Biochar Bamboo Application on Growth and Yield of Red Amaranth (Amaranthus tricolor L)

This study aims to obtain a proper dose of biochar for the growth and yield of red amaranth plants. This study used a complete randomized design of one factor with 4 replications. The tested treatment was bamboo biochar with 4 dose levels (0, 3, 6, 9, and 12 t ha−1). The results showed that biochar treatment gave significant effect to fresh weight of economic yield and oven dry weight of economic yield, but not significant to a variable of plant height and number of the leaf. Biochar as a soil enhancer has been able to improve soil physical properties, increase microbial activity, and improve soil fertility. With soil fertility improvements, it will enhance the ability of plants to absorb nutrients and water in the soil, and encourage the vegetative growth of plants and sunlight interception by leaves to produce photosynthesis. The highest fresh weight of amaranth yields was obtained at biochar 9 t ha−1 of 14.53 g which increased by 34.41% when compared with the fresh weight value of the lowest economic yield on biochar without 10.81 g.


Introduction
Plants Red amaranth known as the scientific name of Amaranthus tricolor L. is a yearly plant of shrubs (shrubs) are much loved by all levels of society. This red amaranth besides tastes good and soft also can facilitate digestion. Red amaranth as one source of antioxidants needs to be developed because of the potential as a vegetable is very useful because of the high content of phenols and flavonoids that function as antioxidant compounds [1].
Biochar contains high carbon (more than 30%), has large pores and large surface area, and has high water holding capacity. Biochar containing high carbon (more than 30%) will experience more weathering so that when applied in the soil can survive for long periods of time.
Biochar is much more effective in nutrient retention and availability for crops than other organic materials such as compost or manure. Biochar is more persistent in the soil than any other organic matter, so all the benefits associated with nutrient retention and soil fertility can go much longer than any other common organic form [2]. Biochar can be made from a variety of biomass, even eligible agricultural wastes. History shows, biochar has been used traditionally by farmers in various parts of the world. Various studies show biochar has the potential to improve soil structure and fertility. In the long run, biochar does not disturb the carbon-nitrogen balance, but it can hold and make water and nutrients more available to plants. When used as a soil enhancer with organic and inorganic fertilizers, biochar can increase productivity, as well as retention and nutrient availability for plants.
The effect of biochar on crop productivity depends on the dose used. The results of [3] show that the utilization of bamboo waste biochar dose of 10 tons ha-1 gives a real effect on the plant height and the total wet weight of corn plant. Further research [4] showed that the best growth response of maize crops 1234567890''"" was obtained at the treatment of 10 tons ha-1 biochar, 20 tons ha-1 of compost, and 300 kg ha-1 phonska. [5][6][7] show that utilization of bamboo waste biochar dose of 5-15 ton ha-1 can increase the growth and yield of maize. Furthermore, [8] reported that 5-15 t ha-1 bamboo biochar had not responded significantly to the yield of the pakchoy plants. The results of [9] show that growth and performance results of amaranth plants were significantly higher when planted in a regular pot mixture receiving 100 percent NPK compared with biochar treatment. The biochar application showed no significant variation in growth and amaranth results [9]. Through this research, it is hoped that the application of the exact real biochar dosage can improve the growth and yield of red amaranth plants.

Materials and methods
The materials used in this study are red amaranth, biochar from bamboo waste, and soil media. This experiment was conducted at a greenhouse, Experimental Garden of Agriculture Faculty of Warmadewa University, Denpasar. This study has been conducted from June to Agustus 2016.
The variables observed included plant length, number of leaves, fresh weight of economic yield, and oven dry weight of economic yield of red amaranth. Research data were analyzed statistically with F (ANOVA) test using Microsoft Excel program. If the F test shows a significant effect on the 5% test level, then proceeded with a 5% Duncan test.

Results
The significance of biochar (B) on the observed variables can be seen in Table 1. From Table 1, biochar treatments showed a significant effect (P <0.05) on the fresh weight of economic yield and oven dry weight of economic yield, but unstable (P≥0.05) to variables of plant height and number of leaves.

