Effects of a lowland rice crop and of gypsum on a saline alkali clay

1956 ◽  
Vol 7 (2) ◽  
pp. 110 ◽  
Author(s):  
KP Barley ◽  
JT Hutton
Keyword(s):  
Seedling Establishment ◽  
Surface Soil ◽  
Clay Soil ◽  
Subterranean Clover ◽  
Rice Seedling ◽  
Exchangeable Cations ◽  
Lowland Rice ◽  
Rice Crop ◽  
Soluble Salts ◽  
Clay Dispersion

Lowland rice cropping for one season decreased the soluble salts, particularly the chlorides, in the top 30 in. of a saline alkali clay soil. The calcium:sodium ratio increased for soluble cations, but showed little change for exchangeable cations. The surface soil became slightly more water-stable, but below 3 in. the soil became easier to disperse. These changes had little effect on the growth of an irrigated annual pasture sown after rice cropping, except in the year of establishment. After 2 years' growth of the pasture, part of the soluble salts had returned to the top 30 in. of the soil. The application of gypsum at 2 and 8 tons/acre before growing the lowland rice crop increased the ca1cium:sodium ratio of both soluble and exchangeable cations and reduced clay dispersion. Rice seedling ,establishment and yields of stubble-sown subterranean clover were higher on the gypsum-treated plots.

EFFECT OF ROTATIONS, TILLAGE TREATMENTS AND FERTILIZERS ON THE AGGREGATION OF A CLAY SOIL

1971 ◽  
Vol 51 (2) ◽  
pp. 235-241 ◽  
Author(s):  
G. S. EMMOND
Keyword(s):  
Green Manure ◽  
Crop Residues ◽  
Surface Soil ◽  
Clay Soil ◽  
Soil Aggregation ◽  
Wheat Crop ◽  
Green Manure Crop

Soil aggregation was lowest in a fallow-wheat rotation and increased in other fallow-grain rotations with the second, third, and fourth crops after the fallow year. The best aggregation was under continuous wheat. Rotations containing hay crops, particularly those with grass, increased soil aggregation significantly. The influence of tillage treatments on soil aggregation declined with increased depth. Various tillage treatments affected surface soil aggregation, in the following order: green manure crop plowed under > cultivated with trash cover > crop residues plowed under > cultivated with residues burned off = crop residues disced in. Fertilizer (11–48–0) applied to the wheat crop of the various tillage treatments increased soil aggregation except where the crop residues had been removed. The application of barn manure increased soil aggregation.

scholarly journals Congenital goitre in sheep in southern Tasmania

1975 ◽  
Vol 26 (4) ◽  
pp. 751 ◽  
Author(s):  
M Statham ◽  
AC Bray
Keyword(s):  
Drinking Water ◽  
Soil Type ◽  
Clay Soil ◽  
Subterranean Clover ◽  
Moisture Stress ◽  
Iodine Intake ◽  
Minimum Level ◽  
Soil Ingestion ◽  
The One ◽  
Animal House

Congenital goitre was first recorded in Tasmanian sheep In 1945. Severe but sporadic outbreaks have since occurred in 1956, 1964 and 1968. The disease seemed to be associated with particular farms and its incidence often differed markedly between ewe flocks on the one farm. A survey indicated that the condition was mainly confined to the Derwent Valley and the northern Midlands. Studies involved a grazing trial near Bothwell, where goitre was endemic, and included supporting animal house tnals and plant growth studies. Soil type was shown to be a major factor in the disease: ewes grazing pasture on a sandy soil produced many more goitrous lambs than ewes grazing pasture on clay soil. Analyses of the two pastures revealed that those on sandy so11 contained less iodine than those on clay soil but neither contained the minimum level necessary to prevent goitre. Observations revealed that outbreaks of the disease followed wet autumns with subsequent lush pasture during pregnancy. This correlation could be explained if pasture grown under moist conditions contained less iodine than pasture grown under moisture stress. However, experiments with the two main pasture species (perennial ryegrass and subterranean clover) showed that plant iodine levels were not affected by the water supply. Two goitrogenic agents, nitrate and thiocyanate, were present in the pastures, but they were not considered to be Important in the aetiology of the disease. Similarly, the drinking water was found to be unimportant, even though the two sources available contained widely different amounts of iodine. Apparently, between-year variation in the incidence of goitre and the effect of soil type can best be explained by a varying iodine intake dependent on soil ingestion which varies with pasture availability. This hypothesis is discussed in the light of the results.

