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Brinjal is the second most important vegetable crop after Tomato in relation to its total production. Better production from any crop can only be achieved from a better variety. But in most cases the producers especially the rural farmers are not aware about the selection of high yielding varieties. Without any justification they just buy those seeds are easily available in nearby shops resulting harvest a poor yield with very unsatisfactory return. In this regard five different brinjal (Solanum melongena L.) germplasm collections were evaluated for their major yield and yield contributing attributes along with total chlorophyll content as physiological parameter. The study was conducted in rain shelter 10, at the Faculty of Sustainable Agriculture, Universiti Malaysia Sabah, arranged in Complete Randomized Design (CRD) with five replications. Research findings revealed significant variations for all the measured parameters among different brinjal cultivars. Round purple brinjal (V1=Mte2) had the highest fruit weight (238.60g; which is about 88.14% increased fruit weight over V4), followed by long red purple brinjal (V2=H117) with 167.50g (about 83.10% increased fruit weight over V4), long green brinjal (V3=H249) with 119.70g (about 76.36% increased fruit weight over V4) and the lowest fruit weight (28.30g) was found in brinjal variety V4 (Telunjuk), respectively. On the other hand red purple brinjal (V2) was the longest (24.23 cm) in size with 5.60 cm in diameter, but the highest fruit diameter (12.24 cm) was recorded in V3 brinjal. Long red purple brinjal (V2) showed the shortest days to 50% flowering with 49 days compared to Kermit brinjal (V5) which took the longest 61 days to 50% flowering. The highest total leaf chlorophyll content was detected in V5 (51.02 nmol/mg) while the lowest (44.06 nmol/mg) was in V3. From the correlation analysis significant correlation were detected among days to 1st flowering and days to 50% flowering; plant height and fruit diameter, while significant but negative correlation was seen among numbers of leaves and fruit diameter; plant height and fruit weight with chlorophyll content. From the cluster analysis primarily; V1, V2, and V3 were grouped into one cluster while V4 and V5 into another clusters, while in secondary clustering V1 alone in one group, V2 and V3 in 2nd group and finally V4 and V5 were in third groups which indicated a significant diversity among cultivars. On an average; considering varietal performance for yield and yield contributing attributes of five (5) different brinjal cultivars, it was revealed that the fruits of V1 gained the highest weight, while the fruits of V2 had the highest length and the fruits of V3 gained the highest diameter. Regarding earliness; variety V2 was the earliest among all 5 varieties, which is one of the desirable characteristics for any crops; especially in vegetables.

Excessive N fertilizer use in agriculture results in the release of inorganic N contaminants into surface and groundwater bodies, and other negative environmental effects. The combined application of N fertilizers with charcoal and sago bark ash could help reduce these negative impacts. The objective of this sorption study was to examine the effects of the co-application of charcoal and sago bark ash with ammonium chloride in regulating the adsorption and release of NH4+ in an acid soil. This soil used in the laboratory study was Bekenu series (Typic Paleudults). The treatments evaluated were: (i) 300 g soil only, (ii) 300 g charcoal only, (iii) 300 g sago bark ash only, (iv) 300 g soil + 15.42 g charcoal, (v) 300 g soil + 7.71 g sago bark ash, and (vi) 300 g soil + 15.42 g charcoal + 7.71 g sago bark ash. Regardless of the concentration of the isonormal solution, sago bark ash (T3) showed the highest NH4+ adsorption at equilibrium (Qe) and NH4+ desorbed (Qde). The results for T3 for Qe and Qde were 3.88 mg L−1 and 3.80 mg g−1, respectively, for the 400 mg N L−1 isonormal solution followed by T2 with values of 3.46 mg L−1 and 3.30 mg g−1, respectively. For treatments T2 and T3 that resulted in higher Qe and Qde for NH4+, soil was not included. However, in practical terms, any of the treatments T4, T5 and T6 that included mixing the amendments with soil are better since the results of these treatments were not significantly different in terms of Qe and Qde for NH4+. This is despite the fact that T4, T5 and T6 resulted in lower Qe and Qde for NH4+ compared to T2 and T3. The results also showed a positive linear relationship between NH4+ adsorption and the addition of N. This indicates that NH4+ can be retained temporarily by the amendments. The insignificant R2 (ranging from 0.10 to 0.38) of the Langmuir regression equations suggest that the NH4+ adsorption data did not fit the Langmuir isotherms well. Future studies could explore fitting the NH4+ sorption data into other sorption models. The higher adsorption of NH4+ by the treatment with charcoal is related to its high number of adsorption sites or negative charges of these materials. Incorporating charcoal and sago bark ash as soil amendments in agriculture has the potential to reduce the usage of chemical fertilizers. The reliance on commercial lime could also be reduced due to the alkaline characteristics of these materials. Therefore, the co-application of charcoal and sago bark ash could contribute to improve the utilization of N fertilizer by effectively controlling NH4+ availability for timely crop use, reducing losses, and preventing soil and water pollution.

