BIOTROPIA Vol. 30 No. 2, 2023: 232 - 241 DOI: 10.11598/btb.2023.30.2.1902 232 USE OF BIOLOGICAL ORGANIC FERTILIZERS AND PESTICIDES TO IMPROVE POTATO CULTIVATION IN SLOPE ANDISOLS TAMAD1*, LOEKAS SOESANTO2 AND AKHMAD RIZQUL KARIM3 1Department of Soil Science, Faculty of Agriculture, Jenderal Soedirman University, Purwokerto, Central Java, 53123, Indonesia 2Department of Phytopathology, Faculty of Agriculture, Jenderal Soedirman University, Purwokerto, Central Java, 53123, Indonesia 3Department of Agribusiness, Faculty of Agriculture, Jenderal Soedirman University, Purwokerto, Central Java, 53123, Indonesia Received 21 February 2023 / Revised 13 March 2023 / Accepted 13 March 2023 ABSTRACT In the 1990s, potato yield in the Andisols of Dieng, Central Java, Indonesia, was approximately 30 t ha–1, but this value decreased rapidly to 12–15 t ha–1 in recent years. This rapid decline could be attributed to the use of unbalanced organic and chemical fertilizers, without the application of conservation techniques. Therefore, this study aimed to sustainably improve the local potato cultivation pattern of farmers on Andisols using biological organic fertilizers and pesticides (BOFP). A randomized block design was used with two factors, namely: 1) 20 t BOFP, 300 kg Urea, 500 kg SP 36, 300 kg KCl, and 200 kg lime ha–1, and 2) comparison with the pattern of farmers, consisting of 20 t of chicken manure, 1–t NPK, and 250 kg ZA ha–1. The potato plant mounds were tilted 10% to the contour direction, and each treatment was carried out with 16 replications. Granola seeds were used to plant potato during the rainy season from March-June 2022. The results showed that the plants cultivated using the local pattern of farmers were affected by wilt from Fusarium spp, while the use of BOFP decreased the incidence of the disease by 80%. Furthermore, the BOFP pattern significantly increased Andisols organic-C from 1.78% to 3.83% and total soil P from 5.20% to 11.34%, compared to the pattern of farmers. It also increased potato yields from 12.31 t ha–1 to 22.93 t ha–1 and the R/C from 0.85 to 1.23, compared to the pattern of farmers. Based on the results, the use of BOFP pattern decreased wilt attacks by Fusarium spp, improved the productivity of Andisols, as well as increased potato production and profits of farmers. Keywords: beneficial microbes, farmer income, manure, potato, soil productivity INTRODUCTION Farmers on the Andisols slopes have been cultivating potato using unbalanced organic and chemical fertilizers, without applying conservation techniques. Furthermore, potato plant mounds are often prepared toward the hill (Figure 1), which causes a decrease in soil fertility due to nutrient imbalances and intensive erosion. This planting pattern has also led to a decrease in potato production of 10–15 t ha–1 compared to the volume recorded in the 1990s. The decline was due to a reduction in the productivity of Andisols and an increasingly intensive potato plant disease. Dieng, Central Java, Indonesia, is situated on Andisols land, which is known to have a high adsorption capacity for phosphorus (P), leading to low availability of P for plants. This high adsorption capacity is due to the presence of aluminol groups (Al–OH and Al–OH2 +), ferrihydrite, and Al-humus complex (Pizarra et al. 2008; Delfim et al. 2018). The application of a large amount of P fertilizer to the Andisols does not necessarily increase the availability of P to plants, as the efficiency of P fertilization is low, ranging from 10% to 20% of applied P (SACRC 2004; Elásquez et al. 2016). However, the available P can be increased through the use of organic fertilizer enriched with phosphate microbial (PM), organic matter ameliorant (humic-fulvic), and signal quorum sensing (QS), as a regulator of the effectiveness of biological agents. *Corresponding author, email: tamad_1965@yahoo.com; tamad@unsoed.ac.id