Ph.D. - Soil Science

Permanent URI for this collection


Recent Submissions

Now showing 1 - 10 of 28
  • Item
    Effect of the use of lime and other soil amendments on amorphous and differentially crystallized subsoil of the Akaka series
    ([Honolulu], 1965) Dias, Irwin Patrick Solomon
    While calcium has long been known as an essential macro-nutrient for plants, it has had the distinction of having been used as a soil ameliorating agent from the very beginning of organized soil husbandry (Thompson, 1957). Calcium is ascribed several roles in plant nutrition, among which is its role in the formation of cell wall constituents, that of nitrogen metabolism and as activator of several enzyme systems. (Meyer et al., 1960). Even so, Fried and Peech (1946) discussing calcium as a nutrient, carne to the conclusion that supplying calcium as such was not important, on the probable assumption that most well-cultivated agricultural soils have a sufficient supply of calcium for nutritional purposes. Thus, it is no surprise that most of the work done with calcium has been on its role as a soil ameliorating agent, or as a liming material on acid soils, for promoting the growth of certain crops. Under the general term of lime, many materials, such as calcium carbonate, hydrated lime, dolomitic limestone, silicic slags of various descriptions, crushed serpentine rocks, cement kiln dusts, etc., have been included. Numerous reasons have been adduced by several workers for the ameliorating effect of these soil amendments in relation to the growth of specific plants on these acid soils. Among these, some of the more important are: a) Promotion of more favorable soil physical conditions (Coleman et ~, 1958). b) Improvement in the fixation of nitrogen by improved soil microbial activity (Black, 1957). c) Beneficial effect of phosphorus release from the breakdown of organic phosphates (Ghani & Aleem, 1942). d) Reduction of phosphorus fixation in soils (Mitscherlich, 1947). e) Reduction of toxic levels of manganese and aluminum in soils (Mulder & Gerretsen, 1952). f) Increasing the general effectiveness of other elements (Truog, 1953). The literature also gives ample evidence of injury to crops due to overliming (Richardson, 1951; Russel, 1961). In tropical soils, while a great deal of research has been concentrated on the amelioration and utilization of leached-out acid soils, nevertheless many gaps as in a "jigsaw puzzle" yet remain to be filled. 111is situation is best illustrated in the words of Schmehl et al., (1950) " . . . the poor plant growth associated with acid soils is a complex function of many contributing factors, all of which may be modified by liming. Not until the relative importance of the different beneficial effects of liming acid soils is fully evaluated will it be possible to make the most intelligent use of lime . . ." As for the research findings reported in this thesis, it must be pointed out that much work has already been done on the amelioration with lime of these Akaka soils (Monteith, 1961; King, 1961; Rixon, 1962; Clements, 1962, 1963; Reddy, 1964; Rana, 1964). The present work is thus an extension of the work already done, in which Akaka subsoil (2-5 feet depth) has been investigated. The main areas where the work to be reported here would contribute to additional. knowledge are: a) The laboratory study of the progressive dehydration of these soils from the state of field moistness to complete dryness, with respect to certain chemical, physical, as well as mineralogical changes. b) Use of these soils at three different moisture levels (moist, 50% moist, dry)1 for studying their response to liming. This is the first time that an intermediate moisture level has been investigated in fertility studies in these soils. c) An investigation concerning the physical mixing of the moist and dry soils in varying proportions with respect to response to lime and plant growth. d) The use of crushed Olivine Sand as a soil amendment, since this material is found occurring in abundance in the Hawaiian islands. It would prove to be an economic soil amendment if found efficacious. In addition to crushed Olivine sand, crushed coral rock and calcium silicate (TVA) was also investigated.
