Influence of inorganic fertilizers and organic amendments on soil organic matter and soil microbial properties under tropical conditions

 Soil organic matter level, mineralizable C and N, microbial biomass C and dehydrogenase, urease and alkaline phosphatase activities were studied in soils from a field experiment under a pearl millet-wheat cropping sequence receiving inorganic fertilizers and a combination of inorganic fertilizers and organic amendments for the last 11 years. The amounts of soil organic matter and mineralizable C and N increased with the application of inorganic fertilizers. However, there were greater increases of these parameters when farmyard manure, wheat straw or Sesbania bispinosa green manure was applied along with inorganic fertilizers. Microbial biomass C increased from 147 mg kg^–1 soil in unfertilized soil to 423 mg kg^–1 soil in soil amended with wheat straw and inorganic fertilizers. The urease and alkaline phosphatase activities of soils increased significantly with a combination of inorganic fertilizers and organic amendments. The results indicate that soil organic matter level and soil microbial activities, vital for the nutrient turnover and long-term productivity of the soil, are enhanced by use of organic amendments along with inorganic fertilizers. Received: 6 May 1998     

Pathogenicity,host specificity and anastomosis groups ofRhizoctonia spp. isolated from soils in Israel

One hundred and twenty-nine isolates ofRhizoctonia spp. were obtained from soil samples in Israel and from culture collections in the U.S.A. and Japan. The isolates varied in host range and disease severity when tested on six to eleven different host plants. Approximately 30% of the isolates were nonpathogenic to all the host plants tested. Mycelial growth rate of the nonpathogenic strains did not differ significantly from that of the virulent isolates. The 107 Israeli isolates represented anastomosis groups (AG) 1, 2, 3, 4, 5 and 6 ofR, solani, two groups ofR. zeae, and three groups of binucleateRhizoctonia AG: A, F and K.     

Growth of SiO2 at room temperature with the use of catalyzed sequential half-reactions

Films of silicon dioxide (SiO2) were deposited at room temperature by means of catalyzed binary reaction sequence chemistry. The binary reaction SiCl4 + 2H2O --> SiO2 + 4HCl was separated into SiCl4 and H2O half-reactions, and the half-reactions were then performed in an ABAB ellipsis sequence and catalyzed with pyridine. The pyridine catalyst lowered the deposition temperature from >600 to 300 kelvin and reduced the reactant flux required for complete reactions from approximately 10(9) to approximately 10(4) Langmuirs. Growth rates of approximately 2.1 angstroms per AB reaction cycle were obtained at room temperature for reactant pressures of 15 millitorr and 60-second exposure times with 200 millitorr of pyridine. This catalytic technique may be general and should facilitate the chemical vapor deposition of other oxide and nitride materials.     

Nile delta: the defunct pelusiac branch identified

The course of the ancient Pelusiac branch of the Nile River has been traced on a deltaic plain east of the Suez Canal, between the El Baqar Canal and Tell el Farama (ancient Pelusium). Two minor distributaries branched northward. The critical stage in the process of the silting up of the lower reaches of the Pelusiac branch, due to prograding beach accretion, occurred around A.D. 25. Ancient ruins in the area are closely associated with the courses.     

Antisporulant activity of 8-hydroxyquinoline and its 5- and 6-n-alkyl derivatives against Gloeosporium fructigenum berk

The antisporulant activities of 8-hydroxyquinoline (oxine) and members of the homologous 5- and 6-n-alkyloxine series against Gloeosporium fructigenum at varying ambient pH values and in the presence or absence of added Cu²⁺, Zn²⁺ and Fe²⁺ are described. Whilst changes in the pH value only influenced the antisporulant activity of oxine at low concentrations, lowering the ambient pH increased considerably the activities of the 5- and 6-alkyl isomers at all concentrations. Below pH 7.0 the addition of these ions to the oxines resulted in decreased antisporulant activity (Fe²⁺ > Zn²⁺ > Cu²⁺) whereas, at pH 8.0, the addition of Cu²⁺ increased the activity of some oxines. It is suggested that at low pH (3.2) the oxine cation is an important toxicant.     

