Improving soil phosphorus availability and yield of Zea mays l. using biochar and compost derived from agro-industrial wastes

Tropical soils such as Ultisols fix phosphorus (P) because of their characteristically high contents of aluminium and iron. Organic amendments could be used to mitigate P fixation. This study aimed to: i) improve soil P availability, nutrients uptake, and yield of Zea mays L. using biochar and pineapple leaf residues compost; and ii) determine if the use of biochar and pineapple leaf residues compost could exert a residual effect on P. Two cycles of field trials were carried out and the test crop used was Zea mays L. hybrid F1. At harvest, the plants were harvested, partitioned into leaves and stems, and analysed. Soil samples were also collected and analysed. The results suggest that the soil total P, available P, inorganic P, and organic P recovered from the treatments with the organic amendments were higher compared with the nonorganic amendments. The availability of soil macro-nutrients in the soils and Zea mays L. yield were higher in the treatments with the organic amendments in the first and second field trials. Amending chemical fertilisers with organic amendments have a larger residual effect than chemical fertilisers only and can be used to ameliorate P fixation of acid soils to improve maize production on acid soils

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

Problem Statement: Ammonia loss significantly reduces urea-N use efficiency in crop production. Efforts to reduce ammonia loss are laboratory oriented, as such limited in reflecting actual field conditions. This paper reports the effects of urea amended with triple superphosphate (TSP) and zeolite (Clinoptilolite) on soil pH, soil nitrate, soil 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. Approach: The treatments evaluated were: (i) Normal N, P, K application (74.34 g urea, 27.36 g TSP, 24.12 g KCl) (T1), (ii) Urea-TSP mixture (74.34 g urea+27.36 g TSP)+24.12 g KCl (T2), (iii) 74.34 g urea+27.36 g TSP+9.0 g zeolite (T3), (iv) 74.34 g urea+27.36 g TSP+13.5 g zeolite (T4) and (v) No fertilization (T5). Note, the same amount of 24.12 g KCl was used in T3 and T4 plots. Standard procedures were used to determine the selected chemical properties of zeolite, soil, TSP and urea. The pH of the urea, zeolite, soil and TSP were determined in a 1:2.5 soil: distilled water suspension and/or 0.01 N CaCl2 using a glass electrode. The CEC of the zeolite was determined by the CsCl method. Soil CEC was determined by leaching with 1 N ammonium acetate buffer adjusted to pH 7.0 followed by steam distillation. Soil samples at harvest were analyzed for pH using the method previously outlined. Exchangeable ammonium and nitrate at harvest were extracted from the soil samples by the method of Keeney and Nelson and the amount determined using a LACHAT Autoanalyzer. Total N of the plant tissues (stem and leaf) was determined by the Micro-Kjeldhal method. Results: Urea amended with 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. Conclusion: Urea amended with TSP and zeolite has a potential of reducing ammonia loss from surface-applied urea

Potential PGPR properties of cellulolytic, nitrogen fixing, phosphate-solubilizing bacteria in rehabilitated tropical forest soil

In the midst of the major soil degradation and erosion faced by tropical ecosystems, rehabilitated forests are being established to avoid the further deterioration of forest lands. In this context, cellulolytic, nitrogen-fixing (N-fixing), phosphate-solubilizing bacteria are very important functional groups in regulating the elemental cycle and plant nutrition, hence replenishing the nutrient content in forest soils. As is the case for other potential plant growth-promoting (PGP) rhizobacteria, these functional bacteria could have cross-functional abilities or beneficial traits that are essential for plants and can improve their growth. This study was conducted to isolate, identify, and characterize selected PGP properties of these three functional groups of bacteria from tropical rehabilitated forest soils at Universiti Putra Malaysia Bintulu Sarawak Campus, Malaysia. The bacteria were isolated based on their colonial growth on respective functional media, identified using both molecular and selected biochemical properties, and were assessed for their functional quantitative activities as well as PGP properties based on seed germination tests and indole-3-acetic acid (IAA) production. Out of the 15 identified bacterial isolates that exhibited beneficial phenotypic traits, a third belong to the genus Burkholderia and a fifth to Stenotrophomonas sp., with both genera consisting of members from two different functional groups. The results of the experiments confirm the multiple PGP traits of some selected bacterial isolates based on their respective high functional activities, root and shoot lengths, and seedling vigor improvements when bacterized on mung bean seeds, as well as significant IAA production. The results of this study suggest that these functional bacterial strains could potentially be included in bio-fertilizer formulations for crop growth on acid soils

Glucose-6-Phosphate Dehydrogenase Deficiency, Chlorproguanil-Dapsone with Artesunate and Post-treatment Haemolysis in African children treated for uncomplicated Malaria