Efficient management of N fertilizers enhances crop yields and contributes to sustainable food security. Tropical acidic soils with high Al and Fe are prone to easy loss of basic cations, such as NH4+, via leaching and erosion. Appropriate soil amendments and agronomic practices minimize the loss of fertilizer nutrients, improve soil nutrient retention, and maximize their uptake by plants. This study aimed to evaluate the effects of co-applying charcoal and sago bark ash with inorganic fertilizers on N availability, uptake, use efficiency, and dry matter production of sorghum in a tropical acid soil. The results revealed that the co-application of inorganic fertilizers with charcoal and sago bark ash increased sorghum plant height, dry matter production, N uptake and N use efficiency. The soil treated with a combination of 100% of the recommended rate of charcoal and sago bark ash (C1A1) resulted in significantly higher sorghum dry matter production, N uptake, and use efficiency compared with normal fertilization (U1). The C1A1 treatment resulted in significantly lower soil available N compared with U1. The C1A1 treatment enhanced the uptake of N by the sorghum plants, resulting in less available N in the soil after the experiment. Although the effects of co-applying charcoal and sago bark ash on soil total N were not glaring, this practice increased soil pH and total C, and reduced exchangeable acidity and Al3+. A long-term field study is recommended to confirm the effects of co-applying inorganic fertilizers with charcoal and sago bark ash on sorghum productivity, economic viability, and soil nutrient residual effects.

Sandy-textured soil infertility poses a problem for sustainable crop cultivation. This problem is usually dealt with by the addition of chemical fertilizers, which are expensive and can cause serious environmental issues if not managed well. A better alternative to improve and manage sandy soil infertility is the use of organic amendments produced from agro-wastes. This two (2)-year field study was conducted in a sandy-textured soil grown with black pepper to evaluate mainly the effects of chemical fertilizer, fermented plant and fruit juices, compost, and biochar on soil properties and morpho-physiological characteristics and yield of black pepper. Generally, the results indicated that the combination of fermented fruit juice, compost, and biochar was comparable to and in some cases better than chemical fertilizer in terms of soil physical, chemical, and biological properties as well as crop performance. These findings were even more pronounced in the second year of measurements. There were strong positive relationships between soil N and pepper leaf chlorophyll content and between soil microbes and soil respiration. The findings showed that these soil amendments produced from agro-wastes are a good alternative to the use of chemical fertilizers on sandy soils to improve soil fertility and productivity and the yield of black pepper sustainably.

