they maintain the balance of biodiversity. It is a rational and safe way in plant nutrition and disease control in alternative agriculture, since it does not pose risks to man and the environment [6].

The culture of lettuce

Lettuce is among the main vegetables for daily consumption, there is great potential in the market among organic products, since it is consumed preferably raw, in the form of salads and presents high content of vitamins and minerals, fundamental in the human diet [7].

Lettuce is considered a fast cycle (50 to 70 days, depending on the cultivar, time and place of cultivation). It is extremely demanding in nutrients, especially nitrogen, phosphorus, potassium and calcium, but the importance of the others cannot be ignored. It is a culture that presents slow initial growth, until the 30 days, when, the weight gain is accumulated until the harvest [8].

It is a delicate, herbaceous plant with a tiny stem, to which are attached the leaves that are broad and grow in rosette, and can be smooth or curly, forming or not “head”, with a coloration in various shades of green or purple, according to the cultivar. The root system is much branched and shallow, exploring only the first 25 cm of soil. It is an annual crop, blossoming under long days and high temperatures.

Short days and mild temperatures favor the vegetative stage, which shows that all cultivars produce better under such conditions. Resistant to low temperatures and slight frost. The reproductive stage, which begins with the appendage, is favored by long days and high temperatures. Originally the lettuce was a fall - winter culture in the south center. Over time genetic materials with good adaptation tolerance allowed planting during spring and summer. Therefore, it is possible to plant and harvest lettuce throughout the year depending on the cultivar chosen [9].

Organic cultivation

In organic cultivation, the farmer cannot use any type of agrochemical and/or chemical fertilizer of high concentration and solubility, being able only to make use of products of organic origin free of contaminants, thus having a product that does not degrade the higher quality and higher added value. All this, making use of conservationist agricultural practices, such as organic fertilizers and compounds, biofertilizers, green manure, alternative pesticides (silts, oils and natural extracts), intercropping, crop rotation, no-tillage and tolerant and adapted varieties [10].

Producers who use this method of cultivation are usually small and seek organic products for their source of income and the diversification of agricultural activities within the property. It is observed today that the layers of society that have a greater purchasing power are the ones that have been looking for products of organic origin and in a larger scale, making that the organic products become competitive together with those of conventional origin.

Organic fertilizers

Producing organic fertilizers in rural property is not a very difficult task, because the raw material to be used is obtained from organic waste such as household waste and crop residues (leaves, branches, fruit peels, etc.), that is, all matter that would be discarded [11,12].

Organic fertilizers, besides providing nutrients to the soil, play a very important role in the sustainability of production systems, influencing physical, chemical and biological attributes of the soil, with a reflection on the stability and productivity of the crop. With the decomposition of organic matter, the release of nutrients, especially macronutrients (N, P, K) and micronutrients, increases water retention and is mainly responsible for the increase of the cation exchange capacity (CTC ) of the soil [13].

Organic fertilizers work as soil inoculants, accumulating macro and microorganisms beneficial to crops (fungi, bacteria, actinomycetes, protozoa and earthworms) that are soil-forming [14].

Liquid biofertilizers

According to Silva et al. [14] liquid biofertilizers are natural products obtained from the fermentation of organic materials with water in the presence or absence of air (aerobic or anaerobic processes), having a highly complex composition, which may contain almost all necessary macro and microelements to plant nutrition.

There is no standard formulation for the production of biofertilizers, while the ingredients can be added according to nutritional and fermentative needs, but cattle manure is the most used in the recipes because it is quite fermentative and has already been inoculated with efficient decomposing bacteria due to feeding of animals [15].

Usually the biofertilizer is used as sprinkler as a leaf fertilizer or directly in the soil, and can be used in cultivation by hydroponics. Liquid biofertilizers are assimilated more rapidly by plants, which is extremely useful for crops that require a large amount of short cycle nutrients, such as some olive groves [16].

According to Mendes et al. [10] the fermentation time of the mixture is a variable factor, and can be concluded around 30 days in the summer and 45 days in the winter, i.e., depending on the temperature. The absence of fermentation may be linked to contamination, abrupt change of the compound or when manure is derived from animals treated with antibiotics. The pH may range from 7.0 to 8.0 and may be lower when fermentation is incomplete.

Organic compound bokashi

The bokashi organic compound was developed and adapted by Teruo Higa in 1980. It was brought by the Mokiti Okada Foundation to Brazil, where it is widely used among Japanese-Brazilian farmers and organic farmers [17]. It is a word of Japanese origin that means “fermented organic matter” and also a Japanese painting technique that means “to dilute” or “to erase”, adapted by the farmers to the practice of mixing the organic matter to the land of the forest, leaving it to ferment before mixing it to the crop land [18].