Malaria is a leading cause of mortality, particularly in sub-Saharan African children. Prompt and efficacious treatment is important as patients may progress within a few hours to severe and possibly fatal disease. Chlorproguanil-dapsone-artesunate (CDA) was a promising artemisinin-based combination therapy (ACT), but its development was prematurely stopped because of safety concerns secondary to its associated risk of haemolytic anaemia in glucose-6-phosphate dehydrogenase (G6PD)-deficient individuals. The objective of the study was to assess whether CDA treatment and G6PD deficiency are risk factors for a post-treatment haemoglobin drop in African children<5 years of age with uncomplicated malaria

Effect of grain size on selected physico-chemical properties of clay

Mixture of the right proportion of expanding and non-expanding clays to improve plasticity (moldability) of clays used in the pot industry of Malaysia is yet to be well investigated. In addition, little is known about the choice of the right clay size to eliminate or reduce the content of undesirable compounds such as Fe2O3, Al2O3 to improve the strength of pots and roofing tiles in the country. The objective of this study was to investigate how selected physico-chemical properties of pottery clay relate to grain size of Nyalau series ((Typic Paleudults). Approach: Soil samples were refined into 25, 20 and 63 µm using size grading method. The mineralogical composition of the samples was determined using X-Ray Diffraction (XRD). The chemical composition of the samples was also determined using standard procedures. Firing was done at 800°C) in a muffle furnace and the cracks of the samples recorded. Results: The clay particles with sizes 20 and 25 µm were higher in LOI and total C than that those of 63 µm regardless of grain size, the clay investigated had quartz (SiO2), illite-montmorillonite, Anatase ((TiO2) and kaolinite. Grading affected the concentrations of Fe, Al and Si as clays with particle sizes 20 and 25 µm had higher contents of the aforementioned elements compared with those of 63 µm. The clay with particles 63 µm had the best strength and this was so because the clay particles had the lowest amount of Fe, Al and Si. Conclusion: The strength of Malaysian pots could be improved upon proper grading of the clay particles

Effects of selected functional bacteria on maize rrowth and nutrient use efficiency

Plant growth-promoting rhizobacteria (PGPR), which include isolates from genera Paraburkholderia, Burkholderia and Serratia, have received attention due to their numerous plant growth-promoting mechanisms such as their ability to solubilize insoluble phosphates and nitrogen-fixation. However, there is a dearth of information on the potential plant growth-promoting effects of these three groups of bacteria on non-legumes such as maize. This study determined the influences of the aforementioned strains on soil properties, maize growth, nutrient uptake and nutrient use efficiency. A pot trial using maize as a test crop was done using a randomized complete block design with 7 treatments each replicated 7 times. The treatments used in this study were: Control (no fertilizer), chemical fertilizer (CF), organic-chemical fertilizers combination without inoculum (OCF) and with inocula consisting of single strains [cellulolytic bacteria (TC), organic fertilizer and chemical fertilizer with N-fixing bacteria (TN), organic fertilizer and chemical fertilizer with P-solubilizing bacteria (TP)) and three-strain inocula (TCNP), respectively. The variables measured included plant growth and nutrient content, soil nutrient content and functional rhizospheric bacterial populations. Paraburkholderia nodosa NB1 and Burkholderia cepacia PB3 showed comparable effects on maize biomass and also improved N and P use efficiencies when compared to full chemical fertilization. Nitrogen-fixing rhizobacteria had a positive effect on above-ground biomass of maize. Paraburkholderia nodosa NB1 improved soil total C and organic matter contents, besides being the only bacterial treatment that improved K use efficiency compared to OCF. The results suggest that P. nodosa NB1 and B. cepacia PB3 have potential usage in bio-fertilizers. In contrast, treatments with Serratia nematodiphila C46d and consortium strains showed poorer maize nutrient uptake and use efficiency than the other single strain treatments. Bacterial treatments generally showed comparable or higher overall N and P use efficiencies than full chemical fertilization. These findings suggest that at least half the amounts of N and P fertilizers could be reduced through the use of combined fertilization together with beneficial bacteria

Effect of N, P and K humates on dry matter of Zea mays and soil pH, exchangeable ammonium and available nitrate

Ammonia volatilization from surface-applied urea reduces urea-N use efficiency in crop production and it also pollutes the environment; it is an economic loss. A greenhouse study was conducted to confirm the effect of similar fertilizer formulations (N, P and K humates) on soil pH, exchangeable ammonium, available nitrate retention and dry matter of Zea mays cultivated on an acid soil (Typic Paleudults). The fertilizers were applied 10 days after planting (DAP) in each pot containing 10 kg of soil. Soil and plant samples (stems, leaves and roots) were collected at 31 DAP. Soil samples were analyzed for pH, ammonium, and nitrate content. Urea amended with humic acid (HA), acidified (HA+FA) and humin without TSP and MOP were not effective in increasing the dry matter production of the test crop. Urea amended with fulvic acid (FA) alone significantly increased plant dry matter. Complete fertilizer consisting urea, triple superphosphate (TSP) and mono triphosphate (MOP) amended with or without HA, FA, acidified HA and FA and humin significantly increased the dry matter of the test crop with significant retention of soil exchangeable ammonium. However, only the complete fertilizer with and without HA and humin amendment significantly retained soil available nitrate. The findings in this study may only be applicable to similar acid soils. The outcome of this study may contribute to the improvement of urea N use efficiency as well as reducing environmental pollution.Key words: Humic acids, fulvic acids, triple superphosphate, muriate of potash, soil exchangeable ammonium, available nitrate, Zea mays, dry matter

