Edi Santosa

Fly ash and bottom ash, or coal combustion products (CCP), are wastes from coal-fired boilers of electricity power plants. CCP were evaluated as a soil amendment and partial fertilizer substitute in a short-term pot experiment and showed potential to influence growing media properties under controlled conditions. However, these findings are limited to the early growth stage and pot-scale conditions, and further studies under field conditions through harvest are required to confirm their effects on plant growth. The study examined the leaching of N/P/K from sweet corn growing media enriched with different CCP proportions. Latosol soil was incorporated with 0%, 25%, 50%, 75%, and 100% CCP (m/m) to support sweet corn seedlings in a pot experiment. N, P, and K leaching from the growing media was evaluated. The results showed that sweet corn growth was restricted in CCP-amended media. Increasing CCP proportion markedly reduced plant growth, with decreases of up to 57.00% in seed emergence, 59.56% in plant height, 42.50% in leaf number, 70.59% in dry weight, and 38.00% in root number compared to 100% soil; however, the 25% CCP treatment increased root volume. Increasing the CCP proportion also increased N and K leaching and leachate pH; conversely, P leaching was lower than in 100% soil. Since there were no toxicity symptoms in sweet corn, CCP could be used as a soil amendment and a potential source of NPK, with precautions to prevent nutrient leaching.

Potassium is an essential macronutrient that supports major physiological processes in plants and strongly influences soybean productivity. This study aimed to evaluate the effects of different potassium fertilization levels on plant physiology, yield performance, and seed nutritional composition in two soybean varieties, ‘Dena 1’ and ‘Denasa 1’.The research employed a factorial completely randomized group design with five potassium fertilizer levels (0, 15, 30, 45, and 60 kg K2O/ha) and two soybean varieties (‘Dena 1’ and ‘Denasa 1’), with three replications. The results showed that the potassium dose significantly affected plant height and leaf number but did not influence photosynthetic rate or stomatal conductance. The ‘Dena 1’ variety exhibited better growth, greater leaf greenness, and faster generative development than ‘Denasa 1’. The optimal potassium dose of 45 kg/ha improved yield components, resulting in a 30.7% increase in seed weight and a 45.8% increase in the number of filled pods compared with the control. A positive correlation was found between plant potassium content and key physiological traits, such as photosynthesis and transpiration rates. Seed nutrition analysis showed that soybean varieties significantly influenced nitrogen and phosphorus levels at the R7 and R8 stages, whereas the potassium fertilization dose had no significant effect on seed nutrient concentrations. Nutrient levels increased from R6 to R7 before declining at R8, reflecting nutrient redistribution during seed filling. Overall, the results suggest that applying 45 kg K2 O/ha is an effective fertilization rate for enhancing soybean physiological performance and yield, while varietal characteristics remain the primary factor shaping seed nutritional composition.

Ultisols are characterized by low pH, low alkaline saturation, low cation exchange capacity, and high levels of soluble Al and Fe. Compost is usually applied to increase soil fertility, but its effect is only temporary in tropical conditions because organic matter decomposes quickly. Biochar and fly ash-enriched compost have been proposed as a synergistic approach to improve the chemical properties of Ultisols. This study evaluated the effect of compost enriched with biochar and fly ash on soil chemical dynamics over 16 months in pineapple plantations in Lampung, using a randomized block design with three treatments: compost enriched at the initial stage, compost alone as a control, and compost enriched at the end of composting. The results showed that biochar and fly ash increased soil pH during the initial phase by supplying alkaline cations. Fluctuations occurred during the intermediate stage due to the decomposition of organic matter and nitrogen transformation: organic C and total N increase, influenced by microbial activity and environmental conditions. Phosphorus followed a mineralization-immobilization-remobilization pattern, with late-stage enrichment producing P. Potassium, calcium, and magnesium initially increased but later decreased, likely due to leaching. Early-stage enrichment provided a more stable release of alkaline cations. Fe, Mn, Cu, and Zn show fluctuations in the enriched treatment. The application of biochar and fly ash-enriched compost synergistically with early-stage enrichment effectively enhances the chemical properties of Ultisol.