In Malaysia, the main constraints of rice yield and productivity are infertile soils and poor management practices because these soils are characterized by low pH, low nutrient availability, low organic matter, and high exchangeable Al and Fe ions, due to high rainfall and hot temperatures. Thus, an incubation study was conducted to determine the optimum amount of calcium silicate (HmbG brand) to improve the soil pH, electrical conductivity (EC), exchangeable Al, available P, and cation exchange capacity (CEC) of a paddy soil in Sabah, Malaysia. The Kelawat series (Typic Dystrudept) soil was incubated with calcium silicate at the application rates of 0 (T1), 1 (T2), 2 (T3), and 3 t ha−1 (T4) using a Completely Randomized Design (CRD) in triplicates for 30, 60, 90, and 120 days. The calcium silicate used significantly improved soil pH because of the release of SiO44− and Ca2+ ions, which neutralized and immobilized H+ ions. Furthermore, the neutralizing effects of the amendment impeded Al hydrolysis by up to 57.4% and this resulted in an increase in the available P in the soil by 31.26% to 50.64%. The increased availability of P in the soil was also due to the high affinity of SiO44− to desorb P from soil minerals and it is believed that SiO44− can temporarily adsorb exchangeable base cations such as K+, Ca2+, Mg2+, and Na+. Moreover, applying calcium silicate at 3 t ha−1 improved soil CEC by up to 54.84% compared to that of untreated soils (T1) because of increased pH and the number of negatively charged sites. The most suitable application rate of the calcium silicate was found to be 3 t ha−1 (T4). These findings suggest that calcium silicate can improve soil productivity and agronomic efficiency in rice farming. Greenhouse and field trials are necessary to ascertain the effects of the recommended treatments of this incubation study on soil productivity, rice growth, and yield.

Inappropriate drainage and agricultural development on tropical peatland may lead to an increase in methane (CH4) emission, thus expediting the rate of global warming and climate change. It was hypothesized that water table fluctuation affects CH4 emission in pineapple cultivation on tropical peat soils. The objectives of this study were to: (i) quantify CH4 emission from a tropical peat soil cultivated with pineapple and (ii) determine the effects of water table depth on CH4 emission from a peat soil under simulated water table fluctuation. Soil CH4 emissions from an open field pineapple cultivation system and field lysimeters were determined using the closed chamber method. High-density polyethylene field lysimeters were set up to simulate the natural condition of cultivated drained peat soils under different water table fluctuations. The soil CH4 flux was measured at five time intervals to obtain a 24 h CH4 emission in the dry and wet seasons during low- and high-water tables. Soil CH4 emissions from open field pineapple cultivation were significantly lower compared with field lysimeters under simulated water table fluctuation. Soil CH4 emissions throughout the dry and wet seasons irrespective of water table fluctuation were not affected by soil temperature but emissions were influenced by the balance between methanogenic and methanotrophic microorganisms controlling CH4 production and consumption, CH4 transportation through molecular diffusion via peat pore spaces, and non-microbial CH4 production in peat soils. Findings from the study suggest that water table fluctuation at the soil–water interface relatively controls the soil CH4 emission from lysimeters under simulated low- and high-water table fluctuation. The findings of this study provide an understanding of the effects of water table fluctuation on CH4 emission in a tropical peatland cultivated with pineapple.

Increase in cost of chemical fertilizers encourages the use of soil amendments such as biochar and zeolites to improve soil fertility. In this study, biochar produced from empty fruit bunch-palm oil mill effluent (EFB-POME) and clinoptilolite zeolite were used as soil amendments to improve soil fertility. The field experiment was carried out for two planting cycles to determine the effects of different rates of EFB POME biochar (0, 10, and 20 t ha -1 ), clinoptilolite zeolite (0, 1.25, and 2.5 t ha -1 ), and urea (60 and 120 kg ha -1 ) on selected soil chemical properties of Tanjung Lipat ( Typic Paleudults ). Biochar produced from EFB-POME increase soil total N, P, K, Ca, and Mg. The higher soil total N, P, K, Ca, and Mg could be related to the increase in soil pH, cation exchange capacity, and total organic carbon in soil with EFB-POME biochar but not with clinoptilolite zeolite. Thus, EFB-POME biochar was more suitable to be used in a tropical soil ( Typic Paleudults ) compared to clinoptilolite zeolite for improving the selected soil pH, CEC, TOC and available P, K, Ca and Mg.

