trash management on sugarcane

SUGARCANE CONFERENCE 2017 IN CONJUNCTION WITH WORLD PLANTATION CONFERENCES AND EXHIBITION 2017 (WPLACE2017) Bali Nusa Dua Convention Center (BNDCC), Bali October 18th - 20th, 2017

The Application of Sugarcane Trash Management on Manual Harvesting and Its Impact on Sugarcane Productivity Sandi Gunawan*, Syahrial Koto and Purnomo Aji Jengkol Sugar Research Center, Perkebunan Nusantara X, Ltd. Jengkol, Plosokidul, Plosoklaten, Kediri, East Java, Indonesia 64175 *Corresponding author email : sgunawan19@gmail.com

ABSTRACT Burning sugarcane trash (tops and dry leaves) is a common practice on ratoon cane management in Indonesia after manual harvesting, due to difficulties of further cane cultivation if the trash is not being removed. Whereas the effect of burning trash gives negative impact on soil fertility and sugarcane productivity in the long term. The study described the technique of sugarcane trash management, that was the technique for retaining sugarcane trash in the field as a source of in situ organic matter. The application of sugarcane trash management included : 1. Shredding the trash after harvest using rotary mulcher implement attached to 90 HP tractor which to reduce the size of trash to accelerate the trash decomposition rate and minimize risk of rats attack, 2. Arranged the shredded trash in to 2-1-2 system (2 interrow empty from the trash and 1 interrow containing the trash) using hay rake implement. The usage of this method showed that the next cane crop cultivation processes, included off-baring+1 st fertilization, subsoiling, off-baring+2nd fertilization and deep subsoiling can be done. Further more, sugarcane trash management and retention had a direct positive impact on soil fertility, although not significantly increase sugarcane productivity in the short term.

Keywords : Sugarcane, Trash Management, Ratoon Management, Organic Matter, Soil Fertility

INTRODUCTION Sugarcane (Saccharum officinarum L.) is a crop that is classified in Graminae family and known as sugar producer. Sugar is a strategic food commodity and included in one of nine staples of Indonesian people. Generally, sugar cane based industry in Indonesia is highly dependent on the supply of sugarcane raw material from sugarcane growers. Subiyono (2014) said that there are two models of sugarcane cultivation or plantation in Indonesia. First, the sugar mill belongs to state-owned enterprise (SOE), especially in Java island, almost all sugarcane raw materials are cultivated by the growers or sugarcane farmers. Sugar mill’s SOE do partnerships with the growers, foster and educate the growers and mill or process the sugarcane become sugar, while growers as supplier of sugarcane raw material. Second, the sugar mill belongs to private-owned company, especially in Sumatera island, sugar mills cultivate and manage their own land sugarcane plantation. Sugar demand definitely increase year by year in line with the population and economic growth.

1

SUGARCANE CONFERENCE 2017 IN CONJUNCTION WITH WORLD PLANTATION CONFERENCES AND EXHIBITION 2017 (WPLACE2017) Bali Nusa Dua Convention Center (BNDCC), Bali October 18th - 20th, 2017

Observing the national sugar productivity journey from 1918 until 2014, seems a continues decline trend with rate of 0.103 tonnes/ha annually, from an average initial 13.1 tonnes of sugar/ha to 5.6 tonnes of sugar/ha (Koto et al., 2015). The achievement of national sugarcane production at last 12 years (from 2004 - 2015) were fluctuated, sugarcane productivity in the range of 67.3 - 81.8 tonnes/ha, sucrose content in the range of 6.47 - 8.28% and the sugar productivity in the range of 5.29 - 6.11 tonnes/ha (Wirasuta, 2016). Many factors influenced the decline of national sugar productivity, one of them is the decrease of soil fertility, showed with low of soil organic matter.

Effort lack of adding organic matter into the field such as compost and worsed by the removal or burning of sugarcane trash or crop residues, made the decrease of soil organic matter more quickly. Burning sugarcane trash can be detrimental to soil structure and nutrient availability due to the loss of soil organic matter. So, retaining the sugarcane trash in to the field is one of some solutions for increasing soil organic matter.

Sugarcane trash retention after harvest has many benefits includes reduces the dosage of anorganic fertilizer, increases soil organic matter and soil properties, increases available nitrogen, extends the ratoon cycles, and increased sugarcane crop productivity (Mendoza et. al., 2001; Munoz-Arboleda and Quintero-Duran, 2010; Suma and Savitha, 2015). Most of the sugarcane growers in Indonesia burned the sugarcane trash after harvest, due to difficulties of further crop cultivation if the trash is not being removed. The aims of this study were to get an efficient and applicable method or technique for retaining sugarcane trash into the soil surface in sugarcane manual harvest and to know the effect of trash management on sugarcane productivity and soil organic matter.

