Osumanu Haruna Ahmed

Ammonia volatilization and ammonium accumulation from urea mixed with zeolite and triple superphosphate

Abstract Ammonia volatilization from surface-applied urea fertilizer reduces N fertilizer use efficiency by crops. Beneficial formation of NH4 over NH3 leading to reduction of NH3 loss may be possible through addition of zeolite and acidic materials. The objective of this laboratory study was to evaluate the effect of four different urea-triple superphosphate (TSP)-zeolite mixtures on NH3 volatilization and NH4 and NO3 contents in soil, compared with surface-applied urea without additives. The soil was a sandy clay loam Typic Kandiudults (Bungor Series). The mixtures significantly reduced NH3 loss by 34 to 49% compared with urea (straight urea, 46% N) and larger reductions were obtained with higher rates of zeolite (0.75 and 1 g kg−1 of soil). All the mixtures of acidic P fertilizer and zeolite with urea significantly increased soil NH4 content but not NO3 content. The mixtures with acidic P fertilizer and zeolite also significantly increased soil-exchangeable Ca, K and Mg, and benefited the formation of NH4 over NH3 compared with urea without additives. The increase in soil-exchangeable cations, and temporary reduction of soil pH, might have impeded urea hydrolysis in the microsite immediately around the fertilizer. It could be possible to improve the efficiency of urea surface-applied to high value crops by addition of TSP and zeolite.

A Modified Way of Producing Humic Acid from Composted Pineapple Leaves

ABSTRACT Purification of humic acid (HA) is time-consuming (takes between 2 to 7 days). A study was conducted to investigate whether HA produced from composted pineapple leaves could be purified within a day through washing with distilled water. Standard procedures were used to produce 0.1 M KOH and pineapple leaves compost. The KOH was used to extract HA in the compost using standard methods with some modifications. The HA was purified by suspending it in 100 ml distilled water, equilibrated for 1 hour, centrifuged for 15 minutes, supernatant decanted, filtered through glass wool and the liquor analyzed for K, Ca, Mg, Na, Zn, Mn, and Cu using an atomic absorption spectrophotometer (AAS). This procedure was repeated four times after which the washed HA was oven dried at 30°C to a constant weight. Washing HA for four consecutive times within a day was able to reduce the ash content of the HA to 0.1%, a value less than the generally accepted value of less than 1%. This observation was attributed to the remarkable decrease in K, Ca, Mg, Na, Zn, Mn, and Cu with washing. This finding can help in facilitating the production of K-rich humate (organically based fertilizer) from composted pineapple residues in a relatively short time since the HA can be purified within a day for its reconstitution to produce K-humate (38% K) instead of the conventional method that takes between 2 to 7 days.

Improving Phosphorus Availability in an Acid Soil Using Organic Amendments Produced from Agroindustrial Wastes

In acid soils, soluble inorganic phosphorus is fixed by aluminium and iron. To overcome this problem, acid soils are limed to fix aluminium and iron but this practice is not economical. The practice is also not environmentally friendly. This study was conducted to improve phosphorus availability using organic amendments (biochar and compost produced from chicken litter and pineapple leaves, resp.) to fix aluminium and iron instead of phosphorus. Amending soil with biochar or compost or a mixture of biochar and compost increased total phosphorus, available phosphorus, inorganic phosphorus fractions (soluble inorganic phosphorus, aluminium bound inorganic phosphorus, iron bound inorganic phosphorus, redundant soluble inorganic phosphorus, and calcium bound phosphorus), and organic phosphorus. This was possible because the organic amendments increased soil pH and reduced exchangeable acidity, exchangeable aluminium, and exchangeable iron. The findings suggest that the organic amendments altered soil chemical properties in a way that enhanced the availability of phosphorus in this study. The amendments effectively fixed aluminium and iron instead of phosphorus, thus rendering phosphorus available by keeping the inorganic phosphorus in a bioavailable labile phosphorus pool for a longer period compared with application of Triple Superphosphate without organic amendments.

Enhancing the urea-N use efficiency in maize (Zea mays) cultivation on acid soils amended with zeolite and TSP.

Ammonia loss significantly reduces the urea-N use efficiency in crop production. Efforts to reduce this problem are mostly laboratory oriented. This paper reports the effects of urea amended with triple superphosphate (TSP) and zeolite (Clinoptilolite) on soil pH, nitrate, exchangeable ammonium, dry matter production, N uptake, fresh cob production, and urea-N uptake efficiency in maize (Zea mays) cultivation on an acid soil in actual field conditions. Urea-amended TSP and zeolite treatments and urea only (urea without additives) did not have long-term effect on soil pH and accumulation of soil exchangeable ammonium and nitrate. Treatments with higher amounts of TSP and zeolite significantly increased the dry matter (stem and leaf) production of Swan (test crop). All the treatments had no significant effect on urea-N concentration in the leaf and stem of the test crop. In terms of urea-N uptake in the leaf and stem tissues of Swan, only the treatment with the highest amount of TSP and zeolite significantly increased urea-N uptake in the leaf of the test crop. Irrespective of treatment, fresh cob production was statistically not different. However, all the treatments with additives improved urea-N uptake efficiency compared to urea without additives or amendment. This suggests that urea amended with TSP and zeolite has a potential of reducing ammonia loss from surface-applied urea.

