Phosphorus isotherms were measured from three different soils collected from NSW areas ofAustralia. Various concentrations of NaCl were added to the soils to determine the isotherms and to attain maximum phosphorus adsorbed values using Langmuir Equation. Three different methods of salt additions were used including direct addition of salt solution, salt incubated soils, and soil when shaken for extended time with salt solution (72 h). Phosphorus adsorption was increased greatly when salt was added to all soil samples. There were no significant differences in phosphorus adsorption. However, when varying the concentrations of salt (0.003-0.12 M NaCl), salinity was found to increase phosphorus adsorption in all soils, but further increases in NaCl concentrations did not show any increment in phosphorus adsorption. Soils shaken for longer periods with NaCl solution appeared to reduce the overall phosphorus adsorption capacity. The effects of salinity with various procedures of salt imposition were discussed.
Keywords: Phosporus adsorption, salinity, phosphorus adsorption isotherm, Langmuir Equation
Tannery industries create serious environmental problems especially in terms of polluting organic effluent and the hazardous solid wastes as a result of hides and skin processing. Tannery waste is categorised as toxic and hazardous waste in Malaysia due to the high content of Cr (in excess of 500 ppm) and other heavy metals. It is very important that tannery wastes in the form of sludge and shavings are managed in an environmentally sound manner. This study focused on utilisation of tannery wastes as substrate additives to grow tomatoes. The results showed that there was a significant difference between initial and final sample in terms of electrical conductivity (EC), pH, root to shoot ratio and plant height. However, % seed germination at 5 days was inhibited and significantly reduced at 14 days from sowing date with 100%, 75% and 50% of both sludge and shaving. The results also indicated that 50% and 25% treatments of both wastes provide more appropriate media for plant growth compared to other treatments.
Keywords: Tannery sludge, shaving, tomato, germination, growth, electrical conductivity
Tillage systems obtained from twelve factorial combinations of tractor forward speeds achieved with four transmission gear positions (Gear 1 High, Gear 2 Low, Gear 3 Low and Gear 4 Low) and three rotary tilling speeds (140 rpm. 175 rpm 200 rpm) were compared during the 2003 off- and main cropping seasons on rice seed multiplication plots at the Sungai Burong Compartment of the Tanjong Karang Rice Irrigation Scheme, Malaysia. The effect of the rotary tillage systems some soil physical properties was also investigated. Speed and time, energy and fuel requirements were measured for an 80”-rotavator and a 110”-rotavator most commonly used to perform tillage operations in Malaysian paddy fields. The field operating and energy data were determined from three tillage passes (first rotavation, second rotavation and third rotavation). Experimental results showed that there was an overall decrease in bulk density, cone index, plasticity index and organic matter of the soil, possibly as a result of the tillage treatments applied. Highest effective field capacity of 0.83 ha h-1 was achieved with Gear 1 High and rotary speed of 140 rpm, followed by Gear 1 High and rotary speed of 175 rpm (0.82 ha h-1) during first rotavation, while Gear 4 Low with rotary speed of 200 rpm gave the highest effective field capacity of 1.11 ha h-1, followed by Gear 1 High with rotary speed of 175 rpm (1.08 ha h-1), which also consumed the least amount of fuel (6.24 Lha-1) during second rotavation. Minimum total energy consumption of 1374.45 MJ ha-1 was observed for Gear 1 High with rotary speed of 175 rpm. Test results also varied according to tillage operations, with the maximum average energy consumption of 759.63 MJ ha-1for first rotavation, followed by second rotavation, which was 519.61 MJ ha-1. The results of the study indicate that Gear 1 High in combination with 175-rpm rotary tilling speed is more efficient in terms of energy conservation and effective field capacity for first and second rotary tillage operations in a paddy field. These results could be helpful to farmers, planners and decision-makers in the selection of tillage systems for paddy fields.
Keywords: Rotary tillage, soil physical properties, effective field capacity, energy consumption, paddy field
Heavy metal and nutrient content in ditch sediment from Kg. Tumbuk to Tg. Tumbuk and coastal sediment along Tg. Tumbuk to Tanjung Sepat were determined. Sampling stations included abandoned palm oil estate, pig farm effluent retention pond, ditch sediment starting from pig farm effluent outlet to the beach and coastal sediment samples obtained from three localities along the coastal stretch from Tg. Tumbuk to Tg. Sepat. This particular coastal stretch has been receiving effluent from agricultural areas, pig farming and townships. Available and exchangeable nutrients and selected heavy metals in soil and sediment were determined. Sediment properties expected to influence the presence and enrichment of heavy metal and nutrient such as particle-size, organic matter content, pH and electrical conductivity were also determined. Soluble and available nutrients were relatively higher in areas receiving effluent from pig farm, followed by areas receiving effluent from townships, then areas receiving effluent from agricultural land. Heavy metal such as As, Cr and Zn were higher in the area receiving effluent from pig farm compared to the rest.
Keywords: Land use, heavy metal and nutrient profile, ditch and coastal sediment
Cultivation of traditional transplanted rice with continuous standing water in Asia uses relatively high water input. With increasing water scarcity, there is a need to develop alternative systems that requires less water. This study was conducted to determine the effect of low flooding on rice yield and phosphorus concentration. This study showed that significant amounts of water could be saved compared to the traditional continuous inundation irrigation. There were five treatments simulating different flooding depths and durations: W1 (continuous flooding at 5 cm); W2 (continuous flooding at 1 cm): W3 (continuous flooding at 5 cm in the first 3 weeks then 1 cm flooding); W4 (continuous flooding at 5 cm in the first 6 weeks then 1 cm flooding); and W5 (continuous flooding at 5 cm in first 9 weeks then 1 cm flooding) with 4 replications. SPS200 porous ceramic cups were used to collect sample and phosphorus concentration was measured at weekly intervals. The results showed no significant effect of low flooding on rice yield and phosphorus concentration with time, indicating rice production could be implemented under low flooding water.
Keywords: Water saving irrigation, bioavailability of phosphorus, rice
Plant structure is among some of the parameters often used to evaluate usefulness of applied fertilizers. A study was conducted to evaluate the responses of plant structure to cotton (Gossypium hirsutum L.) plant grown on varying levels of potassium fertilization. Treatments consisted of four cotton cultivars (CIM-448, CIM-1100, Karishma, S-12), four K-rates (0, 62.5, 125.0. 250.0 kg K ha-1) and two K-sources [sulphate of potash (K2S04) and muriate of potash (KCl)]. Main stem height achieved its plateau at first boll split stage and remained almost leveled off at maturity. Cultivars differed significantly amongst themselves in terms of plant height. Cultivar CIM-1100 attained the highest main stem height compared to cv. S-12. Main stem height increased with concurrent varying potassium levels. Addition of potassium fertilizer in the form of K2S04 did not show an edge over KCl on reproductive growth. There were significant correlations co-efficient (0.7l**,0.53**, 0.51**) between dry weights, number of total fruiting positions and number of intact fruits, respectively. The number of nodes on main stem was little affected because of K-rates and sources. However, lengths of inter-nodes differed significantly due to cultivars and K-rates.
Keywords: Potassium fertilizer, potassium sources, plant structure, Gossypium hirsutum L., irrigated condition