mailto:tamad_1965@yahoo.com mailto:tamad@unsoed.ac.id Potato Cultivation in Slope Andisols – Tamad et al. 233 Figure 1 The potato cultivation system with mounds in the direction of the slopes in Dieng, Central Java, Indonesia PM, such as Pseudomonas trivialis, P. putida, and P. fluorescens, has the potential to increase P availability (Arcand and Schneider 2006; Tian et al. 2021; Yadav et al. 2021) by dissolving inorganic–P and mineralizing organic–P. In Andisols, these microbes have been found to increase the dissolution of inorganic–P by 535– 575%, mineralization of organic–P by 336– 387%, and reduced adsorbed–P to 15–30% (Tamad et al. 2021). Intensive disease infestation, including late blight, potato bacterial wilt, tuber rot, fusarium wilt, and dry spot caused by Phytopthora infestans, Ralstonia solanacearum, Colleotrichum coccodes, Fusarium sp., and Alternaria solani, can contribute to low potato production. An alternative for controlling potato disease is the use of Bio P60, a biological pesticide containing crude secondary metabolites of bacterial antagonist P. fluorescens P60 (Soesanto et al. 2011). Another critical factor that must be considered during cultivation in Andisols is the need for soil amendments. Humic materials include humin, humic acid C10H12O5N, and fulvic acid C12H12O9N. Humic acid is brownish-black, resistant to degradation, and contains a negative charge that is dependent on pH. Several studies showed that humic-fulvic had the potential to be used for soil amendment (Stevenson 1994; Baveye and Wander 2019). However, the effectiveness of Andisol amendments is greatly influenced by soil microbial activity. The biochemical process that regulates population density-dependent microbial behavior through crucial signaling molecules is known as quorum sensing (QS) (Teplitski et al. 2011; Ma et al. 2018; Coquant et al. 2020; Ward et al. 2001). Gram-negative bacteria typically produce N-acyl–homoserine lactones (AHL) as a QS signal (Ward et al. 2001; Muras et al. 2020). A previous study also showed that plant root extracts could serve as a source of N–AHL (Tamad et al. 2020). The enrichment of organic fertilizers with microbes and signal quorum sensing as biological organic fertilizers effectively increases soil fertility. Tamad et al. (2020a) stated that using biological organic fertilizer (BOF) of up to 20 t ha–1 increased potato yields by 2 t ha–1 compared to the cultivation pattern of farmers in Kaligua, Central Java, Indonesia. The use of BOF in potato cultivation also increased R/C from 1.13 to 1.53, and profits rose by IDR 29.995.573 ha–1 compared to the practice of farmers. Therefore, this study aims to improve the local potato cultivation pattern of farmers on Andisols using BOFP. The results are expected to increase potato production, sustainably improve the quality of Andisols, and increase the income of farmers. MATERIALS AND METHODS This study was carried out in Andisol Dieng, Central Java, where the soil had slightly acidic pH H2O, medium organic–C, high K2O, high P2O5, and medium N of 5.63, 2.39%, 0.4%, 3.20%, and 0.34%, respectively. Furthermore, the region had an area of 3000 hectares and an altitude of 1,000–2,500 m above sea level, which was very suitable for potato cultivation. This study utilized biological organic fertilizers and pesticides, which were applied using conservation techniques in partnership with local farmer groups. BOFP Formulation The BOFP formula was produced using chicken manure inoculated with phosphate solubilizing microbial and Bio P60 (107 CFU g–1) BIOTROPIA Vol. 30 No. 2, 2023 234 at a concentration of 0.025% v w–1, followed by the addition of humic-fulvic acids and 1% v w–1 QS signal. The BOFP components were then mixed with the granulator under moist conditions, as shown in Figure 2. Subsequently, the product obtained was incubated for four weeks with 15–20% moisture content. Figure 