Sustainable cultivation of red chili plants (Capsicum annuum L.) through a composition of NPK and biological organics fertilizers

One form of sustainable agricultural activity that can be carried out is by implementing environmentally friendly agriculture, such as applying inorganic and biological organic fertilizers. The research aims to obtain a composition of NPK doses and biological organic fertilizer on red chili plants in reducing use of NPK fertilizer to support sustainable chili farming. The fertilizer provided is in the form of palm oil processing waste (sludge) and biofertilizer based on a bacterial consortium. The experimental design used in this research was a completely randomized design (CRD) with six treatments and four replications. The treatment given consisted of a composition of 100% NPK added petroganics (P1), added sludge compost (P2), a composition of 75% NPK added sludge compost (P3), added sludge compost + biofertilizer (P4), a composition of 50% NPK added sludge compost and biofertilizer (P5), and a composition of 25% NPK added sludge compost and biofertilizer (P6). Based on the results, the composition of 75% NPK added sludge compost + biofertilizer gave results relatively the same as the composition of 100% NPK + petroganic fertilizer in several parameters. This shows that sludge compost + biofertilizer can reduce the use of inorganic fertilizer by as much as 25%.


Introduction
The demand for chili plants continues to increase every year so that chili plants are a horticultural plant that has high economic value to cultivate.According to [1], red chili productivity in Riau is still low, namely 8.3 tons ha -1 , while national production reaches 10.17 tons.ha -1 .Therefore, efforts need to be made to meet the demand for chilies by increasing chili productivity through appropriate fertilization techniques.Some farmers have used organic fertilizer as a companion to inorganic fertilizer in chili cultivation.Excessive use of inorganic fertilizers can have a negative impact on the environment [2].Several things that will happen include a decrease in the organic matter content of the soil, the soil is susceptible to erosion, permeability and the population of soil microbes decreases, so it is best solution with add organic fertilizer to the soil [3].The use of inorganic fertilizers without being balanced by adding organic fertilizers to the soil is certainly not an environmentally friendly agricultural practice.In fact, environmentally friendly agricultural practices are one form of activity that supports sustainable agriculture.Therefore, efforts need to be made to add organic fertilizer to every cultivation activity while maintaining productivity.One of the organic materials that has the potential to become organic fertilizer in Riau Province to support the cultivation of chili plants is sludge waste which is a by-product of palm oil processing.[4] reported that the used of sludge from palm oil compost can increase oil palm growth.
Direct utilization of sludge in plants has disadvantages such as high cellulose content, so the decomposition process is needed to accelerate the provision of nutrients to plants, one of which is biologically by adding microorganisms such as cellulolytic bacteria that can produce enzymes to break down organic matter.There are six cellulolytic bacterial isolates that can be used, namely Providencia vermicola SA1, and Bacillus cereus SA6, Proteus mirabilis TKKS3, Proteus mirabilis TKKS7, Bacillus cereus JP6, Bacillus cereus JP7 [5].
The given cellulolytic bacterial consortium can also be applied in the form of biofertilizer.The biofertilizer has been applied to several plants, namely rice plants [6] and corn plants [7].Some of the functions of biofertilizer are increasing the availability of essential macro nutrients (N, P and K) [8], producing phytohormones that can stimulate plant growth [9], NPK fertilizer can be reduced by 30%, and yields increase in horticultural crops.[10].This study aims to obtain a composition of NPK doses and biological organic fertilizer on red chili plants (C.annuum L.) in reducing use of NPK fertilizer to support sustainable chili farming.

Materials and methods
Cultivating chili plants for this research in Langsat Permai Village, Bunga Raya District, Siak Sri Indrapura Regency, Riau Province.The chili seeds used in this study were red chili seeds of Kopay local variety.The fertilizers used in this study consisted of several doses of NPK, sludge compost and biofertilizers.The bacteria used in making compost and biofertilizer consisted of six isolates of cellulolytic bacteria [5].Both organic fertilizers were applied after making sludge compost and biofertilizer.

. Sludge from palm oil composting
Making compost begins with refreshing the bacterial consortium of bacteria in 10 ml Nutrient Broth (NB) media.The growing suspension was then inoculated on 100 ml sludge media consisting of several ingredients including 0.75g yeast extract, water, palm oil sludge waste, 5 kg of sugar, 0.075g MgSO 4.7H2O, 0.1125g NH4NO3, 0.375g K2HPO4, 0.1875 KH2PO4, 0.0075g FeSO4.7H2O,0.015g CaCl2.2H2O.Incubation was carried out for three days at 28 o C.After the bacteria were grown on sludge media, then the bacteria were given to sludge waste and the composting process was carried out for 4 weeks.

