Malaysian Society of Soil Science

Abstract
A study was conducted to evaluate the suitability of sandy soils in the Kelantan - Terengganu Plains (Peninsular Malaysia) and suggest measures to improve their fertility for kenaf production. The coastal landscape is scarcely utilized for crop production due to the inherently low soil fertility, nutrient imbalance and water deficit which can seriously inhibit crop growth. Three sandy Spodosols with humus - rich spodic horizon were found, locally named as Rhu Tapai, Rudua and Jambu Series with sandy matrix (> 95% sand), low CEC (0.16 - 4.52 cmol_c kg^-1) and high acidity (pH 4 - 5). The mineralogy data showed quartz (dominant), with gibbsite, hematite and feldspars in trace amounts that result from high degree of weathering. The C_org of Bs and Bhs horizon was about 2%, with C/N ratio of 14 to 25, respectively; this can be exploited for kenaf production. Hence, we evaluated these sandy Spodosols for kenaf production using Wong (2009) Crop-Suitability Classification and found the soil to be marginally suitable under Class 4 described as 4Dnt where D stand for drainage, n for nutrient and t for texture. The major limitations were found to be excessive drainage, nutrient imbalance and sandy texture. Therefore, management practices recommended to improve the soils are (1) mulching the soils with different types of organic materials to retain water and plant nutrients; and (2) irrigating the soils during the dry period. If these agronomic practices are carried out, these soils could be productively used for growing kenaf.

Abstract
GeoWEPP, an integration of WEPP and TOPAZ within a GIS interface, was used to predict sediment load and runoff at the Lui Watershed, Selangor, Malaysia. Input files for land cover, slope, climate, soil, and management were generated within GeoWEPP and WEPP interfaces and topographic data comprising 1017 hillslopes were parameterized using TOPAZ algorithm. CLImate GENerator (CLIGEN) was used to estimate stochastic climatic parameters. Soil properties such as frequency of soil particles, CEC, OC, and rock fragment were utilised to define a reasonable range of soil parameters. A management file was generated using EPIC algorithm for different land use typesand for all hillslopes during the simulation period 1996 - 2008.The results showed an over-estimation of sediment load and an underestimation of runoff compared to measured data. This work shows that GeoWEPP is able to predict runoff more accurately than sediment load. 

Abstract
Effects of soil amendments, tillage practices and season on the yield of amaranthus were evaluated from field experiments carried out on a sandy loam acidic Typic Paleudult from Okpuno, South-eastern Nigeria, during dry and rainy seasons and tillage practices. The treatments which comprised compost at 0, 20, 40, 60 t ha^-1, 30 t ha^-1 compost plus + 20 t ha^-1 ash and fertilizer NPK 15:15:15 at 112 kg ha^-1 were laid out in a randomized complete block design, and replicated thrice for the two tillage practices and seasons. Results indicated that treatment and tillage significantly raised post-harvest soil exchangeable Ca and Mg. Soil organic matter sequestration was higher for untilled plots, being 11.07 g kg^-1. Treatment significantly increased soil pH in both years. Plots amended with fertilizer had lower pH and nutrient contents. Available P was > 400% of the control in the second year. Significantly high positive correlation (r = 0.792) was obtained between organic C and available P. The effect of tillage and season were significant only for exchangeable Ca and total N in the first year. Crop yield increased with treatment. Tillage and season had no significant effect on crop yield.

Abstract
Recycled Paper Mill Sludge (RPMS) is currently disposed off in the landfill and the costs are becoming expensive. Therefore, an alternative disposal through land application of RPMS and empty fruit bunches (EFB) (as a bulking agent) compost requires investigation. This study was conducted to determine the physico-chemical characteristics of composted RPMS and EFB mixtures, their phytotoxicity and the effect of the composts on plant growth performance. Composting experiment was arranged in a completely randomized design (CRD) with four replicates. The RPMS were mixed with EFB in 3 ratios, that is 1:1, 1:2 and 1:3 (RPMS: EFB) based on volume/volume. The mixtures were filled in a polystyrene box up to 90% volume and water was sprinkled onto the compost (50% moisture content) to accelerate decomposition. During composting, the compost was turned every three days to ensure that the material on the outside of the pile was turned from the center outwards to dissipate heat.  The RPMS and EFB compost mixtures were evaluated for physical, chemical, phytotoxicity and short term plant growth effects. These composts mixtures had no toxicity effects on plants, had 100% seed germination, high in nutrient contents, low in C/N ratio and had fine particle size of < 18 mm. The concentrations of heavy metals were also within the recommended level of the Council of European Communities (CEC) for compost. Compost produced from a ratio of 1:1 volume is suitable for land application as compared to 1:2 and 1:3 (RPMS: EFB). However, further study should be carried out to evaluate the effect of raw and RPMS compost on soil fertility, plant productivity and quality.

