Role of seaweed extract and NPK on the growth and yield of onion ( Allium wakegi L . Varaggregatum

. Onion is one of the primary commodities of growing in Central Sulawesi and is a raw material for the fried shallot processing industry cv. lembah palu. This study aimed to determine the effect of seaweed extract and NPK on the growth and yield of the onion. This research was performed at the Faculty of Agriculture farm, Tadulako University. This research was prepared using a Randomized Block Design (RBD) consisting of seven treatments, with the following details: (A1) = Caulerpa sp Extract 100 ml/pot; (A2) = Sargassum sp Extract 100 ml/pot; (A3) = Ulva sp. Extract 100 ml/pot; (A4) = 0.25 g NPK fertilizer per plant; (A5) = 100 ml of Caulerpa sp. Seaweed Extract and 0.25 g NPK per pot; (A6) = Sargassum Sp Extract 100 ml and 0.25 g NPK per pot; (A7) = Ulva sp. Extract 100 ml and 0.25 g NPK per pot. Thus, there are seven treatments. Each treatment is repeated three times so that there are 21 experimental units. The results showed that the treatment of seaweed extract and NPK obtained better number of leaves, plant height, fresh plant weight, fresh tuber weight, plant dry weight, and number of tuber clumps.


Introduction
Shallots are a spice vegetable crop that is sometimes used by someone worldwide.In every region uses shallots at every food, which function as a aroma enhancer and enhance food taste with a distinctive aroma.In addition, this crop can also be used as a food industry [1].
In the province of Central Sulawesi, especially in the Palu Valley, there are local superior shallot commodities are well known as a source of raw material for fried onions and are very distinctive compared to other onions in Indonesia [2].
The "Palu Valley" shallots were developed, considering that consumer demand from time to time continues to increase.In addition, with the development of the fried onion industry, there will also be an increase in the need for shallots.
The use of seaweed in horticulture and agriculture has yet to be widely used [3,4].In contrast, Indonesia is some of the countries seaweed producers.Seaweed is the largest part of marine plants, which grows in almost all Indonesian oceans and is one of the marine commodities that has been used for a long time as an export commodity [5].This seaweed has essential economic value because its use is extensive as a cosmetic industry, textile industry, pharmaceutical industry, raw material of food, and fertilizer industry [6].
This study aimed to determine the effect of seaweed extract and NPK on the growth and yield of shallots of the lembah palu variety.

Materials and methods
This experiment was carried out at the Green House of the Faculty of Agriculture, Tadulako University glasshouse.The tools used in this study were a shovel, sieve, polybag (14 cm x 18 cm) scales, analytical balance, stirrer, scissors, aqua bottle, ruler, cutter, oven, and stationery.
Shallot seeds of the lembah Palu variety were used in this study.Also seaweed, (Caulerpa Sp, Sargassum, Ulva sp) Aquades, and NPK fertilizer included as part of material in this study.
The data obtained were analyzed by analysis of diversity (5% F test).The treatment had a significant effect, and a further honest significant difference test (HSD) was conducted.

Plant height
Based on the 5% HSD test, it showed the application of seaweed extract fertilizer and NPK on the observation of the number of leaves (Table 1).At the age of 2 WAP, A5 treatment gave the highest score of 28.45.but significantly different from A1, A2, A3, A4 and A7.But the difference was not significantly different in the A6 treatment.At the age of 3, WAP A6 gave the biggest score of 37.80.But it was significantly different from the treatments A1, A2, A3, A4, A5, and A6.At the age of 4 WAP treatment, A1 gave the biggest value, namely 43.00, significantly different from treatments A3, A4, A5, and A7.But not significantly different from A2 and A6 treatments.

Number of leaves
Based on the results of the 5% HSD test, it showed that the application of seaweed extract fertilizer and NPK on the observation of the number of leaves (Table 2) showed that at the age of 1 WAP, the A6 treatment gave the highest value of 8.73, and significantly different in treatment A1, A2, A3, and A4, but not significantly different in A6 treatment.At the age of 2 WAP, A5 treatment gave the highest score of 28.45.but significantly different from A1, A2, A3, A4 and A7.But the difference was not significantly different in the A6 treatment.At the age of 3, WAP A6 gave the highest score of 37.80.But it was significantly different from the treatments A1, A2, A3, A4, A5, and A6.

Plant fresh weight
Based on the results of the 5% HSD test, it showed that the application of seaweed extract fertilizer and NPK on plant height observations (Table 3) showed that at the age of 60 DAP treatment A3 gave the highest value of 39.33 and was significantly different in treatment A1, A4, A5, and A6.Note: Different letter next to the number in the same column indicated significantly different at the 0.05% HSD test level.

Dry weight of plants
Based on the results of the 5% HSD test showed that the application of seaweed extract fertilizer and NPK in the observation of plant dry weight (Table 4) showed that at the age of 60 DAP treatment A3 gave the highest value of 14.24 and was significantly different from treatment A7.However, there was no significant difference among A3, A1, A2, A4, A5, and A6 treatments.Note: Different letter next to the number in the same column indicated significantly different at the 0.05% HSD test level.