. Manufacture of biofertilizer
The biofertilizer applied to plants also contains the same cellulolytic bacteria as the sludge compost.The growth medium for the biofertilizer consists of bacterial inoculants in NB media, rice washing water, and brown sugar.Incubation of biofertilizers was carried out for 2 weeks before being applied to plants.The biofertilizer given is 10 ml and is given three times with the same dose.

Growth of chili plants given various doses of composition of NPK fertilizers with organic fertilizers
Providing the composition of NPK and organic fertilizer based on analysis of variance had no significant effect on plant height, but had a significant effect on dichotomous height and harvest age.Further test results (DNMRT at 5% level) of red chili plant height dichotomous height, and harvest age tested in Table 1.
Table 1.Plant height, dichotomous height, and harvest age of red chilies by applying several fertilizer compositions.
Note: According to the 5% level of the DNMRT test, the same letters in numbers in different columns are not significant Table 1 shows that giving a composition of 75% NPK + sludge compost + biofertilizer gives the same plant height as giving 100% NPK + petrogenic fertilizer, even if there is a reduction in the dose of NPK fertilizer by 25% and 50% of the recommended dose used still gives the same plant height as the use of 100% NPK fertilizer without sludge compost and biofertilizer.Indicates that the application of sludge compost and biofertilizer is able to meet the plant's nutrient needs to support the growth of the vegetative phase such as the height of the chili plants.The analysis results show that the content contained in sludge compost is 1.52% N-Total (Table 5).The nutrients produced from compost support the growth of plant height, while the bacteria in biofertilizer provide nutrients in the soil.The use of biofertilizer containing bacterial consortium is also able to play a role in providing nutrients and phytohormones, one of which is Bacillus cereus bacteria contained in the biofertilizer used.[11] stated that the use of Bacillus-based biofertilizers can produce hormones that can support growth and increase plant production.
Providing biofertilizer based on Bacillus sp.bacteria show an increase in the growth and production of red chili plants [12].Providing a composition of 75% NPK fertilizer + sludge compost without biofertilizer produces a dichotomous height relatively the same as 100% NPK, however, applying biofertilizer produces a dichotomous height relatively the same as giving 100% NPK fertilizer.This indicates that a reduction in the dose of NPK fertilizer by 25% is still able to provide a dichotomous height that is relatively the same as the application of 100% NPK + petrogenic fertilizer.Good dichotomous height growth is caused by the high N content produced from the application of sludge compost followed by the provision of biofertilizers that are able to fix N 2 to produce phytohormones to support the vegetative period of plants.Giving sludge compost can help the availability of nutrients that can increase vegetative growth in the dichotomous height of red chili.The sludge compost given showed the N-total content reached 1.52% (Table 5).
The provision of biofertilizer based on a consortium of bacteria, one of which is Bacillus, is able to bind N2 in the atmosphere and form phytohormones, which are growth regulators that are beneficial in growth.Bacillus sp. can synthesize auxin phytohormones (Indole 3-Acetic Acid/IAA) which functions to increase growth, because the dichotomy of chili plants can grow optimally [13].[14] added plant height can increase thanks to the application of biofertilizer made from Bacillus.  1 shows that the composition of 75% NPK fertilizer + sludge compost is able to provide harvest age relatively the same as the provision of 100% NPK fertilizer.This means that a 25% reduction in the dose of NPK fertilizer followed by the provision of sludge compost + biofertilizer is able to provide harvest age tends to be the same as the provision of 100% NPK fertilizer + petrogenic.Giving a composition of 75% NPK fertilizer + sludge compost shows the results of the harvest age of chili 8-9 days faster than the harvest age description which is 80-90 DAP (day after planting).

Treatment
The availability of nutrients in the soil increases due to the application of sludge compost and biofertilizer.Based on the results of soil analysis after planting, the P nutrient content increased by an average of >1,000 ppm (Table 4a dan 4b).According to [15], phosphorus plays a role in plant metabolic activities, namely accelerating the formation of flowers into fruit.In line with the results of research [16] that increasing P fertilizer results in a faster harvest age due to the availability of P nutrients, where P nutrients play a role in plant metabolic processes, resulting in a faster harvest age.