Sustaining soil health cannot be divorced from sustainable crop production. Organic, or natural, farming is being promoted as a good sustainable agriculture practice. One aspect of organic farming that could significantly enhance and sustain soil health, soil quality, and crop productivity is the use of high-quality soil conditioners or organic amendments produced from agro-wastes. Thus, the objective of this study was to characterize the chemical and biological properties of selected agro-wastes with potential for use as organic amendments in sustaining soil health. Standard procedures were used to produce and characterize the soil conditioners, namely fermented plant juice (FPJ), fermented fruit juice (FFJ), palm kernel shell (PKS) biochar, and kitchen waste (KW) compost. The fermented juices (FPJ and FFJ), PKS biochar, and KW compost exhibited chemical and biological properties with good potential as soil conditioners or organic amendments to sustain soil health. The fermented juices contained important microbes that can solubilize P and K in soil for crop use. The high pH and C content of the biochar and compost and the high cation exchange capacity of the biochar are good indicators of the potential of these materials to sustain soil health in terms of the liming effect of acid soils, nutrient and water retention, nutrient reserves, and a suitable habitat for microbial life. Moreover, the organic amendments contain reasonable amounts of macro- and micro-nutrients, which could be released to increase soil fertility. Despite these potential benefits, field application of these organic amendments is necessary to evaluate their effects on soil health and crop production in both the short and long term.

Using value-added products such as compost in farming systems could enable optimization of nitrogen (N) fertilizers whose world-wide demand is on the increase. The objectives of this study were to: (i) produce compost through co-composting rice husk (RH) with chicken dung slurry (CDS), chicken feed, and molasses, (ii) determine the effects of optimum rate of urea and RH compost on minimizing ammonia (NH3) volatilization, and (iii) determine total N, exchangeable ammonium (NH4+), and available nitrate (NO3−) retained in soil following co-application of urea and RH compost. Compost was produced for 60 days by mixing RH, CDS, chicken feed, and molasses at a ratio of 20:1:1:1. The color of RH compost was dark brown and had significant amounts of major nutrients such as N (1.15%), phosphorus (3101 mg kg−1), potassium (2038 mg kg−1), calcium (863 mg kg−1), magnesium (276 mg kg−1), organic matter (OM) (60.67%), organic carbon (35.17%), and humic acids (5.87%). The C/N ratio of the RH compost was 30. The electrical conductivity and pH of the RH compost were 2.79 µS cm−1 and 6.55, respectively, and they were not phytotoxic because paddy seeds were successfully germinated in all of the RH compost extractants. The high cation exchange capacity (CEC) of the RH compost (100.67 cmolc kg−1) at the end of composting was one of the determinant factors that controlled NH3 loss from urea. The effectiveness of the RH compost in minimizing urea-N loss was determined using a close-dynamic air flow system. The RH compost significantly minimized NH3 volatilization because of the high affinity of the RH compost for NH4+. An attestation of this reaction was that the high negative charges due to high CEC and OM of the RH compost temporarily protected NH4+ from being transformed into NH3 gas. Further evidence is the higher soil total N and exchangeable NH4+ for the treatments with RH compost than with urea alone. High quality compost can be produced from RH to reduce urea-N from being lost from urea. For the optimum rate, co-application of 60 g RH compost and 2.9 g urea per trough is recommended to mitigate NH3 volatilization instead of the existing practice (7.3 g urea alone per trough).

Numerous benefits of the system of rice intensification (SRI) have been documented since SRI was popularized 30 years ago. To date, more than 58 rice growing countries are practicing SRI, covering around 4 million ha of paddy fields and involving more than 10 million farmers. Many paddy farmers shy away from practicing SRI due to extreme labour endurance and number of labors required, especially during transplanting and frequent weeding. The manual transplanting technique to ensure proper root establishment of the seedlings, makes SRI less appealing to many paddy farmers. Furthermore, the transplanting shock is a problem arises from manual transplanting technique needs to be solved that resulted to damaged roots causing delays in crop establishment and reducing productivity. Mechanized transplanting of the young single seedlings into the paddy fields at a wider plantation area eliminates drudgery and enables better exposure to sunlight, water, air, and nutrients. This paper presents a solution to overcome the problem of transplanting shock and the back-breaking manual transplanting, which was achieved by containing the roots of each seedling in a grid of isolated cells. Several designs of the isolated cells to contain the root system were fabricated and tested. These include using aluminum square cells, polyvinyl chloride pipe circular cells, biodegradable grid cells, biodegradable conical capsules, and germinated seeds sowed in a grid without isolated cells. The typical grid cell size was 15 mm by 15 mm with a depth of each cell varied from 40 mm to 60 mm. The most promising design was one with single seedlings raised in bio-degradable capsules arranged close together to fit the conventional rice seedling tray of 300 mm by 600 mm and can accommodate 684 capsules per tray. Upon reaching 2-3 leaf stage, the seedlings with undisturbed roots are ready to be transplanted into the paddy fields using the currently available rice transplante rs.