According to Oliveira et al. [11], Bokashi-type fermented organic compounds are obtained based on ingredients that do not contain toxic residues. There is no standard formulation for bokashi, with empirical recipes that are very varied, more or less complex and adapted to different purposes, but are usually made from materials with a high N content, mixed with materials with high carbohydrate content.

The bokashi have been widely used, generating good results in fruit and vegetable productivity, as a substitute for chemical fertilizer. Its most important action is to introduce beneficial microorganisms in the soil, which trigger a fermentation process in the available biomass, providing favorable conditions for the multiplication and performance of the existing beneficial microbiota, such as fungi, bacteria, actinomycetes, mycorrhizas and nitrogen fixers, which are part of the process balanced plant nutrition and soil and plant health [18,19]. The objective of this work was to evaluate the effects of the use of organic biofertilizer associated with the bokashi organic compound on lettuce production, with the aim of implementing tools that aim to improve the productivity of organic foods.

Materials and Methods

Experimental area

The experiment was carried out in the Santo Antônio Site, property of Marcos Antônio Rigino e Outro, located in the municipality of Potirendaba - SP, with geographic coordinates of 20° 57’38.32 ‘’S and 49° 25’42.62’’O and altitude of 480 m. The property is certified by IBD Certifications, since 2010 it works with the organic system. The production of the liquid biofertilizer, the installation of the beds and the planting of the seedlings took place in the property and that analyzes in the laboratory of the University Center of North Paulista - UNORP. The experiment was conducted from April to June 2016.

Production of biofertilizer

The biofertilizer was produced in the property, using five different mixtures, being a protein mixture (MP), according to Table 1, and four mineral mixtures (MM), according to Table 2, divided into nine stages, in a plastic tank of 200 liters.

Table 1: Ingredients for the preparation of the protein mixture (MP).

Amount Unit of measurement Ingredients
9 Liters Whey and/or milk
9 Liters Cane molasses
0,9 Liters Blood
0,9 kg Ground beef
1,8 kg Bone meal
1,8 kg Limestone
1,8 kg Phosphate from Araxa
80 kg Bovine manure

Table 2: Ingredients for the preparation of the mineral mixture (MM).

Mineral mixtures Amount Unit of measurement Ingredients
M1 2,0 Kg Zinc sulfate
2,0 Kg Magnesium sulphate
0,3 Kg Copper sulphate
0,3 Kg Iron sulphate
M2 2,0 Kg Calcium chloride
1,0 Kg Boric acid
M3 0,05 Kg Cobalt Sulphate
0,3 Kg Manganese Sulfate
M4 0,01 Kg Sodium Molybdenum

Nine stages of preparation were performed with interval of three days each. All ingredients of the protein mixture (MP) were divided into nine equal portions and reserved for later use, except for fresh bovine manure, which was used 20kg on the first day and the remainder divided into eight equal portions. The mineral mixture (MM) was divided into four mixtures, M1 used from 2nd to 4th stage, M2 used from 5th to 7th stage, M3 used at 8th and 9th stage and M4 used only at 9th stage.

• 1st stage: 1st day, 100 l of water and MP (with 20 kg of manure) were added;

• 2nd stage: 4th day M1+MP;

• 3rd stage: 7th day M1+MP;

• 4th stage: 10th day M1+MP;

• 5th stage: 13th day M2+MP;

• Step 6: 16th day M2+MP;

• 7th stage: 19th day M2+MP;

• 8th step: 22nd day M3+MP;

• 9th step: 25th day was added M3+M4+MP;

On the 30th day the temperature and the bubbles were checked to see if there was any fermentation. The preparation was stirred at least 2 times a day and left to rest without contact with the sun or rain. It was expected about 15 days to get ready for use. The bokashi used was produced according to the one proposed by Siqueira and Siqueira [17]. The crisphead lettuce seedlings were purchased from VECHI, a company based in the city of Mirassol/SP, which produces and sells vegetable seedlings.

Conduct of treatments

The experimental area was in fallow stage. It was divided in three beds of 1.20 mx25m and each plot divided into four plots of 1.20 mx6m, being these homogeneous as to the color of the soil, texture, degree of drainage. At the ends of the beds, 0.5 m of safety band was adopted (Figure 1).

Figure 1:Disposition of treatments, where: TR1 (liquid biofertilizer), TR2 (liquid biofertilizer+bokashi), TR3 (bokashi) and TS (control).

A completely randomized experimental design was used, and each plot received a different treatment. All the parcels of the witness stayed in the upper part of the land so that there was no contamination of any kind.

The treatment with bokashi was incorporated in the soil seven days before the transplant of the seedlings, on April 30, 2016, in the dosage of 200 g/m2. Transplanting of seedlings was carried out on May 7, 2016. Throughout the crop cycle the plants were irrigated by spraying, thus maintaining sufficient moisture for the proper development of the crop.