. Yield of chili plants given various doses of composition of NPK fertilizers with organic fertilizers
Providing the composition NPK and organic fertilizers based on analysis of variance had no significant effect on the parameters of the number of fruits per plant.The results of further tests (DNMRT at 5% level) on the number of fruits per red chili plant in Table 2.The observation of the number of fruits of chili plants in Table 2 shows that the reduction in the dose of NPK fertilizer by 25%, 50% and 75% followed by the application of 100% sludge compost + biofertilizer gives the same number of fruits as the application of 100% NPK + petrogenic fertilizer.This indicates that the application of sludge compost followed by biofertilizer will have a positive impact on the soil so that it can improve the level of fertility and nutrient availability which will affect plant growth and development.According to [17], the use of organic matter and biofertilizer is a solution in overcoming the low level of soil fertility and the ability of microorganisms contained in compost to spur plant growth, fix nitrogen and dissolve phosphate.The number of fruits is the total number of fruits formed in each sample plant in each plot.The number of fruits is related to the percentage of flowers formed, the more percentage of flowers formed, the chance of fruit formation also increases.The process of flower and fruit formation in the generative period of plants requires macro-nutrients, one of which is P nutrient.
The role of phosphate for plants is to spur plant generative growth.The provision of sludge compost + biofertilizer is able to have a positive impact on the soil so that it can help increase nutrient availability.Sludge compost P 2O5 analysis content of 3.4% (Table 5), in addition to composition of 75% NPK fertilizer + sludge compost + biofertilizer showed a very high available P content that reached 1,860 ppm (Table 4a dan 4b).The need for nutrients in the generative phase of plants and the reduction in NPK fertilizer are thought to be contributed by the simultaneous application of sludge compost fertilizer and biofertilizer.The high availability of nutrients, especially P elements, will have an impact on the formation of flowers, fruits and seeds of red chili plants.The results of research [18], the number and weight of fresh fruit from chili plants increases due to the nutrient content in the biofertilizer being able to be absorbed by the chili plants.
Based on the observation of fruit length in Table 2, the composition of 75% NPK fertilizer + sludge compost + biofertilizer was able to provide the same fruit length as 100% NPK + petrogenic fertilizer.NPK fertilizer can be reduced by 25% of the recommended dose used due to the application of sludge compost fertilizer followed by biofertilizer.The simultaneous application of sludge compost and biofertilizer is considered to be able to have a positive influence on soil and plant growth.[19] reported that chili plants treated with biofertilizers produce fruit lengths 1.05 cm longer than chili plants that are not treated with biofertilizers.In this study, the application of biofertilizers containing bacterial consortium is considered capable of containing a consortium of bacteria is considered capable of playing a role in providing nutrients and maximizing plants to absorb nutrients, one of which is Bacillus bacteria.The results of research [20] Bacillus sp. is often found in the rhizosphere area and is known to be able to form a symbiotic relationship with roots and solubilize phosphate.
The length of chili fruit is also influenced by nutrients, especially phosphorus.Metabolic processes require phosphorus plants.According to [21], the fulfillment of phosphorus causes photosynthesis to run smoothly and the chili fruit will be large.A high rate of production and allocation of assimilates is needed in the yield formation phase.The availability of carbohydrates and nutrients in the soil increases the rate of photosynthesis.Carbohydrates are very important to sustain the development of flowers, fruits and seeds [22].The results of observations of weight per fruit in Table 2 show that the composition of 75% NPK fertilizer + sludge compost + biofertilizer is able to provide the best weight per fruit, which is 5.68000 g compared to the provision of 100% NPK fertilizer + petrogenic 4.96500 g.This means that the provision of sludge compost followed by sludge compost + biofertilizer is able to provide the best weight per fruit.This means that 25% NPK fertilizer can be reduced by 25% through the application of sludge compost and biofertilizer, but the reduction in the dose of NPK fertilizer beyond 25% has not been able to give good results on weight per fruit.This result shows a higher value of weight per fruit compared to the value of weight per fruit in the description which is 3-5 g.
