Impaginato 25 Adv. Hort. Sci., 2024 38(1): 25­34 DOI: 10.36253/ahsc­14940 Shallot cultivation in tropical climate ecosystems using floating and non­ floating systems with different doses of cow manure S. Susilawati 1 (*), I. Irmawati 1, M. Umar Harun 1, B. Ichwan 2 1 Faculty of Agriculture, Universitas Sriwijaya. Jl. Raya Palembang‐ Prabumulih Km 32, Ogan Ilir 30662, South Sumatra, Indonesia. 2 Faculty of Agriculture, Universitas Jambi Jl. Jambi ‐ Muara Bulian No. KM. 15, Mendalo Darat, Kec. Jambi Luar Kota, Kabupaten Muaro Jambi, Jambi, Indonesia. Key words: Fertilizer, raft, shallot bulb, swamp, yield. Abstract: Deep swamp is swampland with the longest flooding period, making it challenging for crop cultivation. However, by adopting a floating system, this pro­ longed duration of flooding can be used for shallot growing. Thus, this study aimed to ascertain the growth and yield of shallots cultivated in polybags using conventional non­floating and floating systems with the application of different doses of cow manure. The research was located in the experimental field and reservoir of the Faculty of Agriculture, Sriwijaya University (3°13’30.3ʹʹ S; 104°38’55.1” E). Non­floating and floating farming systems were utilized with the application of 0, 10, 15 and 20 ton/ha of cow manure. The findings demonstrated that shallots cultivated in the floating system had lower numbers and length of leaf but could produce more bulbs in comparison to the conventional method. The application of 15 ton/ha manure in the floating system resulted in higher weights of fresh and air­dried bulbs per plant, weighing 74.40 g and 64.82 g, respectively, compared to those in the non­floating system (46.77 g and 37.84 g, respectively). In conclusion, the Bima Brebes shallot variety potentially can be cultivated in a floating system with the application of 15 tons of cow manure per hectare. 1. Introduction As one of the strategic commodities widely consumed in Indonesia, shallot (Allium ascalonicum L.) is a vegetable crop that significantly con­ tributes to the country’s horticultural production and inflation rate. According to the findings of the Socio­Economic Survey in September 2021, Indonesians consume an average of 2.49 kg of shallots per person each month. Shallots are required for the food sector, where they are processed into ready­to­use seasonings for sprinkling on food dishes, as well as for usage in households as a seasoning for cooking (Ministry of (*) Corresponding author: susilawati@fp.unsri.ac.id Citation: SUSILAWATI S., IRMAWATI I., HARUN M.U., ICHWAN B., 2024 ­ Shallot cultivation in tropical climate ecosystems using floating and non‐floa‐ ting systems with different doses of cow manure. ­ Adv. Hort. Sci., 38(1): 25­34. Copyright: © 2024 Susilawati S., Irmawati I., Harun M.U., Ichwan B. This is an open access, peer reviewed article published by Firenze University Press (http://www.fupress.net/index.php/ahs/) and distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Competing Interests: The authors declare no competing interests. Received for publication 18 July 2023 Accepted for publication 29 November 2023 AHS Advances in Horticultural Science https://doi.org/10.36253/ahsc-14940 http://www.fupress.net/index.php/ahs/ http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/ Adv. Hort. Sci., 2024 38(1): 25­34 26 Agriculture, 2019; Irjayanti, 2022). The amount of shallots needed for household consumption and the food industry continues to increase. The government’s involvement in meeting these needs is through a program to organize and grow shallot production centers outside Java Island so that production centers are not just concentrated on Java. This program aims to