Production, proportion biomass and sugar content of samurai sorghum harvested with the system ratoon pattern as feed raw material

Anwar Efendi Harahap^1,2, Luki Abdullah³, Panca Dewi Manuhara Karti³ and Despal³

¹ Graduate School of Animal Nutrition and Feed Technology, IPB University, Bogor, Indonesia
labdull@apps.ipb.ac.id
² Department of Animal Science, State Islamic University of Sultan Syarif Kasim, Pekanbaru, Indonesia
³ Department of Animal Nutrition and Feed Technology, Faculty of Animal Science, IPB University,Bogor 16680, Indonesia

Abstract

Sorghum is one of the energy sources of feed crops, is drought tolerant, can be harvested several times, and has high dry matter production. This study aims to evaluate the productivity and the proportion of sorghum biomass by giving a dose of urea fertilizer and different harvest times for milk dough, soft dough, and hard dough phases for each ratoon. This study used a factorial randomized block design (3 x 3) with 4 replications. The first factor was the harvest age of 80, 90, and 95 DAP, and the second was urea fertilizer doses of 200, 300 and 400 kg/ha^-1. Parameters were fresh biomass (tons/ha^-1), sugar content in stems (% Brix), and proportion of leaves, stems and panicles (%) in each ratoon until the third harvest (ratoon 2). Harvester I (primary) showed no interaction (p>0.05) on all production parameters and biomass proportion but was different (p <0.05) on the panicle proportion parameter (%). The second harvest (ratoon 1) showed an interaction (p<0.05) in the proportion of leaf (%). Furthermore, the 3rd harvest (ratoon 2) showed interaction (p<0.05) in the proportion of panicles (%). The increasing time of harvesting until the 3rd harvest (ratoon 2) resulted in a growing proportion of fresh stems (%) but a decrease in the proportion of panicles and fresh leaves (%). There was an increase in biomass production (tons/ha^-1) and stem sugar content (%) in line with increasing harvest time until the 3rd harvest (ratoon 2) samurai sorghum 1

Keywords: biomass, production, ratoon, samurai 1, sorghum

Introduction

One alternative that can be considered in providing feed sources of carbohydrates from forage is sorghum (forage sorghum). Based on agronomic conditions, sorghum has the potential to be developed as fodder for ruminants, especially samurai 1. Samurai 1 has characteristics including production of plant height, stem length, stem weight, leaf length and leaf width, which are higher than Samurai 2, BMR, Patir 37 and chisel (Matalantang et al 2019). Sorghum can regenerate maximally after the first harvest, the plant keeps its root system alive so as to allow regeneration for regrowth (ratoon) in producing biomass and reducing planting costs (Calvino and Messing 2012), then it can grow to a height of 2 m and is able to produce fresh biomass 48 tons/h^-1 in the hard dough phase (Silva et al 2019, Teixeira et al 2017).

The high growth, production and nutritional performance of sorghum is strongly supported by the availability of fertilizers during planting (Sebetha and Modisapudi 2019). The use of urea fertilizer at a dose of 200 kg/ha on sorghum produces the highest biomass production and protein content and the lowest fiber content so it is suitable for use as feed (Almodares et al 2009), in addition to fertilization, the right harvest time must also be considered. Various studies have stated that the harvest age of the milk dough phase results in optimal production. However, there have not been many research studies on harvesting age with ratoon patterns in the soft and hard dough phases until aging because the proportion of cell contents in this phase is getting lower which causes the nutritional value of plants to decrease (Sriagtula 2016). Nitrogen fertilization with the right dose of sorghum is thought to accelerate vegetative growth, slow down the decline in forage quality which is characterized by an increase in cell content, especially soluble carbohydrates and slow the formation of fiber, especilly fiber that is difficult to digest

Efforts to develop sorghum as feed were constrained by limited information about the potential of ratoons in these plants. Preliminary research indicates the potential of ratoon in samurai sorghum. However, the productivity and quality of the forage are not yet known. Therefore, research has been carried out to examine the productivity of sorghum feed at the time of harvest in different phases of milk dough, soft dough, and hard dough for each ratoon

Materials and method

The Education Unit, Jonggol Livestock Research (UP3J) IPB Bogor has conducted the research activity. The research indicators were the measurement of sugar content (% brix), leaf, stem, and panicle ratio (%), and new biomass production (ton/ha^-1 ). This study used a factorial randomized block design (3 x 3) with 4 replications. The first factor is the harvest age of 80, 90, and 95 DAP and the second factor is the dose of urea fertilizer consisting of 200, 300, and 400 kg/ha^-1

