Plant and Soil

Whiteley, G.; Dexter, A.

doi: 10.1007/BF02143606pmid: N/A

Experimental methods are described for observing the behaviour of roots growing over the surfaces of undisturbed soil clods and for roots growing along narrow cracks between two clods. Seminal roots of pea, rape and safflower were compared for a range of soil strengths and angles of inclination of the clod surfaces. For all three plant species, the ability of the roots to penetrate ped surfaces decreased with increasing soil strength and increasing angle of the surface relative to the horizontal. However, there was considerable variability of behaviour between roots. Roots were able to elongate more rapidly in cracks narrower than the root diameter than through undisturbed clods without cracks, provided that the crack was not orientated at an oblique angle to the preferred geotropic growth direction.

White, R.; Ayoub, A.

doi: 10.1007/BF02143607pmid: N/A

Green manuring was simulated in the laboratory by adding six-week-oldVica faba residues (C/P ratios between 123 and 506) to a calcareous soil (Kingston series) at a rate equivalent to 8 t C ha−1 15 cm. The mixtures were incubated at 25°C for 42 days. Only residues with the lowest C/P ratio increased NaHCO3-extractable inorganic P (Pi) above the control (5.8 compared to 3.9 μg P g−1 soil at 42 days). This increase was small relative to the total extractable P in the soil-residue mixture of 38.4 μg g−1 (=76.8 kg P ha−1 15 cm) at the start of decomposition. Plant P appeared to be rapidly adsorbed by the soil. In the first 24h, when microbial uptake was negligible, 54 and 64 percent of the total extractable P in the low C/P ratio and high C/P ratio mixtures, respectively, was mobilized.

Burggraaf, A.; Linden, J.; Tak, T.

doi: 10.1007/BF02143608pmid: N/A

Four Frankia isolates ofAlnus glutinosa were studied in relation to the location of infectible cells along 10 day oldAlnus glutinosa roots. For all isolates tested a clear zonation in infectible cells was found just above the position of the root tip at the time of infection.

Warman, P.; Fairchild, G.

doi: 10.1007/BF02143609pmid: N/A

A field study conducted for three years on three different, soil types showed that the insecticide, endosulfan, had little effect on crop yield and plant tissue composition of cabbage, potato and strawberries. These crops were sprayed 0,2 or 8 times per season with a commercial endosulfan preparation. The mature tissue was analysed for N, P, K, Ca, Mg, Mg, Zn, Cu and B.

Chamber, M.

doi: 10.1007/BF02143610pmid: N/A

Two field experiments were planted using different techniques for inoculation of soybeans. Three cultivers each belonging to a group of growth habit were inoculated by four methods in the first experiment. In the second one, two strains ofRhizobium japonicum (USDA 110 and 122) inoculated by other four methods, were compared on two indeterminate varieties, (Amsoy-71 and Williams).

Gill, H.; Meelu, O.

doi: 10.1007/BF02143611pmid: N/A

To work out efficient utilization and to standardize P requirement of rice-wheat rotation, a field experiment is in progress on Fatehpur loamy sand (Typic, Ustochrepts) soil at PAU Farm Ludhiana, since summer 1977. Soil of the experimental site was non-saline, alkaline, low in available P, N and oxidizable organic matter and medium in available K. Three years' yield data revealed that only wheat responded to fertilizer P in the rotation indicating thereby that 26 kg P ha−1 applied to wheat only, in rice-wheat rotation, was sufficient to meet P requirement of both crops. This suggested that for efficient use and economic returns from fertilizer input, the fertilizer schedule should be worked out in the cropping system rather than on a single-crop basis.

Sahrawat, K.

doi: 10.1007/BF02143612pmid: N/A

Relationships between available nitrogen determined by two anaerobic incubation methods (30°C for 2 weeks: 40°C for 1 week) and seven chemical indexes (Organic C, total N, ammonium released by acid dichromate, acid permanganate, alkaline permanganate, hydrogen peroxide and dilute sulfuric acid) and nitrogen percent in rice plant, nitrogen uptake and dry-matter yield of IR 26 rice grown under submerged conditions in pots were investigated using 39 Philippine wetland rice soils differing markedly in their capacities to supply nitrogen. It was found that all the availability indexes were best correlated with nitrogen uptake of rice followed by N% in rice plants at 55 days after seeding. Dry-matter yield of rice was also significantly correlated with the available nitrogen status but the correlation coefficients were the lowest. It is concluded that for unfertilized soils, nitrogen uptake provides a better criterion for evaluating the performance of nitrogen availability indexes for wetland rice.

Carter, M.

doi: 10.1007/BF02143613pmid: N/A

The growth and mineral composition of barley and wheat was measured across sequences of Solonetz and Solod soils. Growth of both species, along with root penetration was reduced on the Solonetz compared to the Solod soil. Mineral composition of the foliage and roots indicated that a Na−K interaction was present for the barley across the Solonetz-Solod sequences. Such factors were considered to be characteristics of soil—plant relationships on Solonetzic soils.

Sylvester-Bradley, R.; Ayarza, M.; Mendez, J.; Moriones, R.

doi: 10.1007/BF02143614pmid: N/A

Three experiments were conducted in an acid infertile Oxisol from the Llanos Orientales of Colombia. It was shown that greater increases in nitrogen yield in the tops (N yield) due to N fertilization ofPueraria phaseoloides (CIAT germplasm accession no. 9900),Stylosanthes capitata no. 1019,Centrosema macrocarpum no. 5065 andDesmodium ovalifolium no. 350 occurred in undisturbed soil cores than in pots of disturbed soil. Inoculation significantly increased N yield ofC. macrocarpum in soil cores, but not in pots.

Melin, J.; Nômmik, H.; Lohm, U.; Flower-Ellis, J.

doi: 10.1007/BF02143615pmid: N/A

The distribution and quantitative recovery of isotopically labelled fertilizer N was studied in aPinus sylvestris L. stand in central Sweden. The investigation was carried out with root-isolated plots, area 31.2 m2, having a Scots pine aged 120–140 years in the centre of each plot. The fertilizer application rate was 100 kg ammonium nitrate-N per hectare, with either ammonium or nitrate being enriched with15N. The treatments comprised both a single and a split application.