Reducing soil phosphorus fixation to improve yield of zea mays l. cultivation on a tropical acid soil using compost and biochar derived from agro-industrial wastes

Phosphorus is an essential element required to maintain profitable crop production. Most soils of the tropics, such as Ultisols, are acidic and fix phosphorus because of their characteristically high contents of aluminium and iron. Compost and biochar could be used to mitigate phosphorus fixation by reducing the phosphorus sorption sites. This study aimed to: (i) improve soil phosphorus availability, nutrient uptake, and yield of maize using biochar and pineapple leaf residue compost; and (ii) determine if the use of biochar and compost could exert a residual effect on phosphorus nutrition in the second cycle of the field trial. Field trials were carried out using a Zea mays L. hybrid as the test crop. At harvest, the plants were harvested, partitioned into leaves and stems, and analyzed. Soil samples were also collected and analyzed. Ears were harvested to determine the yield from each treatment. The results suggest that the soil total phosphorus and available phosphorus recovered from the treatments with the organic amendments were higher compared with the non-organic amendments. The availability of soil nutrients (nitrogen, potassium, calcium, magnesium, and sodium) in the soils and yield of maize were higher in the treatments with the organic amendments in the first and second field trials. These results further confirm that amending chemical fertilizers with organic amendments have a larger residual effect than chemical fertilizers only. Amending chemical fertilizers with organic amendments can be used to ameliorate phosphorus fixation of acid soils to improve maize production on acid soils

Reduction of ammonia volatilization through mixing urea with humic and fulvic acids isolated from palm oil mill effluent sludge

Problem statement: Ammonia volatilization from surface-applied urea may be substantial but it is possible to control it by mixing urea with acidic substances such as Humic Acids (HA) and Fulvic Acids (FA). The objective of this study was to compare the effects of urea-HA, urea-FA, urea-acidified (HA+FA) mixtures on ammonia loss, soil pH, soil exchangeable ammonium and available nitrate accumulation compared to urea alone. Approach: The effects of urea amended with or without HA and FA were evaluated in a laboratory condition using a closed-dynamic air flow system. Ammonia loss, soil pH, soil exchangeable ammonium and available nitrate were determined using standard procedures. Results: Humic acid alone was not effective in controlling ammonia volatilization even though ammonium retention was found to be significantly higher compared to urea alone. Fulvic acid significantly reduced ammonia volatilization by 50% compared to urea alone. It also caused the highest retention of soil exchangeable ammonium and available nitrate. However, there was no ammonia volatilization with acidified HA and FA. Ammonium and nitrate accumulation for FA was better than acidified HA and FA. Ammonia loss could be reduced by improving ammonium retention. It must be stressed that results obtained in the incubation experiment using an acidic (pH water 6.32) soil of Typic Paleudults (Bekenu series) may only be applicable to similar acid soils. Conclusion: Urea amended with HA or HA and FA significantly reduced ammonia loss. The outcome of this study might be contributed to the improvement of urea N use efficiency as well as reducing environmental pollution

Reduction of ammonia loss from urea through mixing with humic acids isolated from peat soil (saprists)

Problem statement: Application of urea as a source of nitrogen fertilizer has an adverse effect on ammoniacal loss to the environment. This study was conducted to reduce ammonia loss from urea by mixing with Humic Acids (HA) isolated from Saprists peat. Approach: The effects of urea amended with four different amounts of humic acids, 0.25, 0.50, 0.75 and 1.00 g were evaluated in laboratory conditions using a closed dynamic air flow system. The mineral soil that was used as medium for the study was Bekenu series (typic paleudults). Amnonia loss, soil pH, exchangeable ammonium, available nitrate, exchangeable K, Ca, Mg and Na were determined using standard procedures. Results: All the treatments with HA significantly reduced ammoinia loss compared to urea alone. Increasing the amount of HA also significantly retained soil exchangeable ammonium and available nitrate. Treatments with HA had no significant effect on the concentrations of Mg, K and Ca, except for Na. The effect of HA in the mixtures on ammonia loss was related to their effect on the formation of ammonium over ammonia. Conclusion: Surface-applied urea fertilizer efficiency could be increased when coated with 1.00 g of HA