Urbanisation and related insufficiency of food sources is due to the high urban population, insufficient urban food sources, and inability of some urban communities to afford food due to rising costs. Food supply can also be jeopardised by natural and man-made disasters, such as warfare, pandemics, or any other calamities which result in the destruction of crop fields and disruption of food distribution. The COVID-19 pandemic exposed the impact of such calamities on the fresh food supply chain in Malaysia, especially when the Movement Control Order (MCO) policy was first implemented. The resulting panic buying caused some food shortage, while more importantly, the fresh food supply chain was severely disrupted, especially in urban areas, in the early stages of implementation. In this regard, urban farming, while a simple concept, can have a significant impact in terms of securing food sources for urban households. It has been used in several countries such as Canada, The Netherlands, and Singapore to ensure a continuous food supply. This paper thus attempted to review how the pandemic has affected Malaysian participation in urban farming and, in relation to that, the acceptance of urban farming in Malaysia and the initiatives and approaches of local governmental and non-governmental organisations in encouraging the urban community to participate in urban farming through peer-reviewed journal articles and other articles related to urban agriculture using the ROSES protocol. About 93 articles were selected after screening to ensure that the articles were related to the study. During the COVID-19 pandemic, the surge in Malaysians’ awareness of the importance of urban farming has offered great opportunities for the government to encourage more Malaysian urban communities to participate in urban farming activities. Limitations such as relevant knowledge, area, and space, however, are impediments to urban communities’ participation in these activities. Government initiatives, such as the Urban Community Garden Policy (Dasar Kebun Komuniti Bandar (DKKB)), are still inadequate as some issues are still not addressed. Permanent Food Production Parks (TKPM) and technology-driven practices are seen as possible solutions to the primary problem of land and space. Additionally, relevant stakeholders play a crucial role in disseminating relevant and appropriate knowledge and methodology applicable for urban farming. Partnerships between government agencies, the education sector, and the private sector are necessary to develop modern urban agricultural technologies as well as knowledge, knowhow, and supports to build and sustain urban community participation in urban farming activities.

Patchouli (Pogostemon cablin Benth.) is a bushy herb native to the tropical region of Asia, and now cultivated for its essential oil usually used in perfume manufacturing. It also widely used throughout the world as treating skin conditions, relieving depression, controlling appetite, and antifungal agents. It also cultivated commercially in Tawau, Sabah for exporting purposes with average oil production up to 26-29 mt per acre in 2016. As they enter the second and third harvesting cycle, the yield started to decline and reach 2.6 mt of oil per acre. This drop-in yield is thought to be either due to soil variabilities, low nutrient levels in volcanic soil, and also diseases. Soil nutrient analysis and leaf coloration patterns are studied before conducting the study. Seaweed extract, banana peel, the mixture of Seaweed extract and banana peel, and pre-formulated 12-12-12 (N-P-K) organic fertilizer (PFF) fertilizer treatments were engaged in the Patchouli plot field experiment. Besides, the agronomical practice for the cultivation of Patchouli is well studied or documented. The pre-study showed that the study plot has a very low conductivity level, a very low level of organic Carbon and low Cation Exchange Capacity (CEC) level. Meanwhile, there were no diseases or nematode occurrences in the area. Plant height, soil pH, and soil conductivity were studied with all the four treatments that have shown a positive significant impact compared with standard estate practice. The treatments using seaweed and seaweed mixture had the highest significant level for soil conductivity with the conductivity improve from 43 to 480 micro Siemens (μS/cm) but it reduces the soil pH. Whereas, plant height data analysis showed that the seaweed mixture was significantly different compared with other treatments at a 0.05 level. Hence, we recommend the Patchouli plantation to use organic fertilizers especially seaweed-based since it is cheap and easily available in Sabah.