  • Item
  • Item
    Effects of heavy applications of lime to soils derived from volcanic ash on the humid Hilo and Hamakua coasts, island of Hawaii
    ( 1962) Rixon, Alan James
    The humid tropics provide an environment conducive to active alteration of geological material. Volcanic ash with its high porosity and extensive specific surface area weathers rapidly under these conditions. There is a heavy loss of silica and bases and an accumulation of iron and aluminum compounds. The resulting soils have a low content of crystalline clay minerals in the clay fraction, an acid reaction and a low base status particularly in regard to calcium. Soils derived from volcanic parent material are of considerable agricultural importance in the humid tropics. Abundant sources of lime in the form of coral stone often occur in the vicinity of these acidic soils. Thus an understanding of the effects of lime application to such soils is desirable. In their natural conditions the soils of the humid tropics support a dense vegetation. Lumber is a natural product from such locations. Where there is favorable topography the natural vegetation is often replaced by agricultural crops and pastures. Modifications, which may include liming of these soils are often necessary to obtain the most efficient production of these introduced species. Liming in the temperate regions has been intensively studied. At this stage there is a fairly comprehensive knowledge of the effects of liming on the soils of these latitudes. Frequently, these studies have been conducted with soils having a high percentage of crystalline clay minerals in their clay fraction. Only sparse and fragmentary knowledge regarding the effects of liming in the humid tropics is available. The existing information is often concerned with relatively light applications of lime. The soils derived from volcanic ash, in this study, are located on the humid Hamakua and Hilo coasts on the Island of Hawaii. They are used for growing sugar cane. A series of lime phosphate experimental plots has been installed on the Hilo and Hamakua coasts, with tie aim of increasing the yields of sugar cane. The high aluminum content and low pH values of these soils present the possibility that toxic amounts of aluminum may be a limiting factor in plant growth. These soils are highly amorphous, having a high capacity to fix phosphates, thus making them sparingly soluble for plant use. It is suggested that benefits to sugar cane, because of heavy liming of these soils, are due to either the reduction of the toxic effects of aluminum or improved phosphate availability. In the latter case, applied lime may produce a liberation of fixed phosphate, or reduced fixation when phosphatic fertilizers are added simultaneously, or a combination of both these effects could occur. Accordingly, in the present study, the effects of heavy lime application on the soil properties, leaching losses, and presence of various elements in sugar cane tissues were investigated. Inasmuch as little information in regard to soil modifications and sugar cane response to heavy lime applications is available, the investigation of this problem appeared worthwhile.
  • Item
    Nitrogen nutrition of the pineapple plant, Ananas comosus (L.) Merr., soil nitrogen status, and dynamics of the reniform nematode population, Rotylenchulus reniformis Linford and Oliveira, in relation to the form of nitrogen fertilizer, soil acidity, and fumigation
    ([Honolulu], 1969) Englerth, Edward Jerome
    Unpublished studies in the files of the Pineapple Research Institute of Hawaii indicate that under present cultural conditions the .pineapp1e plant displays superior performance with a foliar applied combination of ammonium and nitrate nitrogen than with either form of nitrogen alone. The studies presented here were undertaken to evaluate ammonium nitrate as a nitrogen source under different soil pH levels and fumigation regimes, using soil application of the carrier rather than foliar sprays. The studies compared ammonium nitrate with the all-ammonium fertilizer ammonium sulfate and the all-nitrate fertilizer calcium nitrate at rates of 100, 200, and 300 1b/A, using soil pH values of 4.5 and 5.5. Fumigation used in conjunction with the nitrogen sources included no fumigation, fumigation with 1,2-dibromo-3-chloropropane at 3 gal/A, and fumigation with a mixture of 1,3-dichloropropene and related hydrocarbons at 40 gal/A. A separate experiment was set up using the high and low rates of nitrogen to examine the effects of carriers and soil pH on reniform nematode numbers in the absence of fumigation. All experiments were of randomized complete block design with a factorial arrangement of treatments. Plants supplied with ammonium nitrate exhibited a slightly greater uptake of total nitrogen, no difference in protein nitrogen, a soluble nitrogen fraction intermediate in size, and a medium to high nitrate content compared to plants on all-ammonium and all-nitrate nutrition. Leaf calcium remained high compared to plants supplied with the other nitrogen carriers. The relative status of the nitrogen forms supplied was not changed by soil fumigation, though soil nitrification was greatly inhibited, resulting in a greater soluble nitrogen content in plants supplied with the ammonium carriers. The concentration of available soil manganese was increased by fumigation. For reasons not known, both liming and increased rates of ammonium sulfate tended to decrease reniform nematode populations in the absence of soil fumigation.
