Further considerations of the po

Amendment of sandy soil with composts made from animal excreta subjected to the traditional method or by enhancement with earthworms or a microbial inoculum

Nguyen Van Hung, Thomas Reg Preston^* andNguyen Tat Canh^** nvhungcatd@hua.edu.vn^*University of Tropical Agriculture Foundation, UTA^**Faculty of Agronomy, Hanoi University of Agriculture

Abstract

Three experiments were carried out to evaluate the fertilizer value of composts made from three sources of manure (from cattle, swine or caged chickens) and according to three methods of processing (Traditional thermophylic, processing with earthworms or with a microbial preparation). A biotest with maize as the test plant was used \to evaluate the fertilizer value of the composts, grown in a sandy, acidic (pH 4.2) soil.

Speed of composting was fastest when the substrate was manure from cows or swine and slowest when it was chicken manure. In contrast, nutritional value was highest in compost made from chicken manure and poorest in that made from cow manure. Compost from swine manure had a fertilizer value intermediate to composts from chicken and cattle manure. Processing the manure with earthworms or a microbial additive increased the speed of decomposition of the compost and resulted in a higher fertilizer value compared with the traditional thermophylic system. There was a curvilinear response in growth of maize to application of chicken manure compost in the range from 0 to 80 g compost to 1 kg soil, the optimum value being of the order of 40 g compost per 1 kg soil. Soil pH increased linearly from 4.2 to 5.3 when the level of compost was increased from zero to 80g/kg soil.

Keywords: Compost, earth worms, maize, microbial inoculum, sandy soil, thermophilic method

The total territory of Vietnam is 32.92 million ha (Figure 1) but only 35% of it is utilizable for agriculture of which, 95% was already used (9.41 million ha). More than 36% of agricultural soils was classified as light texture soil (such as arenosol and acrisol). Sandy soil area (Photo 1) is getting more and more increased, especially impact of climate change on Vietnam is greater and greater. Meanwhile, sandy soil has low potential for agricultural production, because of poor soil structure, a low inherent supplying capacity, low organic matter content and limited water, fertilizer holding capacity, limit microbial activity, low fertilizer use efficiency. Thus, Nutritional management, especially nitrogen is crucial for plant production in sandy soil because nitrogen easily losses through many ways such as leaching, leading to groundwater; gaseous emission, contributing greenhouse effect; erosion.

One strategy to get over the disadvantages and enhance productive ability of sandy soil is to maximize the stabilization of organic-N inputs to soils and thereby, build up a soil organic matter pool, rich in organic-N.

Meanwhile, wastes of animal production are very abundant and having high nutritional value, especially if they are treated with suitable method. According to research results, nitrogen content in farmyard manure can reach to 3% (1 tonne dry manure ~ 30 kg N). Thus, if animal production waste treatment is good, this will be useful.

The objective of this study is to evaluate effect of applying manure composts made from different manure resources (poultry manure, cow dung, swine feces) which treated by different methods (Microbial method, earthworms) on productive ability of sandy soil. Basing on the research results, suggest the best manure kind and effective composting method to production in sandy soil.

The research was carried out in Hanoi University of Agriculture, Vietnam from January to December 2010.

Experiment 1. Content 1: Study on the most efficient method to make compost from the wastes of animal production

The experimental layout was a split-plot design with 2 factors in a 3*3 arrangement: Main factors were: kind of waste (Swine manure, Cow manure, Chicken manure); method of composting (the split plot): (EW, TC, EM)

Each treatment was replicated three times. Weight of materials for each replication was 25 kg.

Manure was put in a big plastic basket and water added so that the pile was wet enough. Earthworms added to the pile in ratio of 1 kg worms: 50 kg manure

Manure was mixed with 1% calcium powder and 2% Super-phosphate. Then, the mixture was arranged in layers in a basket. Each layer was 20 cm. Enough water was added to the pile to ensure moisture content of 60-70%. Finally, the pile was covered with a mud layer and watered every day.

