Peat Soil Water Research Articles

The Effects of Canal Blocking on Hydrological Restoration in Degraded Peat Swamp Forest Post-Forest Fires in Central Kalimantan

AbstractTropical peat swamp forest is one of the wetland ecosystems on tropical peatlands with many ecological, economic, and socio-cultural functions. In Indonesia, the peat swamp forest ecosystems have been experiencing deforestation and degradation due to land clearing for plantations and agriculture and forest fires. In Central Kalimantan, especially in the ex-area of the 1 million hectares mega rice project (MRP)n in the 1990s, hydrological restoration is done by blocking the canals. We compared the three methods of canal blocking and the areas without canal blocking and the community’s preference on what form of canal blocking is more beneficial for them. Large canal blocking, medium canal blocking, and small canal blocking had positively affected the groundwater level in the driest month above the fire-prone critical point. In contrast, the locations without blocking exceed the necessary fire-prone water level. Small, large, and medium blocking are equally capable of optimizing the peat soil water table. However, the local communities preferred small blocking over other methods because it was simple, labour-intensive, and improved their livelihood when involved in its construction. The local communities choose the big canal blockings less because they block transportation access in and out of the peat swamp forest.

Utilization of Lime and Rice Husk Ash for Peat Soil Stabilization in Different Water Content Condition

Peat soil is a soft soil with more than 75% organic content, very high void ratio, and very high water content. In recent times, the lack of land use has made peat soil as an option for agriculture, drainage channels, and also for construction. Utilization of peat soil usually causes the peat soil water content to decrease. Based on the condition of its water content, the condition of peat soil can be classified into several conditions, which is peat soil with constant water content, peat soil which affected by ambient water content, and dried peat soil. Some of the improvement efforts made include the method of improvement by means of stabilization. The stabilization material used was a mixture of lime (CaCO3) and rice husk ash with the combination of 70% rice husk ash and 30% lime. Based on those studies, the use of the stabilization method is not recommended if the peat soil water content has decreased more than 50%. Therefore, the peat soil water content needs to be maintained in order for the stabilization to be effective and also for the sake of environmental preservation.

Comparison of dissolved organic carbon and nutrients content in Papua peatland

Indonesia’s peatlands degrade due to land conversion and land development. Peatland conversion affects nutrient content in peat soil and peat water, including dissolved organic carbon (DOC). Research on the comparison of DOC and nutrient content was conducted in Papua peatland. It was carried out at Kaliki and Marga Mulia in Merauke, and also at Khanami and Yame in Mappi. This research aimed to determine DOC, soil, and water nutrients, then compare them among peatlands in Merauke and Mappi. At each location, three replications of peat water and peat soil were sampled by digging to a depth of 20 cm. The peat water was estimated for DOC concentration and nutrients, but peat soil was analyzed for nutrients only. The DOC concentration at Yame was the highest among the sites, followed by Khanami, Marga Mulia, and Kaliki. Soil carbon stored was estimated highest at Khanami, followed by Kaliki, Yame, and Marga Mulia. It was concluded that the DOC and soil carbon stored were higher in Mappi peatland than in Merauke peatland because it was still preserved by the community and no peatland conversion in Mappi.

Pengaruh Penyiraman Air Tanah Terhadap Perubahan Sifat Kimia Tanah dan Air Gambut di Kalimantan Tengah