MATERIALS AND METHODS The study was conducted in August 2015 - October 2016 at Jengkol Sugarcane Plantation block C.13, Pesantren Baru Sugar Mill, Plosoklaten District, Kediri Regency, East Java Province, Indonesia. The crop category was first ratoon with the sugarcane variety planted was Bululawang. Soil at the site was sandy soil. Treatments consisted of (1) burning the sugarcane trash after manual harvest and (2) returning the shredded sugarcane trash (the leaves and tops) or trash management to the soil surface.

Sugarcane trash after harvest was shredded by rotary mulcher implement (Shaktiman type SRM 2.2 M) and for managing or collecting the trash was used hay rake implement (Shaktiman type MGR 2500).

Parameters measured included the initial and after harvest soil organic carbon in each plot (trash burnt and trash management), the initial sugarcane trash chemical properties (N total, available P2O5, K2O total, organic carbon, Ca, Mg, Fe, Zn), the sugarcane trash C/N ratio periodically, plant growth over time, sucrose content and sugarcane yield. All analitycal laboratories were conducted in the soil testing laboratory, Jengkol Sugar Research Center of PTPN X. Rainfall data was recorded by automatic weather station.

Fertilizer was applied to whole trial site using fertilizer applicator. The sugarcane was fertilized by 184 kg N/ha, 72 kg P 2O5/ha and 120 kg K2O/ha. First fertilization was applied 92 kg N/ha and 72 kg P 2O5/ha immediately after shredding and raking the sugarcane trash and at second fertilization was applied 92 kg N/ha and 120 kg K 2O/ha.

2

SUGARCANE CONFERENCE 2017 IN CONJUNCTION WITH WORLD PLANTATION CONFERENCES AND EXHIBITION 2017 (WPLACE2017) Bali Nusa Dua Convention Center (BNDCC), Bali October 18th - 20th, 2017

RESULTS AND DISCUSSIONS Production and nutrient content of sugarcane trash The samples of sugarcane trash were collected randomly after the harvest. The quantity of sugarcane trash (leaves and tops) after harvest in this trial field approximately 22.9 tonnes/ha on a dry weight basis. Some studies have reported that a large quantity of sugarcane trash representing 7 to 40 tonnes of dry matter per hectare was left on the soil surface after harvesting (Torres and Villegas, 1995; Robertson and Thorburn, 2000). The study conducted by Romero et. al. (2009) in Argentina, found that trash yields varied from 7 to 16 tonnes/ha and the ratio of dry trash to cane yield varied from 12 % to 23 %. The variability of sugarcane trash production was dependent on some factors such as sugarcane productivity levels and varieties.

The nutrient contents of sugarcane trash were analysed and showed in Table 1.

The trash contains 0.57% total N, 1.08% P 2O5, 0.31% K2O and 48.55% organic carbon.

The results of trash analysis showed that the trash returned after harvest initially contained 11,000 kg C/ha, 131 kg N/ha, 248 kg P2O5, 71 kg K2O/ha and other micronutrients in small quantity.

Table 1. The nutrient content of sugarcane trash.

Parameters

Unit

Result of Analysis

N Total P2O5 K2O C-Organic C/N Ratio Ca Mg Fe Mn Zn

% % % %

0.57 1.08 0.31 48.55 85 0.54 0.10 114 21 8

% % ppm ppm ppm

Amount of Nutrient (kg/ha) 131 248 71 11,167 124 23 2.62 0.48 0.18

The implementation of sugarcane trash management The presence of high volume of sugarcane trash after manual harvest on the field causes difficulties of further crop cultivation or ratoon management, includes offbaring+1st fertilization, off-baring+2nd fertilization and deep subsoiling in the interrows after harvest. To handle and manage large amounts of sugarcane trash efficiently and to not hamper crop cultivation, the first step is shredding or chopping the sugarcane trash after manual harvest using rotary mulcher implement attached to 90 HP tractor with PTO 540 RPM. This machine can shredd or chop the trash in to small size. It can accelerate the trash decomposition rate and minimize risk of rats attack. The work capacity of this implement approximately 0.3 - 0.5 hectares per hour (Fig. 1.b.).