MINERALOGY OF CHAMPLAIN SEA SEDIMENTS AND A RIDEAU CLAY SOIL PROFILE

1961 ◽  
Vol 41 (2) ◽  
pp. 169-181 ◽  
Author(s):  
J. E. Brydon ◽  
L. M. Patry
Keyword(s):  
Soil Profile ◽  
Clay Soil ◽  
Exchangeable Cations ◽  
Canadian Shield ◽  
Metamorphic Rocks ◽  
Carbonate Content ◽  
Remarkable Similarity ◽  
Textured Materials ◽  
Marine Clays ◽  
Mineral Constituents

Marine clays and silts of the Champlain Sea, or "Leda clays", from several locations in the Ottawa and St. Lawrence Valleys, and a Rideau Clay soil profile developed on this material have been examined. Although the textures of the marine sediments varied, there was a remarkable similarity in the nature of the mineral constituents of the sands, silts and clays; feldspars, quartz, amphiboles, micas, and chlorites occurred in all size fractions. In addition, the clay fractions contained small amounts of montmorillonite and interstratified illite-montmorillonite. All but two of the marine samples were slightly calcareous and, in general, the coarser textured materials contained the highest carbonate content. The main source of the deposits is believed to be the igneous and metamorphic rocks of the Canadian Shield, and there is very little evidence of weathering before, during and since deposition.The Rideau Clay is a moderately well-drained regosolic soil with very little difference in exchangeable cations or mineral composition with depth. The occurrence of illuviation could not be shown conclusively because of apparent depositional differences. The Rideau Clay differed from the marine materials in having no carbonates, in being slightly acid throughout, and in having a greater amount and a different type of interstratified clay minerals.

HALOMORPHISM OF SOME CLAY SOILS IN MANITOBA

1958 ◽  
Vol 38 (2) ◽  
pp. 105-115
Author(s):  
W. A. Ehrlich ◽  
R. E. Smith
Keyword(s):  
Exchangeable Cations ◽  
Water Soluble ◽  
Clay Soils ◽  
Exchangeable Sodium ◽  
Soluble Salts ◽  
Exchangeable Calcium ◽  
Causative Agents ◽  
Exchangeable Magnesium ◽  
Soluble Calcium

The analysis of the principal horizons of 11 halomorphic profiles was undertaken in an attempt to ascertain, chiefly, the kind and quantity of soluble salts and exchangeable cations assumed to be the main causative agents in the formation of solonetzic soils in Manitoba. The results showed that water-soluble sodium was equal to or greater in quantity than water-soluble calcium or water-soluble magnesium; that exchangeable calcium followed closely by exchangeable magnesium dominated the exchange complexes; and that exchangeable sodium in excess of 15 per cent of the exchangeable cations was found only in some horizons of the Solonchak, Solonetz and Solodized-Solonetz soils in the Chesterfield Association.

