GRASSLAND RESEARCH ON BLANKET PEAT IN IRELAND

The results from 10 years of grassland research at the Peatland Experimental Station, Glenamoy, are summarized.
Grass and legume species were introduced by surface seeding, without cultivation or by direct seeding after rotavation, depending on the specific situation. The rate of establishment was dependent on pretreatment and the management of grazing animals before and after sowing.
The most suitable species were Trifolium repens, Lolium perenne, Festuca arumlinacea, Festuca rubra and Holcus lanatus .
A level of fertility suited to the introduced species must be reached initially and subsequently maintained. The requirements (per/ac) for Ca, P, K, N, Cu and Co were: 2240 lb (1016 kg) ground limestone, 36 lb (16 kg) P, 112 lb (51 kg) K, 20 lb (9 kg) N, 20 lb (9 kg) CuSO₄ and 2 lb (0–91 kg) CoSO₄ at sowing, with 27 lb (12–25 kg) P and 56 lb (254 kg) K annually.
Dry–matter yields of 6000 lb/ac (6720 kg/ha) were obtained from grass–clover swards without fertilizer N, and approximately twice this quantity where 400 lb N/ac (448 kg/ha) had been applied annually. A liveweight gain of 526 lb/ac (589–12 kg/ha) and a starch equivalent output of 2946 lb (3299–5 kg) were obtained with sheep. The relationship between these results and those on peat soils abroad are discussed.     

Ripening of Tomatoes

Experiments were carried out with aldrin, dieldrin, isodrin, endrin and DDT to ascertain whether, employed as insecticides, these compounds had any effect on cell division in onion root-tips. The doses used were equal to, or greatly in excess of, the recommended rates of application. By germinating onion seeds in direct contact with the insecticide under investigation, it has been shown that none of the compounds had any effects on germination or growth rate. High doses of aldrin, dieldrin or isodrin had a slight toxic effect on the resting cell, which, with aldrin, was also caused by the recrystallized compound. Aldrin and dieldrin had no effect on the dividing cell. Isodrin and endrin caused slight stickiness between chromatids in anaphase, which was insufficient to prevent the completion of division in the cell, and DDT caused a delay in the early stages of prophase and a shortening of chromosomes in metaphase.

Pot experiments, with high doses of each compound, showed that germination and growth rate were unaffected by any of the compounds. Resting cells were not affected and dividing cells were affected only by slight stickiness in anaphase, except with DDT, which also caused a slight delay in metaphase.

Attention has been drawn to the advantages of these compounds over gamma-BHC, chlordane and toxaphene as insecticides, from the point of view of causing less damage to the plant.     

The Response to Epsom Salt Sprays of Mature Apple Trees of Three Varieties on Two Contrasting Rootstocks

Mature trees of Beauty of Bath, Tydeman’s Late Orange and Laxton’s Superb on M.VII rootstock, growing under commercial-type conditions, were severely deficient in magnesium as shown by leaf analysis and typical symptoms. Five sprays yearly of 2% Epsom salt (MgSO₄.7H₂ O) raised the concentration of magnesium in the leaves and largely eliminated symptoms: the concentrations of calcium and, to a lesser extent, of potassium in leaves were reduced. Over six years, there was little effect of Epsom salt on growth as measured, but crop weight was increased by 19–39% according to variety: this was largely, but not entirely, due to increase in fruit set. The proportion of fruit that dropped was decreased for Beauty of Bath and for Tydeman’s Late Orange sprayed with Epsom salt and the weight per 100 fruits of the late varieties Tydeman’s Late Orange and Laxton’s Superb was increased. Untreated trees on M.II rootstock, in contrast to those on M.VII, showed almost no foliar symptoms of magnesium deficiency, made more growth and produced larger crops; the concentrations of magnesium and calcium in the leaves were higher whereas potassium was usually lower. Epsom salt sprays did not increase growth or cropping; indeed, there was a tendency for sprays to reduce the crop weight of Beauty of Bath on M.II, indicating that they should not be used indiscriminately.

Epsom salt foliar sprays increased the “available” magnesium in the soil to a level considered to be medium—high; this effect was mainly shown in the top 6 in. of soil and gradually diminished to the 18–24 in. zone. Nevertheless, in the year following the termination of treatments, the proportion of foliage affected in Laxton’s Superb on M.VII, previously sprayed with Epsom salt, was almost as great as that of untreated trees and the concentration of magnesium in the leaves was as low. It appeared that magnesium in the soil did not reach the leaves.

The increase in “available” magnesium due to sprays was greater in soil carrying trees on M.II than M.VII, a result probably due to the extra quantity of spray required for these larger trees.     

Growth Regulator Effects on Quality and Pre-Harvest Drop of Worcester Pearmain Apples

The application of 2-chloroethylphosphonic acid (CEPA) at 750 or 1500 ppm improved the colour of early harvested Worcester Pearmain apples but greatly increased pre-harvest drop. The drop-promoting effect of CEPA could be overcome by applying succinic acid 2,2-dimethyl hydrazide (aminozide) at 2000 ppm or a-(2,4,5-trichlorophenoxy)-propionic acid (2,4,5-TP) at 20 ppm. The combination of CEPA 750 ppm+2,4,5-TP 20 ppm appeared to be particularly promising for improving the attractiveness, flavour and texture of Worcester Pearmain picked on 1st September and 7th September. No damage was seen on the trees either in the year of application or the following year.     

