The use of biochar fortified compost on calcareous soil of East Nusa Tenggara, Indonesia: 1. evolution of organic matter and nitrogen on composting of farm yard manure (FYM) and Siam weed (Chromolaena odorata L.) biomass added with biochar as a bulking agent.
The importance of soil organic matter in improving and maintaining soil quality has been widely understood. Therefore, a proper soil organic management is an absolute prerequisite for obtaining sustainable crop production. The easiest way to improve and maintain soil organic matter is by adding the fresh organic materials. However, this practice had been known to have a lot of negative effects, such as plant nutrient immobilization, phytotoxic (Butler et al., 2001), and environmental pollution (Adhikari et al., 2009). To minimize this negative effect, the common technology used is by composting the fresh material before it is applied to the soil. Composting is biological processes which could reduced the bulk volume of the fresh materials, increase plant nutrient content, relatively stable, kills pathogen, and make easier for transporting the materials (Westerman and Bucido, 2005).
According to Adhikari et al. (2009) composting would increase the safety of waste cycle, reduce glass house gas emission, and avoid environmental pollution. However, during composting processes there will be a loss of nitrogen due to ammonium volatilization (Martin dan Dewes, 1992; Zhang et al., 1997). In addition, especially in humid tropic condition, when applied in a soil compost material is rapidly decomposed which causes this practice is un-practical and expensive for small farmers (Masulili et al., 2010), and the emission of nitrogen gass will increase the rate of global warming (Lehmann et al., 2007). To overcome the problem of rapid decomposition of compost in the soil, some researches had suggested using the more recalcitrant organic materials called "biochar" (Lehmann et al., 2002). The success story of biochar application for improvement of soil properties had been shown by many workers (Chan et al., 2007; Liang et al., 2006; Rondon et al., 2007). The increase of crop yield due to biochar application had been reported by many researchers, such Yamato et al. (2006) for cowpea; Tagoe et al. (2008) for soybean; Asai et al. (2006) for upland rice; Islami et al. (2011) for cassava, and Sukartono et al. (2011) for maize. Unlike the conventional manure or compost, the crop yield increase due to biochar application could be maintain without addition of biochar in the next cropping seasons (Sukartono et al., 2011; Islami et al., 2013).
Martin and Dewes (1992) showed that nitrogen losses during composting processes was related to the C/N ration of the compost materials. They showed that the high nitrogen losses occurred on the low C/N ratio material. Biochar is a result of combustion of organic materials in no or very low oxygen supply. This material has a high organic carbon and low nitrogen content. Therefore, it is suggested that the addition of biochar in composting processes will reduce nitrogen losses. The increase of compost quality with addition of biochar during composting processes had been shown by Dias et al., (2009). They showed that the organic carbon in the poultry manure-biochar mix compost was characterised by a high polymerization degree of the humic-like substances. Furthermore, they showed that addition of biochar in composting poultry manure decreased the loss of nitrogen in mature compost.
The work described here aimed to study the effect of addition farm yard manure (FYM) biochar in composting FYM and Siam weed (Chromolaena odorata L.) on evolution of organic carbon and total nitrogen. The work as also studied the properties of the mature compost.
MATERIALS AND METHODS
Farm yard manure used in this experiment was collected from cattle farmers' cage in Kupang, East Nusa Tenggara, Indonesia. The manure was air dried to water content of about 15% (w/w), cleaned from stone, gravel, plastics and plant twigs, then crushed to a size of less than 5 cm. Siam weed biomass was obtained from farmers field, it was cut to a size of less than 5 cm, and then air dried to a water content of about 15% (w/w). Biochar was made from FYM with the simple method of Sukartono et al. (2011b)). The properties of the FYM, Siam weed, and FYM biochar were presented in Table 1.
