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Currently, there is an abundance of interest in the methods to reduce ammonia (NH3) volatilization and nitrous oxide (N2O) emissions from cultivated soils. Nitrogen use efficiency (NUE) of applied urea is decreased due to gaseous loss, which also lowers soil N (Nitrogen) content. The purpose of this study was to investigate the potential of microbial-based inoculants to decrease NH3 loss and N2O emissions under controlled conditions. Bacillus subtilis ;(UPMB10), and Bacillus tequilensis ;(UPMRB9) in combination with five different nitrogen (N) fertilizer levels 0%, 25%, 50%, 75%, and 100% were used in this study. Results showed that NH3 cumulative volatilization loss was greater in uninoculated soil treated with a full dose of fertilizer-N (507.27 mg/kg) compared with bacterial-inoculated soil (491.20 mg/kg and 500.71 mg/kg for UPMRB9 and UPMB10, respectively). Emission of N2O increased to a greater level (15.11 mg/kg for B0N100) in uninoculated soil compared to inoculated soil (14.65 mg/kg for UPMRB9N100 and 14.93 mg/kg for UPMB10N100-treated soil) and emission of N2O increases as N application increases. Initially, the emission of N2O was greater which decreased from the sixth day until it became zero. In B0N100-treated soil, emissions of N2O increased and after 30 days of incubation, the inoculated soil had a greater N concentration than the uninoculated soil. The total N loss from applied urea was higher in uninoculated soil than in inoculated soil. According to the findings, microbial inoculants have the potential to reduce the loss of N through NH3 volatilization and N2O emissions. [ABSTRACT FROM AUTHOR]

This study aimed to verify the effect of Plant Growth-Promoting Rhizobacteria (PGPR) and humic acid amendment with different N-fertilizer rates on sweet potato. The results showed that inoculation of UPMRB9 in combination with 50% fertilizer-N produced significantly higher dry matter (DM) in leaves, storage, and fibrous roots, and in the whole plant. Similar trends were observed for nitrogen use efficiency (NUE), in which 75% N+UPMB10 and 50% N+UPMRB9 treatments significantly produced higher efficiency by 44.89% and 40%, respectively. In addition, the highest OD of β-carotene, 0.71 and 0.68 mg g-1, were observed in 50% N+UPMRB9 and 75% N+UPMB10, respectively. Sweet potato plants obtained greater NUE and N uptake when lower rates of N were used with the microbial inoculations. These findings show the ability of PGPR-HA to fix nitrogen and thereby increase N availability of soils, reducing the need to provide mineral nitrogen to crops. Thus, applying biofertilizer containing PGPR amended with humic acid could be a sustainable approach to improving the NUE and total N concentration of sweet potato plants. Higher N use efficiency will lead to savings in the amount of N fertilizer needed, thus reducing costs and promoting an eco-friendly approach at the same time. [ABSTRACT FROM AUTHOR]

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 shelflife 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. [ABSTRACT FROM AUTHOR]

Background: Bambara groundnut is an edible legume that is highly nutritious. This study was carried out to find the effect of nitrogen (N) and phosphorus (P) fertilizers on the growth, yield, nodulation, the proximate and nutritional composition of bambara groundnut [Vigna subterranea (L.) Verdc.]. Methods: During the period of 2018, a glasshouse experiment was conducted in a randomized complete block design (RCBD) at Ladang 15, Faculty of Agriculture, Universiti Putra Malaysia. Different rates of N and P fertilizer were used. Kjeldahl method and HPLC, respectively, determined the protein and amino acid content in seed. Result: N and P fertilizer were found to play a dominating role in increasing the vegetative growth and yield of the plant. Plant height (20.65a), pod number (45.75a) and harvest index (41.61a) increased significantly with the application of N30 + P60 kg ha-1. Application of N30P60 kg ha-1 significantly influenced nodulation and nitrogen yield. Protein, fibre, Mg and amino acid content increased with N30P60 kg ha-1. The application of N30P60 mg kg-1 has increased the growth, yield, nodulation, proximate and nutritional composition of bambara groundnut. [ABSTRACT FROM AUTHOR]

A significant wastewater source in every household is washed rice water (WRW) because it contains leached nutrients (from washing the rice prior to cooking) that could be used as fertilizer. The paper reviewed the current understanding of the potential use of WRW as a plant nutrient source. WRW was shown to increase vegetables growth, such as water spinach, pak choy, lettuce, mustard, tomato, and eggplant. Different researchers have used various amounts of WRW, and their results followed a similar trend: the higher the amount of WRW, the higher the plant growth. WRW has also been used for other purposes, such as a source of carbon for microbial growth. WRW from brown rice and white rice had nutrients ranging from 40-150, 43-16306, 51-200, 8-3574, 36-1425, 27-212, and 32-560 mg L-1 of N, P, K, Ca, Mg, S, and vitamin B1 (thiamine), respectively. Proper utilization of WRW could reduce chemical fertilizer use and prevent both surface and groundwater contamination and environmental pollution. However, only a few of the studies have compared the use of WRW with the use of conventional NPK fertilizer. The major drawback of WRW studies is that they lack depth and scope, such as determining the initial and (or) final soil physico-chemical properties or plant nutrient contents. Considering the rich nutrient content in WRW, it will impact plant growth and soil fertility when used as both irrigation water and plant nutrient source. Therefore, it is recommended that studies on WRW effect on soil microbial population, plant, and soil nutrient contents to be carried out to ascertain the sustainability of WRW use as a plant nutrient source. [ABSTRACT FROM AUTHOR]

Bambara groundnut (Vigna subterranea) has characteristics to grow in the marginal soil and also tolerant into the drought condition and also have potential of nitrogen fixation. Nitrogen is the key plant nutrient that stimulates root and shoot growth. Phosphorus application significantly improves many aspects of plant physiology including photosynthesis, flowering, fruiting and maturation which ultimately result in better yield. Symbiotic nitrogen fixation is a complex process, in which Rhizobium bacteria form a beneficial interaction with a legume crop to fix atmospheric nitrogen and convert it to ammonium for plant uptake. Biological N fixation (BNF) is the natural means to enhance soil fertility status and productivity. Application of nitrogen and phosphorus fertilizer exerted significant effect on root development, photosynthesis, yield contributing character and pod yield of the crop. Bambara Groundnut yields are low due to abiotic and biotic stresses. But with application of nitrogen and phosphorus increase the yield of this crop. It's seeds contain 63 percent carbohydrate, 19 percent protein and 6.5 percent oil and good source of fibre, calcium, iron and potassium. [ABSTRACT FROM AUTHOR]