The provision of NPK fertilizers followed by sludge compost and biofertilizers is considered to be able to have a positive effect on the available nutrients in the photosynthesis process in red chili plants so that chili plants can produce optimal growth and development.Entering the generative phase, chili plants really need elements such as P and K which are sufficient to support the formation of flowers and fruit.The composition of sludge compost and biofertilizer given is one of the factors in the availability of nutrients, one of which is P and K. Sludge compost shows a fairly high content of nutrients N, P, K, namely total N (1.52%),P (3.4%) and K (3.35%) (Table 5).Nutrient content of P > 1,000 ppm and K by 2.86 cmol/kg in this research soil had increase after planting (Table 4a dan 4b).The application of sludge compost and biofertilizer is able to make a good contribution to the soil.The availability of nutrients will also affect the quality of chili fruit, especially K.The element K plays a very important role in the formation of fruit size and quality [23].Plants that lack potassium will experience incomplete fruit growth, small, poor quality, and have low storability.[24], added that the increase in fruit weight is influenced by the sufficiency of K nutrients because the K element plays a role in carbohydrate translocation and starch formation.
Table 2 shows that the application of 75% NPK fertilizer + sludge compost + biofertilizer or without biofertilizer is able to provide results in fruit weight per plant which is relatively the same as the use of 100% NPK fertilizer + petrogenic and, even better than 100% NPK fertilizer + sludge compost.This means that the application of sludge compost + biofertilizer can save the use of NPK fertilizer by 25%, but the reduction in the dose of NPK fertilizer beyond 25% is considered not able to provide better results.Giving a composition of 75% NPK fertilizer + sludge compost + biofertilizer has the potential to optimize and streamline the reduction of inorganic fertilizers and it is thought to be due to added organic materials.That is why yield parameters (fruit weight per plant) can be influenced by the nutrients available in the soil.Fruit weight is strongly influenced by the availability of nutrients and the ability of plants to absorb nutrients, especially P and K.According to [25], the formation of carbohydrates and sugars is influenced by the element K which has an impact on improving the quality of the flowers and fruit produced.According [26], in addition to the K element, phosphorus is very important in increasing plant production because it stimulates and accelerates the percentage of flower formation into fruit.The results of soil analysis of the composition of 75% NPK fertilizer + sludge compost + biofertilizer showed that the K element content increased from the initial soil analysis results of 4.65 cmol/kg (Table 4a dan  b).The addition of biofertilizers containing bacterial consortium also helps in providing nutrients such as phosphorus because there are Providencia vermicola bacteria.According to [27], P. vermicola are potential phosphate solubilizing bacteria, so they are thought to actively contribute P elements in biofertilizers.
The observation of production per plot in Table 2 shows that a 25% reduction in the dose of NPK fertilizer followed by the addition of sludge compost + biofertilizer gave the same production per plot as the use of 100% NPK + petrogenic fertilizer, but the reduction in the dose of NPK fertilizer beyond 25% has not been able to provide better production per plot, but gave the same production per plot relative to 100% NPK + sludge compost.This means that the use of sludge compost + biofertilizer can reduce the dose of NPK fertilizer by 25%.Microbial activity in biofertilizers plays a positive role in providing nutrients and reducing the use of NPK fertilizers.Nutrients have an important role for plants, the nutrients K and P in the soil influence fruit formation.According to [28], nutrient K functions to transport carbohydrates that function as catalysts and the sugar content in the fruit increases so the fruit is heavier.The nutrient content of sludge compost analysis, P (3.4%) and K (3.35%) (Table 5).Increased availability of K and P nutrients in the soil will have an impact on plant growth and development including chili production per plot.
Initial soil analysis results showed an acidic pH and low N-Total content of 1.92% and very low P 2O5 content of 0.36 ppm and very low K2O of 4 cmol/kg.The composition of 75% NPK fertilizer with sludge compost organic fertilizer + biofertilizer based on soil analysis after planting was able to provide nutrient content results that tended to be the same as the composition of 100% NPK fertilizer, even the available P content showed the highest at 1860 ppm and K also showed the highest at 4.65 cmol/kg.

Conclusions
Giving a composition 75% NPK fertilizer (135 g) + sludge compost (720 g) + biofertilizer (10 ml) gave results that were no different from using 100% NPK fertilizer (180 g) + petrogenic (280 g) in several observation parameters except for flowering age parameter.Providing three applications of 75% NPK fertilizer (135 g) + sludge compost (14.4 kg) + biofertilizer (10 ml) can reduce the use of NPK fertilizer doses by 25% of the recommended dose so that chili farming can be achieved sustainably.

Table 2 .
Interaction between fertilizer and insecticide use, fertilizer and insecticide use on sweet corn crop production observations.
Notes: According to the 5% level of the DNMRT test, the same letters in numbers in different columns are not significant

Table 3 .
Soil analysis results before planting.Note: Assessment of soil properties based on Soil Research Center, 2018.

Table 4a .
Soil analysis results after planting.

Table 4b .
Soil analysis results after planting.

Table 5 .
Results of sludge compost analysis.