The control of invasive plants was carried out by weeding with the aid of a hoe.

The liquid biofertilizer was used via foliar, in two applications, with 15 and 30 days, in the dosage of 80 liters/ha. The harvest was performed on June 30, 2016, when the plants had the maximum vegetative development, with well-formed commercial heads.

Ten samples/heads were taken per plot/replicate from each of the three beds, randomly and taken to the laboratory of the University Center of North Paulista-UNORP where they were analyzed in the following criteria: biomass, diameter, height and number of leaves for posterior processing of results.

The data of the experiment were verified from the analysis of variance, being the comparison of means made by the test of Tukey, at the level of 5.0% of probability. To determine the biomass, lettuce gourds were weighed by means of a precision scale (0.01 g). The diameter and height were determined with the aid of a graduated ruler (100 cm)

Results and Discussion

In the biomass criterion, the mean of the results obtained per repetition for each treatment were those presented in Table 3. In the diameter criterion, the average of the results obtained per repetition for each treatment were those presented in Table 4. In the criterion height, the average of the results obtained by repetition for each treatment were presented in Table 5. In the number criterion, the mean of the results obtained per repetition for each treatment were those presented in Table 6.

Table 3: Average biomass (g) of lettuce heads in the different treatments.

Treatment TR1 TR2 TR3 TS
REP1 219.24 153.41 217.54 127.69
REP2 184.40 278.75 256.85 81.22
REP3 201.89 236.05 307.81 85.98

Table 4: Mean diameter (cm) of lettuce heads in the various treatments.

Treatment TR1 TR2 TR3 TS
REP1 29.51 27.60 31.29 25.70
REP2 31.54 32.75 31.47 22.16
REP3 29.51 31.59 32.99 22.37

Table 5: Mean height (cm) of lettuce heads in the various treatments.

Treatment TR1 TR2 TR3 TS
REP1 13.93 14.60 16.26 12.57
REP2 13.70 15.99 18.97 11.77
REP3 13.75 16.37 18.06 11.84

Table 6: Average number of sheets.

Treatment TR1 TR2 TR3 TS
REP1 21.90 21.70 21.00 19.60
REP2 20.90 25.30 22.90 19.50
REP3 20.90 23.60 26.10 19.70

The averages of the results, obtained from the samples in the laboratory, by repetition of treatment, were launched in the Tukey test, at the 5.0% probability level, obtaining also the standard deviation. The results are presented for the biomass, diameter, height and leaf number criteria respectively in Figures 2-5. The results analyzed, taking into account height (Figure 4), TR3 treatment (bokashi) was shown more significant, compared to the other treatments.

Figure 2: Graph of evaluation of the average biomass per plant. Columns with close variance do not differ by Tukey’s test.

Figure 3: Graph of average diameter per plant. Columns with close variance do not differ by Tukey’s test.

Figure 4:Graph of evaluation of the average height per plant. Columns with close variance do not differ by Tukey’s test.

Figure 5:Graph of the average number of leaves per plant. Columns with close variance do not differ by Tukey’s test.

Oliveira et al. [11], when evaluating the lettuce and arugula productivity in a consortium system under organic and mineral fertilization concluded that lettuce leaf yield may be related to the functions that organic fertilizers exert on the physical, chemical and biological properties of soil, since they have conditioning effects and increase the soil’s capacity to store nutrients. In relation to the diameter evaluation (Graph 2), statistical equality between treatments TR1 (biofertilizer liquid), TR2 (biofertilizer liquid+bokashi) and TR3 (bokashi) was verified.

After evaluating the effects of doses and types of organic compounds on lettuce production, it was concluded that the compost obtained from bean straw provided more nutrients than sawdust and eucalyptus bark compounds, obtaining the highest results in leaf numbers with the application of 240g/pot. In the same line, Medeiros et al. [8] obtained a significant effect for the biofertilizer for the number of leaves, when evaluated the development of lettuce seedlings that were developed in different substrates and under the effect of foliar fertilization using biofertilizers.

Plants of TS (control) plots that were cultivated without any type of fertilization presented lower results in all evaluated criteria, as well as Silva et al. [16] when evaluating different types of organic compounds in lettuce production.

Conclusion

Based on the results obtained, it was possible to evaluate that the lettuce (Lactuca sativa L.) cultivated in soil treated with the bokashi organic compound and with the liquid biofertilizer presented better quality in all the criteria evaluated by this work in relation to the control, only bokashi treatment the results obtained were higher. Further comparative studies are needed to prove this superiority and to determine whether there are advantages in terms of the nutritional value of the lettuce produced in soil treated with the bokashi organic compound.

References

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