Procedure

The study began with land preparation that was processed mechanically. Fourteen days after tillage, the samurai I sorghum seeds was planted singly in the hole, with a spacing of 15 cm, while the distance between the lines was 75 cm. In each hole are planted 3-4 sorghum seeds with a depth of 1-2 cm and then immediately given manure. Fertilizer was applied at the age of 14 days after planting and carried out at the same age until the 3rd harvest (ratoon 2). Fertilizer consists of various levels of urea dosage, namely 200, 300, 400 kg/ha-1. Fertilizer is given only once at each cutting. The pattern of fertilizer application is carried out with the same method until the second ratoon

Harvesting was carried out at 85, 90, and 95 days in each ratoon. Sorghum Harvesting is carried out above the first node of the soil surface (± 10 cm above the soil surface). Samples from each plot were separated from panicles from stems and leaves and then weighed, and the biomass was measured.

Variables and data Collection

The observed biomass parameters of new biomass production (ton/ha-1 ) were calculated based on the fresh weight of the plant at harvest times, the biomass production (tonnes) and the harvested area (ha). Sugar content in stem (% brix) was measured from stem juice using a refractometer. The proportion of leaves, stems and panicles (%) by comparing the weight of leaves, stems and panicles with the total weight of plants (fresh). The data obtained were analyzed using SPSS 20 software and if different, it was further tested

Results and discussion

Samurai 1 SorghumProduction and Biomass Proportion Primary Harvest

The potential profile of samurai 1 sorghum biomass in primary harvesting can be seen in Table 1.

The results showed that there was no interaction (p>0.05) between harvest time and the dose of urea administration on the value of the proportion of stems, leafs and panicles in fresh form (%) in the first harvest, there was only a difference (p<0.05) in the proportion of panicles based on the dose of administration. fertilizers, as well as differences in panicle proportions based on harvest time. The value of the proportion of stems ranged from 63.50 - 71.81%, the proportion of leaves with an average value of 21.53 - 31.21% and the proportion of panicles ranged from 6.64 - 9.54%. The high proportion of fresh panicles (%) in the treatment of urea fertilizer at 200 kg/ha indicated that at that dose, the application of urea fertilizer with the right dose of N in stimulating the growth of the generative phase. The results also showed that panicle production had a significant effect (p<0.05) due to harvesting time, where the highest value was at harvest time of 90 days with a value of 8.56%. The increase in the proportion of fresh panicles at this age is due to plant growth entering the end of flowering or already in the milk dough phase towards soft dough. This phase is the beginning of seed development in panicles so that the fresh weight of the panicles produced is also high

Furthermore, based on the biomass parameter (tons/ha) there was no interaction (p>0.05) between the harvest time and the application of different doses of urea fertilizer. It was also the same with the brix parameter in stems (%). Biomass is the combined yield value of all plant parts in fresh form at harvest time which is calculated based on the plot. N absorption at harvest periods 80, 85, and 90 days ( early generative) tends to decrease compared to the vegetative phase of plants so that the transfer of photosynthetic material is not optimally distributed to the stems. Furthermore, stem brix produced the same value (p>0.05) ranging from 6.70-8.11%. This result illustrates that assimilate yields, especially non-structural carbohydrates, are distributed in the same amount in all harvesting ages. Maw et al (2016), Almodares and Darany (2006) found that adding nitrogen fertilizer had no significant effect on sugar content in sweet sorghum stalks. The results of this research biomass research are higher than the report of Barik and Messing (2017), with a biomass production of 2.31 tons/ha but the yield of stem brix values is lower, with a yield of 8.11% vs 10.91% in sorghum aged 100 - 130 DAP

Production and proportion of biomass sorghum samurai 1 second harvest (Ratoon 1)

The response of plants due to the treatment of harvest time and the administration of urea fertilizer based on the biomass parameters of sorghum samurai 1 at the 2nd cutting (ratoon I). The results of the study can be seen in Table 2

Based on the analysis that there was no interaction (p>0.05) between harvest time and the dose of urea fertilizer on the proportion of fresh stems and panicles but the treatment of harvest time had a significant effect (p<0.05) on the proportions of fresh stems and panicles. The value of the proportion of stems based on the harvest time, respectively, is 75.54; 73.26, and 74.17. The high proportion of fresh stems (%) at harvest time of 80 DAH on samurai 1 sorghum was because the sorghum plant entered the final vegetative phase, so that the production of material which is a product of photosynthesis, was mostly sent to the stem. In comparison, the highest proportion of panicles was at a harvest time of 90 DAH, with the highest value 7.04%. This is because the harvest time of 90 HSP has entered the soft dough phase towards the hard dough, which tends to accumulate in this phase is relatively high. Furthermore, there was an interaction (p<0.05) between harvest time and the administration of urea fertilizer to the proportion of fresh leaves produced. The highest value was found in the treatment at harvest time of 85 DAH with a dose of urea fertilizer of 200 kg/ha with a value of 23.88% and the lowest was found in the treatment at harvest time of 80 DAH with a dose of urea fertilizer of 200 kg/ha with a value of 16.87%. The average value of the proportion of fresh leaves before curing (cutting I) with a range of 21.23 - 31.21% g was actually higher than the average proportion of fresh leaves after curing I (2nd cutting) with a value ranging from 16.87 - 23, 88%