3

SUGARCANE CONFERENCE 2017 IN CONJUNCTION WITH WORLD PLANTATION CONFERENCES AND EXHIBITION 2017 (WPLACE2017) Bali Nusa Dua Convention Center (BNDCC), Bali October 18th - 20th, 2017

a

b

Figure 1.a. View of sugarcane trash in the field after manual harvest, b. Shredding sugarcane trash using rotary mulcher.

After shredding the trash, raking and arranged the trash is needed for avoiding the restriction growth of ratoon cane and also simplify of further crop cultivation. The shredded trash were collected in to 2-1-2 system, it means 2 interrow empty from the trash and 1 interrow containing the trash using hay rake implement (Fig. 2).

a

b

c

d

Figure 2.a. View of shredded sugarcane trash in the field, b. Collecting the shredded trash into 2-1-2 system using hay rake implement, c. Collected shredded trash in the interrow, d. Crop growth age 3 weeks.

4

SUGARCANE CONFERENCE 2017 IN CONJUNCTION WITH WORLD PLANTATION CONFERENCES AND EXHIBITION 2017 (WPLACE2017) Bali Nusa Dua Convention Center (BNDCC), Bali October 18th - 20th, 2017

The work capacity of hay rake or wheel trash rake implement is about 1 hectares per hour. After both mechanical work, other mechanical cultivation practices in the interrow such fertilization and deep subsoiling using tractor can be implemented.

Decomposition of sugarcane trash The decomposition rate of sugarcane trash was significantly correlated with average monthly precipitation at the trial site (Fig. 3). The year in which the trial was conducted (September – October 2015) was very dry and the decomposition rate in the early of the trial was very slow. The decomposition rate increase when the rainfall started. The initial sugarcane trash C/N ratio was 85 and continue decline until below 30 after 6 months. This result is similar to the research result conducted by Robertson and Thorburn (2007), that decomposition rate of the trash was correlated with rainfall.

Shredding the sugarcane trash into finer particles also has been found to increase decomposition rates (Kennedy and Arceneaux, 2006).

350

90 80

300

60 200

50

150

40

C/N Ratio

Precipitation (mm)

70 250

30 100 20 50

0 September 2015

10

December 2015

Precipitation (mm)

January 2016

Month

0 March 2016

C/N Ratio

Figure 3. The correlation between monthly precipitation (mm) and sugarcane trash decomposition rate (C/N ratio).

The production results The production results for sugarcane trash management treatment plot and control plot (trash burnt conventional) included cane yield, sucrose content and sugar yield showed in Table 2. Both treatment are producing similar yields, although trash management treatment plot produced 3.10 tonnes higher than burnt trash conventional plot. The plot with trash management treatment yielded 90.10 tonnes cane/ha, while the burnt trash after harvest treatment yielded 87.00 tonnes cane/ha. Sugarcane sucrose content in the trash management treatment plot was higher about 0.6 point than trash burnt treatment plot. As well as sugar yield of trash management treatment higher than trash burnt after harvest treatment.

5

SUGARCANE CONFERENCE 2017 IN CONJUNCTION WITH WORLD PLANTATION CONFERENCES AND EXHIBITION 2017 (WPLACE2017) Bali Nusa Dua Convention Center (BNDCC), Bali October 18th - 20th, 2017

Some studies showed that trash management gives an impact for the long term.

Munoz-Arboleda and Quintero-Duran (2010) showed that after the eighth crop cycle, the plot without trash retention and with fertilizer application yielded 139 tonnes cane/ha, while the combination of residues retention and the application of fertilizer maximised the yield up to 160 tonnes cane/ha. The increased cane yield might be attributed to increased germination percent, increased soil fertility and over all positive effect of trash mulching on soil health (Suma and Savitha, 2015).

Table 2. Effect of sugarcane trash management on cane yield, sucrose content and sugar yield in the field C.13 of Jengkol Sugarcane Plantation, Pesantren Baru Sugar Mill in the 2016 milling season.

Parameters Treatments Cane Yield Sucrose Sugar Yield (tonnes/ha) Content (%) (tonnes/ha) Trash management 90.10 7.33 6.61 Trash burnt after harvest 87.00 6.73 5.86

Soil organic matter content Soil organic matter content between trash burnt treatment and trash management treatment showed in Figure 4. In the early treatment or after harvest, the soil organic matter was 1.26 % for both treatment plot. A year after treatment, the soil organic matter of trash burnt treatment plot and trash management plot were increase respectively 1.64 % and 1.76 %. The increase in soil organic matter content is consistent with what would be expected for trash retention or trash management treatment, and the soil organic matter in the burnt trash plot may increase due to retention of leaf stripping residue before harvest.