2 The formulation of biological organic fertilizers pesticides (BOFP) Preparation of Phosphate Microbial (PM) Culture PM consortium of Pseudomonas trivialis, P. putida, and P. fluorescens was grown on molasse culture for one week (end of log phase) (Tamad et al. 2020). The Standard Plate Count (SPC) method was then used to determine PM at a minimum population of 107 CFU mL–1. Production of Bio P60 Culture Bio P60 was an isolate of P. fluorescens P60 cultured in snail broth for one week (Soesanto et al. 2013). The SPC method was utilized to assess the microbial population at a minimum of 107 CFU mL–1. Humic-Fulvic Acids Extract Humic-fulvic acids were obtained from harvested top potato plant waste. Furthermore, extraction was carried out by soaking the waste in 1 M technical NaOH for two weeks (modified Tan 1998; Dulaquais et al. 2018). N-AHL Extract Potato plant root waste was used as a source of quorum-sensing signals for microbes (Tamad et al. 2020). N-AHL compound, a quorum sensing signal, was obtained by soaking the waste in 5% acetonitrile for two weeks (Rani et al. 2011). BOFP Application This study used a randomized block design with two factors, namely: 1) the application of 20 t BOFP, 300 kg Urea, 500 kg SP 36, 300 kg KCl, and 200 kg lime ha–1, and 2) comparison with the application pattern of the farmers, consisting of 20 t of chicken manure, 1–t NPK, and 250 kg ZA ha–1, with 16 repetitions. The potato Granola plant mounds were tilted at a 10% contour coverage rate per ha, as shown in Figure 3. The seed potato was 800 kg ha–1, and the plant was spaced at 30 cm x 70 cm interval total obtain a total population of 47,000 ha–1. Fertilization was performed every 20 days: a) At 20–40 days after planting (DAP) when tuber growth begins; b) At 40–60 DAP when tuber enlargement begins; c) At 60-90 DAP (plant optimal enlargement); and d) At 90–110 DAP after all the leaves dry up. Furthermore, the variables observed included soil parameters, growth and yield components of potato (10% of the population were sample plants), and farming analysis (revenue and total cost). The variable of pH was measured with a pH meter, EC was assessed with an EC meter, C was analyzed with Walkley and Black, and P was evaluated with the HCl extraction method. Figure 3 The design of potato mounds cutting a 10% sloping slope in Dieng, Central Java, Indonesia Statistical Analysis Variance analysis was carried out on the data on soil, potato growth, and yield using Fisher's test (P<0.05). Subsequently, significant differences were determined by calculating the mean value using Duncan's multiple range test. The statistical analysis was performed using the CoStat Ver 6.451 application. The difference in the effect of the treatments on the economic value was carried out by assessing the production costs, income, and profits (R/C ratio). Potato Cultivation in Slope Andisols – Tamad et al. 235 RESULTS AND DISCUSSION Soil, Potato Growth, and Potato Yield The growth of potato appeared normal up to 60 DAP, as shown in Figure 4. However, at 80 DAP, the BOFP pattern demonstrated better growth compared to farmers’ pattern, which was infested by diseases, as indicated by the falling and withering of leaves in Figure 5. The plant often faced several challenges during the rainy season, including falling of leaves and intensive wilt disease. Figure 4 The optimal growth of potato plant at 60 the day after planting (DAP) in Andisols Dieng, Central Java, Indonesia, with mound tilt of 10% contour direction Figure 5 The differences in potato growth at 80 DAP in Andisols between farmers’ pattern and BOFP pattern treatments This study showed significant improvement in soil, potato, and economic variables in BOFP pattern compared to farmers’ pattern, as shown in Table 1. It was observed that the plant was susceptible to Fusarium infection, which caused wilt symptoms (Thanaa et al. 