Manure was mixed with 1% calcium powder and 2% Super-phosphate. The mixture was treated with a EMINA following the recommendation of the producer (1 liter EMINA per 50 kg materials). The first step was to separate the manure pile into five parts equally. The second step was to dissolve the micro-preparation in water to make a suspension and sprinkle it on each of the manure layers equally. Finally, the pile was covered with a plastic sheet. Every seven days, the pile was turned and checked for moisture and water added as necessary. This activity was repeated until the composting process was finished. When the compost was dark brown, crumbly, and earthy-smelling, it was assumed the incubation process was completed.

Measurements were made of: Incubation time (from start to finish), decomposition speed (determined by reduction in weight of the pile after seven days), fragmentation (compost was dried and sieved with 2 mm size and weighed and the two fractions weighed) and nutrient content (% N, % P₂O₅, % K₂O). DM content of each kind of manure was determined at the start of the compost and at the end.

The data were analyzed by IRRISTAT software to determine CV%, LSD5%, (model used or sources of variation??)

Experiment 2: Evaluate nutritional value of different composts processed with different methods

A biotest with maize as pilot plant (Boonchan Chantaprasarn and Preston 2004) was used to evaluate sources of manure and processing of the same, according to a to a split-plot design with two factors: the main factor was substrates (Swine manure, cow manure, chicken manure [collected from cage]; the split plots were processing (Composting, earthworms).

The experimental soil was analyzed for organic matter (OM), N, P₂O₅, K₂O and pH before carrying out the experiment. The three sources of compost and the worm casts were mixed with the soil in the ratio of 50 g compost: 1 kg soil. The mixtures were put into plastic bags, which had many holes in the lower part so any excess water could drain out. Two seeds of maize were planted in each bag according to the experimental layout. Water was applied uniformly to all bags every morning and evening except on rainy days. When the seeds germinated, one plant was removed to leave only one seedling in each bag.

The height of the maize plants, diameter of the base and leaf area index were measured every seven days over a total growth period of 35 days. After 35 days, the plants and roots were removed from the bags, washed free of soil, and the green parts (leaves and stems) and the roots weighed. These components were chopped and representative samples analyzed for DM, ash and N acccording to AOAC (1990) methods.

The data were analyzed by IRRISTAT software. The ,model was ????/Sources of variation

proompost was made from chicken manure (from cage system??) according to the procedure described in Experiment 1. The experimental layout was a randomized complete block design with three replications.

The experimental soil was analyzed for OM, N, P₂O_5,K₂O and pH before carrying out the experiment. The experimental procedure, measurements, analyses of plant material, and statistical analysis were the same as in Experiment 2.

Soil composition

The analysis of the soil showed that it was very acidic with a low content of nutrients (Table 1).

Table 1. Physiochemical characteristics of experimental sandy soil
Item	Unit	Mean
pH_KCl		4.10
Texture
2-0.2 mm	%	66.6
0.2-0.02 mm	%	19.8
0.02-0.002 mm	%	7.08
<2 μm	%	5.59
OC	%	1.08
N	%	0.06
P₂O₅	%	0.02
K₂O	%	0.18

Effect of composting methods on decomposition speed and quality of compost pile made from the different wastes of animal production

The different manure sources had different effects on the speed of decomposing of the compost pile (Table 2; Figure 1). Decomposing speed (DS) and composting time (CT) of cow dung were the fastest (DS: 0.39g/day after 30 days of incubation, CT: 40 days), followed by swine feces (DS: 0.37 g/day, CT: 40 days) and the slowest in chicken manure (DS: 0.15 g/day, CT: 60 days).

