Penilaian Keberkesanan Beberapa Jenis Baja Fosfat Ke Atas Tanaman Jagung (Zea mays, L.) Evaluation of the Effectiveness of Various TyPeS of Phosphate Fertilizers on Growth of Maize (Zea mays, L.)

Satu percubaan telah dijalankan untuk mengkaji keberkesanan empat jenis baja fosfat.terhadap tumbesaran pokok jagung yang ditanam pada tanah Sin Munchong (Tropeptz"cHaplorthox). Empat jenis baja fosfat yang ·terdiri daripada Tripel Superfosfat, Superfosfat Tunggal, Fosfat Batuan, Christmas Island and Fosfat Batuan Moroccon; telah digunakan pada kadar 50, 100 dan 200 kg P ha - 1. Baja- baja daripada jenis superfosfat didapati" menghasilkan berat kering dan pengambilan P yang lebih tinggi daripada baja-baja jenis batuan. Berat kering dan pengambilan P oleh pokok jagung juga bertambah dengan penambahan hadar pembajaan P. Kehadiran P yang diperolehi" oleh pokok jagung didapati" berkait rapat dengan kandungan P larut air dan P yang sedw. ada dalam baja

Effect of green manures on P solubilization and uptake from phosphate rocks

The effect of fresh leaves of t Gliricidia sepium, Acacia mangium, Leucaena leucocephala and Senna siamea on P availability and uptake from phosphate rocks from North Carolina (NCPR), Christmas Island (CIPR), China (CPR), Algeria (APR) and Tunisia (TPR) was studied. The 32P isotope dilution technique was used in a pot experiment with sweet corn. APR was the most reactive PR whilst CPR was the least reactive in the absence of green manures (GMs). GMs generally increased the solubility of the less reactive PRs and depressed that of the more reactive ones. This was believed to be through nutrient supply and release of P; and indirectly by decreasing or increasing P fixing capacity. The extent of the influence was observed to be dependent on GM quality, especially C:P ratio

The Initial and Residual Value of Phosphorus from Apatite Rock Phosphates and Superphosphates as Measured by 32p Dilution Technique

A pot trial using maize (Zea mays, L.) grown on an Ultisollabelled with 32p was carried out to evaluate the agronomic value of nine types of apatite rock phosphates and triple superphosphate. Results show that the effectiveness of tested rock phosphates is variable as compared to superphosphate, when measured at 30 days after planting. However, these rock phosphates were three to five times more effective than triple superphosphate in the second cropping

Jerapan Sulfat oleh Beberapa Jenis Tanah Malaysia

Satu kajian untuk menilai keupayaan beberapa tanah Malaysia untuk menjerap unsur sulfat telah dijalankan. Empat jenis tanah dari susunan Oxisol dan Ultisol telah digunakan. Sepuluh gram tanah telah diseimbangkan dengan larutan 0.1 M CaCl2 yang mengandungi beberapa paras sulfat selama 24 jam. Banyaknya sulfat yang hilang dari larutan telah dikirakan sebagai sulfat terjerap. Data-data penjerapan telah dinilaikan dengan menggunakan persamaan isoterm Langmuir. Keupayaan jerapan sulfat bagi keempat- empat siri tanah ini telah didapati berlainan dan bertambah mengikut susunan Munchong>Bungor> Melaka>Padang Besar. Kadar maxima penjerapan sulfat adalah 200.40 p,g S g-1 tanah bagi siri 1V1unchong, 115.61 p.g S g-1 tanah bagi siri Bungor, 107.99 p,g S g-1 tanah bagi siri Melaka dan 56.82 p,g S g-1 tanah bagi siri Padang Besar

Kesan Ion Fosfat ke atas Jerapan Sulfat oleh beberapa Tanah Malaysia.