Bulbs dry weight
The 5% HSD test results in Figure 1 show that the A3 treatment tends to be better than other treatments for the dry weight of shallot bulbs, with the highest value of 7.11.

Fresh weight of bulbs (g.)
Based on the 5% HSD test, it showed that the application of seaweed extract and NPK fertilizer on the observation of the fresh weight of tubers (Table 5) showed that at the age of 60 DAP treatment A1 gave the highest value of 12.84 and was significantly different from others treatment.Note: Different letter next to the number in the same column indicated significantly different at the 0.05% HSD test level.

Number of tubers per clump
Based on the 5% HSD test, it showed that the application of seaweed extract fertilizer and NPK on the observation of the number of tubers in the cluster (Table 6) showed that at the age of 60 DAP treatment A2 gave the highest value of 18.07 and was significantly different from treatment A3 and A5.Note: Different letter next to the number in the same column indicated significantly different at the 0.05% HSD test level.
The combination between NPK and seaweed extract treatment produced the highest value compared to without NPK or seaweed treatments.This may be affected by the mix between NPK and seaweed extract given together to shallots plants.NPK is an essential element [7] that plants need in sufficient quantities.Treatment of NPK and various types of seaweed extract in pot trials significantly affected the experimental parameters such as , number of leaves, plant height, fresh plant weight, tuber fresh weight, number of tubers in the cluster, and plant dry weight.
That could be the effect of seaweed extract given to plants, which consists of an essential element that plants need in sufficient quantities.The application of seaweed extract can increase soil properties such as chemical, biological, and physical properties [8][9][10].Sufficient nutrient content in the soil or to be given in the form of liquid organic fertilizer will lead to better vegetative growth in shallots.
Seaweed contains macro mineral components, such as calcium, manganese, potassium, and micro minerals, and phytohormones as growth regulators, such as auxin, gibberellin, and cytokinins [11].Every kind of hormone has its role; auxin compounds can stimulate cell division growth, protein synthesis, and differentiation; While, gibberellins can stimulate cambium growth, dormancy, parthenocarpy, geotropism, abscission, and, stimulate nodes growth so that plants are grow vigorously.On the other hand, cytokinins play an important role in plant cell to stimulate resulting growth, sprout germination, fruit growth, and [12] and much more.
Many products taken from seaweed have been used as additional bio stimulants and or organic fertilizers (biofertilizers) to improve yields and growth because these seaweeds contain plant hormones.That hormones substances in seaweed include auxin [12,13].
Crops take elements from whole plant cell surfaces, including growth regulators.Nutrient absorption on plant surfaces causes the competence of cells to grow and develop to form new larger organs so that the formation of leaves becomes more [14,15].Furthermore, these substances are converted into proteins, nucleic acids, polysaccharides, and other complex molecules, so that the plant's dry weight and fresh weight increased [16].An increase in metabolic processes in plants causes an increase in the formation of carbohydrates, fats, and proteins, and in the end, the potential for crop yields can be achieved [17].
Growth and development are basically affected by the adding of manure and the availability of amendment in the soil [10,18].Absorption of nutrients is limited by different nutrients in a minimum state.Optimal growth can be reached if those nutrients are balanced, meaning that no single nutrient is a limiting factor.In addition, seaweed consist many vital minerals; seaweed also contains hormone that have been proven to increase plant growth and crop yields [19].Therefore, extracts of seaweed are naturally degradable and safe for both animals and humans and can be used as an organic fertilizer or liquid fertilizer [10].

Conclusions
Applying seaweed and NPK show an effect on plant growth and development.Based on the explanation of the research results above, it can be concluded that the given seaweed extract and NPK to shallot growing in polybag condition at the same time shown better than given only NPK alone.

Fig. 1 .
Fig. 1.Graph of Lembah palu variety shallots of the on the application of various seaweed extracts and NPK on dry tuber weight (g) at 60 DAP.

Table 1 .
The average value of the lembah palu variety shallot on the application of various seaweed extracts and NPK to plant height (cm) aged 2 WAP, 3 WAP, and 4 DAP.Different letter next to the number in the same column indicated significantly different at the 0.05% HSD test level.

Table 2 .
The average value of the lembah palu variety on the application of various seaweed extracts and NPK to the number of leaves at aged 1 WAP, 2 WAP, 3 WAP, and 4 DAP

Table 3 .
The average value of the lembah palu variety shallots on the application of various seaweed extracts and NPK on plant fresh weight (g) at 60 DAP.

Table 4 .
The average value of the lembah palu variety shallots on the application of various seaweed extracts and NPK to the dry weight of plants (g) aged 60 DAP.

Table 5 .
The average value of the lembah palu variety shallots on the application of various seaweed extracts and NPK to the fresh weight of tubers (g) aged 60 DAP.

Table 6 .
The average value of the lembah palu variety shallots on the application of various seaweed extracts and NPK to the number of tubers (g) aged 60 DAP.