Composting experiment was done in Composting house of Nusa Cendana University, East Nusa Tenggara, Indonesia (10o 9' 21" S dan 123o 40' 16" E). The experimental treatments were: (i) 100% FYM (pure FYM); (ii) 75% FYM + 25% biochar (FYM + biochar: 3/1); (iii) 50% FYM+ 50% biochar (FYM + biochar: 1/1); (iv) 100% Siam weed (pure Siam weed); (v) 75% Siam weed+ 25% biochar (Siam weed + biochar:3/1) and 50% Siam weed + 50% biochar (Siam weed + biochar:1/1). Composting was done by put in about 150 kg of compost materials (air dry weight) in a plastic box of 60 cm x 60 cm x 70 cm for 120 days. During composting processes the compost was manually turnover for every 7 days. The humidity during composting was maintained at about 60%, temperature (at a depth of about 20 cm) during composting processes was recorded daily.
The compost sample was taken at days: 0, 3, 7, 15, 60 dand120 for laboratory analysis. Five samples (were taken from each box, mixed and taken of about 0.5 kg, then this composite samples were air dried, grinded and passed through a 1.0 mm diameter sieve for further analysis.
The pH of the compost was determined in [H.sub.2]0 solution 1:1, measured with pH-meter (Jenway 3305); ash content analysis was carried out with the method of Dias et al. (2009); soil organic carbon was determined with the Walkley and Black method (Soil Survey Laboratory Staff, 1992), and total-N with the Kjeldahl method (Bremner and Mulvaney, 1982). To determine cation exchange capacity (CEC) the sample was extracted with CH3COONH4 (I N; pH 7.0) and the base concentration measured with AAS (Shimatzu AA 6800, Shimatzu Corp., Kyoto, Japan). Phosphorus content was extracted with wet oxidation with [HNO.sub.3] dan [HClO.sub.4] (Association Official Agriculture Chemists, 2002) and the concentration of P was measured with spectrometer (Vitatron Scientific Instruments Dieren, the Netherlands).
The change in organic matter was calculated with the first order kinetic equation as done by Paul and Clark (1989), i.e.:
[A.sub.t] = [A.sub.o] [e.sup.-kt] (1)
In which At is the organic-C in the compost (%) at the time t (in days), and k is the constant of decomposition rate
The loss of total nitrogen was calculated similar to that of Paredes et al. (2000) technique, i.e.:
Loss of total - N (%) = 100 - 100[([X.sub.1][N.sub.2])/([X.sub.2][N.sub.1])] (2)
Here [X.sub.1] and [X.sub.2] are the initial and final ash content respectively; and [N.sub.1] and [N.sub.2] are the initial and final total nitrogen content respectively.
The changes in total nitrogen content were calculated with the first order kinetic equation of Paredes et al. (2000), i.e.:
Loss of total - N = Nt (%) = A(1 - [e.sup.-kt]) (3)
In which A is the maximum decomposed total-N (%), k is the constant rate of nitrogen loss, and t is composting time (in days).
The calculation of organic-C changes was done with Excel for windows program, and the calculation of total-N changes was done with SPSS version 16.00 for Windows program. Analysis of variance (ANOVA) was performed for pH and C:N ratio data, and if there were a significant differences the Duncan Multiple Range test at 5% probability was done.
RESULTS AND DISCUSSION
The temperature changes during composting processes presented in Figure 1 followed a general trend in organic matter decomposition (Hsu and Lo, 1999; Dias et al., 2010). The initial mesophilic phase occurred for less than 24 hours and then followed by thermophilic phase which occurred for 11 to 25 days, after which the temperature decreases and it was relatively constant close to air temperature at 60 days after incubation.
Looking the results given in Figure 1a and 1b, it can be concluded that FYM compost base had a shorter thermophilic phase (11 days) compared to that of Siam weed compost base. This is a reasonable phenomenon because FYM has a lower C/N ratio compared to Siam weed (Table 1), and therefore it would be easier to be decomposed. Furthermore, the result in Figures 1a and 1b show that during decomposition, FYM compost base had a lower maximum temperature ([61.sup.0] C) compared to Siam weed compost base ([66.sup.0] C). To ensure that the compost really mature, although the temperature already constant at 60 days, the composting processes was continued till 120 days.
