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Plant growth-promoting rhizobacteria (PGPR) is a soil bacterium that positively impacts soil and crops. These microbes invade plant roots, promote plant growth, and improve crop yield production. Bacillus subtilis is a type of PGPR with a short shelf-life due to its structural and cellular components, with a non-producing resistance structure (spores). Therefore, optimum formulations must be developed to prolong the bacterial shelf-life by adding humic acid (HA) as an amendment that could benefit the microbes by providing shelter and carbon sources for bacteria. Thus, a study was undertaken to develop a biofertilizer formulation from locally isolated PGPR, using HA as an amendment. Four doses of HA (0, 0.01, 0.05, and 0.1%) were added to tryptic soy broth (TSB) media and inoculated with B. subtilis (UPMB10), Bacillus tequilensis (UPMRB9) and the combination of both strains. The shelf-life was recorded, and viable cells count and optical density were used to determine the bacterial population and growth trend at monthly intervals and endospores detection using the malachite green staining method. After 12 months of incubation, TSB amended with 0.1% HA recorded the highest bacterial population significantly with inoculation of UPMRB9, followed by mixed strains and UPMB10 at 1.8x107 CFUmL-1, 2.8x107 CFUmL-1and 8.9x106 CFUmL-1, respectively. Results showed that a higher concentration of HA has successfully prolonged the bacterial shelf-life with minimal cell loss. Thus, this study has shown that the optimum concentration of humic acid can extend the bacterial shelf-life and improve the quality of a biofertilizer.

Azolla pinnata is a small floating fern which widely occurs in certain regions such as Southeast Asia. Azolla is utilized in the new plant research on the currently existing products for soilless growth media. Soilless growth media are an alternative component to replace soil for cultivation uses. In urbanization scenario nowadays, most of the flatten open-area soil is used for development, affecting the soil supply for plants. To introduce a new component such as the soilless growth media, it must have the same or more nutrients than soil or other existing soilless growth media. A study found that Azolla is used as a soilless growth media in the nursery for olive trees cultivation. According to the study, the nutrients obtained from Azolla are sufficient to replace soil as a growth media. In this experiment, the Single Dry Ashing, and Kjeldahl and Dummas methods were used to evaluate and compare both macro and micronutrients of Azolla to Midorie Pafcal and Jiffy-7 pallets. Based on the results, the values were 0.94 % (N), 4352.00 ppm (P), and 563.13 ppm (K); compared to 1.35% (N), 377.13 ppm (P), 1512.33 ppm (K); and 0% (N), 563.13 ppm (P), 1343.67 ppm (K), respectively. The results also showed the values of Copper (Cu), Iron (Fe), and Zinc (Zn) for Azolla, Midorie Pafcal and Jiffy-7 samples were 15.33 ppm (Cu), 2579.67 ppm (Fe), 93.63 ppm (Zn); 7.53 ppm (Cu), 9988.33 ppm (Fe), 26.77 ppm (Zn); and 13.01 ppm (Cu), 1150.30 (Fe), 12.40 ppm (Zn), respectively. In conclusion, Azolla pinnata is capable of providing the nutrients required for a plant, making it suitable as a soilless growth media for all plants.

Indole-3-acetic acid (IAA) phytohormone plays an essential role in forming and initiating main, lateral, and adventitious roots in vegetative propagation. Plants are receiving IAA naturally from a diverse group of soil-plant associated rhizobacteria. However, IAA synthesis by rhizobacteria is influenced by abiotic growth conditions. Three indigenous Bacillus isolates were subject to in vitro assay for the effects of abiotic factors (temperature, salinity and pH) on growth and IAA production. All isolates grew well between 25 - 40°C, and only B. megaterium UPMLH3 was capable of synthesising IAA (21.18 µg/ml) at 40°C. All three bacterial growth under saline stress were slightly dropped over control (0% NaCl), but still producing IAA up to 1% NaCl condition. B. cereus UPMLH24 revealed high resistance to salinity up to 5% NaCl. The optimum growth of all three Bacillus spp. was at pH 7. B. cereus UPMLH1 and UPMLH24 discovered higher IAA production in slightly alkaline conditions (pH 8). Each rhizobacterium shows different physiology trait against each abiotic factor. However, the multiple tolerance ability of PGPR against abiotic factors is an indication that its ability to survive under harsh soil and plant environments while delivering benefits to the plant. Thus, B. cereus UPMLH1, B. megaterium UPMLH3 and B. cereus UPMLH24 might serve as potential biofertiliser, enhancing the growth performance of test plants at various environmental conditions.