The study of adaptation mechanisms in cayenne pepper under shade stress is crucial for further exploration. Cayenne pepper is one of the primary commodities that play an essential role in the agricultural industry. This research focuses on the adaptation of morphological, physiological, and secondary metabolite characteristics of cayenne pepper under shading treatments, while also examining the role of microclimate on these characteristics. The study was conducted from August 2023 to February 2024 at the Leuwikopo experimental field of Bogor Agricultural University, using five genotypes of cayenne pepper cultivated under two shading treatments: 0% and 50% shading, achieved using shade netting. The results showed that among the five genotypes tested, shade-loving genotypes, such as “Bonita,” and shade-tolerant genotypes, like “Ori 212,” displayed a greater morphological response in terms of plant height and canopy width under 50% shade compared to the other genotypes. In terms of yield traits, shade-tolerant genotypes, such as “Ori 212”, exhibited the highest fruit weight per plant under a 50% shading treatment compared to the other genotypes. Regarding physiological responses, specifically pigment content, no significant effect of shading treatment was observed. However, in terms of secondary metabolite content, all genotypes responded by increasing total phenol and flavonoid levels when grown in unshaded conditions or under full light intensity. This study provides insights into the adaptive responses of various cayenne pepper genotypes to microclimatic conditions in their growing environment.

Produktivitas cabai katokkon perlu ditingkatkan untuk menekan fluktuasi harga cabai rawit, terutama di dataran rendah. Penelitian ini bertujuan mengevaluasi pemberian GA3 dan kinetin terhadap pertumbuhan dan hasil cabai katokkon. Percobaan dilaksanakan pada bulan Oktober 2023 hingga Mei 2024 di Kebun Percobaan Leuwikopo, IPB Darmaga, Bogor. Penelitian menggunakan rancangan acak kelompok dua faktor zat pengatur tumbuh (ZPT) yaitu GA3 (0, 100, 200 ppm) dan kinetin (0, 100, 200 ppm). ZPT diaplikasikan melalui semprot daun pada umur 30, 40, dan 50 hari setelah tanam. Hasil penelitian menunjukkan bahwa kinetin 100 ppm meningkatkan jumlah cabang primer, sekunder, dan tersier. Kombinasi kinetin 200 ppm dan GA₃ 200 ppm meningkatkan bobot panen per tanaman sebesar 26.45% pada panen ke-3 dan 96.83% pada panen ke-4 dibandingkan kontrol, meskipun total hasil panen tidak berbeda nyata. Penelitian ini menyimpulkan bahwa kinetin dan GA₃ berpotensi dimanfaatkan untuk meningkatkan percabangan dan hasil awal cabai katokkon. Penggunaan kinetin 100 ppm direkomendasikan untuk meningkatkan percabangan, sedangkan kombinasi kinetin 200 ppm dan GA₃ 200 ppm dapat digunakan untuk meningkatkan hasil panen pada fase awal produksi. Kata kunci: giberelin, jumlah cabang, produktivitas, sitokinin, zat pengatur tumbuh

Amomum compactum (Javanese cardamom) is valued for its unique flavor and aroma, commonly used as a culinary spice or medicinal ingredient. The numerous accessions of cardamom in Indonesia present a significant potential for developing this spice. However, the specific potential of each accession remains to be discovered. This study records the variation of agronomical traits and metabolomic profiles of nine cardamom accessions from Central Java, Indonesia. Multivariate analysis using a heatmap on agronomical traits indicated significant variation among accessions, with clustering based on growth locations. Genetic parameter analysis revealed high phenotypic variability, but varying broad-sense heritability among traits, suggesting the influence of both genotypic and environmental factors. Metabolomic analysis using GC-MS reveals the presence of specific compounds in certain accessions, such as beta-panasinsene in the Kulonprogo Putih accession, 1-docosene and alpha-terpinene in the Banyumas Putih accession, and 9-tricosene in the Banyumas Hybrid, which can serve as markers for these accessions.