The emergence and early growth of French and runner beans (Phaseolus vulgaris L. and Phaseolus coccineus h.) sown on different dates

The results are reported of an investigation into the effects of sowing on different dates on the emergence and growth of various cultivars of Phaseolus vulgaris and P. coccineus under field conditions. In 1969 five cultivars of French bean and three of runner bean were sown in the field at fortnightly intervals from April onwards. The experiment was repeated, with the addition of two cultivars, in 1970. Consistent differences were found between and within species for a number of growth parameters.

(1) Especially in the early sowings, seedlings of runner beans emerged before those of French beans, and small-seeded cultivars of French bean (in particular Comtesse de Chambord) before larger-seeded cultivars.

(2) The mean relative growth rates measured after emergence were greater in French beans than in runner beans, but differences within species were not significant. Very early sowing appeared to have a lasting depressive effect on the growth rates of seedlings of both species.

(3) The estimated weights of seedlings at emergence (estimated from regressions of seedling weight on time since emergence and on seed weight) were lower in the early sowings than in later sowings, and especially so in the cultivar Comtesse de Chambord.

The main results in each year were similar, but some differences in detail were found. In particular there were differences between years in the emergence of cultivars as affected by soil temperature. The discrepancies were attributed to a difference in the temperature regimes of the two sites.     

Distribution and Phytoavailability of Lead in a Soil Contaminated with Lead Shot

Water, Air, &; Soil Pollution - This paper presents a study of Pb contamination of soil at a clay target shooting facility in Canterbury, New Zealand. The spatial distribution of Pb...     

Modifications of wheat flour proteins during in vitro digestion of bread dough, crumb, and crust: an electrophoretic and immunological study

The proteins of wheat flour have several biological activities that can affect human health and physiology when wheat-based foods are consumed. The modifications of bread crumb and crust proteins during an in vitro peptic/pancreatic digestion process were studied by electrophoresis and immunoblotting with polyclonal antibodies specific for single proteins or groups of homologous proteins of the wheat flour, and the results were compared to those obtained for an unheated dough sample. The results show that baking affects the extent of proteolysis and the immunological and physicochemical features of the digestion products in relation to the level of the heat treatment. Therefore, the results concerning the digestion of the unheated wheat flour or dough are not representative of what happens when baked products enter the human digestive tract.     

运用SWRRB模型研究西班牙Teba流域水量和沉积物量: Ⅰ. 模型输入及模拟实验

Water yield and sediment yield in the Teba catchment, Spain, were simulated using SWRRB (Simulator for Water Resources in Rural Basins) model. The model is composed of 198 mathematical equations. About 120 items (variables) were input for the simulation, including meteorological and climatic factors, hydrologic factors, topographic factors, parent materials, soils, vegetation, human activities, etc. The simulated results involved surface runoff, subsurface runoff, sediment, peak flow, evapotranspiration, soil water, total biomass, etc. Careful and thorough input data preparation and repeated simulation experiments are the key to get the accurate results. In this work the simulation accuracy for annual water yield prediction reached to 83.68%.     

Estimation of soil strength properties for critical rooting conditions

Methods to aid in the large-scale testing and characterization of Coastal Plain soils based on their susceptibility to root-limiting strength problems were developed and analyzed. They were basically regression equations modeled after a Taylor series expansion. The equations relate changes of soil strength, bulk density and soil water content between field and “critical rooting conditions”. Once equations wered eveloped from a data set of 426 laboratory samples, critical rooting bulk density was predicted for a separate set of laboratory and field samples. All laboratory samples and appropriate field samples were equilibrated at — 100 kPa soil-water potential. Soils used were sandy Ultisols, which may limit the scope of equations.

In many cases, changes in the water contents were not a significant factor in the prediction of soil strength. This may be a reflection of the limited capabilities of the equations, the uniform equilibration of soil-water potential of the soils, or the fact that the slope of the strength vs. bulk density curve is independent of water content over the range of samples considered. Nevertheless, it does simplify the equations and may suggest that a series of several equations for different soil types would be better than a single equation that requires soil-water content.     

Determination and toxicity of saponins from Amaranthus cruentus seeds.

The concentrations of four triterpene saponins present in amaranth seeds were determined with high-performance liquid chromatography. It was shown that the total concentration of saponins in seeds was 0. 09-0.1% of dry matter. In germinating seeds an increase in concentration to 0.18% was observed after 4 days of germination, which remained stable for the next 3 days and later dropped to 0.09%. Highly purified extracts from the seeds were tested for their toxicity against hamsters. The hydrophobic fraction obtained by the extraction of seeds with methylene chloride showed no toxicity; the behavior of tested animals was similar to that of the group given an equivalent dose of rapeseed oil. A crude saponin fraction, containing approximately 70% of pure saponins in the matrix, showed some toxicity; the approximate lethal dose was calculated as 1100 mg/kg of body weight. It is concluded that low contents of saponins in amaranth seeds and their relatively low toxicity guarantee that amaranth-derived products create no significant hazard for the consumer.