The Effect of Different Soil Types on Growth and Nodulation of Vigna radiata (L) Wilczek Inoculated with Vesicular-arbuscular Mycorrhiza (VAM)

The potential of using a 'natural' soil with high mycorrhizal spore count as a source of inoculum was evaluated in this preliminary experiment using 4 soil types .. Serdang, Munchong, Malacca and Bungor. Results obtained on the dry weight and P content ofplant tops was not significant between treatments but was significant between the soil types used. This could be due to the duration of the experiment being too short to enable these endogonaceous species to establish well in these soils and bring about significant growth response of the mungbean plants

Distribution of VA Mycorrhizal Spores in Sandy Beach Soils under Cashew

Surface horizons (0-15 em) of sandy beach soils from Besut and Kuantan, (Malaysia) under cashew (Anacardium occidentale L) were sampled for Vesicular-Arbuscular Mycorrhizal (VAM) spores. Isolation of VAM spores were made from both the Rudua and Jambu series in Besut as well as the Rudua and Baging series in Kuantan. There were more spores isolated from the Kuantan than the Besut areas. The results also indiate a positive relationship between spore number to percent organic matter present in the topsoil. The abundant spores isolated from the Kuantan areas (in contrast to Besut) could have some significance in the P nutrition of cashew and probably explain the yield differences existing between these two areas

Loss of nitrogen from decomposing nodules and roots of the tropical legume Centrosema pubescens to soil

Samples (20 g) of an air-dry, sieved (<2mm) silty loam with or without (controls) the incorporation of 200 mg root portions of Centrosema pubescens, were moistened to 50% moisture holding capacity at 0.33 bar (33 kPa). The root portions were healthy, freshly harvested, clean samples of nodules, laterals or radicles; treatments Nod, Lat and Rad respectively. Soil samples were incubated aerobically at 30 C for 16 weeks. The radicles, laterals and nodules respectively contained 1.65, 3.46 and 6.91 mg N per sample and their C to N ratios were 16.5, 7.0 and 4.2. The root fragments disappeared rapidly and less than 40% and 10% of their initial dry weight remained after 1 and 16 weeks respectively; nodules decomposed more rapidly than laterals and laterals more quickly than radicles. At 16 weeks the total N contents of the controls had not changed but Rad, Lat and Nod soils respectively showed gains over the controls from week 1 onwards and by week 16, these amounted to 8.2, 17.1 and 31.8%. Concentrations of mineral N increased in all soils from week 4 onwards and by week 16, the amounts of mineral N that had accumulated in Nod, Lat and Rad were 1.62, 1.16 and 1.14 times greater than in the controls (201 ~ N g-l oven-dry soil). Under the conditions of this experiment, the legume root and nodule tissues discomposed rapidly and all of the legume root N (except an unaccounted for 5.6% of the nodule N) was transferred to the soil without any apparent net loss or gain of volatile N

Nitrogen and phosphorus requirement of winged bean (Psophocarpus tetragonolobus (L.) DC.) in Oxisol and Ultisol

The response of winged bean (Psoph ocarpus tetragonolobus) to 6 different soil P levels and 3 different soil N levels were compared in two soil types (an Oxisol and an Ultisol) for a period of 4 months. Moderate applications of N and P fertilizers (i.e. 14 kg N/ha and 13 kg P/ha) were found to be optimum for maximum plant growth in the Serdang soil. However. Munchong soils were found to support just as much growth as Serdang when higher levels of P were applie