A field investigation was conducted in a Fusarium-infected area to evaluate the effectiveness of silicate compounds with antagonist bacteria on morpho-physiological growth performance in bananas. The roots of banana plants were treated by drenching the soil with four different treatments: control (without any treatment), CBZ (Carbendazim fungicide alone), SS + BS (integration sodium silicate with Bacillus subtilis), and CBZ + SS + BS (integration CBZ, SS, and BS). All treatments were arranged in a randomized complete block design with four replications. The results confirm that plant height, pseudo-stem diameter, and canopy diameter markedly increased from weeks 2 to 10 after transplantation. Amendment with these elements induced a higher total chlorophyll content, which contributed to the increased rate of leaf gas exchange and biochemical changes for controlling Fusarium wilt disease infection. From these findings, the CBZ + SS + BS application in the farm had significantly reduced disease incidence by 16.07% and disease severity by 14.28%. The same treatment achieved the greatest disease reduction by 63.05%. Therefore, the integration between CBZ + SS + BS had good significant effects in controlling Fusarium wilt disease and enhanced the morpho-physiological growth performance with an average yield production of about 24.72 kg per fruit bunch.

Acid soil is an obstacle to agricultural development and a concern regarding food and environmental security. Therefore, a study was carried out for two consecutive years to see how lime and organic manure (OM) amendments affect yield and nutrient absorption in the Transplanted (T.) Aman–Mustard–Boro cropping pattern in an acidic terrace soil. With nine treatments and three replications, the experiment was set in a randomized complete block design. The treatments were applied to the first crop, T. Aman, with different dosages of lime (dololime at the rate of 1 and 2 t ha−1), OM (cow dung at 5 t ha−1, poultry manure at 3 t ha−1) and lime–OM combination, and their residual effects were studied in the following mustard and boro rice crops. Results demonstrate that the effect of lime and manure was more pronounced in the case of the second and third crops in the first year and of all crops in the pattern in the second year. In the first year, grain and straw yield of T. Aman as well as the overall system productivity were not influenced significantly by the application of lime and manure, but significant increases were obtained in the second year. As an average of both years, the highest grain yield of 5.2 t ha−1 (12% over control) was recorded for T. Aman, 1.7 t ha−1 (41% over control) for mustard and 5.9 t ha−1 (47% over control, 3.9 t ha−1) for boro rice when dololime was applied in combination with poultry manure. In both years, N, P, K and S uptake were significantly increased compared to the control in all the crops due to the combined application of lime and cow dung or poultry manure. Combined application of lime and manure amendment significantly improved nutrient availability and soil quality. Therefore, applying lime in combination with manure can be practiced to uplift crop productivity in acidic terrace soils.

Co-composting is an effective approach to biowaste management. The co-composting potential of banana pseudostem (BPS) and mushroom media waste (MMW) with chicken manure (CM) has not been explored, let alone their suitable ratios of co-composting being determined. Meanwhile, the imbalance ratios of the feedstocks used in the process severely restrict the physicochemical properties and quality of the finished product. For this reason, six different ratios of BPS, MMW, and CM, viz. 1:1:1, 1:2:1, 1:3:1, 2:1:1, 2:2:1, and 2:3:1, respectively (T1–T6), were composted together in aerobic conditions to identify the suitable ratio by evaluating the changes in the physicochemical properties in the composting process. According to the ratio of treatments, the feedstocks were mixed on fresh weight basis. The turning process of co-composting piles was repeated at seven-day intervals to maintain the uniform aeration throughout the composting period. The piles having BPS, MMW, and CM at ratios of 1:2:1, 1:3:1, and 2:3:1, respectively, demonstrated a longer thermophilic phase, indicating more complete decomposition and earlier maturity compared to piles with higher amount of BPS. Of the ratios, BPS:MMW:CM at 1:2:1 ratio (T2) resulted in the highest total nitrogen (1.53%), lowest C:N ratio (12.4), organic matter loss (54.5%), and increased CEC (41.3 cmol/kg). The highest germination index (129%) was also recorded in the T2 compost, indicating that it was toxic-free and safe for seed germination. The nutrient-rich compost with high alkaline pH (≥10) can effectively ameliorate soils of an acidic nature, for example, the acidity of Ultisols and Oxisols.