Plant height
The result of statistical analysis on plant height showed that biochar treatment (B) was not significant (P≥0.05) to plant height ( Table 1). The average plant height in biochar treatment is presented in Table  2.
Based on Table 2 it can be seen that the average plant height tended to be obtained at a biochar dose of 9 t ha -1 (B3) of 34.13 cm was not significantly different from other biochar dose treatments, whereas the lowest value of plant height was obtained in treatment without biochar (B0) of 29.35 cm. The biochar dose relationship with average plant height can be seen in Figure 1.

Number of leaves
The results of statistical analysis showed that the giving of biochar (B) was not significant (P≥0.05) on the number of leaves ( Table 1). The average number of leaves on the biochar treatment can be seen in Table 2.
From Table 2, the average value of the highest leaf number tends to be obtained at the dose of biochar 9 t ha -1 (B3) of 9.25 strands is not significantly different from the biochar dosage treatment others, while the lowest value of the number of leaves obtained in the treatment without biochar (B0) of 7.50 strands. The biochar dose relationship with the average number of leaves can be seen in Figure 2.

Fresh weight of economic yield
The results of statistical analysis showed that biochar application (B) had a significant effect (P <0.05) on fresh weight of economic yield ( Table 1). The average fresh weight of economic yields on biochar treatment can be seen in Table 3.
From Table 3, the highest value of the fresh weight of economic yields was obtained at a biochar dose of 9 t ha -1 (B3) of 14.53 g, but the lowest value of the weight fresh economic yields was obtained on treatment without biochar (B0) of 10.81 g. The biochar dose relationship with the average fresh weight of economic yield can be seen in Figure 3. Table 3. The average fresh weight of economic yields and dry weight of economic yield on biochar treatment.
The average value followed by the same letter in the same treatment and column different, not significant at 5% Duncan test level.

Oven dry weight of economic yield
The result of the statistical analysis showed that biochar application (B) had the significant effect (P <0.05) on oven dry weight of economic yield ( Table 1). The average oven dry weight of economic yield on biochar treatment can be seen in Table 3.
Base on Table 3, it can be seen that the highest value of oven dry weight of economic result is obtained at dosage biochar 9 t ha -1 (B3) of 1.29 g, but the lowest value of oven dry weight of economic yields was obtained in the treatment without biochar (B0) of 0.92 g. The biochar dose relationship with the average oven dry weight of economic yield can be seen in Figure 4.

Discussion
The results of this study showed that the highest fresh weight of the highest economic yield was obtained on biochar 9 t ha -1 (B2) of 14.53 g or increased by 34.41% when compared with the freshest weight value of the lowest economic yield on biochar (B0) of 10.81 g ( Table 3). The high yield of a fresh yield of a red amaranth economic result is supported by the positive correlation of maximum plant height variable (r = 0.995**), maximum leaf number (r = 0.983**), and oven dry weight of economic result (r = 0.985**) ( Table 4).
This is presumably because biochar as a soil enhancer can improve soil physical properties, encourage increased microbial activity, and improve soil fertility. With the improvement of soil fertility, it will increase the ability of plants to absorb nutrients and water in the soil, and encourage the vegetative growth of plants and sunlight interception by the leaves to produce photosynthesis. These photosynthates will be transferred to the plant organs that are active in the metabolism process to encourage the growth of roots, stems, and leaves of plants to obtain the results of fresh weight of the maximum plant economy. Biochar serves as a soil aggregate and adhesive agent between soil particles to form soil aggregates, so biochar is essential in the formation of soil structures. In soils, porous biochar granules, in addition to nutrient and water retention in the soil, may also provide habitat for soil microorganisms. Nutritional and water retention has an effect on the addition of nutrients to the plant, causing an increase in soil porosity, water holding capacity, C-organic, and microbial activity in the soil [10].
Application of biochar made from raw bamboo to the soil can improve the fertility of the agricultural soil. In this case, the properties of soil repaired by biochar are aggregation and soil water retention capacity, pH, and cation exchange capacity (CEC) and the increase of biological population and activity in the soil [6], [11][12][13].

Conclusion
Application of soil enhancers from bamboo biochar showed the significant effect on the fresh weight of economic yield and oven dry weight of economic yield, but not significant to plant height and number of leaves of red amaranth plant. The highest yield of fresh weight of economic yield on red amaranth plants was obtained in the application of biochar dose of 9 t ha-1 of 14.53 g, which increased 34.41% when compared with the fresh weight of the lowest economic yield on biochar without 10.81 g.