Nutritional value of some non-conventional plant foods of India

Thirteen non-conventional foods including fruits, leaves and grains consumed in various parts of the Indian subcontinent were analysed for their nutritional value. Khejri beans (Prsopsis cineria), Pinju (Capparis decidua) and Kachri (Cucumis species) contained considerable amounts of protein (15–18%). Kachri was rich in fat (13%). Bhakri (Tribulus terristris), Gullar (Ficus glomerata) and Peehl (Salvadora oleoides) were found to be rich sources of calcium; Gullar contained about 15 times the amount of calcium present in wheat. Phosphorus content of Santhi (Boernavia diffusa), Khejri beans, Bhakri, Pinju and Lehsora (Cordia dichotoma) were noticeable. Zinc was present in high amounts in Peepalbanti (Ficus religiosa) and Gullar; as was iron in Santhi and Bhakri and manganese in Santhi. Besides iron, zinc and calcium, Pinju contained appreciable amounts of -carotene and vitamin C. However, Santhi contained high amounts of oxalic acid.     

Antinutrients in amphidiploids (black gram × mung bean): varietal differences and effect of domestic processing and cooking

Phytic acid, saponin and polyphenol contents in grains of various varieties of black gram (Vigna mungo) Mung bean (Vigna radiata L.) amphidiploids ranged from 697 to 750, 2746 to 2972 and 702 to 783 mg/100 g, respectively. Domestic processing and cooking methods including soaking, ordinary and pressure cooking of soaked and unsoaked seeds, and sprouting significantly lowered phytic acid, saponin and polyphenol contents of the amphidiploid seeds. Soaking for 18 h removed 31 to 37% of the phytic acid; the extent of removal was higher with long periods of soaking. Saponins and polyphenols were relatively less affected. Loss of the antinutrients was greater when soaked instead of unsoaked seeds were cooked. Pressure cooking had a greater effect than ordinary cooking. Antinutrient concentrations declined following sprouting; the longer the period of germination the greater was the reduction.     

Induced resistance of cucumber seedlings caused by some non-pathogenicRhizoctonia (np-R) isolates

Among 153 isolates ofRhizoctonia spp. obtained from 95 soil samples collected from different fields in the USA, 42 (27.5%) isolates were hypovirulent or non-pathogenic on cabbage (tested on tap water agar plus 250 μg/ml chloramphenicol plates). Of these, 14 (33.3% of the np-R) isolates protected >60% of the cabbage seedlings againstR. solani, and the best eight isolates protected 73–95% of the cucumber seedlings. The np-R isolates RU56-8 (AG-P) and RU89-1 [AG-B(o)] induced the highest resistance against hypocotyl challenge inoculation with virulentR. solani (38.3–85.7%), whereas most of the challenged control seedlings (85–100%) collapsed. Similarly, isolates RU56-8 and RU89-1 induced the highest resistance (22.2–87.5%) against hypocotyl challenge inoculation withPythium aphanidermatum, whereas most of the challenged control seedlings collapsed (90–100%). Isolates RU56-8 and RU89-1 significantly reduced the lesion numbers and area/leaf (to 8.9–42.0% of the control) caused by challenge inoculation of the first true leaves withPseudomonas syringae pv.lachrymans. No np-R isolate could be recovered from the upper hypocotyls or from the leaves, indicating that there was no contact between the inducer and the pathogen. Root colonization with some np-R increased seedling tolerance to low soil moisture levels.     

Pharmacokinetics and urinary excretion of sulphadimidine in buffalo calves

Pharmacokinetics and urinary excretion of sulphadimidine (SDI) were determined in buffalo calves following single oral administration (150 mg/kg). The plasma levels of free sulphadimidine were above minimum effective therapeutic concentration (> 40 micrograms/ml) between 4 and 12 h and the N4-acetylated form of the drug was in the range of 7.2-19.3%. Kinetic evaluation of plasma levels was performed using a two-compartment open model. The absorption and elimination half-lives of SDI were 3.01 and 11.94 h, respectively. Based on this study, an optimal dosage regimen of sulphadimidine in buffalo calves would be 100 mg/kg, followed by 50 mg/kg at 12 h intervals. Sulphadimidine was mainly excreted in the urine as free amine. The percentage of N4-acetyl sulphadimidine in urine was comparatively higher than in plasma.