Most plants require soil as a growth media. Soilless media has been introduced to overcome the lack of soil for plant cultivations. An Azolla cube was developed as soilless growth media with nutrient-rich and water-storing capabilities through the usage of Azolla pinnata sp. Azolla cube is a new research product, providing an alternative to the existing products, such as Midorie Pafcal and Jiffy-7 pellets. This research introduced four samples of Azolla cubes at different formulations to evaluate the performance of the cubes on water absorption, water loss, and water retention. This product was developed by using two types of binder method: tapioca starch (Cassava starch) and Bentonite clay. Based on the results, sample C held an estimation of 5.94 g ± 0.01 of 10 g of water within 6 hours at room temperature while that of Sample A, B, and D was 5.45 g ± 0.01, 3.37 g ± 0.01, and 4.70 g ± 0.01, respectively. Sample C also lost an estimation of 2.56 g ± 0.01 of water within 2 days of observation. The results also showed that sample C had the highest percentage of moisture content (15.4%) after undergoing four stages of applied pressure, 0 kPa, 1 kPa, 33 kPa, and 1500 kPa, for the water retention test, in which the value of water movement remained constant. In conclusion, Azolla cube was shown to be capable of providing the nutrients needed for plants and absorbing more water compared to the current products.

This study was conducted to (i) Determine dry matter production, nutrients concentration, nutrients uptake and use efficiency of Zea mays by including clinoptilolite zeolite in the fertilization program of Zea mays planted on an acid soil and (ii) Determine the effect of including Clinoptilolite zeolite in the fertilization program of Zea mays on selected chemical properties of an acid soil. The effect of Clinoptilolite zeolite application with 75% of fertilizers (C2) and 100% fertilizers (C1) on soil chemical properties were statistically similar. Similar observation was made for dry matter production, nutrients concentration, nutrients uptake and nutrients use efficiency. These suggest that substituting 25% of N, P and K fertilizers with Clinoptilolite zeolite is more beneficial compared to 100% application of these fertilizers. Clinoptilolite zeolite strong affinity for monovalent cations ensured timely availability of P by exerting more soil exchange sites to occupy Al3+ and Fe2+.

Ammonia volatilization from urea and ammonium containing compound fertilizers cause higher cost of fertilization in agriculture. In this study, an incubation experiment was carried out to compare the effect of different ratios of compound fertilizer amended with clinoptilolite zeolite on NH3 volatilization, soil exchangeable NH4 and available NO3 contents on Bekenu Series (Tipik Tualemkuts) with surface-applied urea without additives. Treatments with zeolite significantly reduced NH3 loss when compared with urea without addictives. They also improved retention of exchangeable NH4 and NO3 and this was possible because zeolite favoured formation of ammonium and nitrate over ammonia. There is a potential for compound fertilizer with zeolite to improve nitrogen efficiency by lowering ammonia volatilization and increasing accumulation of exchangeable NH4 and NO3. Key words: Ammonia volatilization, compound fertilizers, clinoptilolite zeolite, soil exchangeable ammonium, available nitrate.

