Evaluation of Different Organic Fertilizers in the Sustainable Cultive of Coriander

The excessive use of agrochemicals in agriculture has been causing irreversible environmental impacts, from this point of view, organic farming appears as an economically viable alternative to minimize these impacts. So, the objective of this work was to evaluate the effect of different types organic fertilizers in the development and production of coriander harvested at different epochs. The experiment was conducted during the period from August to October 2016, in an area of the experimental farm of University of International Integration of Afro-Brazilian Lusophony. The experimental design was a randomized complete block design, in a 5 × 4 factorial scheme, consisting of five organic fertilizers and four harvesting epochs (28, 35, 42 and 49 days after planting-DAP) and five blocks. The variables stem diameter, plant height, root size, number of leaves, leaf length and productivity were evaluated. All the analyzed variables responded significantly by the F test, either for the qualitative factor, fertilizer sources, or the quantitative, epochs of evaluation. Regarding the cultivation epochs, when the first evaluation period (28 DAP) was compared with the last (49 DAP), it was verified that the variables presented linear responses over time, with increases of 34.4% for height , 29.5% for stem diameter, 37.07% for root length and 64.44% for production. In relation to the fertilizer sources, in general, the cattle manure provided a greater growth and production of the coriander plants, being therefore the most suitable for the cultivation.


Introduction
Among the major problems faced in the last decades, environmental degradation has been highlighted, potentiated by some factors, such as high demand for food, use of chemical inputs for agricultural production and land misuse (Woolpert, 2015).It is known that with the exponential increase of the population and the increasingly scarce natural resources, producers have sought new techniques and sustainable alternatives to improve agricultural production and the production system as a whole (Silva et al., 2017).
Faced with this problem, organic agriculture appears as an alternative proposal for the use of chemical inputs, which encompasses besides the benefits to the environment, local participation and the empowerment of family farmers.According to Zen and Brandão (2018), among vegetables produced by small producers, vegetables stand out, with a rapid cycle, good financial return and economic viability, but they are highly demanding with regard to nutrition.
Coriandrum sativum L., an annual herbaceous herring crop of considerable value and importance in several regions of Brazil, especially in the Northeast, where it is widely consumed (Linhares et al., 2015).The fertilization used in this crop is usually done in a random way, without any theoretical and scientific basis, which often makes the plants do not present good answers.demand in relation to nutrient availability in the soil, thus avoiding immobilization or mineralization of them.The development of strategies related mainly to the use of resources derived from the agricultural property itself, allows the recycling of by-products, reducing expenses and reducing dependence on non-renewable resources (Costa et al., 2017).
In this perspective, organic matter, bovine manure and earthworm humus appear as important components in the formulation of organic fertilizers, because when mixed with the soil, they contribute with physical and chemical attributes, improving the soil structure and providing the necessary nutrients to the plant development (Costa et al., 2017;Saldaña et al., 2014).The use of these byproducts ends up reducing the cost of production of the horticulturists, providing an increase in the production of this important crop and linked to that, enable a more sustainable agricultural production.However, despite the numerous studies in the area of organic production, there are still few that compare organic fertilizers used in the same experiment to distinguish which is the best.Many confine themselves to making comparisons with chemical fertilizers, or with other research, leaving environmental and regional factors somewhat aside.In this context, the objective of this work was to evaluate the effect of different types of organic fertilizers on the development and production of coriander harvested at different times.

