Comparative effects of black and green gram (mung beans) and grain sorghum on soil mineral nitrogen and subsequent grain sorghum yields on the Eastern Darling Downs

A field trial was carried out on a black earth (Waco series) at Cambooya on the Eastern Darling Downs to compare the effect of black gram, green gram, grain sorghum and a summer fallow on soil mineral nitrogen (NO3-N + NH4-N) and the yield of grain sorghum grown in the following summer. The initial sorghum treatment severely depleted soil mineral nitrogen to 120 cm; even after a 173-d fallow, there was still 34 kg/ha less nitrogen present than initially in this treatment. Black and green gram also reduced levels of soil mineral nitrogen during crop growth, but these recovered to exceed pre-trial levels by 29 and 42 kg N/ha, respectively, after a winter fallow. The fallow treatment accumulated 100 kg N/ha of mineral nitrogen between January and October, but mineralization was markedly reduced from August to October. Sorghum grown on all plots in the second summer responded markedly to prior treatments, and grain yields and responses to nitrogen applied at 0, 34 and 68 kg N/ha reflected mineral nitrogen levels at planting. Yields of sorghum grain obtained without fertilizer after black gram, green gram and fallow were 8333, 7477 and 9663 kg/ha, respectively, compared with 4658 kg/ha after sorghum. Prior crops of both grams increased sorghum yield as much as a fertilizer application of 68 kg N/ha.

Studies on the uptake of exogenous phosphoglycerides by Escherichia coli B cells

The uptake of exogenous lipids by Escherichia coli B was studied under various conditions. Lysophosphoglycerides were absorbed more readily than diacyl analogues when sonicated dispersions of a single lipid were used. When these same lipids were admixed with coliform lipids and dispersed as vesicles, the uptake of lysophosphoglyceride diminished and was approximately equal to that of diacyl analogues. Neutral lipids such as diglyceride, fatty acid, and cholesterol were also absorbed when admixed and dispersed as vesicles with coliform lipids. The uptake of lysophosphoglyceride was stimulated slightly by all divalent cations tested except Mg2+; monovalent cations were ineffective. Uptake was accompanied by conversion of lysophosphoglyceride to diacyl analogues. In the presence of Ca2+, lysophosphatidylethanolamine also formed a more polar lipid product yet unidentified. The uptake of lipid did not cause release of 3H label into the medium from cells that had been grown in [3H]acetate-containing medium. Also, the [3H]phosphoglyceride content of such labelled cells remained constant. Thus the uptake process did not involve exchange of membrane lipid with the medium or an enhanced hydrolysis of endogenous lipids, but it represented a net gain of lipid by the cell. The uptake did not seem to involve a stable adsorption of lipid at the surface of the cell as could be judged from electron microscopic examination of the cells after incubation; the cell surfaces were devoid of adsorbed vesicle or liposomal types of structures and did not display evidence of expansion. [3H]Cholesterol-[32P]phospholipid mixtures were taken up without a change in isotopic ratio. This result together with the other evidence presented indicate a net uptake of exogenous lipid by a process likely involving fusion.

Comparison of four wheat cultivars for yield and protein response to nitrogen fertilizer

Four wheat cultivars were compared for grain yield and grain protein response to nitrogen fertilizer at rates up to 135 and 336 kg N ha-1, in two field experiments, All varieties showed large responses to nitrogen in both years. The Mexican semi-dwarf WW15 and its white-grain derivative, Condor, yielded more than the standard cultivars Timgalen or Gatcher. Semi dwarf cultivars were found to respond significantly more to nitrogen than either Timgalen or Gatcher in the first year of these trials. Protein percentage of the grain was depressed by low rates of nitrogen in one year but increassd at higher rates. Gatcher and Condor had similar protein percentages; WW15 had the lowest and Timgalen the highest. Only Timgalen with high nitrogen reached a protein level for premium payment in the first year. In the second, all cultivars when fertilized qualified for similar premium payments per unit of land area. A simplified economic analysis showed that it was more profitable to grow and to fertilize the higher-yielding cultivars.

The role of nodulation and damping-off in lucerne establishment on acidic sandy soils on the Darling Downs

Four experiments on two soils with deep acid sand A horizons on the western Darling Downs in 1968 and 1969 investigated poor establishment of lucerne. Rates of rhizobial inoculation, lime pelleting, lime banded with the seed, and incorporation of fungicides in the lime pellet or applied to the soil, were examined. The main factor in poor establishment was seedling losses from damping off caused by Pythium irregular.. Establishment increased when the fungicide Dexon was incorporated in the lime pellet, and Dexon had no adverse effects on nodulation. To obtain full nodulation the use of higher than minimum standard quality inocula and lime pelleting were required. On the more acidic soil (pH 5.0, 0-10 cm) additional lime banded at 250 kg ha-1 was beneficial.