Problem statement: Exchangeable ammonium (NH4+) could be recovered by humic and fulvic acids from humic substances. The ability of these acids in fixing or retaining NH4+ has been demonstrated in many findings and reports. Both acids could affect the plant growth, nutrients uptake by enhancing photosynthesis rate and root growth among others. Thus, in this study, the effect of both acids (in liquid form) on soil exchangeable NH4+, dry matter production and available nitrate (NO3-) was investigated. Approach: Humic molecules were isolated using standard procedures, followed by liquid organic N fertilizers formulation. Organic based N fertilizers were applied to soil in pots at 10 Days After Planting (DAP) and 28 DAP. Treated soils and plant parts were sampled at 54 DAP or at tasselling stage. Soil samples were analyzed for pH, ammonium and nitrate content. The plant samples were weighed to assess dry matter production. Results: Under acid condition, organic based liquid N fertilizers (fulvic acid or both, humic and fulvic acids) increased accumulation of NH4+in soil. The presence of carboxylic groups in humic molecules increased NH4+ retention with increasing soil's stock labile carbon. However, low percentage of these acids reduced their full effect on dry matter production. The availability of nitrate was not statistically different for all treatments. Low soil pH could had reduced nitrification processes and simultaneously soil NO3- content. Conclusion: Liquid form of humic and/or fulvic acids could play an important role in enhancing urea efficiency. However, their contribution needs to be studied in detail in relation to humic molecules characteristics. This study had a potential in the development of liquid and foliar organic fertilizers.

Problem statement: Fertilizer N use efficiency is reduced by ammonia volatilization. Under low soil CEC and high pH, N from soil solution is released to the atmosphere. Ammonia loss due to low worldwide N use efficiency (33%) has been implicated in global warming. Thus, the objectives of this laboratory study were to evaluate the effectiveness of liquid humic and fulvic acids, isolated from tropical peat soils in reducing N loss from urea fertilizer as well as to investigate the ability of these acids to retain NH4 + and NO3 ¯ or reduce soil pH. Approach: Formulated liquid N fertilizers consisting of urea and different types of humic molecules (HA or FA or mixture of both), solid and liquid urea were surface applied to 250 g of soil. A closed dynamic air flow system was used to trap NH3 loss in boric acid after which samples were titrated with 0.01 M HCl to estimate NH3 loss. After 30 days of incubation, the soil was air dried and analysed for pH, exchangeable NH4 + , available NO3 ¯ and exchangeable cations. The results were analysed using SAS and treatments means were compared using Duncan's New Multiple Range Test (DNMRT). Results: The use of humic molecules reduced NH3 loss and increased exchangeable NH4 + . The high CEC of Humic Acids (HA) made the LHA treatment the best in reducing N loss after surface application. The presence of HA and Fulvic Acids (FA) increased NH4 + recovery. Even though, the soil pH of all the treatments were high, significant reduction of N loss was observed for humic molecules treatments. Conclusion: The use of liquid organic N fertilizer has the ability to reduce NH3 volatilization in acid soil. The use of both humic and fulvic acids could be effective in promoting NH4 + retention. Thus, it can be concluding that, humic substances, in general, have great ability in controlling NH3 loss and retaining NH4 + in acid

The objectives of this study were: To investigate whether a purification period of HA isolated from Hemists peat soils could be reduced and to investigate whether distilled water could be used to purify HA isolated from Hemists peat soils. Standard procedures were used to extract and fractionate HA in a Hemists peat soil. The isolated HA was purified by suspending the HA 50 mL distilled water, centrifuged for 10 minutes, supernatant decanted and the liquor analyzed for K, Ca, Mg and Na by atomic absorption spectrophotometry. The entire procedure was repeated five times after which the purified HA samples were oven dried at 40ÂoC to a constant weight. Washing HA for 5 consecutive times (10 min for each washing) reduced the ash (mineral matter) content of the HA to an acceptance level of 2%. This finding was associated with significant decrease in K, Ca, Mg and Na contents with increased washing time. This observation also suggests that the distilled water used during the purification process served as Bronsted-Lowry acid thereby donating more H+ which may have replaced some of K+, Ca2+, Mg2+ and Na+ at the exchange sites of the HA. The C, carboxylic COOH, phenolic OH, total acidity and E4/E6 values of the purified HA were consistent with standard values, a further indication of the effectiveness of using distilled water in purifying HA from Hemists peat soil. Humic acids isolated from Hemists peat soil can be purified within one hour using distilled water without altering the true nature of HA.