The results in Figure 1a and 1b show that addition biochar into compost materials had different effects on the composting processes. For FYM based compost (Figure 1a) addition biochar shortened the thermophilic phase and lowered the maximum temperature of composting processes. If there was no biochar addition (pure FYM compost treatment), the thermophilic phase occurred for 17 days with maximum temperature of 63[degrees] C, whereas in a mix of 50% compost and 50% biochar (Compost + biochar 1/1), the thermophilic processes decreased to 11 days with maximum temperature of 59% C. It seems that the addition of organic carbon from biochar decreased microbial activity, and hence slows down the decomposition processes. A different phenomenon was observed for the compost made from Siam weed (Figure 1b). Similar to the compost made from FYM, a mix of biochar with Siam weed shortened the thermophilic phase from 26 days (pure Siam weed compost) to 23 days (a mix of Siam weed + biochar). However, the maximum temperature of composting processes increase from 63o C (pure Siam weed compost) to 66o C (a mix of Siam weed + biochar). It seems that the addition of biochar decreased the porosity of the compost material so that slow down the release of the heat generated during the composting processes, which in turn would resulted in a higher temperature.
The change of compost pH:
The initial of compost pH was influenced by the pH of the materials and the proportion of the biochar added (Table 2). The initial pH of compost made from FYM was higher (7.8) compared to that of made from Siam weed (6.9). Addition of biochar in compost materials increased pH of the two compost materials. Furthermore, increasing biochar proportion would further increase compost pH. For the compost made from FYM, for example, the pH of pure FYM was 7.8, increased to 8.0 in if the compost was mixed with biochar (3/1), and further increased to 8.4 if the proportion of biochar was increased to 1/1.
The increase of compost pH with addition biochar is reasonable because biochar has a higher pH compared to both FYM and Siam weed compost materials (see Table 1). Indeed, the increase of biochar proportion would make a further pH increase.
The results in Table 2 show that during the first 30 days of composting processes, the pH increased with increasing of composting time, and then decreased steadily until the end of composting processes (120 days). Different from the initial composting processes, the pH of the mature compost was not significantly different. The increase of pH in the initial phase of composting processes was probably due to the decomposition and demineralization of organic acid and protein into inorganic anion such as [NH.sub.4]+ and OH- (Paredes et al., 2000; Sanchez-Monedero et al., 2001). The decrease of compost pH after 30 days of composting processes was thougt caused by the production of acid (especially humic and fulvic acid) with the change of the fresh materials to the compost (Dias et al., 2009).
Evolution of organic matter content:
The experimental result presented in Figure 2a and b shows that the organic carbon content of FYM based compost was lower than that of Siam weed based compost. Furthermore, addition of biochar into compost materials decreased the rate of decomposition and demineralization rate of organic matter content in the compost materials.
The decrease of organic carbon with composting time followed the first order kinetic equation (eq. 1), with the resulted k constant value for FYM pure FYM, FYM + biochar (3/1) and FYM + biochar (1/1) were -1.42, 1.29 and -1.01 respectively, and that for Siam weed compost were: - 3.73, -3.01, and -2.09 for pure Siam weed, Siam weed + biochar (3/1) and Siam weed + biochar (1/1) respectively (see equations 4 - 9).
MB0: C = -1.42ln(t) + 23.58 (4)
[R.sup.2] = 0.87
MB1: C = -1.29ln(t) + 23.72 (5)
[R.sup.2] = 0.89
(MB2) C = -1.01ln(t) + 25.92 (6)
[R.sup.2] = 0.86
CB0: C = -3.73ln(t) + 43.30 (7)
[R.sup.2] = 0.88
CB1: C = -3.10ln(t) + 41.45 (8)
[R.sup.2] = 0.79
CB2: C = -2.09ln(t) + 35.92 (9)
[R.sup.2] = 0.82
The decrease of k value of with addition (and increase of the proportion) of biochar in the compost materials indicated that the rate of organic matter decrease in biochar enrichment compost went slower than that in no biochar added compost. This was reasonable because, as had been suggested by previous workers, organic carbon in biochar is more resistant to be decomposed (Lehmannn et al. 2006).