2018). Furthermore, Fusarium is one of the most important genera of phytopathogenic fungi, causing potato wilt in the field (Azil et al. 2021). The results showed that the application of BOFP and conservation techniques to Andisols improved the growth of potato plants and reduced fungi attack. P. fluorescens as Bio P60 microbes produced secondary metabolites, which helped to inhibit Fusarium sp wilt (Soesanto et al. 2011; Deveau et al. 2016). A previous study explored the antifungal activity of the extracellular metabolites of the most effective isolates of Fusarium species infecting potato (Trabelsi et al. 2016). Table 1 The effect of BOFP pattern and farmers’ pattern treatment in Andisols on soil and potato variables average No Variable N0a N1b 1 Soil pH H2O 5.56 a 6.04 b 2 Soil pH KCl 4.68 a 5.30 b 3 Soil electric conductivity/EC (mS cm–1) 409.11 a 324.29 a 4 Soil organic–C (%) 1.78 a 3.83 b 5 Soil total–P (%) 2.27 a 4.95 b 6 Plant height (cm) 54.88 a 63.19 b 7 Leave number (pieces) 60.38 a 116.69 b 8 Fall leave age (days) 85 a 100 b 9 Fusarium spp attack (%) 80 20 10 Tuber number 5.2 a 6.0 a 11 Tuber diameter (mm) 51.24 a 56.74 b 12 Tuber length (mm) 68.56 a 73.92 b 13 Tuber volume (mmh3) 631.88 a 723.75 b 14 Tuber weight (g plant–1) 301.69 a 561.81 b 15 Tuber yield (t ha–1) 12.31 a 22.93 b 16 Tuber P uptake (%) 0.23 a 0.23 a 17 Tuber P (g plant–1) 5.46 a 8.81 b 18 R/C ratio 0.85 1.23 Note: aN0 = Farmers’ pattern treatment is 20 t chicken manure ha–1, 1 t NPK ha–1, and 250 kg ZA ha–1 bN1 = BOFP pattern treatment is 20 t BOFP ha–1, 300 kg Urea, 500 kg SP 36, 300 kg KCl, and 200 kg calcite ha–1 BIOTROPIA Vol. 30 No. 2, 2023 236 Enrichment of chicken manure with Bio P60 led to a significant reduction in the intensity of the fusarium wilt attack on potato plants, thereby increasing their productive age. Bio P60 is a secondary metabolite formula derived from the antagonist bacterium P. fluorescens strain P60, which has been tested to treat various plant diseases. Furthermore, P. fluorescens produced secondary metabolites that contain several bioactive compounds. It also played an essential role in inhibiting microbial growth in the soil, including Fusarium sp., the cause of wilt in potato (Soesanto et al. 2011; Deveau et al. 2016). P. fluorescens is a ubiquitous soil bacterium that promotes plant health, and some of its strains produce secondary metabolites, such as 2,4– diacetyl phloroglucinol (DAPG), phenazines, and hydrogen cyanide, thereby inhibiting soil- borne pathogens (Neidig et al. 2011). The strain P. fluorescens P60 inhibited fusarium wilt of shallots (Santoso et al. 2007) and tomatoes (Soesanto et al. 2011), stem rot of peanuts, chili virus, tomato microbe wilt (Soesanto et al. 2013), and stem base rot of dragon fruit (Hamarawati et al. 2018). The results showed that BOFP pattern (N1) increased the soil pH (H2O) from acid to slightly acid and decreased the electrical conductivity compared to the farmers’ practice (N0) (Figure 6). Furthermore, it significantly increased soil pH (KCl), organic–C, and total–P. The application of the BOFP pattern was also shown to improve the quality of Andisol by enhancing some chemical characteristics. The application of BOFP improved the chemical characteristics of Andisols. Furthermore, the enrichment of chicken manure with PM and balanced chemical fertilization improved the soil pH, organic-C, and total–P. Based on the results, the inoculation of phosphate-solubilizing microorganisms increased soil biomass and microbial activity (Wang et al. 2022). PM had been reported to mediate the bioavailability of P by mineralizing organic–P and dissolving the inorganic variant. The soluble P in Andisols was affected by inorganic–P solubility, mineralized organic–P, and adsorption–P (Tian et al. 2021). Phosphate solubilizing microorganisms as a component of the entire soil community can be manipulated to be more effective