2 1.8

Soil organic matter content (%)

1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0

Trash burnt

Trash management

Figure 4. The content of soil organic matter for trash burnt treatment plot and trash management treatment plot.

6

SUGARCANE CONFERENCE 2017 IN CONJUNCTION WITH WORLD PLANTATION CONFERENCES AND EXHIBITION 2017 (WPLACE2017) Bali Nusa Dua Convention Center (BNDCC), Bali October 18th - 20th, 2017

CONCLUSIONS Sugarcane trash management can be implemented in the field with manual harvest by shredding the trash and collecting the shredded trash in to 2-1-2 system (2 interrow empty from the trash and 1 interrow containing the trash) in order to simplify further crop cultivation. Using this technique, sugarcane trash management can be implemented without hampering the ratoon cane cultivation practices included offbaring+1st fertilization, subsoiling, off-baring+2 nd fertilization and deep subsoiling.

Further more, sugarcane trash management and retention had a direct positive impact on soil fertility, although not significantly increase sugarcane productivity in the short term.

ACKNOWLEDGEMENTS The authors are grateful to Mr. Kiswoyo, Mr. Agus Widarto and Mr. Misdi for technical assistance, and Mrs. Lhaksmi Ermayani, Mr. Slamet Riyadi and Mr. Purwo Nurhadianto for laboratory or chemical analysis. We also thank to Mr. Juni Yanto and Mr. Martinus Surya Prayitno (Pesantren Baru Sugar Mill) who have helped us and accommodating this study on their field.

REFERENCES Kennedy, C.W. and A.E. Arceneaux. 2006. The Effect of Harvest Residue Management Inputs on Soil Respiration and Crop Productivity of Sugarcane. Journal of American Society of Sugarcane Technologists, Vol. 26 : 125-136.

Koto, S., M. Ma’ruf, N. Setyanisngsih, A. K. Sari, S. Gunawan, I. Ilhamsyah dan M. B. Nugroho. 2015. Panduan Aplikasi Budidaya Tebu. Cetakan Pertama. PT Perkebunan Nusantara X. Surabaya.

Mendoza, T.C., R. Samson and T. Helwig. 2001. Evaluating The Many Benefits of Sugarcane Trash Farming Systems. Philippine Journal of Crop Science 2001, 27 (1) : 43-51.

Munoz-Arboleda, F. and R. Quintero-Duran. 2010. Trash Management After Green Cane Harvesting And Its Effect On Productivity And Soil Respiration. Proc. Int. Soc. Sugar Cane Technol., Vol. 27 : 1-8.

Robertson, F.A. and P.J. Thorburn. 2000. Trash Management-Consequences for Soil Carbon and Nitrogen. Proc. Aust. Soc. Sugarcane Technol., Vol. 22 : 225-229.

Robertson, F.A. and P.J. Thorburn. 2007. Decomposition of Sugarcane Harvest Residue in Different Climatic Zones. Australian Journal of Soil Research Vol. 45 : 1-11.

Romero, E.R., J. Scandaliaris, P. Digonzelli, L. Alonso, F.L. Neme, J. Giardina, S. Casen, J. Tonatto and J.F.D. Ulliva rri. 2007. Sugarcane Potential Trash Estimation : Variety and Cane Yield Effect. Proc. Int. Soc. Sugar Cane Technol., Vol. 26 : 421-425.

Subiyono, 2014. Terobosan Pemikiran Menggapai Kejayaan Industri Gula Nasional.

Cetakan Pertama. PT Perkebunan Nusantara X (Persero). Surabaya.

7

SUGARCANE CONFERENCE 2017 IN CONJUNCTION WITH WORLD PLANTATION CONFERENCES AND EXHIBITION 2017 (WPLACE2017) Bali Nusa Dua Convention Center (BNDCC), Bali October 18th - 20th, 2017

Suma, R. and C.M. Savitha. 2015. Integrated Sugarcane Trash Management : A Novel Technology for Sustaining Soil Health and Sugarcane Yield. Adv Crop Sci Tech., Vol. 3 : 1-4.

Torres, J., and F. Villegas. 1995. Green cane management under heavy trash conditions. Proc. Int. Soc. Sugarcane Technol. Vol. 22 : 142-149.

Wirasuta, G. 2016. Kebijakan dan Fasilitas Pemerintah dalam Mekanisasi Perkebunan Tebu. Disampaikan pada Semiloka Membangun Sistem Mekanisasi Perkebunan Tebu. Yogyakarta, 6 April 2016.

8