This study observed the changes in chemical properties of peat soil and ground water after irrigation of two peat types: inland and transition peat. The research was carried out in the Basic and Analytic Laboratory of Palangka Raya University. Inland peat and water samples were obtained from Palangka Raya City, meanwhile and transitional peatland was taken from Pulang Pisau Regency, Central Kalimantan Province. Research methods consisted of survey and experimental test with complete randomized design (CRD) consisted of groundwater irrigation treatment and was repeated 3 times. The experimental parameters are soil chemical properties such as Ash Content, Base Saturation (KB), Nitrogen (N), Phosphor (P), Exchangeable Potassium (K-dd), Interchangeable Sodium (Na-dd), Interchangeable Calcium (Ca-dd), Interchangeable Magnesium (Mg-dd), Cation Exchange Capacity (CEC), Aluminum Saturation, Iron (Fe), Sulfate (SO₄), Hydrogen Concentration (pH), and Electrical Delivery Power (EDP), and water chemical properties such as pH, EDP, cation, and anions.. The results showed that there has been an increase in the value of CEC, P, Na-dd, SO₄, pH, and decreased of Ash Content, N, K-dd, Ca-dd, and EDP on transitional peat soils. Meanwhile, the inland peat soils showed an increase of Ash Content, N, P, Mg-dd, a saturation of Al and Fe, and decreased in the value of CEC, Ka-dd, Na-dd, Ca-dd, SO₄, pH, and EDP. There were similar effect of groundwater irrigation, towards soil chemical properties, with an exeption of iron levels (Fe). Iron levels (Fe) in transitional peat increase, but decreased in inland peat.

Hydraulic and Physical Properties of Managed and Intact Peatlands: Application of the Van Genuchten‐Mualem Models to Peat Soils

AbstractUndisturbed peatlands are effective carbon sinks and provide a variety of ecosystem services. However, anthropogenic disturbances, especially land drainage, strongly alter peat soil properties and jeopardize the benefits of peatlands. The effects of disturbances should therefore be assessed and predicted. To support accurate modeling, this study determined the physical and hydraulic properties of intact and disturbed peat samples collected from 59 sites (in total 3,073 samples) in Finland and Norway. The bulk density (BD), porosity, and specific yield (Sy) values obtained indicated that the top layer (0–30 cm depth) at agricultural and peat extraction sites was most affected by land use change. The BD in the top layer at agricultural, peat extraction, and forestry sites was 441%, 140%, and 92% higher, respectively, than that of intact peatlands. Porosity decreased with increased BD, but not linearly. Agricultural and peat extraction sites had the lowest saturated hydraulic conductivity, Sy, and porosity, and the highest BD of the land use options studied. The van Genuchten‐Mualem (vGM) soil water retention curve (SWRC) and hydraulic conductivity (K) models proved to be applicable for the peat soils tested, providing values of SWRC, K, and vGM‐parameters (α and n) for peat layers (top, middle and bottom) under different land uses. A decrease in peat soil water content of ≥10% reduced the unsaturated K values by two orders of magnitude. This unique data set can be used to improve hydrological modeling in peat‐dominated catchments and for fuller integration of peat soils into large‐scale hydrological models.

ISOLASI CEMARAN ENTEROBAKTER PADA AIR TANAH GAMBUT DI WILAYAH KUBU RAYA

Background. Peat soil is a type of soil that is formed from the accumulation of half-decayed plant debris. High organic matter content and some minerals with a thickness of approximately 50 cm. The high content of organic matter in peat soils is thought to be one of the factors that play an important role in supporting the process of adaptation of functional microbes. This is because the availability of organic materials needed by functional microbes for growth and metabolism is met.Method. The sampling method used is purposive sampling. Peat water samples were taken in a composite manner from 2 locations with 10 points on the right and 10 points on the creek flow with a distance of about 10 meters at each point with a trench flow length of 100 meters. Samples were taken in the morning, afternoon, and evening from each point then the inspection was carried out at the Polytechnic Laboratory of the Ministry of Health Pontianak.Results. The distribution of Enterobacter in peat soil water samples taken in the morning, afternoon, the evening is still high with based on identification obtained an average percentage of bacteria Klebsiella Pneumonia 100%, Shigella Dysentery 100%, Proteus Vulgaris 80%, Escherichia Coli 70% and Salmonella 70% and Salmonella Typhi 20%. The coagulation test to determine the type or species of a bacterium from the Enterobacter group is carried out with an antisera test.Concl. There is a relationship between morning water samples with afternoon and evening. Based on the Kendall Tau test, the value of the p-value smaller than α (0.05) is 0.009.