Indonesia has significant potential for food diversification through the development of sago as an alternative carbohydrate source. This study aims to analyze the processing methods, morphological characteristics, chemical properties, and heavy metal content of local sago in Bangka and Bangka Tengah Regencies. The research was conducted across six villages from November 2023 to March 2024, with chemical and heavy metal testing performed in accredited laboratories. The results indicate that modern processing methods produce high quality starch with a starch content ranging from 79.06% to 83.73% and heavy metal levels such as tin (Sn), lead (Pb), and cadmium (Cd) below the established safety limits, making it safe for consumption. Morphologically, habitat differences influence the physical characteristics of sago, such as trunk height, bark thickness, and leaf area, which affect starch productivity. The study also identifies that environmental factors, including nutrient availability and soil moisture levels, influence the chemical composition of sago. This research provides a scientific foundation for the integrated management of sago, supporting national food diversification efforts and opening opportunities for the development of sago based products that meet national quality standards (SNI) with an environmentally friendly approach. These findings are relevant for stakeholders in optimizing sago's potential as a strategic commodity contributing to national food security. Keywords: Food diversification, Heavy metal, Sago, Starch content, Sustainable agriculture.

Bawang merah (Allium ascalonicum L.) merupakan komoditas penting dalam perekonomian Indonesia, namun pertumbuhannya di lahan kering seringkali terhambat oleh keterbatasan air dan kondisi lingkungan yang tidak optimal. Penelitian ini bertujuan untuk mengevaluasi pengaruh penggunaan mulsa plastik terhadap pertumbuhan dan hasil panen bawang merah di lahan kering dengan sistem irigasi tetes. Percobaan dilaksanakan di Kebun Percobaan Cikarawang, IPB University, selama bulan September-Desember 2022, menggunakan rancangan kelompok lengkap teracak (RKLT) non-faktorial dengan perlakuan mulsa plastik dan tanpa mulsa. Penggunaan mulsa plastik cenderung menurunkan pertumbuhan tanaman. Namun, mulsa plastik efektif dalam mengurangi penyusutan bobot umbi, yang dapat meningkatkan potensi pendapatan petani. Temuan ini memberikan wawasan penting untuk pengembangan teknik budidaya bawang merah yang berkelanjutan di lahan kering. Namun, mulsa plastik efektif dalam mengurangi penyusutan bobot umbi, yang dapat meningkatkan potensi pendapatan petani. Temuan ini memberikan wawasan penting untuk pengembangan teknik budidaya bawang merah yang berkelanjutan di lahan kering. Kata kunci: irigasi tetes, lahan kering, mulsa plastik, produksi bawang merah, susut bobot

Realizing sustainable urban agriculture is one of the sustainable development goals (SDGs) targets that must be achieved. This research was conducted to analyze and explain environmental risk control for the development of sustainable urban agriculture. The research location was in East Jakarta, one of the cities in Indonesia that has implemented urban farming practices. Identification of urban agricultural environmental risks caused by biotic and abiotic factors determined of 17 categories of questions that can be represented in this research. Three risk assessment scales were used, low, medium and high risk. The environmental risk of urban agriculture caused by biotic and abiotic factors was found to have the highest risk in the air dust category. Based on the research results, it was concluded that, in general, respondents had quite effective knowledge of environmental risks but needed to increase their knowledge and deeper understanding of creating sustainable urban agriculture. Urban agriculture, due to its social, economic, and environmental benefits, should be considered part of a dynamic urban system during planning and implementation.

Soybeans are among the best plant-based sources of protein. However, a high intake of rich potassium legumes such as soybean could have negative impacts on people who are sensitive to high potassium. A study on NPK stoichiometry of the most popular Indonesian soybean varieties was conducted as a preliminary evaluation to develop low-potassium soybeans. The experiment was conducted at Cikabayan Experimental Station, IPB University, from January to April 2024. The field experiment was arranged in randomized block design using 12 soybean varieties: “Anjasmoro”, “Deja 2”, “Dena 1”, “Dering 1”, “Denasa 1”, “Denasa 2”, “Dering 3”, “Devon 1”, “Devon 2”, “Grobogan”, “Mallika”, and “Slamet”. Results showed that “Slamet” produced the highest stover while “Anjasmoro” was the lowest. “Slamet”, “Dering 1”, and “Mallika” produced the highest bean production per hectare (3.75-4.73 t ha- 1). N uptake was higher than P, and K. Seed of “Dena 1” had the lowest K content, while the highest was “Denasa 1”. The stoichiometric ratios of N/P, N/K, P/K showed different values according to varieties. Thus, decreasing the K level in seed could be done by selecting a low K variety.