Co-composting of pineapple leaves and chicken manure slurry

BackgroundThe common practice of clearing pineapple (Ananas comosus) residues for land preparation for cultivation is by burning, an unsustainable agricultural practice that causes environmental pollution. Chicken manure produced from the poultry industry is also increasing. Inappropriate disposal or treatment can pose harm to the environment and humans. In order to reduce environmental pollution, pineapple leaves and chicken manure slurry were co-composted to obtain high-quality organic fertilizer. The shredded pineapple leaves were thoroughly mixed with chicken manure slurry, chicken feed and molasses in polystyrene boxes. Co-compost temperature readings were taken three times daily.ResultsNitrogen and P concentrations increased whereas C content was reduced throughout the co-composting. The CEC increased from 32.5 to 65.6 cmol kg-1 indicating humified organic material. Humic acid and ash contents also increased from 11.3% to 24.0% and 6.7% to 15.8%, respectively. The pH of the co-compost increased from 6.14 to 7.89. The final co-compost had no foul odour, low heavy metal content and comparable amount of nutrients. Seed germination indices of phytotoxicity test were above 80% of final co-compost. This suggests that the co-compost produced was phytotoxic-free and matured.ConclusionHigh-quality co-compost can be produced by co-composting pineapple leaves and chicken manure slurry and thus have potential to reduce environmental pollution that could result from poorly managed agricultural wastes.

Effect of K-N-Humates on Dry Matter Production and Nutrient Use Efficiency of Maize in Sarawak, Malaysia

Agricultural waste, such as sago waste (SW), is one of the sources of pollution to streams and rivers in Sarawak, particularly those situated near sago processing plants. In addition, unbalanced and excessive use of chemical fertilizers can cause soil and water pollution. Humic substances can be used as organic fertilizers, which reduce pollution. The objectives of this study were to produce K- and ammonium-based organic fertilizer from composted SW and to determine the efficiency of the organic-based fertilizer produced. Humic substances were isolated using standard procedures. Liquid fertilizers were formulated except for T2 (NPK fertilizer), which was in solid form. There were six treatments with three replications. Organic fertilizers were applied to soil in pots on the 10th day after sowing (DAS), but on the 28th DAS, only plants of T2 were fertilized. The plant samples were harvested on the 57th DAS during the tassel stage. The dry matter of plant parts (leaves, stems, and roots) were determined and analyzed for N, P, and K using standard procedures. Soil of every treatment was also analyzed for exchangeable K, Ca, Mg, and Na, organic matter, organic carbon, available P, pH, total N, P, nitrate and ammonium contents using standard procedures. Treatments with humin (T5 and T6) showed remarkable results on dry matter production; N, P, and K contents; their uptake; as well as their use efficiency by maize. The inclusion of humin might have loosened the soil and increased the soil porosity, hence the better growth of the plants. Humin plus inorganic fertilizer provided additional nutrients for the plants. The addition of inorganic fertilizer into compost is a combination of quick and slow release sources, which supplies N throughout the crop growth period. Common fertilization by surface application of T2 without any additives (acidic and high CEC materials) causes N and K to be easily lost. High Ca in the soil may have reacted with phosphate from fertilizer to form Ca phosphate, an insoluble compound of phosphate that is generally not available to plants, especially roots. Mixing soil with humin produced from composted SW before application of fertilizers (T5 and T6) significantly increased maize dry matter production and nutrient use efficiency. Additionally, this practice does not only improve N, P, and K use efficiency, but it also helps to reduce the use of N-, P-, and K-based fertilizers by 50%.