Photo 1. Root profile of samurai 1 sorghum plants to the 2nd harvest (Ratoon I)

The value of biomass production (tons/ha^-1) and stem brix (%) in ratoon 1 (2nd cutting) showed that there was no interaction (p >0.05) due to harvesting with different times and doses of fertilizer. The resulting biomass production ranged from 24.89 - 35.96 tons/ha higher, with biomass production in the I (primary) cutting with an average value of 19.73 - 26.30 tons/ha, as well as the stem brix value at the 2nd cutting (ratoon 1) resulted in a higher average value than the 1st (primary) brix value of the cutting rod with an average value of 10.14 - 12.40 % compared to 6.70 - 8.11%. The results of this study indicate that the sorghum biomass in primary plants leading to the 2nd cutting (ratoon 1) tends to increase. This is different from what was reported by Efendi et al 2013 that there was a decrease in sorghum biomass in the black Selayar variety in primary harvesting towards the 2nd harvest ( ratoon 1) with a value of 47.4 - 32.1 tons/ha, but there was an increase in the value of stem brix, namely 9.8 - 11.3%. The following is a plant profile due to the 2nd cutting process (Ratoon I)

Production and Proportion of Biomass Sorghum Samurai 1 Third Harvest (Ratoon 2)

In the 3rd harvesting period (ratoon II), samurai sorghum I still have the ability and tends to increase in producing biomass production. This is in accordance with what was reported by Tsuchihashi and Goto (2008) that sorghum plants can be harvested two to three times, including primary crops.

The results of the analysis showed that the proportion of fresh stems and leaf (%) had no interaction (p>0.05) due to the treatment of harvest time and fertilizer application with different doses, while the proportion of fresh panicles had an interaction (p<0.05) due to the effect of harvesting time and dose administration. different fertilizers. The results of the parameters of the proportion of fresh stems and leafs were not affected by the age of harvest and the dose of urea fertilizer because at harvest age 80 - 90 DAP was the maximum vegetative growth condition so that there was a slowdown in fresh weight in almost all parts of the plant and the tendency of plant maturity to increase. The following is a plant profile due to the 3rd cutting process (Ratoon 2)

Photo 2. Root profile of samurai 1 sorghum plants to the 3nd harvest (Ratoon II)

Furthermore, the difference in harvest age had a significant effect ( p<0.05) on the proportion of fresh leaves. The interaction occurred in the observation of the parameter of the proportion of fresh panicles where the highest value was found in the combination of treatment at harvest age of 80 DAP with the total dose of urea administration at the level of 400 kg/ha yielded a value of 9.82% and the lowest combination treatment was found in the combination of harvest age of 90 DAP with dose administration. Urea fertilizer at the level of 200 kg./ha yielded a value of 5.03%. The parameters of biomass (tons/ha-1) and stem brix (% ) also had no significant effect (p<0.05) due to differences in harvest age and different fertilizer doses. The average value of biomass produced ranged from 29.21 - 43.61 tons/ha, while the value of brix produced ranged from 12.33 - 14.16 %. The results of biomass and stem brix parameters on the 3rd harvester (ratoon 2) continued to experience an increasing trend compared to the 2nd harvester (ratoon 1) and 1st harvester (primary). Long et al (2006) stated that the sugar content of sorghum stems would be lower at the beginning of flowering and then increase gradually from the early milky stage to the seed maturation phase

Conclusion

The increasing time of harvesting until the 3rd harvest (ratoon 2) resulted in an increasing proportion of fresh stems (%) but a decrease in the proportion of panicles and fresh leaves (%). Furthermore, there was a significant increase in biomass production and stem sugar content (%) with increasing harvest time until the 3rd harvest (ratoon 2) samurai sorghum 1.

Acknowledgement

The author would like to thank the Directorate of Research and Community Service, Deputy for Strengthening Research and Development, Ministry of Education, Culture, Research and Technology of the Republic of Indonesia for the support financial Doctoral Dissertation Research (PDD) in 2022.

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