Agricultural drainage increases the photosynthetic capacity of boreal peatlands

A drained boreal bog with active drainage ditches and the introduction of forage grass was compared with a natural bog site to assess the effect of agricultural drainage on the photosynthetic capacity of boreal peatlands. In this study, the net carbon dioxide uptake and the ecosystem respiration were measured using a pair of clear and dark chambers, connected to a greenhouse gas analyzer in order to estimate the gross primary production (GPP). Environmental factors, including photosynthetically active radiation (PAR), peat soil temperature, soil moisture, electrical conductivity and water table depth (WTD), and dissolved organic carbon (DOC) in the soil pore water were also investigated at each site. Our results confirmed a correlation between water table depth, peat soil temperature, electrical conductivity and peatland productivity. Changes in electrical conductivity, water table depth, and peat soil temperature together explained 61% of gross primary productivity variance at our drained peatland pasture site. In general, plant functional types/growth forms did not have any significant difference in their GPP at the drained site except shrubs which had a significantly higher GPP at PAR level greater than 1000 μmol/m2/s (F(3,30.84) = 11.64, p < 0.001). At the natural site, GPP was significantly higher at the hollow (0.168 ± 0.02 mg/m2/s) compared to the hummock (0.098 ± 0.01 mg/m2/s) where relatively the higher WTD was recorded. We therefore concluded that water shortage to the shallow rooting depth of shrubs on our hummock subplots may be the cause of the low productivity. At PAR greater than 1000 μmol/m2/s, productivity at the hollow was still significantly higher (0.17 ± 0.002 mg/m2/s) compared to the hummock (0.10 ± 0.00 mg/m2/s). This suggests that, for ecosystem carbon modelling, the minimum PAR level at which the GPP is estimated is very crucial. All the growth forms at the drained site recorded a significantly higher GPP than the microforms at the natural site. We speculate that not only hydrological changes via agricultural drainage can affect the carbon balance of boreal peatland ecosystem through photosynthesis, but also the hydrological changes in the peat due to the differences in peat soil makeup, structure and density. We, therefore, conclude that differences in microtopography and the corresponding changes in vegetation, land-use practice and its effects on peat soil properties and hydrology should be taken into account when modelling the gross primary production in a peatland ecosystem.

Improving Nitrogen Availability on a Tropical Peat Soil Cultivated with Ananas comosus L. Merr. Using Pineapple Residue Ash

The objectives of this study were to use pineapple residue ash to (i) reduce ammonium and nitrate leaching and (ii) improve essential nutrient availability on a tropical peat soil under pineapple cultivation. Laboratory leaching experiments were carried out to determine the effectiveness of pineapple residue ash in controlling nitrogen loss from a tropical peat soil. Ion exchange resin method was used to determine nitrogen availability. Treatments evaluated were (i) different amounts of pineapple residue ash (25, 50, 70, and 100%) + NPK fertilizer, (ii) NPK fertilizer, and (iii) peat soil alone. Peat soils with pineapple residue ash reduced ammonium and nitrate losses because of adsorption of ammonium and nitrate by hydroxyl and C–O radicals of the pineapple residue ash. There was an improvement in ammonium and nitrate availability because the pineapple residue ash was able to increase the peat soil pH and this facilitated organic nitrogen mineralization and nitrification. The pineapple residue ash also improved nitrogen uptake, pineapple fresh fruit yield, and fruit quality. Ammonium and nitrate varied with soil depth because of high preferential flow of the peat soil water. Combined use of NPK fertilizers and 25% pineapple residue ash improved nitrogen availability whereas amending NPK with 50%, 70%, and 100% pineapple residue ash were more effective in improving nitrogen uptake, fresh fruit yield, and fruit quality of pineapple. Pineapple residue ash can also have significant liming effect.

