Application of Biogas Digestate as Biofertiliser for Paddy Rice Cultivation in Southern Vietnam
Hoang Khanh Nguyen1, Anh Hung Le1, Michael Böhme2
1Industrial University of Ho Chi Minh City, Institut of Environmental Sciences, Vietnam
There are different trends in agriculture, one is related towards fertiliser supply of crops and another towards reuse of organic residues. For sustainable cultivation of crops the amount of mineral fertilisers should be reduced and partly replaced with organic fertilisers. A sustainable way is the use of biogas digestate as fertiliser for paddy rice cultivation. Therefore, an experiment was designed in the Mekong delta with mineral and organic fertiliser treatments. The treatments were differentiated based on the amount of nitrogen in four variants: 1st 100% mineral nitrogen fertiliser, 2nd 100% digestate as biofertiliser, 3rd 50% mineral fertiliser and 50% biofertiliser and 4th 75% mineral fertiliser and 25% biofertiliser. The results show that, the parameters characterising the growth of the rice plants were not significant different. The colour of the rice plant leaves was also measured and showed significant differences between treatment 1 and 4. The plants heights of the rice plants showed no treatment effect, and were for the four treatments 78.5±2.06 cm, 75.0±3.00cm, 73.5±4.09cm and 72.5±3.04 cm, respectively. After harvesting, the length of the paddy rice inflorescences were measured. The differences between the variants were small and not significant, e.g. the length of the inflorescence in the 4th variant was 17.90 ±1.75cm and in the 1st variant (control) 20.50±1.29cm. The most important parameter is the yield that means the number of seeds and their quality. The most important parameter is the grain yield that means the weight of the seeds and their quality. The highest yield was found for treatment 3 in comparison to the other treatments. It can be conclude that it is possible to replace mineral fertiliser in rice cultivation to some extent with biofertiliser as for example with digestate from biogas plants. Further experiments regarding the exact amount of biofertiliser, and the frequency of application are necessary.
Keywords: Biofertiliser, biogas plant, digestate, mineral fertiliser, nitrogen supply
Contact Address: Hoang Khanh Nguyen, Industrial University of Ho Chi Minh City, Institut of Environmental Sciences, 12 Nguyen Van Bao Str. W4, Ho Chi Minh City, Vietnam, e-mail: nguyenkhanhhoangiuh.edu.vn