Material and Methods
The experiment was conducted during the period from August to October 2016, in an area of the experimental farm of the International University of Afro-Brazilian Lusophony (UNILAB), located in the Piroás, in the municipality of Redenção, in the Maciço of Baturité, Ceará (04º14′53″ S, 38º45′10″ W and average altitude ranging from 240 to 340 m).According to the classification of Köppen, the climate of the place is Aw', that is, tropical rainy, very hot, with predominance of rains in the seasons of summer and autumn.
The organic inputs were obtained from the experimental farm of UNILAB.Bovine manure (obtained still moist) was disposed in the form of a pile and placed for tanning during the period of 30 days.The pile was wetted daily and mixed every two days.The organic matter was obtained through the composting of residues from sugarcane (bagasse and leaves) and foliage of ornamental plants, following the same format used in manure, but in a period of 40 days and with the temperature being checked daily.As for worm humus, this was obtained through vegetable remains of vegetables in a period of 30 days.
After obtaining the inputs, they were duly sieved in a 2 mm mesh and sent for chemical analysis in the Laboratory of Chemistry and Fertility of the soil of the Federal University of Ceará (UFC), together with a soil sample (T1) where it was carried out the experiment (argisol).The results obtained are available in Table 1.
Table 1.Chemical soil attributes, in the 0 to 0.20 m depth layer, and of the fertilizers Note.T1 = no fertilization (reference treatment), T2 = bovine manure, T3 = earthworm humus, T4 = vegetal organic matter and T5 = bovine manure + earthworm humus + vegetal organic matter Source: Laboratory of Chemistry and Soil Fertility of the Federal University of Ceará.
Fifteen days before planting the inputs were incorporated into the beds.Seeds of the true variety were used, distributed in five beds, each measuring 10 m in length, 1.20 m in width and 15 cm in height.The amount of 3 g of seeds distributed per meter of furrow was standardized and the sowing was performed manually and directly in 4 furrows spaced 20 cm to 1 cm deep.Irrigation was performed twice per day by micro-sprinkler irrigation, calculated on the basis of evapotranspiration estimated from evaporation in the Class A tank.
At the defined seasons (28,35,42 and 49 DAP), 50 plants were collected from the central grooves at each treatment (10 plants per block) and the following variables were verified: plant height (PH), stem diameter (SD), root length (RL), leaf length (LL), number of leaves (NL) and productivity (PROD).For these determinations a digital caliper, a scale graded in cm and a precision scale were used.With the postion of these data, was still calculated the plant height ratio and stem diameter (PH/SD).
The qualitative nature data of the analyzed variables, were submitted to analysis of variance and, later, when significant by the F test, submitted to Tukey's test at the 5% level of significance.For the data of quantitative nature conducted a regression analysis, the equations that best fit to the data, were selected based on the significance of the regression coefficients to 1% and 5% probability by the F test and with greater determination coefficient, or higher R².For the statistical analysis the computational program "ASSISTAT 7.7 BETA".