The experiment on the effect of phosphate ion on sulfate adsorption in soils showed that phosphate ion is effective in exchanging with the adsorbed sulfate ions on the soil colloids. The quantity of sulfate ions adsorbed tended to decline with increasing amounts of P added. Sulfate desorption occurred when P concentration reached 200 g P g-1 soil for Bungor and Melaka series and 400 1kg P g-l soil for Padang Besar and Munchong series. This shows that these ions had different affinities for adsorption by the soils, and both ions seemed to go for the same adsorption site

Patterns of decomposition and nutrient release by fresh Gliricidia (Gliricidia sepium) leaves in an ultisol

Legume leaves used as green manure are a potential alternative to the use of commercial N fertilizers for non-legume crop production. Thus it is important to understand the rate of legume leaf decomposition and its release of nutrients. This paper reports the results of a litter bag experiment using fresh Gliricidia sepium leaves under field conditions. The leaves were confined in litterbags (5.3 mm mesh) and buried 10 cm in the soil. Dry matter, C, N, P, K, Ca, and Mg remaining after decomposition was determined at 0, 5, 10, 20, 30, 40, 50, 60 and 70 days. A rapid initial phase followed by a much slower one was identified in the decay and nutrient release patterns. The duration of the former ranged from 21 to nearly 30 days for dry matter and nutrients. Potassium and Ca were the most rapidly released nutrients, with the early phase lasting 28 and 6 days respectively. Nitrogen and P showed similar patterns of release and initial phase duration (21 and 22 days). Their rate constants were also 10 and 8 times that of their respective slow phases. C:N and C:P ratios increased initially and then decreased in the subsequent phase of decomposition. Magnesium also gave an identical pattern and rate of release as N in the early phase. No influence of rainfall was observed on the parameters studied

Upland rice root characteristics and their relationship to nitrogen uptake

Nitrogen and phosphorus efficiencies are the main constraints to food production in the sub-humid and humid tropic soils. A laboratory and glasshouse study was initiated to examine the differences in the root architecture of Malaysian upland rice landraces and relate them to efficiency of the nitrogen fertilizer uptake. Six upland rice landraces, obtained locally, were soaked in water and allowed to germinate using the cigar role method. The seedlings were fertilized with a complete nutrient solution daily and the roots which were allowed to develop after 14 days were measured using the WINRHIZO. The same landraces were planted in the glasshouse in polybags containing 25 kg soil in four replications. N-15 labelled urea was applied at 170 kg N/ha and N use efficiency was measured at harvest. Significant differences in root length, surface area, root volume, average root diameter, and number of forks, between the 6 landraces were studied. Nitrogen in the plant (derived from fertilizer applied) was found to range from 6.22 – 27.6%. Nevertheless, a poor correlation was obtained between the length of root and the dry matter yield and the total N uptake. Five of the landraces tested showed a good potential in taking up the fertilizer N applied

Accumulation and Migration of Phosphate Applied as Rock Phosphate in an Oil Palm Plantation

An experiment was conducted to study the accumulation and migration of P applied as Christmas Island Rock Phosphate (15% P) to an oil palm crop grown on Kuala Brang soil series (Typic Paleudult). These oil palm trees were fertilized for 17 consecutive years at the rate of 0, 44 and 88 kg P/ha/year. Most of the P was found to accumulate mainly in the top 10 cm of the soil and were present in the order of Ca-P > Fe-P > Al-P. Olsen extractable P, total P, inorganic P fractions, soil CEC and pH were found to increase with increasing rates of P applied

Nitrogen Contribution by Palm Oil Mill Effluent to Young Oil Palm (Elaeis guineensis Jacq.) as measured by 15N Isotope Dilution Technique

Palm oil mill effluent (POME) is an organic waste material produced at the oil palm mills. In its raw form, POME is highly polluting due to its high content of biological and chemical oxygen demand. It must be treated before being discharged into the waterways. But in view of its high nutrient content, it can be recycled to the soil as a fertilizer for agricultural crops. Two nursery trials were conducted using oil palm (Elaeis guineensis Jacq.) seedlings planted in polybags containing 8 kg Selangor series soil (Aeric Tropaquept) to evaluate the nitrogen contribution by POME applied to the soil. The trials were carried out for a period of 40 weeks using the nitrogen-15 isotope dilution technique. The nitrogen in the plants contributed by the POME at various times was calculated using the isotope dilution procedure described by Fried and Dean (1952). It was found that the amount of nitrogen contributed by POME in both the experiments ranged between 4.9 to 12.1 percent of the total nitrogen content of the POME applied. A higher N was utilized from POME that contained higher total solids