Abstract
A study examining the decomposition rates of leaf and fine root residues of oil palm (Elaeis guineensis), sago (Metroxylon sagu) and pineapple (Ananas comosus) crops in peatland soils were conducted under controlled conditions. The fourteen- month study showed that sago leaf residue was the most resistant to decomposition with only 30% mass loss, while pineapple leaf residue was found to be the easiest to decompose, accounting for 90% of the mass loss. In contrast, the highest (70%) mass loss of fine roots was observed in sago, while the lowest (50%) was in pineapple. Nutrient concentration in plant tissues correlated significantly with mass losses of leaf and fine root residues. The high C:N in plant tissues, resulted in slow decomposition of sago leaves and pineapple fine roots. Decomposition of the different plants were in the order: pineapple > oil palm > sago drained = sago undrained for leaf residues, and, sago drained  = sago undrained > oil palm > pineapple for fine root residues.

Abstract
This study was conducted to determine soil organic carbon, nitrogen, available phosphorus and pH at 3 soil depths under different ages and cycle of Acacia mangium after thinningof planted forestas well as to determine their variability in a tropical forest. Composite soil samples were collected at depths of 0 - 5, 5 - 10 and 10 - 30 cm in each plot and were analyzed for organic C, total N, available P and pH. Composite surface litters were analyzed for total C, N, P, Ca, Mg and K. Soil C and N were significantly higher at 0 - 10 cm depth in the 2^nd cycle of A. mangium which were 0 - 3 months older than the natural forest. Available phosphorus decreased in the 1^st rotation of Acacia mangium of more than 20-year-old stands and in plots which underwent thinning. Soil C, N, P decreased with increasing soil depth. Calcium in leaf litter of more than 20-year-old stands was significantly lower than in the other study plots. N, P and K concentrations were higher in leaf litter of thinned plots and in more than 20-year-old stands.

Abstract
Accumulation of NO₃^- -N (nitrate nitrogen) in the soil and its leaching into ground water is an important issue regarding ground water pollution especially in intensively fertilized agricultural areas. The study was undertaken to study the levels of residual soil NO₃^- -N in intensively fertilized banana producing farms at Jalgaon district of Maharashtra, India. A total of 144 composite soil samples was collected from post-harvested banana farms at various soil depths and analysed for NO₃^- -N content. The results obtained showed higher NO₃^- -N content in the soil and the mean values of NO₃^- -N were 63.2, 72.5 and 80.6 mg kg^-1 in Chopda, Raver and Yawal regions, respectively. A total of 10% of the samples contained NO₃^- -N at more than 100 mg kg^-1 which is in the high NO₃^- -N category, 74% in the medium category with NO₃^- -N levels between 50 to 100 mg kg^-1and 16% in the low NO₃^- -N category which contained NO₃^- -N below 50 mg kg^-1. Analysis of NO₃^- -N at various depth profiles was also carried out; 28.36% of samples showed accumulation of NO₃^- -N at depths of 0 to 10 cm.  Successive decreases in NO₃^- -N content in soil were observed with increasing depths, up to 40 cm. The residual soil NO₃^- -N may leach down to the ground water of the region and deteriorate water quality. To control for NO₃^- -N levels in ground water and to avoid accumulation in the soil, application of organic manure is recommended early in the season. In addition, it is suggested that chemical fertilizers be applied late in the season, which will reduce the leaching losses and higher amounts of NO₃^- -N will be available as per the requirement of the crop.