Loss of nitrogen:
The rate of nitrogen loss during the composting processes is presented in Figure 3, and the total nitrogen loss in Figure 4. The results in Figure 3a and 3b show that the rate of nitrogen loss from FYM based compost was lower compared to that of Siam weed based compost, and biochar addition decreased the rate of total nitrogen loss.
The loss of nitrogen during composting processes indicated that there was nitrogen immobilization due to the decomposition and demineralization of organic nitrogen compound (such as protein, amino acid) into inorganic nitrogen. The cumulative nitrogen loss with composting time was calculated with the first order kinetic equation (eq. 3) as done by Paredes et al. (2000), and the resulted equations were (see also Fig. 3)
MB0: Nt-loss = 39,1(1-[e.sup.-0,064t]) (10)
[R.sup.2] = 0,95
MB1: Nt-loss = 35,0(1-[e.sup.-0,061t]) (11)
[R.sup.2] = 0,97
MB2: Nt-loss = 32,1(1-[e.sup.-0,053t]) (12)
[R.sup.2] = 0,94
CB0: Nt-loss = 74,1(1-[e.sup.-0,079t]) (13)
[R.sup.2] = 0,96
CB1: Nt-loss = 54,5(1-[e.sup.-0,072t]) (14)
R2 = 0,94
CB2: Nt-loss = 45,7(1-[e.sup.-0,049t]) (15)
R2 = 0,97
The rate of nitrogen loss calculated with equation (10 -15) show that the rate of nitrogen loss from pure FYM compost was 0.064%/day, and addition 50% biochar (FYM + biochar 1/1 treatment) decreased the rate of nitrogen loss to 0.053%/day. The rate of nitrogen loss from pure Siam weed compost was 0.079%/day and addition of 50% biochar (Siam weed + biochar 1/1) decreased the rate of nitrogen loss to 0.049%/day.
In line with the rate of nitrogen loss The calculation of total nitrogen loss presented in Figure 4 show that total nitrogen loss from pure FYM compost was 39.1%. Addition of 25% biochar into FYM (FYM+biochar 3/1) decreased the total nitrogen loss to 35.5%, and further increase in biochar proportion (FYM+biochar 1/1) decreased the total nitrogen loss to 32.2%. The same phenomena was observed in Siam weed based compost material.
The decrease of nitrogen loss with biochar addition, especially in the Siam weed based compost was thought that biochar addition decreased aeration of the compost so that reduced the loss of nitrogen in the form of
N[H.sub.3]. In addition, in line with Tiquia and Tam (2000) experimental result, it seems the loss of nitrogen during composting processes was also influence by the initial C/N ratio of the compost materials. The increase initial C/N ratio of the compost material would decrease the nitrogen losses. Addition of biochar into FYM based compost, for example, increased C/N ratio from 16.8:1 (pureFYM) to 24.9:1 (FYM+biochar 1/1). The same phenomena were observed in Siam based compost material.
The addition of biochar as bulking agent for composting FYM and Siam weed decreased the loss of organic C and total nitrogen. The loss of organic carbon and total nitrogen from pure FYM were 36.5% and 39.1% decreased to 26.0% and 32.2% with addition of 50% biochar (FYM + biochar 1/1 treatment). For Siam weed based compost, the loss of organic carbon and total nitrogen were 50.7% and 74.1% (pure Siam weed compost) decreased to 32.5% and 45.7% for Siam weed + biochar 1/1 treatment. Addition biochar increased the initial pH, but did not significantly the pH of mature compost.