Status of some fishery resources in a tropical mangrove estuary of Sarawak, Malaysia

Abstract This study was carried out to assess the fishery resources of the Sibuti River estuary, Sarawak, Malaysia. Data were collected from the study area for a period of one year in different seasons. The estuary is relatively species-rich and a total of 4675 individuals of 32 families from 60 species of fish (55), crab (four) and shrimp (one) were collected. Coilia dussumieri was the dominant species (22.63%) followed by Nemapteryx caelata (11.85%), Otolithes ruber (7.85%) and Ilisha elongata (5.80%). Marked seasonal variations were found among most of the hydrobiological factors; however, seasonal variations were not significant for the diversity indices such as Shannon–Wiener, Margalef and Evenness. The number of fish taxa caught in different mesh size gill nets was 1 inch (42 species) > 2 inch (36 species) > 4 inch (25 species), suggesting that smaller mesh nets are more suitable for assessing the diversity of fishery resources. SIMPER analysis showed that Coilia dussumieri was the most abundant species in the dry (10.3%) and intermediate (8.1%) seasons, whereas N. caelata was most abundant in the wet season (7.1%). Significant differences (ANOSIM and nMDS) were observed in the species community structure between dry–intermediate and dry–wet seasons; however, species compositions were not significantly different between intermediate and wet seasons. Canonical correspondence analysis (CCA) showed that most of the species assemblages were positively correlated with turbidity and chlorophyll a, followed by phosphate, nitrate and zooplankton density. The findings suggest that the Sibuti mangrove estuary is productive in terms of diversified fishery resources, which are influenced by the hydrobiological factors.

Ammonia loss, ammonium and nitrate accumulation from mixing urea with zeolite and peat soil water under waterlogged condition

Ammonia loss from urea significantly hinders efficient use of urea in agriculture. In order to reduce ammonia loss and, at the same time, improve beneficial accumulation of soil exchangeable ammonium and nitrate for efficient utilization by plants, this laboratory study was conducted to determine 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 waterlogged condition. The soil used was Bekenu Series (Fine loamy, siliceous, isohyperthermic, red-yellow to yellow Tipik Tualemkuts). The mixtures significantly reduced ammonia loss by 25 to 38% compared with urea (straight urea, 46% N). All the mixtures of zeolite and peat soil water with urea significantly increased soil exchangeable ammonium (by 59 to 80 mg kg -1 ) and available nitrate (by 5 to 12 mg kg -1 ) contents. The temporary reduction of soil pH may have retarded urea hydrolysis. 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, peat soil water, exchangeable ammonium, available nitrate.

Compost maturity and nitrogen availability by co-composting of paddy husk and chicken manure amended with clinoptilolite zeolite.

The availability of paddy husk from rice processing plants remains high owing to increase in the worldwide rice consumption. Increasing demand for chicken products leads to poultry wastes production. Co-composting of the aforementioned wastes could solve the indiscriminate disposal of these wastes. Thus, co-composting of paddy husk and chicken slurry with clinoptilolite zeolite and urea as additive was carried out. Clinoptilolite zeolite was used to enhance ammonium and nitrate retention in the compost. Temperature of the compost was monitored three times daily for 55 days. Cation exchange capacity, organic matter, ash, humic acids, pH, total C, N, C/N ratio; total P, exchangeable Ca, Mg, K, NH4+, NO3−, and heavy metals contents were determined using standard procedures. pH, total N, humic acids, ash, NH4+, NO3−, P, Ca, Mg, and K contents increased but the salinity, heavy metals contents, and microbial population were low after the co-composting process. Zea mays L. (test crop) seed germination rate in distilled water and the compost were not significantly different. Growth of Spinach oleracea (test crop) on a peat-based growing medium and the compost was also not significantly different. These findings were possible because the clinoptilolite zeolite used in co-composting reduced accumulation of heavy metals that may have damage effects on the test crops. Mature compost with good agronomic properties can be produced by co-composting chicken slurry and paddy husk using clinoptilolite zeolite and urea as additives.

Towards Sustainable Use of Potassium in Pineapple Waste

Due to the 1997/98 haze problem in South-East Asia and the increasing need for sustainable food production and development, the usual management of crop residues (including pineapple wastes) through burning is prohibited. As a result, the need for alternative uses of pineapple wastes in pineapple production has been emphasized. This study investigated an environmentally friendly means of recycling pineapple leaves for agricultural use. Pineapple leaves were shredded and composted in a composting drum for 30 days. Part of the shredded leaves was ashed in a muffle furnace for 4 h. Humic acid (HA), K-fulvate, and K in HA and compost were analyzed using standard procedures. An ash to water ratio of 1:7 was used to extract 0.1 molar (M) KOH from the shredded leaves. The 0.1 M KOH contained 50% K and was able to extract 20% HA from the composted pineapple leaves. Percent K in the fulvate using 0.1 M KOH was 43. Besides serving as a foliar spray (supplement soil application K fertilizers), source of K for freshwater fish (e.g., tilapia), the HA produced can be used as a soil conditioner. Studies show that between 0.05—0–01 g of HA per kg soil retards runoff by 36% in sandy and sandy loam soils. The K-fulvate can be used as a fluid fertilizer. In addition, the pH of 2 of the K-fulvate suggests it could be used to dissolve phosphate rocks, particularly those in the arid regions where high soil pH does not facilitate the dissolution of these important rocks that serve as one of the sources of phosphorus fertilizer in agriculture.