High nitrogen use efficiency (NUE) is important for improving crop yield. There are many nitrogen (N) fractions in soil and their uptake by crops varies. Most of the N that is taken up by plants is not native to the soil but usually from fertilizer added to the soil. However, the unbalanced use of fertilizers is currently an important issue that needs to be addressed. The objectives of this work were to determine the effects of using the recommended chemical fertilizers together with inorganic and organic amendments on (i) soil organic and inorganic N fractions, (ii) N uptake and use efficiency, and (iii) maize (Zea mays L.) dry matter production and ear yield. A randomized complete block design field trial, using maize as a test crop, was done with seven fertilizer treatments, each replicated thrice for two crop cycles. The treatments included different combinations of urea N, clinoptilolite zeolite (CZ), rice straw compost, and paddy husk compost. The variables of the study were soil N fractions, ear yield, and N use efficiency. Generally, the combined use of the recommended chemical fertilizers with CZ and organic amendments resulted in significantly higher soil N fractions, N use efficiency, and ear yield of maize for both crops. The two treatments with a 50% reduction in recommended chemical fertilizers, CZ, and rice straw compost or paddy husk compost (treatments four and six) are recommended instead of the 100% recommended chemical fertilizer treatment (treatment one). The organic materials used for these two treatments are abundantly available and will reduce the economic and environmental costs of applying large quantities of chemical fertilizers alone.

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.

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.

Soil acidity compromises agricultural output in tropical acid soils. Highly weathered tropical acidic soils are characterized by low pH, organic matter, nutrient availability, but high aluminium and iron concentration. Hence, N availability becomes a limiting factor in such soils. To this end, these leaching and pH buffering capacity studies were conducted to determine the effects of co-application of charcoal and sago bark ash on the N leaching or retention and pH buffering capacity of acid soils. The soil leaching experiment was conducted for 30 days by spraying distilled water to each container with soil such that the leachates were collected for analysis. The rate of urea used was fixed at 100% of the recommended rate. The rates of charcoal and sago bark ash were varied by 25%, 50%, 75%, and 100%, respectively, of the recommended rates. The pH buffering capacity was calculated as the negative reciprocal of the slope of the linear regression. The leaching study revealed that the combined use of charcoal, sago bark ash, and urea does not only reduce leaching of NH4+ and NO3− but the approach also improves soil pH, total C, and soil exchangeable NH4+. This effect is related to the fact that the sago bark ash deprotonates the functional groups of charcoal because of its neutralizing components such as Ca, Mg, Na, and K ions. As a result, the combined use of charcoal and sago bark ash was able to retain NH4+ in the soil. The carbonates in the sago bark ash and functional groups of charcoal improve pH buffering capacity. Thus, the combined use of charcoal and sago bark ash improved soil exchangeable NH4+, soil pH, and soil total C, but reduced exchangeable acidity and amount of NH4+ leached out from soil. This study will be further evaluated in a pot trial to confirm the results of the present findings.

Blending fertilizer with biochar followed by densification to make it into a tablet can enhance the adsorption of fertilizer on the biochar surface and reduce the nutrient loss during handling. However, the nutrient release and ammonia volatilization from biochar-blended fertilizer with and without densification are not well understood. The objectives of this study were to determine the nutrient release and ammonia volatilization from an acid soil applied with biochar-blended NPK fertilizer with and without densification. The nutrient release of biochar-blended NPK was determined using water incubation for 30 days, whereas daily loss of ammonia was measured using a closed dynamic air flow system for 10 days. The densified biochar-blended NPK caused stronger physical binding of the nutrients within the tablet in addition to stronger chemical bondings between the nutrients with the biochar’s functional groups. As a result, nutrient release in the water incubation from the biochar-blended NPK fertilizer tablet was slower. However, blending the biochar with the NPK fertilizer increased soil ammonia volatilization relative to the NPK fertilizer alone. This demonstrates that the biochar-blended fertilizer tablet has the potential to serve as a slow release fertilizer for crop cultivation.