realize shallot self­suf­ ficiency in every province in Indonesia (Ministry of Agriculture, 2019; Indriyana et al., 2020). South Sumatra is one of the provinces targeted by this pro­ gram; this is because shallot production in South Sumatra is still low at only 0.057% of national pro­ duction or 1125 tons in 2021 (Central Bureau of Statistics for South Sumatra Province, 2022; Directorate of Statistical Dissemination, 2022). Even though South Sumatra is a lowland region that is suit­ able for growing shallots, there are still several chal­ lenges that may affect the shallot growth. One of these is the land’s condition as swampland, particu­ larly lebak swampland. Lebak swampland, with its alluvial soil type, has considerable potential to increase the production of food and horticultural crops. However, the use of lebak for crop cultivation is faced with high­water fluctuations that cause flooding in the rainy season and drought in the dry season. The typology of lebak swampland based on the height and duration of standing water is divided into shallow, middle and deep swamp. Once or twice a year, rice can be grown in the shallow and middle swamps. During the dry season, horticultural crops, particularly vegetable crops, can also be grown, although there is a risk from drought (Djafar, 2013; Suprapto, 2016; Suryana, 2016; Widuri et al., 2016; Pujiharti, 2017; Simatupang and Rina, 2019). Deep swamp is an inland swamp area with stagnant water for more than six months and even during the dry season it remains stagnant. As a result, cultivating plants becomes quite challeng­ ing. The deep swamp is mostly left unutilized during the high flooding period. Utilizing a floating cultiva­ tion technique is one option for making use of this area (Siaga et al., 2018; Jaya et al., 2019; Lakitan, 2021; Susilawati et al., 2023). According to Hasbi et al. (2017), a projected floating farming system for the cultivation of vegetables was created based on the statements of farmers who are interested in using the newly introduced floating farming. Shallots are one of the many crops that may be grown in the floating system. One of the factors that affect the growth of shal­ lots is the planting medium used. The texture and structure of the soil have significant impact on the production and quality of shallots. Applying organic fertilizer will create the fertile, loose soil that shallots need for the development of their bulbs. One of the components that can increase the physical, chemical and biological qualities of the soil to boost the pro­ ductivity of shallot plants while reducing the amount of phosphorus (P) fertilizers added to P­deficient soils is organic fertilizer (Noviyanty and Salingkat, 2018; Susikawati et al., 2018; Nguyen et al., 2021). One organic fertilizer that can promote plant develop­ ment is cow manure (Sudarsono et al., 2014; Atman et al., 2018; Musdalifah et al., 2021). Thus, this research was conducted with the aim of evaluating the growth response and production of shallot plants cultivated in polybags using non­floating and floating systems with the application of various doses of cow manure fertilizer. 2. Materials and Methods Research gate The research was located in the experimental field and reservoir of the Faculty of Agriculture, Sriwijaya University, Indralaya Ogan Il ir (3°13’30.3ʹʹS; 104°38’55.1”E). Figure 1 shows the arrangement dur­ ing the dry season in tropical climate ecosystems of South Sumatra, Indonesia, from May to August 2022. Typical agroclimatic conditions at the outdoor research facilities are shown in figure 2. Procedures The shallot bulbs used were of the Bima Brebes variety originated from the shallot seed farmers in Brebes, Central