Table 2. Effect of the different composting methods and different manure sources on decomposing speed of compost pile
Experimental formulas	Decomposing speed of compost pile (g/day) after composting day
Experimental formulas	10 days	20 days	30 days	40 days	50 days	60 days
EW-Swine	0.16	0.38	0.37	0.33	0.28	0.23
EW-Cow	0.21	0.41	0.40	0.34	0.29	0.25
EW-Chicken	0.05	0.08	0.10	0.15	0.18	0.18
TC-Swine	0.14	0.31	0.32	0.27	0.24	0.21
TC-Cow	0.20	0.35	0.34	0.28	0.26	0.23
TC-Chicken	0.07	0.13	0.13	0.16	0.21	0.19
EM-Swine	0.26	0.49	0.41	0.32	0.28	0.24
EM-Cow	0.32	0.52	0.43	0.35	0.30	0.26
EM-Chicken	0.16	0.21	0.22	0.21	0.21	0.17
CV%	13.2	6.00	4.60	3.20	2.90	11.0
LSD_5%	0.04	0.03	0.02	0.01	0.01	0.04
Prob	0.47	0.001	0.001	0.001	0.001	0.56
EW: Earth Worm, TC: Thermophilic Composting, EM: EM preparation

Two popular composting methods to treat the wastes of animal production are hot pile and cool pile. However, both of them have the same disadvantages, which are a prolonged incubation time and severe decrease in nutritional value. To overcome these disadvantages, alternative ways are to use "efficient" microorganisms or soil organisms such as earthworms to add to the composting pile.

The differences in rate of decomposition of the compost pile could be due to differences in the C/N ratio. Nitrogen needs carbon as substrate to decompose as well as carbon needs nitrogen in order to be decomposed. Both nitrogen and carbon have to be available in sufficient proportions to ensure that the micro-organisms have enough nutrients for their activities. The decomposing speed was the highest in manures from cows and pigs (C/N ratio of 21:1 and 15:1) and the lowest with chicken manure (C/N of 31:1). This finding is simlar to that of Tiwaree and Noohoom (2001), that carbon decomposition rate was fastest in the piles with initial ???? .

The different composting methods also affected the rate of decomposition of the compost pile (Figure 2). The EMINA microbial preparation (EM) supported the fastest decomposing speed of the pile (from 0.22 to 0.43 g/day within 30 days after composting. The incorporation of earthworms (EW) had the second fastest decomposing speed that ranged from 0.10-0.40 g/day within 30 days after composting. Decomposing speed was the lowest for the thermophilic method (TC) (range from from 0.13-0.34 g/day in the first 30 days). During the first 10 days, the rate of decomposition was very slow, after that the speed increased corresponding to the increase in temperature of the compost pile.

The best results from the microbial method (EM) may have been due to the introduction, or the increase in numbers, of microorganisms which have an effective decomposing capacity of the organic matter such as Bacillus subtilis, Pseudomas mesentericus, P. aeruginose and other cellulose decomposers. In the early stage of the earthworm (EW) treatment, the decomposition of the pile was slow, because only a few earthworms were present. After 20 days it is assumed the numbers of earthworms had increased, leading to a more rapid rate of decomposition of the compost. Probably the slow rate of decomposition in the thermophilic treatment was because there were fewer organisms present in this system. This idea is supported by the report of Hiraku Sasaki (2006) that there were greater numbers of mesophilic aerobes, anaerobes and thermophilic aerobes with the microbiological additive than in the untreated compost. Variations in succession and diversity in microbial communities during the thermophilic phase of composting have been reported (Fogarty&Tuovinen, 1991; Tiqula, 2005) What is the meaning and relevanvce of this statement?.

Nutritional value of the compost

Chicken compost had the highest nutritional value (Table 3; Figure 3) followed by that from swine with lowest values for cow manure compost. Similar conclusions were made by Wolf (2004) and Evans et al (1977). The nutritional value of the compost was similar for the earthworm and microbial treatments with poorest results for the thermophilic treatment (Figure 4). The decrease in nutritional value of the thermophilic compost, especially the N fraction, was probably because of the evaporative loss of ammonia resulting from the high temperature in the compost pile (~ 60-70^°C). The fast rate of decomposition and short composting time with the earthworm and microbial treatments would also have contributed to the superior nutritional value of the compost made by these methods.