Plant and animal constraints to voluntary feed intake associated with fibre characteristics and particle breakdown and passage in ruminants

1996 ◽  
Vol 47 (2) ◽  
pp. 199 ◽  
Author(s):  
JR Wilson ◽  
PM Kennedy
Keyword(s):  
Organic Matter ◽  
Dry Matter ◽  
Shoot Growth ◽  
Surface Soil ◽  
Clay Soil ◽  
Grass Species ◽  
Soil Nitrate ◽  
The Sun ◽  
N Yield ◽  
Organic Matter Breakdown

Effects of artificial shading to 50% sunlight of nitrogen (N) limited tropical pastures of different grass species on a high (clay loam) and low (granitic loam) fertility soil type were evaluated in a semi-arid. subtropical environment over 3 years. The hypothesis was tested that shade can stimulate shoot growth by providing a modified environment more conducive to organic matter breakdown leading to increased mineralisation and availability of soil N, and the ability of tropical grasses to take advantage of this effect was examined. Unfertilised pastures of green panic (Panicum maximum var. trichoglume), buffel (Cenchrus ciliaris). rhodes (Chloris gayana), and speargrass (Heteropogon contortus) in full sun or shaded by sarlon cloth were sampled on 9 occasions. Additional green panic plots on both soils were irrigated for the first 2 years, and all other plots were dependent on natural rainfall. Shoot and root dry matter and N yield, and soil nitrate and ammonia N, were measured. In one set of green panic plots on each soil, canopy. litter, and surface soil temperatures were monitored continuously, and soil moisture at different depths was measured fortnightly. Shade stimulated shoot dry matter yield over the 3 years by up to 37% in green panic. 22% in rhodes, and 9% in speargrass. Shade decreased buffel yield on the clay soil but had no effect on the granitic soil. Relative increases in yield of shoot N were similar to those for shoot dry matter, except for buffel on the granitic soil where N yield was increased by 39% with no increase in shoot growth. Positive shade responses occurred in all 3 years but were reduced by extreme drought in year 3, particularly on the clay soil. Irrigation gave a greater shade response on the clay but not on the granitic soil. Root mass was lower under shade than in full sun. but there was no long-term trend of progressive decrease. and the change in N yield of roots did not appear to explain the gain in shoot N of the shaded pastures. Nitrogen percentage in the youngest expanded leaf was higher in the shade than the sun leaves only after about 2 to 2 5 months of shading. Surface soil nitrate and ammonia concentrations tended to be higher under shade for most harvests. Shade lowered temperature extremes of surface soil and litter by up to 10-12�C, and improved soil water status. compared with the sun plots. Soil water data were analysed to separate effects on plant water stress and soil microbial activity. The consistent positive response of shoot N yield to shade across grass species. weeds, and soil type. the delay in it becoming evident, and its longevity all support the hypothesis that shade enhances organic matter breakdown and N cycling. Harsh surface temperatures and low soil moisture in open sun pastures appear inimical to high microbial activity. Implications for pasture management are discussed. with the caveat that the outlined benefits of artificial shade may not necessarily arise with tree canopies.

Alkali investigations in the Sudan

1925 ◽  
Vol 15 (4) ◽  
pp. 407-419 ◽  
Author(s):  
A. F. Joseph
Keyword(s):  
Sodium Carbonate ◽  
Clay Soil ◽  
Salt Content ◽  
Sodium Sulphate ◽  
Water Soluble ◽  
Soluble Salts ◽  
Nile Water ◽  
Heavy Clay ◽  
Alkali Salts ◽  
Very High

(1) The cotton growing area in the Gezira consists of a heavy clay soil, the proportion of clay being about 50–60 per cent. in the upper layers with a maximum at about the 4th foot.(2) The water soluble salts amount to about 0·2 per cent. The proportion is highest at about the 3rd to 5th foot. The alkalinity (pH) is highest at the 2nd foot.(3) In the first 2 feet, the salts consist mainly of sodium carbonate and the third and fourth of sodium sulphate.(4) The irrigation (Blue Nile) water is of excellent quality as judged by its natural chemical composition. The concentrated water, however, contains a very high proportion of alkali salts. It is estimated that a season of normal irrigation would cause an increase of 0·01 per cent. in the alkali content of the first 4 feet of soil.(5) The sodium salts can readily act on the clay and the sodium clay so formed hydrolyses with the formation of sodium carbonate.(6) Samples taken at the same time from good and bad plots in the same area show a strong correlation between salt content and cropyielding power. There is also a correlation between pH and fertility.(7) In the same season and in the same area, virgin (i.e. unirrigated) plots give a higher yield than those which have been previously under the same system of cultivation.