Received 2 April 2014
Received in revised form 13 May 2014
Accepted 28 May 2014
Available online 27 June 2014
This article is a part of dissertation of the first author at the School of Post Graduate Study, University of Brawijaya, Malang, Indonesia. Thank to Directorate of Higher education for her financial support, and to PPIKID Team of University of Brawijaya for their help in article preparation.
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(1) M.S.M. Nur, (2) W.H. Utomo, (2) E. Handayanto, (3) W.H. Nugroho and (4) T. Islami
(1) Nusa Cendana University, Kupang, East Nusa Tenggara 85001, Indonesia
(2) International Research Centre for the Management of Degraded and Mining Lands, University of Brawijaya, Malang 65145, Indonesia
(3) Faculty of Mathematic and Science, University of Brawijaya, Malang 65145, Indonesia
(4) Department of Agronomy, University of Brawijaya, Malang 65145, Indonesia
Corresponding Author: W.H. Utomo, International Research Centre for the Management of Degraded and Mining Lands (IRC-MEDMIND), Soil Science Building, University of Brawijaya. Jl. Veteran, Malang 65145, Indonesia.
Tel: +62341553623 E-mail: firstname.lastname@example.org
Table 1: The properties of FYM, Siam weed and biochar used in the experiment. Organic materials pH Organic - C Total - N P K ... % ... Farm yard manure (FYM) 7.8 25,6 1,52 0,19 0,71 Siam weed 6,9 48,4 2,09 0,53 1,54 Biochar 8.7 28,6 0,78 0,21 0,82 Organic materials Ca Mg C:N CEC ... % ... cmol [kg.sup.-1] Farm yard manure (FYM) 0,67 0,64 16,8 12,46 Siam weed 1,58 0,59 23,2 15,96 Biochar 0,79 0,76 36,7 18.83 CEC: cation exchange capacity Table 2. pH change during composting processes of different compost materials Compost materials ph (at.....days of composting time) 0 3 7 15 Pure FYM 7.8 b A 7.9 b A 8.3 cd B 8.5 cd B FYM + Biochar 3/1 8.0 b AB 8.0 b AB 8.3 cd B 8.7 cd C FYM + biochar 1/1 8.4 c B 8.4 c B 8.6 d B 8.7 d B Pure Siam weed 6.9 a A 6.8 a A 7.2 a AB 7.3 a B Siam weed + biochar 3/1 7.0 a A 7.0 a A 7.7 b BC 7.8 a BC Siam weed + biochar 1/1 7.7 b AB 7.6 b AB 8.0 bc C 8.2 bc C Compost materials ph (at.....days of composting time) 30 60 120 Pure FYM 8.6 a B 8.0 a AB 7.6 a A FYM + Biochar 3/1 8.5 a CD 8.0 a AB 7.6 a A FYM + biochar 1/1 8.4 a B 7.9 a A 7.7 a A Pure Siam weed 8.3 a D 7.7 a C 7.4 a BC Siam weed + biochar 3/1 8.2 a D 7.9 a CD 7.5 a B Siam weed + biochar 1/1 8.3 a C 7.9 a B 7.4 a A Means followed by the same letters (small letter for the same column, and capital letter for the same rows) are not significantly different (p = 0.05) Fig. 4: The effect of biochar addition on total nitrogen loss from FYM based and Siam weed based compost materials. (MB0: pure FYM; MB1: FYM + biochar 3/1; MB2: FYM + biochar 1/1; CBO: pure Siam weed; CB1: Siam weed + biochar 3/1; CB 2: Siam weed + biochar 1/1). Nt losses (% of initial value) Compost MB0 39.1 MB1 35.0 MB2 32.2 Nt losses (% of initial value) Compost CB0 74.1 CB1 54.5 CB2 45.7 Note: Table made from bar graph.
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|Author:||Nur, M.S.M.; Utomo, W.H.; Handayanto, E.; Nugroho, W.H.; Islami, T.|
|Publication:||Advances in Natural and Applied Sciences|
|Date:||Jul 1, 2014|
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