The isolation of humic acids from soils is laborious and time consuming. Factors that affect the yield of humic acids isolated from soils include extraction, fractionation and purification periods. This study was conducted to investigate whether a relationship could be separately established between extraction time, fractionation time, and the yield of humic acids of a tropical peat soil (Hemists), as well as the relationship between both variables on the yield of humic acids of this soil. Modified standard procedures using 0.1 M KOH were used to isolate humic acids from a tropical peat soil. Even though there was a quadratic relationship between extraction period and yield of humic acids, there was no relationship between fractionation period and yield of humic acids. There was negative correlation between the yields of extraction and fractionation periods. This finding enables the isolation of humic acids of Hemists in less than 10 h instead of the existing average period of 48 h, therefore helping in facilitating the idea of producing for instance ammonium-humate or K-humate (N and K foliar organic fertilizers) from peat soils.

Ammonia volatilization is a direct loss of available nitrogen in agriculture. The objective of this study was to determine the effect of amending NPK fertilizer with different rates of clinoptilolite zeolite on ammonia volatilization, soil exchangeable ammonium, and available nitrate. Seven treatments evaluated were: 250 g soil alone (T1), 3.28 g ammonium nitrate (AN) without additive (T2), 44.6 g 5:3:2 formulated fertilizer + 31.77 g zeolite (T3), 44.6 g 5:5:5 formulated fertilizer + 26.36 g zeolite (T4), 37.17 g 6:6:6 formulated fertilizer + 18.92 g zeolite (T5), 22.30 g 10:10:10 formulated fertilizer + 4.06 g zeolite (T6), and 14.87 g 15:15:15 commercial fertilizer (T7). The ammonia loss was measured using close-dynamic air flow system method. Soil pH, exchangeable ammonium and available nitrate at the end of this study were determined using standard procedures. The mixture of formulated fertilizer and zeolite significantly reduced ammonia volatilization. Zeolite in the formulated compound fertilizers did not significantly affect soil exchangeable ammonium and available nitrate. Amending N, P, and K compound fertilizer could minimize ammonia loss. Keywords: Ammonium nitrate, zeolite, ammonia volatilization, soil exchangeable ammonium, soil available nitrate

Application of crude humin with urea and Egyptian rock phosphate (ERP) may reduce ammonia loss from urea. This study was conducted to determine the effect of mixing crude humin with urea and ERP on ammonia volatilization and selected soil chemical properties. Crude humin from four different composts was mixed with urea and ERP and ammonia loss from these treatments were evaluated using the closed-dynamic air flow system. Standard procedures were used to determine ammonia loss, soil pH, total nitrogen, exchangeable ammonium, available nitrate, exchangeable phosphorus, cations, organic matter, total organic carbon and cation exchange capacity. Amending urea with crude humin had no effect on total amount of ammonia loss. However, addition of the crude humin significantly increased pH, organic matter, total organic carbon, cation exchange capacity (CEC) and exchangeable cations of Bekenu series (Tipik Tualemkuts). Crude humin from selected waste compost can be used to improve soil chemical properties.

Insufficient supply of P for initial growth of crops does not only limit N uptake but it also leads to poor yield of crops. In acidic soils of the tropics, sorption of P occurs mainly on surfaces of Fe and Al oxides and hydroxides. Most of the P added through mineral fertilizers is fixed by high Al and Fe oxide concentrations and transformed into insoluble P compounds. Reduction of Al and Fe is important so as to ensure adequate supply and readily available P for crops uptake. A number of studies using zeolites as an amendment in the fertilization programs of crops have improved crops production, nutrients uptake, and nutrients use efficiency. However, there is dearth of information on the use of clinoptilolite zeolite (CZ) to reduce P fixation not to mention reduction of N, P, and K fertilizers use in agriculture. This study was conducted to: (i) determine dry matter production, nutrients concentration, nutrients uptake, and use efficiency of Zea mays (Hibrimas variety) by including CZ in the fertilization program of Zea mays planted on an acidic soil, and (ii) determine the effect of including CZ in the fertilization program of Zea mays on selected chemical properties of an acidic soil. Egypt rock phosphate (ERP), urea, and muriate of potash were used in this study. Seventy five percent (w/w) of the recommended N, P, and K fertilizers for Zea mays were combined with CZ. Standard procedures were used to determine soil pH, inorganic nitrogen, available phosphorus, exchangeable aluminium, iron, potassium, calcium, magnesium, and organic matter before and after planting. Zea mays were harvested at tasselling stage and measured for dry matter production, nutrients uptake and use efficiency. The effect of CZ application with 75% of fertilizers (E2) and 100% fertilizers (E1) were statistically similar for selected soil chemical properties, dry matter production, nutrients concentration, uptake of nutrients, and nutrients use efficiency except for N. Nitrogen use efficiency for E2 was better than that of E1. These findings suggest that adoption of CZ with 25% reduction of N, P, and K fertilizers are useful. Further field trials and economic analysis are recommended to confirm the findings of this study. These aspects are being investigated in our on-going field experiments.