Table 3. Mean values for nutrients (%), and maize growth in soils fertilized with the composts, derived from different substrates and different processing methods
	Process				Source of manure
	Microbial	Earthworm	Thermophylic	Prob	Chicken	Cow	Swine	Prob	SEM
Composition, %
DM	31.3	33.6	37.4		41.4	28.6	32.2
N	0.537	0.517	0.413		0.697	0.223	0.547
P₂O₅	0.350	0.390	0.327		0.607	0.150	0.310
K₂O	0.513	0.513	0.373		0.533	0.657	0.210
Growth of maize
Height, cm	98	98	86		111	76.0	95.8
Leaf area, cm²	251	250	230		266	219	246
Weight, g	31.2	30.9	26.6		34.4	22.7	31.6

Growth of maize

The better nutrient status of the compost derived from chicken manure was reflected in the greater growth of maize in the biotest (Table 3; Figure 5) for this treatment. In a similar way, processing of the manure with the microbial preparation or with earthworms supported greater maize growth than when the compost was subjected to the traditional thermophylic process (Table 3; Figure 6).

Effect of compost application on nutrient content and maize growth in sandy soil

There was a curvilinear response in growth of maize to application of chicken manure compost in the range from 0 to 80 g compost to 1 kg soil, the optimum value being of the order of 40 g compost per 1 kg soil (Table 4; Figure 7). An important effect of the compost was the linear increase in the soil pH in response to the level of the compost (Figure 8).

Table 4. Mean values for nutrient content of soils and maize growth with increasing application of compost made from chicken manure
	Compost application, g/kg soil
	0	20	40	60	80
Nutrients in soil fertilized with compost from chicken manure, %
N	0.04	0.04	0.05	0.06	0.06
P₂O₅	0.01	0.01	0.01	0.01	0.01
K₂O	0.17	0.17	0.17	0.17	0.17
pH	4.2	4.4	4.6	5.1	5.3
Maize growth
Height, cm	74.2	101	117	124	124

Conclusions

Acknowledgements

Atiyeh R M, Dominguez J, Subler S and Edward C A 2000 Changes in biochemical properties of cow manure during processing by earthworms (Eisenia andrei Bouche) and the effects on seedling growth. Pedobiologia, volume 44, pp709-724

Boonchan Chantaprasarn and Preston T R 2004 Measuring fertility of soils by the bio-test method. Livestock Research for Rural Development. Vol. 16, Art. No. 78. http://www.lrrd.org/lrrd16/10/chan16078.htm

Hiraku Sasaki 2006 Effect of a commercial microbiological additive on beef manure compost in the composting process. Animal Science Journal, volume 77, pp545-548, from http://www.susane.info/en/ref/Compostingwithmicrobials.pdf

Tiwaree R S and Noohom C 2001 Composting of pig manure using forced-aeration system. Proceeding of the third Asia-Pacific conference, pp519-523, from http://ebooks.worldscinet.com/ISBN/9789812791924/preserved-docs/9789812791924_0093.pdf

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Figure 1. Map of Vietnam	Photo 1. Sandy soil has l;ow production potenital


Figure 1: Effect of different manure sources on decomposing speed of compost pile	Figure 2: Effect of different composting method on decomposing speed of compost pile


Figure 3: Effect of different manure sources on nutritional value of compost	Figure 4: Effect of different composting methods on nutritional value of the compost


Figure 5: Growth of maize with compost produced from different sources of manure	Figure 6: Growth of maize with compost processed by different methods


Figure 7: Effect of compost application on growth of maize in sandy soil	Figure 8: Effect of compost application on pH of sandy soil