A critical contribution on understanding the mechanism and implication of peat irreversible drying

The term irreversible drying is known as a condition when peat soil material is dry and cannot be re-wet after an intensive drying. This condition is a result of peat soil hydrophobicity that occurs when a contact angle between peat soil particles and water is greater than 90° and is always understood to be associated with water content. However, in South Kalimantan, there was a phenomenon of irreversible drying but soil water content was still around field capacity and there was a visible coating substance on the particle surface. The purposes of this study were 1) to clarify the cause of irreversible drying in this location and 2) to show a possible effect of rock phosphate addition on the hydrophobicity’s disappearance. A hydrophobic peat soil sample was taken from the location that is cultivated for oil palm. Field observation was conducted on the peat soil that had been amended by rock phosphate. The peat soil hydrophobicity was identified by the Water Drop Penetration Time method and the surface coating substance was observed using SEM-EDS. The WDPT result shows that the peat soil was in hydrophobic condition, but the water content was still around field capacity. The results from SEM-EDS indicate that the coating substance was found as sulfate salts. The rock phosphate that had been added in the field shows a positive effect on the disappearance of the peat irreversible drying. However, the mechanism of soil properties change due to rock phosphate cannot be confirmed yet and need further investigation.

Impact of water table levels and winter cover crops on greenhouse gas emissions from cultivated peat soils

Drainage and cultivation have turned peatlands from carbon (C) sinks into hotspots for greenhouse gas (GHG) emissions. Raising the water table and planting of winter cover crops are potential strategies to help reduce peat oxidation and re-initiate net C accumulation during the non-cropping period. However, the effects of these practices as well as their interactions on GHG emissions remain unclear. Here, we carried out an outdoor mesocosm experiment to elucidate the effect of water table levels (−30 cm and −50 cm) and winter cover crop cultivation (vetch, rye, no plant) on carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) fluxes during the winter period (November-April). Soil-atmosphere GHG exchange, GHG concentrations within the peat profile and soil water solute concentrations were monitored. Our results showed that high water table significantly reduced ecosystem respiration, while it had no net effect on N2O and CH4 fluxes. Uptake of available N by the cover crop significantly reduced nitrate in soil solution, thereby lowering the potential for leaching and both direct and indirect N2O emissions. No interactive effects between water table levels and cover crops were detected for any of the measured GHG fluxes. Seasonal variations of GHG fluxes were positively correlated with soil air concentrations at −15 cm and −40 cm depths, which were further regulated by dissolved organic C, nitrate concentration, and anaerobic conditions in the soil. This study suggests that there is great potential to raise water table levels and introduce green cover crops to reduce GHG emissions. Further studies are needed to achieve a complete evaluation of these strategies outside of the growing season, which may provide a significant mitigation benefit in C-rich cultivated peatlands.

Dinamika Tinggi Muka Air Tanah Pada Lahan Gambut Yang Terbakar

Seasonal fluctuations of water table depth are very important regarding the sustainable peat management on tropical peatland. Water level depth can affect the greenhouse gases emissions and as the main indicator for peat fire risk management. Therefore, direct measurement of water level dynamics in the peat burning area is absolutely necessary. The research objective was studied the water level fluctuations on burning peatland in Central Kalimantan, Indonesia. Water level measurement performed manually in the field and ditch, every week from February to December 2014. Water level from February to December 2014 were -86.6 and -51.9 cm, on the ditch and field, respectively. Peat soil water level was strongly correlated to the variations of rainfall.

Storage effects on quantity and composition of dissolved organic carbon and nitrogen of lake water, leaf leachate and peat soil water

This study aimed to evaluate the effects of freezing and cold storage at 4 °C on bulk dissolved organic carbon (DOC) and nitrogen (DON) concentration and SEC fractions determined with size exclusion chromatography (SEC), as well as on spectral properties of dissolved organic matter (DOM) analyzed with fluorescence spectroscopy. In order to account for differences in DOM composition and source we analyzed storage effects for three different sample types, including a lake water sample representing freshwater DOM, a leaf litter leachate of Phragmites australis representing a terrestrial, ‘fresh’ DOM source and peatland porewater samples. According to our findings one week of cold storage can bias DOC and DON determination. Overall, the determination of DOC and DON concentration with SEC analysis for all three sample types were little susceptible to alterations due to freezing. The findings derived for the sampling locations investigated here may not apply for other sampling locations and/or sample types. However, DOC size fractions and DON concentration of formerly frozen samples should be interpreted with caution when sample concentrations are high. Alteration of some optical properties (HIX and SUVA254) due to freezing were evident, and therefore we recommend immediate analysis of samples for spectral analysis.