Results and Discussion
Through the statistical analysis (Table 2), it was verified that all the analyzed variables responded significantly to the qualitative factor sources of fertilizer at the level of 1% of probability by the test F.For the quantitative factor evaluation times, only the variable relationship between plant height and stem diameter (PH/SD) did not respond significantly to the F test and, with respect to the interaction between fertilizer sources (F) and seansons (S), it was found that only the leaf length (CF) and leaf number (NF) variables were significantly different at the 1% and 5% probability levels, respectively, by the F test.Note.GL = Degree of freedom; CV = Coefficient of variation; ** Significant at the 1% probability level by the F test; * Significant at the 5% probability level by the F test; ns = Not significant.
According to the mean comparison test (Table 3), it was verified that the highest average found for the variable height of plants was 37.38 cm, and this value was identified when the plants were submitted to treatment with bovine manure (T2).When comparing this value with the minimum value obtained when the plants were cultivated without fertilization (T1), there was a significant reduction of 59.44% in plant height.When the fertilization was carried out with organic matter (T4), the plants presented a mean 0.8% lower than the plants fertilized with bovine manure, thus, there was no significant difference by the Tukey test at 5% probability between both the treatments.Note.T1 = no fertilization, T2 = bovine manure, T3 = earthworm humus, T4 = vegetable organic matter and T5 = bovine manure + earthworm humus + organic vegetable matter.Means followed by the same letter in the column do not differ significantly by the Tukey test at 5% probability.Linhares et al. (2015), when evaluating the productivity of coriander fertilized with different doses of bovine manure, observed that the height of the plants was influenced significantly by the increase of the doses of the input, presenting a maximum height of 18.1 cm when submitted to dose of 60 t ha -1 .The lower height found in the work of Linhares et al. (2015) compared to the data obtained in the present research, may be related to the maturation of manure used in both experiments, climatic factors and growing season.Similar results were found by Tavella et al. (2010), that when working with coriander cultivation under no-tillage system and submitted to fertilization with organic composed of bovine manure and vegetal remains, verified a higher height of plants (30.27 cm) when they were submitted to dose of 30 t ha -1 .
Regarding the diameter of the stem (Table 3), it was found that the highest average was found when the plants were submitted to fertilization with bovine manure (T2), presenting a maximum value of 5.65 mm.When comparing the maximum value with the minimum value (3.48), verified when the plants were fertilized with the mixture between cattle manure + earthworm humus + vegetal organic matter (T5), a reduction of 38.4% was observed in SD.In comparing the best fertilization for this variable (T2) and the treatment without fertilization (T1), a reduction of 24.6% was observed, showing that a quality fertilization for vegetables becomes essential for the development the same.
The positive effect of bovine manure on plant development is due not only to the supply of nutrients but also to the improvement of the physical structure of the soil and to the supply of organic molecules plant growth promoters , such as auxins (Wolka & Melaku, 2015;Zandonadi et al., 2013).Therefore, superior stem diameter results when the plants were fertilized with bovine manure may be related to the physical and chemical improvements when it was used in the soil.
The reduction in stem diameter observed in treatment with bovine manure + earthworm humus + vegetable organic matter (T5), in turn, may be related to the physical properties of humus, which, although not used pure, may have increased retention of water in the soil and consequently decreased its aeration, according to Gonet et al. (2008), thus hindering its absorption by vegetables.
In relation to the variable relationship between plant height and stem diameter (Table 3), in turn, presented a higher mean (8.39 cm -1 mm -1 ), when the plants were submitted to treatment with (T4), while the lowest mean (3.62 cm -1 mm -1 ) was observed in the absence of fertilization (T1), thus a reduction of 56.8%.When exposed to treatment with bovine manure + earthworm humus + vegetal organic matter (T5), the plants presented an average of 7.1% lower than the plants fertilized with organic matter only, and there was no significant difference between both treatments.
This relationship represents the egalitarian elevation between plant height and stem diameter, characterizing non unbalanced growth.Possibly, the vegetal organic matter propitiated a proportionality among these variables due to the slow release of the nutrients, that is directly related to the speed of mineralization of the compound.According to Zandonadi et al. (2013), besides being a source of nutrients, the organic matter presents surface loads that contribute to the increase of the cation exchange capacity (CEC) of the soil and, due to its high reactivity, regulates the availability of several nutrients, in especially the micronutrients, which can be observed in Table 1.
Results divergent to this work were observed by Rodrigues et al. (2010), who evaluated the production of tomato seedlings in substrates with different levels of organic compost and containers in protected environment, found that there was no significant effect of the substrates on the relationship between plant height and stem diameter.time of incorporation, these authors verified that the period of 44 days was the one that promoted a higher average, with the value of 6.6 stems per plant.Therefore, these results demonstrate that coriander when harvested between 40 to 50 days present a high productivity, without however impairing the quality of the final product.

Conclusions
The most efficient compost for coriander productivity was cattle manure, because it provided better results in most of the analyzed variables.The coriander harvest is indicated at 49 days after sowing, because this season favors a higher agronomic performance of the crop.

Table 3 .
Mean of plant height (PH), stem diameter (SD), plant height ratio and stem diameter (PH/SD), root length (RL) and productivity under different sources of organic fertilizer to 49 days after planting