for plant nutrition (Raymond et al. 2021). These microbes can increase phosphate availability through the dissolution of inorganic– P and mineralization of organic–P. The dissolution of inorganic–P was often carried out through the production of organic acids, such as sulfuric acid, nitric, and carbonate. The Mineralization of organic–P occurred due to the production of extracellular enzymes, such as phosphatase, phytase, phosphonatase, and C–P lyase by PM. The phosphatase enzyme converts high molecular weight organic phosphate into low molecules by hydrolyzing the bonds with the release of ions (Prabhu et al. 2018). Figure 6 The effect of the farmers’ pattern (N0) and the BOFP pattern (N1) treatments on the Andisols variables Potato Cultivation in Slope Andisols – Tamad et al. 237 PM significantly increased inorganic–P solubility and organic–P mineralization, while significantly reducing adsorption–P in Andisols. The ability of PM ability to dissolve P was influenced by the type of species, P compounds, organic acids released, and microbe population. Furthermore, its capacity to mineralize organic– P depended on the activity of phosphatase and phytase (Tamad et al. 2021). The results showed that PM increased P availability, improved plant growth, and restored soil fertility. Phosphate-solubilizing microorganisms have enormous potential as biofertilizers because they can increase the bioavailability of P for plants, offer sustainability, improve soil fertility, and increase crop yields (Timofeeva et al. 2022). The PM isolates Pseudomonas trivialis, P. putida, and P. fluorescence released citrate, lactate, malonic, oxalic, and acetic acid of 156.25 mg kg–1. The phosphatase and phytase yields obtained from phosphate microbe ranged from 12 to 47 mg PO4 3– dm–3 h–1. The amount of P dissolved by PM was higher between 147.66 and 194.61 mg P kg–1 compared to the control (31.06 mg P kg–1). Furthermore, PM inoculation produced mineralized organic–P of 63.69 mg P kg–1, compared to the control with 23.7 mg P kg–1 (Tamad et al. 2021). It also increased the dissolution of P up to 300% compared to the control (Tamad et al. 2020). Based on these results, PM can be applied to plants to promote growth or increase P availability, while reducing the dependence on phosphate-based fertilizers and restoring soil fertility (Yadav et al. 2021). BOFP pattern significantly increased plant height, number of leaves, and age of potato plants, as well as decreased fusarium wilt attack compared to farmers’ pattern, as shown in Figure 7. BOFP pattern significantly improved tuber quality in terms of diameter, length, and volume, as shown in Figure 8. It also significantly increased the number of potato plants and yield per ha compared to the farmers’ practice. The yield obtained in the rainy season from farmers and BOFP patterns was 12 t ha–1 and 23 t ha–1, respectively. BOFP pattern treatment significantly increased the total P of Andisols (Figure 6), which supported the uptake of P by potato grown on the soil. The results showed that P uptake in potato tubers was significantly higher in BOFP pattern. However, the P content obtained from both patterns was the same, as shown in Figure 9. BOFP was found to significantly increase potato yield plant–1, as shown in Figure 8. Figure 7 The effect of farmers’ pattern (N0) and BOFP pattern (N1) treatments on potato variables in Andisols BIOTROPIA Vol. 30 No. 2, 2023 238 Figure 8 The effect of farmers’ pattern (N0) and BOFP pattern (N1) treatments on the potato variables in Andisols Figure 9 The effect of farmers’ pattern (N0) and BOFP pattern (N1) treatments on the potato P variables and the R/C ratio in Andisols The application of BOFP in Andisols improved P_absorption, the quality of tubers, and the yields of the plant. Biological organic fertilizer (BOF) is a chicken manure enriched with phosphate bacteria, humic–fulvic acid, and N–acyl