Mineral nitrogen in soils undergoing irrigated rice-upland crop rotations

1980 ◽  
Vol 20 (107) ◽  
pp. 731 ◽  
Author(s):  
IR Willett ◽  
ML Higgins
Keyword(s):  
Ammonium Nitrogen ◽  
Early Growth ◽  
Mineral Nitrogen ◽  
Lowland Rice ◽  
Rice Crop ◽  
Growth Stages ◽  
Poor Growth ◽  
Nitrogen Levels ◽  
Crop Uptake ◽  
Upland Crop

Surface soil (0-150 mm) mineral nitrogen levels were monitored in field plots undergoing rice-wheat-wheat and rice-fallow rotations to study the effects of rice growing on the mineral nitrogen content of soils for subsequent crops. Ammonium nitrogen accumulated in the soils during the first 3 weeks of flooding of the rice crop, reaching 54 mg N kg-1 in a grey clay, and 23 mg N kg-1 in a transitional red-brown earth. Thereafter, ammonium nitrogen decreased so that at the time of drainage the soils contained between 2 and 6 mg N kg-1. Nitrate levels during the flooding period fluctuated between 1 and 7 mg N kg-1. In each subsequent fallowing period, nitrate levels increased so that there was approximately 20 mg N kg-1 as nitrate present during the early growth stages of the post-rice crops. However, at the harvests of each post-rice crop, nitrate nitrogen levels had decreased to between 1 and 7 mg N kg-'. Fluctuations in nitrate levels were interpreted in terms of gains from mineralization and nitrification and losses by crop uptake, although leaching and denitrification during periods of heavy rainfall or irrigations could not be assessed. Ammonium levels in the post-rice period increased in the months of October and November when fallowed, but other fluctuations showed no consistent trends. Nitrite levels were low (< 0.6 mg N kg-1) throughout the experiments. Total mineral nitrogen levels during the early growth stages of the crops grown after the rice corresponded to between 31 and 95 kg N ha-1 in the surface 0-150 mm of soil. It was concluded that in the rotations studied, lowland rice cropping did not lead to depletion of mineral nitrogen to such an extent that it could be implicated as a factor in the poor growth of upland crops grown in rotation with lowland rice.

A Method for obtaining Samples of the Population of Collembola (Symphypleona) in Pastures

1933 ◽  
Vol 24 (3) ◽  
pp. 351-352 ◽  
Author(s):  
J. Davidson ◽  
D. C. Swan
Keyword(s):  
Moisture Content ◽  
Total Population ◽  
Surface Soil ◽  
Relative Proportion ◽  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Food Plants ◽  
Simple Method ◽  
Factors Affecting

In our investigations on Smynthurus viridis, L., a study has been made of the population of this species, in an area of lucerne, at intervals of three and four days throughout the season.The density of the population of the species in a favourable pasture is markedly affected by the relative abundance of certain food-plants, especially leguminous species and particularly clovers such as subterranean clover (Trifolium subterraneum) and lucerne (Medicago sativa).The activity of the insect is intimately associated with the moisture of its environment, and the moisture content of the surface soil is one of the most important factors affecting the environmental conditions.Considering the habits of the insect, it was felt that the sweeping method would not give a reliable record of the total population in a given area of pasture. A sample obtained by sweeping with a net does not include individuals on or near to the surface of the soil. The relative proportion of individuals situated on or near the soil surface and those situated further up the plants varies considerably from time to time, according to the meteorological conditions, the growth of the herbage and the moisture content of the surface soil. It was necessary therefore to devise a simple method by means of which a more accurate record of the total population in a given area could be obtained.

