Effect of azolla green manure on wetland rice and available of azolla-N

A pot experiment and a field experiment were conducted to investigate the effect of Azolla pinnata, applied alone or in combination with urea, on rice plants under Malaysian conditions. Results of the pot experiment show that application of azolla significantly increased the number of tillers and panicles, dry straw weight and grain yield over the control; similar results were obtained from the application of urea. There was no significant difference between the various azolla treatments. In the field, the recovery rate with azolla application at 30 DAT was higher than when applied at transplanting; results with urea-N application were similar

METHANE EMISSION FROM PADDY FIELDS AS INFLUENCED BY DIFFERENT WATER REGIMES IN CENTRAL JAVA

The concentration of methane (CH4) in the atmosphere is increasing at 1% per annum and rice fields are one of the sources that contribute to about 10-15% of the atmospheric CH4. One of the options to reduce greenhouse gas emission from rice fields is probably through water management. A field study was conducted to investigate the effects of water management practices on CH4 emission from rice field plots on a silty sand Aeric Tropaquept soil at Research Station for Agricultural Environment Preservation, Jakenan, Central Java, Indonesia, during the dry season of March to June 2002. Four water regimes tested were: (1) 5 cm continuous flooding (CF), (2) 0-1 cm continuous flooding (ST), (3) intermittent irrigation (IR) where plots received continuously 5 cm of flooding with two times of draining at 15-20 and 25-30 days after transplanting (DAT), and (4) pulse irrigation (PI) where plots were watered until 5 cm level and left to dry by itself until the water table reached 30 cm beneath soil surface then watered again. The total CH4 emissions of the four water treatments were 254, 185, 136 and 96 kg CH4 ha-1 for CF, ST, IR and PI, respectively. Methane emission increased during the early growing season, which coincided with the low redox potential of -100 to -150 mV in all treatments. Dry matter weight of straw and filled grain among the water treatments did not show significant differences. Likewise, total grain yield at 14% moisture content was not significantly different among treatments. However, this result should be carefully interpreted because the rice plants in all water treatments were infested by stem borer, which reduced the total grain yield of IR64 between 11% and 16%. This study suggests that intermittent and pulse irrigation practices will be important not only for water use efficiency, but also for CH4 emission reduction

Waste to health: organic waste management for sustainable soil management & crop production

Organic waste management is essential not only in turning waste into wealth but more importantly in improving environmental quality and health, and contributing to sustainable crop production when it is recycled in the agricultural sector. The agricultural sector in Malaysia produces a tremendous amount of waste which has traditionally been burnt or simply dumped (a common practice till now) making it a source of greenhouse gas emissions and other environmental problems which affect human health. More recently, due to the prohibition of open burning of organic wastes, it has become a trend to convert wastes into wealth, i.e. value added products. Research has escalated to investigate various technologies with the aim of reducing waste through good waste management practices, i.e. recycling in agriculture or conversion into useful products for commercialization. However, returning organic wastes back to agricultural land simply by mulching(e.g. oil palm empty fruit bunches (EFB) applied fresh from the mill or as processed EFB mats to newly transplanted palms and mature palms) or incorporation of crop residues into soils after harvesting contributes to recycling of nutrients and organic matter back into soils, thus building up soil quality and health, prevents land degradation and increases soil productivity. Composting of organic wastes (not limited to agricultural wastes) reduces the bulk of the wastes and concentrates nutrient contents. This process not only converts the wastes into value-added products such as organic fertilizers, soil amendments and soilless potting media but also avoids wastes being exposed to the environment and vulnerable to greenhouse gas emissions (nitrous oxide and methane) and pollution of natural resources (leaching into groundwater and surface run-off into surface waters). The use of soilless potting media derived from organic wastes could partially or totally replace the use of peat which is a slowly renewable resource.Apart from this, there has been an increase in interest, in the last decade, in transforming organic wastes into biological charcoal or biochar under controlled conditions, such as pyrolysis and gasification, with the main objective of using it as a soil amendment in agricultural land, particularly for naturally infertile or degraded soils. Biochar contains carbon that is potentially resistant to microbial degradation and has dual functions. Firstly, biochar improves soil quality and crop productivity due to its high porosity and sorption properties. Secondly, biochar increases carbon storage or sequestration in soil thus reducing carbon dioxide in the atmosphere and mitigating global warming and climate change. Sustainable management and recycling of organic wastes in agriculture is a holistic approach which should be pursued not only with the sole objective of converting wastes into wealth but more seriously for its various benefits to crop production, the environment (clean water and air, and balanced carbon cycle) and, ultimately, human health

Biochar as soil amendment: impact on chemical properties and corn nutrient uptake in a Podzol

A study was conducted to investigate the impact of biochar amendment on chemical properties and corn nutrient uptake in a sandy Podzol soil. Four rates of biochar (0, 5, 10, and 15 g kg−1) and two rates of inorganic fertilizer (0 and local recommendation rate for corn) were randomly applied to a completely randomized design with four replicates. Corn was grown for 45 d in a glasshouse using sandy Podzol. The increase in pH of the soil was concomitant with a decrease of exchangeable Al. The fertilized soil significantly increased total N, with a concomitant decrease in soil pH due to a N nitrification. Positive changes did occur in the soil due to biochar application, leading to a significant increase in dry matter yield and corn height. Corn N and K uptakes were significantly increased by the addition of biochar, but the same was not true for Ca and Mg. However, it was found that the concentrations of N, Ca, and Mg in the corn tissue were still lower than their critical level. Our results demonstrate that application of biochar alone is not able to supply enough nutrients for the healthy growth of corn