homoserine lactone to effectively increase P solubility and increase yield. Furthermore, potato yield in Kaligua, Central Java, Indonesia, using a BOF dose of 20 t ha–1 increased tuber yield to 2 t ha–1 compared to chicken manure (Tamad et al. 2020). The application of BOPF technology to potato cultivation in Andisol during the rainy growing season significant;y increased production and farmers' profits. Profitability of Potato Cultivation Farming Based on the profitability analysis of potato farming, BOFP pattern increased the R/C ratio compared to farmers’ pattern, as shown in Table 2 and Figure 9. Based on the results, the total cost of cultivation with BOFP pattern was greater, namely IDR 5 million ha–1, which was 4% higher than farmers’ pattern. The total revenue for cultivation was 51% greater than farmers’ pattern. BOFP potato cultivation provided a profit of IDR 31.4 million ha–1, while farmers’ pattern led to a loss of IDR 19.5 million ha–1, as shown in Table 2. Potato Cultivation in Slope Andisols – Tamad et al. 239 Table 2 The difference in potato farming between farmers’ pattern and BOFP pattern on revenues, total cost profits, and efficiency per hectare No. Differences Farmers’ pattern BOFP pattern 1 Revenue (IDR) 109.030.000 165.096.000 2 Total cost (IDR) 128.536.667 133.700.667 3 Profits (IDR)a –19.506.667 31.395.333 4 Efficiencyb 0.85 1.23 Note: aProfits = Revenue – Total Cost bEfficiency = Revenue / Total Cost Farming efficiency was calculated based on revenues and total expenses (Anggraeni et al. 2021). Potato cultivation with BOFP pattern had better efficiency compared to the farmer’s pattern, as shown in Table 2. The R/C value of 1.23 in BOFP pattern showed that one unit of the cost used to cultivate potato provided 23% of the profit from the cost. Meanwhile, farmers’ pattern showed that farming was inefficient, as indicated by R/C < 1. The results showed that the profits of farmers increased after the application of BOFP. The increase in yield of potato cultivated with BOFP pattern was shown to exceed the additional cost required. The profit obtained for the use of this pattern also exceeded that of farmers' pattern. During the rainy season, the use of farmers’ pattern led to losses due to rain factors and intensive fusarium wilt disease. The calculation of potato farming efficiency was aimed at comparing the results with the cost of using resources. Potato cultivation with BOFP pattern can provide better results than farmers’ pattern. The average profit from environmentally friendly farming within a year was also shown to be higher compared to conventional methods (Saem et al. 2016). The yield quantity played a significant role in determining the significant gain from potato farming with BOFP. The application of biofertilizers significantly correlated with increased outcomes (Khoiriyah et al. 2018). CONCLUSION The application of BOFP pattern on potato cultivation in Andisols decreased Fusarium spp wilt attack, improved soil characteristics, enhanced vegetative component, and increased yields from 12.32 to 22.93 t ha–1. During the rainy season, farmers’ pattern caused a loss of IDR 19.9 million, while BOFP yielded a gain of IDR 31.4 million. Furthermore, BOFP pattern increased the R/C ratio from 0.85 to 1.23, as well as Andisols’ productivity, potato production, and farmers’ profits. ACKNOWLEDGMENTS The authors are grateful to the Ministry of Education, Culture, Research, and Technology (Kemdikbudristek) as well as the Educational Fund Management Institution (Lembaga Pengelola Dana Pendidikan/LPDP) of Indonesia on Scientific Research Program with Independent Lecturer Scheme, for the funding provided in 2021–2022 with contract number 019/E4.1/AK.04.RA/2021. The manuscript is submitted and publicized in The Biotropia Journal. The authors declare no conflicts of interest. 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