Java. The experiment was arranged using a factorial randomized block design with two factors and three replicates. The treatments consist­ Fig. 1 ­ Non­floating (A) and floating (B) farming practices of shallot cultivation. Susilawati et al. ‐ Shallot cultivation in tropical swampland 27 ed of different farming practices (conventional non­ floating and floating systems) and dosages of cow manure (0, 10, 15 and 20 ton/ha). For all farming practice treatments, the planting media were prepared using the same method: after being completely mixed, they was placed into 35 cm x 30 cm polybags. The planting media were a mixture of alluvial topsoil gathered from lebak swamp combined with cow manure according to the treatments. In the conventional farming technique, the area was prepared by clearing the weeds to make a space for placing the polybags filled with the media. The planting space was 20 cm x 20 cm, follow­ ing the recommendation for shallot cultivation. In the floating cultivation, the polybags were put on a 2 m x 1 m bamboo raft. Each replicate was put on one bamboo raft. The planting media were sprayed with Bio Soil Grow Booster at a concentration of 4 ml/L of water one week before planting. Inorganic fertilizers were also used, with dosages of 69 kg/ha of P2O5, 46 kg/ha of N and 60 kg/ha of K2O. Phosphorus fertilizer was applied 7 days before planting, whereas nitrogen and potassium were applied twice, 7 and 25 days after planting, each time in half the prescribed amount. Before being planted, the top one­third of the bulb was cut off and the bulb was placed into a planting hole at depth 2­3 cm. Shallot plants cultivat­ ed in the non­floating system were watered regularly to ensure sufficient water availability. In the floating system, the plants were not watered because water was continuously supplied through the soil pores by capillary force from the swamp water below. Data analysis The variables were growth characteristics such leaf length, leaf number and leaf color, shallot production variables such as bulb number, bulb diameter, fresh weight, dry weight and shrinkage percentage, as well as estimated production per hectare. Leaf color was measured using a chlorophyll meter (SPAD­502, Minolta) to estimate leaf green­ ness level correlated to the chlorophyll content (SPAD value). Growth parameters were observed every week, whereas the production data were gath­ ered after the harvest. The collected data were ana­ lyzed using R Studio statistical analysis software. The calculated F­value generated from the analysis of variance (ANOVA) was compared to values at p≤0.05 and p≤0.01 for justifying the significant effects of the treatments. Furthermore, if the treatment effect was significant for any measured trait, the least significant difference (LSD) test was conducted to determine significant differences among treatment levels for each specified trait. 3. Results and Discussion Leaf length (cm) and leaf number of shallots Shallot plants grown in tropical climate ecosys­ tems using two farming practices ­ conventional non­ floating (Fig. 1A) and floating (Fig. 1B) systems with various doses of cow manure ­ showed differences in growth and yield. Rainfall continued to decline from May to August 2022, the period when the study was conducted. The rainfall reduced from 206 mm in May to 63 mm in August (Fig. 2A). High rainfall levels at the start of the study provided a favorable environ­ ment for shallot growth in the non­floating cultiva­ tion system (polybags stacked on dry soil). On the other hand, shallots grown in wetlands using the floating system (polybags placed on rafts) did not favor heavy rainfall. From May to August 2022, the temperature and humidity