Changes of methane and nitrous oxide emissions in a transition bog in central Germany (German National Park Harz Mountains) after rewetting

During the last decades, various renaturation programmes have been initialized to recover nutrient sink and ecological functions of peatlands by rewetting. Rewetting, however, often results in the formation of hotspots for methane (CH4) emissions and in temporal dieback of local vegetation. The present study aimed at quantifying changes of CH4 and nitrous oxide (N2O) emissions in a peatland currently under continuous rewetting conditions. Emissions where studied at a permanently flooded site and a non-flooded peat site with fluctuating water tables by using common closed chamber method. The permanently flooded site revealed extremely high CH4 emissions (up to 1195 mg C m−2 d−1) which were positively correlated with temperature, nutrient content, dissolved organic carbon and nitrogen concentration of the peat soil water. In contrast, the non-flooded peat site, with lower and fluctuating water tables (WT), showed significantly lower CH4 emissions and an increasing trend of CH4 release associated with a generally increasing WT caused by the progressing rewetting process. Lower N2O emissions (<24 µg N m−2 d−1) were observed at the flooded site. By contrast, the non-flooded peat site with fluctuating WT showed significantly higher N2O emissions (up to 4178 µg N m−2 d−1), in particular at high temperatures during summer time. The present results indicate that permanently flooded conditions during rewetting processes might cause higher CH4 emissions compared to fluctuating WT which in contrast might enhance N2O emissions. In total, however, no decreasing trend for CH4 emissions throughout the five-year renaturation period could be found. At least for N2O we observed a decreasing trend during rewetting.

Water table fluctuation and carbon dioxide emission from a tropical peat soil cultivated with pineapples (Ananas comosus L. Merr.)

Tropical peat land is an important buffer for climate change as it absorbs atmospheric carbon and stores large carbon reserve. Inappropriate drainage and agricultural development on peat land results in GHG emissions such as CO2 and CH4which could shift the peat land ecosystem from carbon sink to carbon source. The objectives of this study were to: (i) quantify CO2 loss in a tropical soil under simulated water table fluctuation and (ii) determine the relationship between depth of water table and CO2 loss of a tropical soil cultivated with pineapples. Soil CO2 emission was captured using closed chamber method in field lysimeter and quantified using gas chromatography. It was carried out in July (dry month) and December 2015 (wet month). The peat soil water table fluctuation did not significantly affect emission of CO2 in pineapple cultivation. For lower water table, 147.5 t CO2 ha-1 yr-1 was emitted in the dry month whereas for higher water table, 19.6 t CO2 ha-1 yr-1. In the wet month, CO2emission of the lower water table was 23.7 t CO2 ha-1 yr-1whereasfor high water tables the emission was 25.6 t CO2 ha-1 yr-1. Soil CO2 emission for the lower water table was higher than that of the high water table whereas the opposite was true for the higher water table because of increase in soil temperature in the dry month. Regardless of season and depth of peat soil water table, this study will provide significant understanding of the effect of water table management on carbon loss in peat soils under pineapple cultivation.

The short-term degradation of cellulosic pulp in lake water and peat soil: A multi-analytical study from the micro to the molecular level