Excessive uses of fertilizer can create environmental problems such as soil pollution. This problem could be reduced by amending clinoptilolite zeolite with compound fertilizers. The objective of this study was to evaluate the effect of clinoptilolite zeolite rates in compound fertilizers (N: P: K) on maize nutrients uptake and use efficiency. The following treatments were considered and evaluated: soil alone (T1), 44.6 g 5:3:2 formulated fertilizer (12.83 g compound fertilizer + 31.77 g zeolite) (T2), 44.6 g 5:5:5 formulated fertilizer(18.24 g compound fertilizer + 26.36 g zeolite) (T3), 37.17 g 6:6:6 formulated fertilizer (18.25 g compound fertilizer + 18.92 g zeolite) (T4), 22.30 g 10:10:10 formulated fertilizer (18.24 g compound fertilizer + 4.06 g zeolite) (T5), and 14.87 g 15:15:15 commercial fertilizer (T6). Selected soil chemical properties, as well as, dry weight, nutrients concentrations, uptake and use efficiency were measured. Compound fertilizers with zeolite increased soil pH compared to soil alone (T1) and commercial fertilizer (T6). Application of compound fertilizer did no significantly affect total N and available nitrate in the soil. T6 gave better plant height and dry matter production among treatments. Nitrogen concentrations for all plant parts were similar for all treatments. T6 showed better P concentrations, uptake, and use efficiency. K concentrations in maize plant parts were significantly increased for treatments with zeolite except for roots. T5 and T6 significantly increased K uptake. T6 significantly increased N and P uptake and use efficiency, while T2 significantly increased K use efficiency. Amending N, P, and K fertilizers with higher dosage of clinoptilolite zeolite improved soil chemical properties, nutrient uptake of Masmadu variety. Compound fertilizers amended with clinoptilolite zeolite enhanced K use efficiency of Masmadu maize variety.

Adoption of new management techniques, such as clinoptilolite zeolite (CZ) utilization has attracted muchattention in the fertilizer industry. Accordingly, the aims of this study is to evaluate: if CZ, acting as an inertmaterial, when applied to the soil, might improve the selected soil properties, height, dry matter, nutrientconcentration, nutrient uptake, nutrient use efficiency on maize cultivation; the potential for (N:P:K) compoundfertilizer when incorporated with CZ to serve same standard as the commercial fertilizer in fertilizer industry.The effect of T1, T3 and T6 on soil total N was found to be significant, when compared with T7. Treatments withCZ on soil total P, K and available P, K differed significantly relatively to T1 and T7. The treatments T5 and T6had the highest accumulation of exchangeable NH4+ and available NO3- relatively to T1 and T7. The significanteffect of the treatments having CZ on N concentration, in uptake and use efficiency, suggests that CZincorporated with fertilizer can reduce NH3 loss, triggering the formation of NH4+ and NO3- over ammonia andincrease maize uptake. Relatively to P concentration, uptake and use efficiency, it was found that in mosttreatments having CZ, lower values were obtained, relatively to the commercial fertilizer, although T3 clearlyimproved P uptake in roots. Most of the treatments with CZ remained statistically similar in K concentration,uptake and use efficiency compared to commercial fertilizer. It may be concluded that treatments with higheramounts clinoptilolite zeolite ensured good retention of soil exchangeable cations, available P, and NO3- withinthe soil. Treatments with CZ improved N uptake and use efficiency in the maize crop tested.