remained relatively stable at 27.47­27.92°C and 84.51­86.36%, respectively (Fig. 2B). Fig. 2 ­ Typical agroclimatic conditions at the outdoor research facilities: (A) rainfall; (B) temperature and relative humid­ ity. Source: https://www.bmkg.go.id. Adv. Hort. Sci., 2024 38(1): 25­34 28 ANOVA revealed that the variations in farming practices had a significant impact. The results of the LSD test on leaf length demonstrated that the two farming practices differed significantly. In conven­ tional cultivation, the maximum leaf length was 40.43±1.25 cm at 5 weeks after planting (WAP), whereas in the floating system it was only 30.47±0.47 cm at 4 WAP. In the floating agriculture system, the position of the plants was adjusted so that they would always be waterlogged to a height of about 3 cm from the base. In that case, water was continu­ ously supplied via the soil pores by capillary force, causing slower oxygen diffusion. Additionally, when it rains heavily, the media become more water­saturat­ ed, which lowers the amount of accessible oxygen. Oxygen is needed by the roots for respiration and for maintaining healthy cell function (Neira et al., 2015; Ernest, 2018; Jaya et al., 2021; Kartika et al., 2021). Damage to the root will eventually affect the upper plant growth, as seen from the agronomical features. Research by Susilawati et al. (2012) on red pepper plants showed that all cultivars experienced varying degrees of root damage as a result of flooding stress. The amount of oxygen present in the planting media is significantly influenced by the height of the water table. Research on bean plants has shown that the roots, particularly the process of root respiration, were significantly impacted by water levels that were 10 cm below the surface of the planting media. Although organic fertilizer applied to shallots in a floating system did not affect growth, a proper water level and the application of organic matter to shallot plants considerably stimulated growth (Susilawati and Lakitan, 2019; Susilawati et al., 2019, 2022). With regard to leaf length, the application of cow manure showed insignificant results in the first week but sig­ nificant results at 2–8 WAP. The longest leaves (40.19 ± 2.96 cm) were obtained at a P3 treatment dose of 20 ton/ha, which is not significantly different from the 40.06 ± 1.69 cm obtained at a P2 dose of 15 ton/ha. The combination of farming practices and cow manure treatments had a significant effect on leaf length only at 6 and 8 WAP in the conventional P3 treatment, with lengths of 44.74 ± 1.10 cm and 44.92 ± 1.36 cm, respectively. For leaf number, the difference in farming prac­ tices only had a significant effect in the first three weeks. The average number of leaves was mostly higher in the conventional system, except in the fourth week when the leaf number in the floating system was higher at 24.33 ± 1.92 compared to 23.39 ± 1.33 in the conventional system. The research on eggplant showed that increasing the water content of the substrate from 1 to 3 cm would increase the growth of vegetative organs (Jaya et al., 2019). The difference in cow manure dose affected the number of leaves, with the highest leaf number of 31.78 ± 2.65 obtained in P2 treatment at 7 WAP (Table 1). Similarly, research by Feriatin et al. (2021) also showed that the use of cow manure would affect leaf number of the Lokananta shallot variety. The P3 treatment for conventional cultivation and the P2 treatment for floating cultivation produced the high­ est average leaf length and leaf number when cow manure was applied. In the conventional P3 treat­ ment, the maximum leaf length was 37.45 cm with an average of 21.33 leaves, while in the floating P2 treatment