Cellulosic pulp was analysed after two and five years of natural ageing in two different burial environments - lake water and peat soil - in order to investigate the chemical and structural changes undergone by the material. This research is part of a monitoring program developed in the archaeological site of Biskupin, whose final aim is to estimate the best re-burial conditions for an in situ conservation of archaeological wood. We applied SEM, FT-IR, XRD and Py-GC/MS with thermally assisted silylation using hexamethyldisilazane (HMDS) to obtain broad information on cellulosic pulp degradation.SEM provided information on the structural changes undergone by the fibres and on the microbial activity. FT-IR highlighted a depletion of the carbohydrates in the most degraded samples. Py(HMDS)-GC/MS confirmed these observations and provided detailed molecular information on cellulose alteration. The crystallinity index (CI) of cellulose was estimated by XRD, showing that the degradation began in amorphous regions. The correlation between the CI and the relative abundance of anhydrosugars detected by Py(HMDS)-GC/MS demonstrated that pyrolytic reactions are also influenced by the degree of crystallinity of cellulose.A mechanism of cellulose degradation in these natural environments was formulated: the degradation of cellulose in these natural environments proceeds through a depolymerisation step, initially involving the amorphous regions of cellulose, until the size of oligomers becomes sufficiently small to allow metabolisation by microorganisms or solubilisation by water. Secondly, a loss of carbohydrates was detected after five years of ageing and the loss reached 25% and 55% for the dark areas of samples aged in peat soil and lake water, respectively. Peat soil was found to be more suitable than lake water in terms of preservation of carbohydrates.

Deriving Effective Soil Water Retention Characteristics from Shallow Water Table Fluctuations in Peatlands

Core Ideas This is a new approach for determining in situ peat soil water retention characteristics. It only requires data on water table changes, precipitation, and microrelief. Water table rises are used to invert for water retention parameters. Applicability is demonstrated for field data from a peatland. This approach should be applicable to other shallow groundwater systems.We have developed a novel and simple approach that can be used to derive effective in situ soil water retention characteristics from field monitoring time series in peatlands. The simplicity of the approach is given by the very limited data requirements, which comprise only precipitation, water table, and, if relevant, microrelief data. Our approach is built on two main assumptions: (i) for shallow groundwater systems, the soil moisture profile is always close to hydrostatic equilibrium; and (ii) during short time periods of high precipitation, the water storage change due to lateral fluxes is small compared with the precipitation input. Given these assumptions, the height of a water table rise due to a precipitation event mainly depends on the soil water retention characteristics, the precipitation amount, the initial water table depth, and, if present, the microrelief. In this study, this dependency was used to determine the effective van Genuchten parameters by Bayesian inversion assuming a uniform soil profile. We applied our concept to field data from a peatland with microrelief. Results indicated that observations of water table rises caused by precipitation events can contain sufficient information to constrain the soil water retention characteristics around monitoring wells in peatlands to plausible ranges. In principle, the approach should also be applicable to other shallow groundwater systems. Application limits and potential systematic errors are discussed.

Formulation of Indigenous Rhizobacterial Isolates from Healthy Soybean’s Root, which Ability to Promote Growth and Yield of Soybean

Plant growth promoting rhizobacteria are a group of bacteria, that actively colonize plant roots, induce the resistance of plant to pathogen, increase plant growth and yield. Our previous research had showed, that one of rhizobacterial isolates from soybean root effective to promote growth and yield of soybean<em>.</em> To maintain the effectivity of this bacterial isolate during storage, transportation and application, so need to be formulated. The aim of this research was to get the best carrier for formulation to maintain the effectivity of rhizobacterial isolate in storage to promote growth and yield of soybean. This research have used random complete design with 16 treatments and 3 replicates. The treatments were combination of material carrier for formulation of rhizobacterial isolate (peat soil, tapioca flour and coconut water + 1 % palm oil) and time of storage of formula (0, 1, 3, 5 and 7 weeks) and control. The parameter were population density of rhizobacterial isolate on formula, growth development (germination rate, plant height, number of leaves and twigs) generative phase (time of flowering and pod) and yield (weight of seed) of soybean. The results showed that all formulas of rhizobacterial isolate able to increase growth and yield of soybean. The best combination which effective to increase growth and yield of soybean were rizobacteria in peat soil formula and storage for five weeks.

Effect of mixing urea with zeolite and sago waste water on nutrient use efficiency of maize (Zea mays L.)