Abstract
Nitrogen leached from a paddy field could adversely affect subsurface water and groundwater quality. A field plot experiment was carried out to determine the effects of five fertilizer application rates on N vertical leaching from 30 and 60 cm soil layers. Results showed that during the paddy growth, NH₄⁺ -N was the main form of nitrogen with a high environment risk.  The range of NH₄⁺ -N /TN varied from 0.27 to 0.89 with NH₄⁺ -N concentration peak appearing within 2-4 days after three fertilizer application rates; the highest NH₄⁺ -N concentrations were about 38.38 mg L^-1 for the 360 kg ha^-1 or N4 treatment. Significant differences were observed in the two layers between the other four fertilizer application rates. Nitrate concentrations at 30 cm depth soil leachate were higher than at 60 cm depth; however, the peak of about 9.21 mg L^-1 for the 30 cm depth soil leachate appeared 1-2 days later than the NH₄⁺ -N and the concentrations for the 60 cm soil layer leachate which were less than 3 mg L^-1. Nitrogen loss from different nitrogen treatments varied from 2.82 to 5.07% of the urea-based fertilizer applied. The cumulative effect of nitrate leaching on the quality of the shallow ground water should be of concern.

Abstract
In this study, soil samples of different places of Khuzestan province were sampled. The sampling positions were registered and determined through GPS. The geostatistics and Geographic Information System (GIS) techniques were applied, and lognormal kriging were used to map the spatial patterns of Pb. Both soil extractable Pb by diethylene triamine penta-acetic acid (Pb-DTPA) and Pb in rice seed were fitted to the Gaussian model with a range of 85 and 89.5 km, respectively. The mean content of extractable soil lead and plant lead in all the sites investigated were 702.88 and 121.82 µg kg^-1, respectively. Both Pb-DTPA and Pb in rice seeds had moderate spatial dependence due to the effects of natural factors including parent material, topography and soil type. The statistical survey to determine the possible correlation between some soils characteristics with lead distribution in rice seeds was done through SPSS statistical software. The results showed that close relationships existed between  Pb-DTPA  with  organic  matter  (OM)  (r = 0.376**), Pb in rice seed (r=0. 68**), calcium carbonate equivalent (CCE) (r=0.084*) and between Pb in rice seed with CCE (r = -0.716**), Pb-DTPA (r = 0. 68**) and pH (r = 0.263*).

Abstract
The pH of mineral acid soils in Malaysia ranges from 3 to 5, with the pH of Ultisols and Oxisols ranging from 4 to 5, while acid sulfate soils (Sulfaquepts) have a pH < 3.5. Under this condition, Al is present at a toxic level for crop production. Ultisols and Oxisols are dominated by kaolinite and sesquioxides while acid sulfate soils contain jarosite and/or pyrite, mica, vermiculite and smectite beside kaolinite. Studies were conducted in the laboratory, glasshouse and in the field in Malaysia to determine the effects of applying ground basalt and/or organic fertilizer on the chemical properties of the three soil types and on the growth of cocoa and rice. The results showed that basalt application improved the chemical fertility of the Ultisols and Oxisols by way of increasing pH, Ca, Mg, K and P as well as cation exchange capacity. The increase in pH lowered Al in the soil solution as it was precipitated as Al-hydroxides. The pH increase is attributed to the hydrolysis of silicate released by basalt. However, basalt takes time to disintegrate and dissolve completely. Basalt application decreased pHo. The increase in pH and the concomitant decrease in pHo increased the negative charge of the soils and further improved soil productivity. Results from glasshouse experiments showed that basalt application significantly improved the growth of cocoa. The critical Al and Mn concentration in soil solution for cocoa growth was 4.7 and 5.8 µM, respectively. The improvement in cocoa growth due to basalt application was confirmed by a field trial on the Oxisol. Organic fertilizers help improve soil productivity and this was observed when basalt was applied on an acid sulfate soil. Basalt dissolves more rapidly under very acidic conditions. The increase in pH and the decrease in Al as well the release of nutrients resulted in an increase in rice yield.

Abstract
Organic and sustainable farming systems require organic fertilizer as an organic input to sustain soil fertility. As organic fertilizers (OF) are complex and variable, their selection is important since it has a direct influence on the organic produce.Thirty five bags of commercially available OF were obtained from Klang Valley, Selangor and Seremban. The OF were grouped as: a) oil-palm wastes base (OP), b) plant base (P), c) manure base (M), d) plant and manure base (P+M) and e) vermicompost (VC) based on the method of composting and f) unknown (UKN) when the source of material was not known (either from the labels or the suppliers). From this study it is suggested that by adopting uniform definitions, fertilizer manufacturer would be able to designate products that are suitable for organic production. The Department of Agriculture (DOA) should also have proper guidelines on the quality of OF for safe use in the organic farming system especially on adjustment of fertilizer terms and information on the labels. This may reduce the confusion caused by multiple definitions of the word ‘organic’. Organic fertilizer standards are recommended in order to produce high quality organic fertilizers for organic production in Malaysia.