Effect of cropping sequences on soil nitrogen levels, rice growth, and grain yields

1994 ◽  
Vol 34 (7) ◽  
pp. 977 ◽  
Author(s):  
HG Beecher ◽  
JA Thompson ◽  
PE Bacon ◽  
DP Heenan
Keyword(s):  
Grain Yield ◽  
Soil Nitrogen ◽  
Subterranean Clover ◽  
Rice Crop ◽  
Growth And Yield ◽  
Rice Grain ◽  
Grain Yields ◽  
Rice Growth ◽  
Soil Ammonium ◽  
Clover Pasture

The effect of 7 different crop and pasture sequences and cereal stubble management on soil nitrogen (N) levels and growth and grain yield of 2 subsequent rice crops was studied over 6 years (1986-92) on a Birganbigil clay loam soil at Yanco Agricultural Institute. After harvest of an initial rice crop in 1987, the following crop sequences were imposed: continuous annual rice cropping; 2 triticale crops, 2 seasons of pasture; pasture for 4 seasons; a second rice crop, 3 seasons of pasture; a second and third rice crop, 2 seasons of pasture; winter cereals; double cropped (winter-summer) on raised beds. The growth and productivity of 2 subsequent rice crops (1990-91, 1991-92) was then evaluated. Stubble retention rather than burning was practiced on half of each plot. Half of each pasture plot was sown to annual pasture (Trifolium subterraneum), while the other half was sown to perennial pasture (Trifolium repens). All plots returned to rice in 1990-91 and N rates up to 400 kg N/ka were applied. No fertiliser was applied to the 1991-92 crop. Anaerobic incubation ammonium content of soil, sampled before sowing of the 1990-91 rice crop, ranged from 28 to 85 pg/g oven-dried soil. The 1990-91 rice crop reduced soil ammonium by 30 y g/g in all sequences except continuous annual rice cropping. These differences in soil ammonium content were significantly correlated with rice growth and yield. Dry matter at panicle initiation and at physiological maturity and grain yield all increased significantly with N fertiliser application for all crop sequences. This indicates the benefit of N fertiliser, even after a 4-year pasture phase. Modelled grain yield from the unfertilised 2-year subterranean clover pasture (10.4 t/ha) was equal to that from the continuous rice sequence receiving 212 kg N/ha. Applying 320 kg N/ha to continuous rice plots produced yields similar to that of the 2-year subterranean clover pasture sequence, which received 98 kg N/ha. This indicates that the major effect on grain yield of different crop sequences could be alleviated through high N applications. Stubble management had little effect on rice growth or grain yield. Sequences with pasture phases of 2, 3, and 4 years produced similar rice grain yields. Pasture phases still had a positive effect, compared with continuous ricegrowing, on the second rice crop; however, crop growth and grain yield were about half that obtained from the unfertilised plots of the first rice crop. We conclude that continuous, high-yielding, annual ricegrowing can be maintained provided the N supply is adequate, that highly productive legume-dominant pasture phases of 2, 3, or 4 years contribute eqivalent amounts of N to succeeding rice crops, and that stubble management technique or pasture type has little effect on grain yield.

The effect of chemical fertilizers on seedling establishment

1967 ◽  
Vol 7 (25) ◽  
pp. 174 ◽  
Author(s):  
OG Carter
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Potassium Chloride ◽  
Perennial Ryegrass ◽  
Seedling Establishment ◽  
Soil Moisture Content ◽  
Subterranean Clover ◽  
Nitrogen Fertilizers ◽  
Chemical Fertilizers ◽  
Calcium Ammonium Nitrate

The effect of banding a range of commercial fertilizers with the seed, on the establishment of a number of crop and pasture species, was studied. The order of susceptibility of species to germination damage was swede turnips>chou moellier> subterranean clover> phalaris> perennial ryegrass> cowpeas> vetches> wheat > oats, which was least affected of all. Superphosphate caused the least reduction in establishment, potassium chloride was intermediate and nitrogenous fertilizers caused the greatest reduction. Of the nitrogen fertilizers urea was the most harmful, sulphate of ammonia intermediate, and calcium ammonium nitrate caused least effect. Low soil moisture content greatly increased fertilizer damage.

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