Preference for Molineria latifolia var. megacarpa and Rhodomyrtus tomentosa as native urban landscape plants

Factors influencing the perception of landscapes have been the subject of research in the last 40 years. Indigenous and native plants are commonly restricted to informal or naturalistic designed landscapes. This research project investigates the use of native plants as a formal landscape element. As the world is becoming more urbanized (United Nations, 2010), gardens are becoming an increasingly important contributor to people’s health and well-being (Dunnett & Qasim, 2000). The research has highlighted some elements that tend to affect visual preferences. This paper discusses a study conducted to determine preferences of Malaysian landscape professionals and students in landscape architecture and horticulture on two native ornamental plants, Molineria latifolia var. megacarpa (Lemba) and Rhodomyrtus tomentosa (Kemunting), that are grown in soilless media with the potential for use in urban landscapes. Participants of this study comprised of landscape architects (20 respondents), architects (20), nursery owners (20), Bachelor of Horticulture students (80) (Faculty of Agriculture, UPM), and Bachelor of Landscape Architecture students (80 respondents) (Faculty of Design and Architecture, UPM), with a total of 220 respondents. Data collected were analyzed through descriptive analysis, Chi square and reliability test using SPSS. Results indicated that 88.2% of the respondents agreed that Molineria latifolia var. megacarpa (Lemba) could be a potential urban landscape plant, while 92.7% of them agreed that Rhodomyrtus tomentosa (Kemunting) could be domesticated, and is therefore a potential urban landscape plant. Majority of the respondents (49% to 55%) preferred the plants grown individually, while others (40% to 49%) preferred both plants in the form of mass planting. Meanwhile, using the Likert’s Scale, about half (50% to 52%) of the amateurs and professionals of the landscape field rated 4 (Like) for both the plants, whereas 10% to 15% of them marked 5 (Extremely Like) to show their acceptance towards the two new native plants. This finding indicates bright future for the two undomesticated wild native plants to be used as urban landscape plants. Thus, it is concluded that Molineria latifolia var. megacarpa (Lemba) and Rhodomyrtus tomentosa (Kemunting) grown in soilless media have a high potential to become urban, native landscape plants

Characterization of Malaysian sewage sludge and nitrogen mineralization in three soils treated with sewage sludge.

Studies to determine the chemical composition of sewage sludges produced in Malaysia and potentially mineralisable nitrogen (No) and mineralization rate constant (k) of sewage sludge in three Malaysian soils are reported. The sludges collected from ten wastewater treatment plants in Malaysia were acidic in nature and the N, P, K, Ca and Mg contents were variable. The heavy metal (Pb, Cd, Cu, Mn and Ni) concentrations of the sludges, except for Zn, were below the European Union Maximum permitted level in sludges. In an incubation study, three topsoils of Bungor, Jawa and Serdang series were treated with three rates (0, 140 and 420 kg N ha-1) of dewatered sewage sludge and incubated about 60% of the water holding capacity for 12 weeks. Mineralization of N exhibited a slow initial rate, followed by a rapid increase in rate in week 4 to 8. Accumulation of mineral N ranged from 50.5 to 147.6 mg kg-' soil. Bungor and Jawa series had higher N mineralization than Serdang series. Sludge added at 420 kg N ha-' resulted in the highest concentration of net mineralised N. Values of potentially mineralisable N, (No), and mineralization rate constant, (k), ranged from 23.4 to 137.5 mg N kg-' soil and 0.036 to 0.082 week-1, respectively. It was concluded that N mineralization of the sewage sludge treated soils was dependent on the application rate of sludge and soil type

Mass loss and release of nutrient from empty fruit bunch of oil palm applied as mulch to newly transplanted oil palm

Applying a mulch of oil palm empty fruit bunches (EFBs) from processing mills to newly transplanted oil palm is widely practiced for sustainable management and recycling of solid waste from the oil palm industry. Thus, it is important to understand the decomposition and mass loss of EFBs and its nutrient release pattern for better fertility management. The present study was conducted in a newly transplanted oil palm field to investigate the mass loss of applied EFBs and nutrient release pattern over a 12-month period. The treatments evaluated in the present study were: (1) chemical fertiliser (CF) application only; (2) EFB application only; and (3) EFB and CF application (EFB+CF). The treatments were applied immediately after transplanting 13-month-old palms. EFBs were applied around the base of the oil palm at a rate of 170 kg palm–1. Results showed that 50% dry weight of EFB and EFB+CF was lost within 90 days of application. The C : N ratio decreased from 82 to 20 after 180 and 172 days in EFB and EFB+CF respectively. The breakdown of lignin in EFBs was found to be significantly accelerated by the introduction of CF. Soil properties were improved by EFB application with an increase in pH, total mineral N and exchangeable K of the top soil. After 317 DAP, the soil organic C content subjected to treatment with EFB only and EFB+CF was significantly higher (i.e. 1.7%) when compared with that subjected to the control treatment (i.e., 1.3%). Total N increased significantly from 0.06% to 0.12% for both EFB treatments