Nutrients are essential for normal physiological processes in plants, and they play important roles in defence mechanisms against pathogens. Oil palms cultivated on peat are more prone to nutrient deficiency, especially micronutrients, and this may affect their susceptibility to Ganoderma species, the major threat to the sustainability of oil palm throughout South-East Asia. This study was conducted to investigate the association of copper (Cu) and zinc (Zn) in mature oil palm to the spatial distribution of Ganoderma species in the plantations on peat. Foliar samples (frond 17) of oil palm from two plantations (Betong and Miri) on peat in Sarawak, Malaysia, were collected based on the spatial distribution pattern of Ganoderma, and total Cu and Zn were quantified spectrometrically. The experiment was conducted twice at a 1-year interval. The concentrations of Cu and Zn were significantly lower in oil palms from infected areas in contrast to those from uninfected areas. In addition, oil palms in infected areas in Miri suffered Cu and Zn deficiencies. Furthermore, Cu and Zn were significantly lower in the oil palms in Miri that had higher Ganoderma occurrence, as compared to those in Betong, which had significantly higher Cu and Zn but lower Ganoderma occurrence.

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.

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 treatm...

Conversion of fertile lands to other uses has been one of limiting factors for paddy production in Malaysia. Infertile soil such as Beach Ridges Interspersed with Swales (BRIS) soil has a potential for paddy production if it’s fertility has been improved. We, therefore, conducted a study to determine the optimum rate of NPK and chicken manure for growth and yield of TR-9 paddy variety grown on BRIS soil and also to determine the nutrient content of the BRIS soil after different high application rates of NPK and chicken manure. Treatments were three NPK rates at 60:30:30 kg ha^, 100:60:60 kg ha^ and 150:90:90 kg ha^, and three chicken manure rates at 20 t ha^, 40 t ha^ and 60 t ha^, arranged in a complete randomized design. Our results showed that TR-9 paddy variety growth and yield were not significantly affected by combination of NPK and chicken manure when grown on BRIS soil. NPK rate of 60:30:30 kg ha^ produced the highest percentage of productive tillers (71.62 %) and 1000 grains weight (24.73 g). Chicken manure rate of 20 t ha^ produced the highest plant height (127.75 cm), culm height (85.58 cm), percentage of filled grains (83.73 %), 1000 grains weight (25.81 g), extrapolated yield (11.16 tons ha^) and dry weight (464.44 g). Furthermore, application of high NPK and chicken manure to BRIS soil have significantly increased soil nutrients and organic carbon content which in turn can promote better growth and yield., マレーシアでは肥沃な土地が非農業的な用途に使用され、水稲生産の制限要因の一つとなっている。しかし、湿地に散在する浜堤（BRIS）土壌の様な痩せ地でも施肥で改良すれば水稲生産に使用可能である。そこで、我々はBRIS 土壌においてイネ品種TR-9の成長及び収量に最適な化成肥料組成及び鶏糞の施肥量を決定し、種々の組成の化成肥料または異なる量の鶏糞を施肥した後のBRIS 土壌の栄養素含有量の違いを調査する事を目的として研究を行った。３種の化成肥料組成、60:30:30 kg ha^、100:60:60 kg ha^、150:90:90 kg ha^または３種の鶏糞量、20 t ha^、40 t ha^、60 t ha^ を施肥し、完全無作為化法を用いて実験を行った。その結果、 BRIS 土壌で成長させたイネ品種TR-9の成長及び収量に対して化成肥料の組成や鶏糞施肥量の違いがもたらす影響には統計学的に有意な違いはなかった。60:30:30 kg ha^ の化成肥料の施肥区では、円錐花序の付いた稈の産生能（71.62 ％）と 1000 粒重（24.73 g）において、最も高い値が示された。また、20 t ha^ の鶏糞施肥区では草高（127.75 cm）、稈の高さ（85.58cm）、籾の充満率（83.73 %）、1000 粒重（25.81 g）、補外収量（11.16 tons ha^）、乾燥重量（464.44 g）において、最も高い値が示された。さらに、化成肥料または鶏糞を施肥したBRIS 土壌では、有意に土壌養分と有機炭素含有量が増加しており、イネの成長と収量の改善を促進できる事が示された。