The efficiency of urea is poor due to the substantial amount of N lost to the atmosphere by ammonia volatilization. Thus, the objectives of this greenhouse study were to evaluate the effectiveness of mixing urea with zeolite and sago waste water on N, P and K uptake and their use efficiency in maize cultivation, and soil exchangeable ammonium, available nitrate, pH, exchangeable K, and available P contents. The treatments evaluated were: No fertilizer (T0), 2.02 g urea (T1), 2.02 g urea + 30 g zeolite + 7 L sago waste water (T2), 2.02 g urea + 40 g zeolite + 7 L sago waste water (T3), and 2.02 g urea + 7 L sago waste water (T4). Triple Super Phosphate (TSP) and Muriate of Potash (MOP) were used as sources of P and K for all the treatments except for T0. These fertilizers were applied twice that is 10 and 28 days after planting. Phosphorus and K requirements of the test crop were met by applying TSP and MOP (standard rate for the test crop) to plants of all the treatments except T0. The mixtures of sago waste water, and zeolite, with urea had significant effect on dry matter, N, P, K uptake and N, P, K use efficiency compared with urea without additives. These mixtures also significantly increased soil exchangeable ammonium, K, Ca, Mg, available P, and nitrate contents compared with urea without additives. Amending urea with sago waste water and peat soil water can reduce ammonia loss by encouraging formation of ammonium and nitrate over ammonia. Additionally, the mixtures ensure N, P, K uptake and their use efficiency while at the same time making soil ammonium, K, Ca, Mg, P, and nitrate available for plant use.

Enhancing nutrient use efficiency of maize (Zea mays L.) from mixing urea with zeolite and peat soil water

The use of urea as N fertilizer has increased globally but lack of efficiency due to loss through ammonia volatilization has become a subject of considerable recent attention. In line with this, a pot experiment was conducted to determine the effect of mixing urea with zeolite and peat soil water on: (1) uptake and use efficiency of N, P and K in maize cultivation, and (2) soil exchangeable ammonium, available nitrate, pH, exchangeable K, and available P contents. The treatments evaluated were: No fertilizer (T0), 2.02 g urea (T1), 2.02 g urea + 30 g zeolite + 7 L peat soil water (T2), 2.02 g urea + 40 g zeolite + 7 L peat soil water (T3), and 2.02 g urea + 7 L peat soil water (T4). The fertilizers of TSP and MOP were applied twice that is 10 and 28 days after planting for all the treatments except T0. The application of peat soil water, and zeolite with urea had significant effect on dry matter, N, P, K uptake and N, P, K use efficiency compared with urea without additives. The soil exchangeable ammonium, K, Ca, Mg, available P, and nitrate contents were significantly increased compared with urea without additives. Formation of ammonium and nitrate over ammonia were reflected by the mixtures of peat soil water, and zeolite, with urea. Amending urea with zeolite and peat soil water can reduce ammonia loss by encouraging formation of ammonium and nitrate over ammonia. In addition, the mixtures ensure N, P, K uptake and their use efficiency while at the same time rendering soil ammonium, K, Ca, Mg, P, and nitrate available for plant use.

Ammonia loss, soil exchangeable ammonium and available nitrate contents from mixing urea with zeolite and peat soil water under non-waterlogged condition.

Efficient utilization of urea-N in most agricultural systems is impeded by ammonia volatilization. This study investigated the effect of mixing urea with zeolite and peat soil water on ammonia volatilization, soil exchangeable ammonium and available nitrate contents, compared with urea without additives under non waterlogged condition. The mixtures significantly reduced ammonia loss by 5 to 14% compared with urea without additives (straight urea, 46% N). The pH of the soil with the mixtures was also significantly different compared with that of urea without additives. All the mixtures of zeolite and peat soil water with urea significantly improved soil exchangeable ammonium (by 42 to 76 ppm) retention compared with urea without additives. Only one mixture significantly increased soil available nitrate content. The temporary reduction of soil pH may have retarded urea hydrolysis. This encouraged beneficial formation of ammonium over ammonia hence, the significant reduction of ammonia volatilization upon the use of the mixtures produced in this study. It could be possible to improve the efficiency of urea surface-applied to high value crops by addition of zeolite and peat soil water. Key words: Ammonia volatilization, urea-N use efficiency, peat soil water, exchangeable ammonium, zeolites, available nitrate.