the highest leaf length was 29.80 cm with 23.14 leaves. Cow manure is an organic fertilizer that can alter the structure and texture of the soil, making the media crumblier, which explains the difference in the dosage of cow manure between the two cultiva­ tion systems (Fig. 3). Meanwhile, as a result of the relatively high moisture of the planting media in the floating culture, cow manure already affects the tex­ ture and structure of the media at lower doses (Elisabeth et al., 2013; Gudugi, 2013; Ekwealor et al., 2020; Wisdom et al., 2021). SPAD value In this study, the parameter of leaf greenness ­ which serves as an indicator for chlorophyll content ­ was quantified using the SPAD tool without damaging the leaves measured from the second to the eighth week. At 4 and 6 WAP, the culture technique treatment significantly affected the SPAD value but had no significant effect at 2 and 8 WAP. Shallots cul­ tivated in the floating system were recorded to have higher values at 2, 4 and 6 WAP (77.69±2.69, 64.10± 4.41 and 48.18 ± 1.25, respectively) compared to those in the conventional system (74.68±3.08, 48.18±1.25 and 48.79±1.43). However, at 8 WAP, the SPAD value in the conventional system was higher than in the floating system (44.78±1.33 vs. 43.22±4.48). The SPAD value of the two cultivation techniques was at its highest at 2 WAP and then con­ tinued to decrease until 8 WAP. In comparison to other models, the polynomial model’s regression analysis of the SPAD value in the shallot cultivation resulted in the largest determination coefficient (R2), which is close to 1: 0.9123 for the conventional sys­ tem and 0.9618 for the floating system. The magni­ Susilawati et al. ‐ Shallot cultivation in tropical swampland 29 tude of the R2 value indicates that the SPAD value is affected by the cultivation technique in a quadratic manner, increasing until it reaches the peak before starting to decline (Table 2). A study on corn resulted in a similar result, where the SPAD values would decrease after reaching their peak, mostly affected by the environment (Ghozali, 2016; Kandel, 2020; Szulc et al., 2021). The higher SPAD values in the floating system, especially at 4 and 6 WAP, indicated that the photosynthesis process is going well due to sufficient water availability. In contrast, if there is a deficit of water (moisture stress), photosynthetic activity will be reduced due to chlorophyll damage (Pallavolu et al., 2023). The research results of Ai Nio et al. (2019) showed that the water deficit induced by PEG 8000 with media water potential (WP) ­0.25 and ­0.5 MPa reduced the total leaf chlorophyll content, leaf chlorophyll a and leaf chlorophyll b. This study also found that the increase in cow manure dosage increases the SPAD value, with the Fig. 3 ­ Effect of cow manure dosage on leaf length (A) and leaf number (B) in the different farming practices. Table 1 ­ Leaf length (cm) and leaf number of shallot with the application of cow manure (ton/ha) in different farming practices Treatment Weeks after planting (WAP) 1 2 3 4 5 6 7 8 Farming practice Leaf length (cm) Conventional 11.67 ± 0.66 a 26.60 ± 0.79 a 36.43 ± 1.03 a 40.32 ± 1.45 a 40.43 ± 1.69 a 38.39 ± 1.71 a 38.39 ± 1.66 a 36.09 ± 1.95 a Floating 8.28 ± 0.32 b 20.04 ± 0.56 b 27.58 ± 1.09 b 30.47 ± 1.43 b 29.45 ± 1.90 b 26.66 ± 2.08 b 25.66 ± 1.82 b 24.88 ± 1.76 b Significance ** ** ** ** ** ** ** ** LSD0.05 1.516 1.375 2.209 1.961 1.992 2.208 2.536 4.549 Leaf number Conventional 7.83 ± 0.39 a 12.38 ± 0.43 a 17.78 ± 0.69 a 22.13 ± 0.93 23.39 ± 1.33 25.69 ± 1.50 26.00 ± 1.43 23.64 ± 1.21 Floating 5.88 ± 0.21 b 10.38 ± 0.47 b 15.66 ± 0.61 b 20.94 ± 1.25 24.33 ± 1.92 25.25 ± 2.15 23.61 ± 2.06 20.03 ± 1.91 Significance ** ** * ns ns ns ns ns LSD0.05 0.777 1.303 1.548 2.479 2.929 3.831 4.679 4.567 Cow manure (ton/ha) Leaf length (cm) P0 (0) 9.31 ± 0.90 21.37 ± 1.74 b 27.53 ± 2.37 b 29.07 ± 2.54 b 26.80 ± 2.99 c 24.83 ± 3.09 c 25.61 ± 3.07 c 25.24 ± 2.96 b P1 (10) 10.19 ± 1.23 22.09 ± 1.24 b 30.71 ± 1.86 a 33.59 ± 2.21 b 32.72 ± 2.64 b 29.26 ± 3.12 b 29.86 ± 3.00 b 30.29 ± 2.58 b P2 (15) 9.54 ± 0.87 25.30 ± 1.58 a 35.52 ± 1.81 a 39.69 ± 1.74 a 40.06 ± 1.69 a 38.93 ± 1.33 a 37.84 ± 1.34 a 37.16 ± 1.80 a P3 (20) 10.86 ± 1.12 24.52 ± 1.89 a 34.26 ± 2.31 a 39.23 ± 2.82 a 40.19 ± 2.96 a 37.10 ± 3.46 a 34.76 ± 4.63 a 29.27 ± 4.69 b Significance ns ** ** ** ** ** ** * LSD0.05 2.144 1.945 2.189 2.773 2.817 3.122 3.587 6.434 Leaf number P0 (0) 6.00 ± 0.40 b 10.33 ± 0.31 14.33 ± 0.41 b 17.55 ± 0.62 b 17.72 ± 0.88 c 19.50 ± 1.64 c 20.50 ± 2.11 b 19.39 ± 2.28 P1 (10) 6.94 ± 0.59 ab 11.33 ± 1.06 16.78 ± 1.11 a 20.39 ± 1.12 b 22.50 ± 1.32 b 25.99 ± 1.47 b 26.28 ± 2.09 ab 23.11 ± 2.04 P2 (15) 6.72 ± 0.58 ab 11.39 ± 0.76 17.22 ± 0.99 a 24.00 ± 1.59 a 29.05 ± 2.38 a 31.78 ± 2.65 a 29.67 ± 2.39 b 25.94 ± 1.88 P3 (20) 7.78 ± 0.68 a 12.50 ± 0.55 18.55 ± 0.59 a 24.22 ± 0.80 a 26.16 ± 1.32 ab 24.61 ± 1.78 bc 22.78 ± 2.14 b 18.89 ± 2.36 Significance * ns ** ** ** ** * ns Data represent the mean and standard error. Values followed by different letters within each column indicate a significant difference at LSD 0.05. 30 Adv. Hort. Sci., 2024 38(1): 25­34 highest SPAD value of 82.54 obtained in the P3 treat­ ment and the lowest (31.21) in the P0 treatment. The SPAD value has been widely used to estimate the chlorophyll content of other crops, such as tomatoes (Jiang et al., 2017). Furthermore, the application of cow manure could also increase leaf chlorophyll, as indicated by the SPAD value in wheat and rice plants (Shah et al. , 2017; Atman et al. , 2018). The combination of cultivation techniques and cow manure treatments resulted in no significant effect at 2 and 8 WAP, a significant effect at 4 WAP and a highly significant effect at 6 WAP. The highest SPAD values were obtained in the floating cultivation with a cow manure dose of 20 ton/ha: 77.01 ± 5.35 at 4 WAP and 75.11 ± 3.96 at 6 WAP (Table 3). Bulb number, bulb diameter (mm) and weight of fresh and air‐dried bulbs (g) The yield components include the number of bulbs, bulb diameter and weight for both fresh and Table 3 ­ The SPAD value of shallot in different farming practices with the application of cow manure Table 2 ­ Regression analysis correlations of the SPAD value with several mathematical models of farming practices using different doses of cow manure ** Significant difference at p < 0.05. Farming practice Linear model y = ax + b Logarithmic model y = a ln x + b Polynomial model y = ax2 + bx +c Power model y = axb Conventional y = -8.9073x + 76.38 y = -21.1ln(x) + 70.877 y = 5.6238x2-37.026x + y = 70.35x0.357 R2 = 0.6917 R2 = 0.8417 R2= 0.9123 R2 = 0.8842 r = 0.8316** r = 0.9174** r = 0.9551** r = 0.9432** Floating y =­10.769x + 88.122 y = -22.56ln(x) + 79.122 y = -0.7451x2-7.0429x + y = 80.712x0.375 R2 = 0.9581 R2 = 0.9116 R2 = 0.9618 R2 = 0.8804 r = 0.9788** r = 0.9547** r = 0.9807** r = 0.9383** Treatment SPAD value 2 WAP 4 WAP 6 WAP 8 WAP Farming practice Conventional 74.68 ± 3.08 48.18 ± 1.25 b 48.79 ± 1.43 b 44.78 ± 1.33 Floating 77.69 ± 2.88 64.10 ± 4.41 a 59.78 ± 4.55 a 43.22 ± 4.48 Significance NS ** ** ns LSD value 7.996 6.040 4.381 4.615 Cow manure (ton/ha) P0 (0) 68.16 ± 2.38 45.31 ± 2.88 c 40.90 ± 2.71 c 31.21 ± 4.08 c P1 (10) 75.74 ± 5.19 58.48 ± 5.77 ab 56.21 ± 4.35 b 44.61 ± 2.93 b P2 (15) 78.27 ± 4.09 55.78 ± 4.94 b 55.98 ± 3.73 b 46.60 ± 2.09 b P3 (20) 82.54 ± 2.98 65.00 ± 6.08 a 64.04 ± 5.28 a 53.60 ± 3.80 a Significance NS ** ** ** LSD value 11.307 8.542 6.197 6.527 Farming practice x Cow manure (ton/ha) Conventional x P0 68.47 ± 5.10 46.81 ± 1.43 b 43.29 ± 3.72 ef 39.69 ± 3.16 c Conventional x P1 74.13 ± 10.00 46.93 ± 1.68 b 48.02 ± 1.74 de 43.42 ± 10.00 bc Conventional x P2 74.01 ± 4.26 46.00 ± 1.36 b 50.87 ± 0.68 bc 46.57 ± 4.26 bc Conventional x P3 82.13 ± 4.21 52.99 ± 3.47 b 52.98 ± 1.17 cd 49.46 ± 4.21 ab Floating x P0 67.86 ± 1.46 43.81 ± 6.11 b 38.52 ± 4.15 f 22.73 ± 1.46 d Floating x P1 77.37 ± 5.68 70.03 ± 5.53 a 64.41 ± 4.95 b 45.81 ± 5.68 bc Floating x P2 82.54 ± 6.90 65.56 ± 4.94 a 61.10 ± 6.57 bc 46.63 ± 6.90 bc Floating x P3 82.97 ± 5.15 77.01 ± 5.35 a 75.11 ± 3.96 a 57.73 ± 5.15 a Significance NS * ** NS LSD value 15.991 12.081 8.763 9.231 WAP= Week after planting. Data represent the mean and standard error. Values followed by different letters within each column indicate a significant difference at LSD 0.05. Susilawati et al. ‐ Shallot cultivation in tropical swampland 31 air­dried bulbs. The farming practice had no significant impact on the quantity of bulbs but a very significant impact on the weight of fresh and air­ dried bulb and the bulb diameter. The conventional method produced the greatest number of bulbs, whereas floating cultivation produced the best results in terms of bulb diameter and weight of fresh and air­dried bulbs. The growing media conditions strongly affected how the bulbs were initially formed. Since water was constantly accessible from beneath the growing media through capillaries, floating cultivation used growing media that were somewhat moist. There was also intense rainfall during early growth of the shallots, causing the planting media to be very wet. There were about 7.78 ± 0.35 bulbs formed in conventional cultivation and 7.75 ± 0.33 in the floating cultivation. However, the number of bulbs was not linearly correlated with the greater dose of cow manure applied, as the largest number of bulbs was obtained at a dose of 15 ton/ha (Table 4). The largest numbers of bulbs (8.33 in convention­ al cultivation and 8.22 in floating cultivation) were obtained from the same manure treatment, which was P2. The lowest numbers (6.78 in conventional cultivation and 6.67 in floating cultivation) were also obtained from the same manure treatment, P0. Plant growth can thus be supported by appropriate cultiva­ tion methods (Khorasgani and Pessarakli, 2019; Cahyaningrum et al., 2023). The average diameter of bulbs grown using float­ ing cultivation was 23.51 ± 1.29 mm, which is much larger than the 20.62 ± 1.62 mm average diameter of bulbs grown using conventional cultivation (Fig. 4). The largest diameter of bulbs produced as a result of cow manure application was at a dose of 15 ton/ha, and the lowest was at 0 ton/ha (Table 4). Based on the combination of treatments, P2 treatment (15 ton/ha) in floating cultivation produced the largest bulb diameter of 30.78 mm, and P3 treatment (20 ton/ha) in conventional cultivation produced the largest bulb diameter of 25.36 mm. The two cultiva­ tion methods produced the smallest bulb diameters in the same treatment, P0 (0 ton/ha), with the con­ ventional system producing a diameter of 15.22 mm Table 4 ­ Shallot yield components for different farming practices with the application of cow manure Treatment Number of bulbs Diameter of bulb (cm) Fresh weight of bulb (g) Air­dried weight of bulb (g) Farming practice Conventional 7.78 ± 0.35 20.62 ± 1.76 b 35.36 ± 6.14 b 26.79 ± 5.64 b Floating 7.75 ± 0.33 23.51 ± 1.29 a 42.33 ± 3.52 a 35.69 ± 2.94 a Significance NS ** * ** LSD value 1.016 1.741 6.419 4.703 Cow manure P0 (0) 7.44 ± 0,45 15.44 ± 0.77 c 20.57 ± 2.85 c 14.71 ± 2.12 d P1 (10) 7.44 ± 0.50 19.88 ± 0.84 b 34.46 ± 2.36 b 25.64 ± 1.49 c P2 (15) 8.28 ± 0.53 27.10 ± 1.74 a 58.24 ± 7.76 a 48.22 ± 7.75 a P3 (20) 7.89 ± 0.44 25.84 ± 0.81 a 42.11 ± 2.94 b 36.39 ± 1.84 b Significance NS ** ** ** LSD value 1.437 2.461 9.078 6.651 Farming practice x Cow manure Conventional x P0 6.78 ± 0.72 15.22 ± 1.40 e 19.58 ± 4.90 e 13.15 ± 3.18 f Conventional x P1 8.22 ± 0.58 18.49 ± 0.98 de 33.01 ± 3.72 cd 24.57 ± 1.99 de Conventional x P2 8.33 ± 0.76 23.43 ± 0.81 bc 42.08 ± 1.87 bc 31.61 ± 0.73 bcd Conventional x P3 7.78 ± 0.44 25.36 ± 1.03 b 46.77 ± 4.21 b 37.84 ± 0.89 b Floating x P0 8.11 ± 0.22 15.66 ± 0.99 e 21.57 ± 3.95 de 16.28 ± 3.15 ef Floating x P1 6.67 ± 0.57 21.28 ± 0.80 cd 35.92 ± 3.45 bc 26.71 ± 2.44 cd Floating x P2 8.22 ± 0.90 30.77 ± 1.02 a 74.40 ± 6.05 a 64.82 ± 4.92 a Floating x P3 8.00 ± 0.88 26.32 ± 1.40 b 37.45 ± 1.96 b 34.96 ± 2.56 b Significance NS * ** ** LSD value 2.032 3.481 12.838 9.406 WAP= Week after planting. Data represent the mean and standard error. Values followed by different letters within each column indicate a significant difference at LSD 0.05. Adv. Hort. Sci., 2024 38(1): 25­34 32 and the floating system a diameter of 15.66 mm. The high bulb diameter in the floating culture was greatly supported by the conditions of the growing media, where during the growth stages the rainfall contin­ ued to decline, so the media in floating culture was not saturated with water and oxygen was still avail­ able. Nutrient absorption, water uptake and root res­ piration are all affected by oxygen availability, which is a crucial component for plant growth. The use of biological fertilizers or a combination of biological and organic fertilizers can increase the shallot bulb diameter compared to controls (Neira et al., 2015; Xiong et al., 2015; Purba et al., 2020; Widyastuti et al., 2021). Shallot production is highly dependent on the weight of fresh and air­dried bulbs. The floating cultivation system yielded the greatest average data, which was significantly different from conventional cultivation (42.33±3.52 g vs. 35.69±2.94 g (Table 4). According to Jaya et al. (2019), the availability of water below the plant media in the floating system significantly promotes plant growth and yield. Based on the results, conventional farming required a high­ er dosage of cow manure (20 ton/ha) compared to floating farming, which required only 15 ton/ha. In terms of cost and bulb production, Paputri et al. (2016) found that a cow manure dose of 20 ton/ha was economically feasible. However, Arzad et al. (2017) found that mustard plants needed up to 25 ton/ha of cow manure. The estimated production per hectare was calculated using data on air­dried bulb weight under the assumption of a planting space of 20 cm x 20 cm. The highest estimated production was obtained in the floating system from P2 treatment with 21.61 ton/ha, while the highest production in the conven­ tional system was from P3 treatment with 12.61 ton/ha. The P0 treatment had the lowest estimated yield, at 4.38 and 5.43 ton/ha in the conventional and floating cultivation systems, respectively (Fig. 5). Fig. 4 ­ Shallot bulbs produced by the conventional (A) and floating (B) systems with the application of cow manure. Fig. 5 ­ Estimated production of shallot from different farming practices with the application of cow manure. Based on the results, it was concluded that the Bima Brebes shallot variety has the potential to be cultivated using the floating technique with the application of 15 ton/ha cow manure, as seen from production estimation reaching 21.61 tons of dry bulb, which is higher than the 9.9 ton/ha of dry bulb reported by the Ministry of Agriculture (2019). 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