  • Item
    Root properties of sugarcane (Saccharum officinarum) in relation to nutrient uptake
    ([Honolulu], 1969) AbuZeid, Mohammed Osman
    An investigation was undertaken to select the appropriate methods and sampling times for measuring root cation exchange capacity (C.E.C.) and anion exchange capacity (A.E.C.) and these together with root weight and root surface area index (g saturated calcium nitrate solution covering the root surface) were related to the total uptake of N, P, K, Ca, Mg, Si and S by four sugarcane varieties (HSO-7209, HS7-5174, NCo 310, and HS6-5840) grown in solution and soil culture. The three methods selected for measuring root C.E.C. in decreasing order of differentiation between varieties, were equilibration of Ca45 with chilled fresh roots, exchange of Ca40 with chilled fresh roots and a titration method using ground dry roots. Displacing P from P saturated fresh roots with NaOH solution was appropriate in differentiating reproducibly between varieties, for measuring root A.E.C. The root C.E.C. and A.E.C. results were expressed as weight C.E.C. or A.E.C. (m.e./100 g dry roots), surface area index C.E.C. or A.E.C. (m.e./100 g saturated calcium nitrate solution) and C.E.C. or A.E.C./pot (m.e./ pot). Root type (sett or shoot) had no effect on root C.E.C. values. The C.E.C. for sett roots increased with increasing age whereas that of shoot roots decreased with increasing age. The range of C.E.C. and A.E.C. values for shoot roots was narrow for the varieties examined. Better differentiation between varieties was obtained when C.E.C. was measured by equilibration of Ca45.Varietal rankings were consistently reproduced in the several experiments when C.E.C., as measured by the three methods, was expressed on a surface area index or total pot bases. The root C.E.C. and A.E.C. values increased with increasing root weight when greater amounts of potassium were applied in both culture media. The root C.E.C. decreased in soil with better physical conditions. The cane varieties grown in solution and soil were markedly different in their growth and nutrient uptake. In the solution culture the growth and uptake were in the decreasing order of HS7-5l74, HS6-5840, HSO-7209 and NCo 310. In the soil the array was HS7-5l74, NCo 310 and HSO-7209. The C.E.C. and A.E.C. were essentially unrelated to the amounts of cations or anions sorbed by the plant, probably because total ion uptake is primarily controlled by diffusion and active absorption rather than exchange. In solution culture the root weight, root surface area index and exchange capacity values/pot were significantly correlated with shoot weight and, except for P and Si, all nutrients analyzed for. The greatest relationships were obtained with root surface area index. In the soil the root weight was significantly correlated with shoot weight and the uptake of N, Mg and S. The root weight, root surface area index and exchange capacity values/pot measured in the solution culture were related to the root weight, shoot weight and ion uptake in the soil. Possibly the measurement of root weight, root surface area index and exchange capacity values/pot by the solution culture method may aid in making a preliminary assessment of varietal differences in nutrient uptake in the field.
  • Item
    Phosphorus-silicon interactions in soils and plants
    ([Honolulu], 1969) Roy, Animesh Chandra
  • Item
    Solute dispersion in selected tropical soils
    ([Honolulu], 1969) Cagauan, Bernardino Garcia
    The dispersion of chloride, nitrate, potassium, calcium, and phosphate was investigated in three tropical soils represented by three Hawaiian soils through a specially designed flow apparatus. Observed differences in the dispersion of these solutes for the range of velocities tested were attributed to differences in ion adsorption capacity and pore geometry. Tritium showed negligible interaction with these soils and was used to trace fluid dispersion. Tritium breakthrough curves differed because of different dead-end porosities of these soils and were estimated to range from 4 to 30 per cent. Potassium, calcium, and phosphate showed trends in their breakthrough curves that were due to dead-end pores. When dead-end pore volume was large, adsorption was relatively small even when the potential for adsorbing ions was great. Because of dead-end porosity a new dimension is added to the interpretation of adsorption data. This in some cases invalidates predicted adsorption based on traditional equilibration techniques. A theoretical model was found adequate to describe the dispersion of tritium, phosphate, chloride, and nitrate under saturated-flow conditions. The unsaturated breakthrough curves of chloride and nitrate also agreed fairly adequately with theory. The unsaturated and saturated breakthrough curves of chloride and nitrate differed because of the added effect of diffusion and restriction of adsorption sites due to stagnant pores in the unsaturated case. A quantity, Ve, which is a volume measured at the arrival of one-half of the initial concentration appears to be a more useful qualitative (as well as quantitative) index of dispersion and adsorption than the dispersion coefficient, D. The experimentally obtained ratio of Ve/Vo can be interpreted to indicate the following: Ve/Vo > 1, dispersion and adsorption; Ve/Vo = 1, dispersion only; Ve/Vo < 1, dispersion in the presence of stagnant or dead-end pores. Vo is the total pore volume. Since Ve is a function of the type of solute, its concentration and pore velocity, and can be estimated by simple inspection of the breakthrough curve, its usefulness becomes more apparent than D. The dispersion approach to the study of silica-phosphate interrelations yielded results which were not in general agreement with adsorption data obtained by non-flowing, batch equilibration techniques. The adsorption of phosphate as shown by breakthrough curves was enhanced by silica treatment in two soils. Less phosphate adsorption (fixation) reported in the literature which have been attributed to silica treatment was not shown to occur in the test soils. This particular finding suggests that the reasons given for crop response to silicate applications to soil need to be reexamined.
  • Item
    Nature and distribution of organic nitrogen in tropical soils
    ([Honolulu], 1969) Briones, Angelina Mariano
    Distribution of total nitrogen, organic nitrogen forms, and organic matter fractions was studied in -a number of tropical soils. The mineralizable fraction of organic nitrogen and nature of humic and fulvic acids in soils as well as the interaction of these organic matter fractions with soils were also examined. Amounts of total soil nitrogen and its organic forms (hydrolyzable ammonium-N, amino sugar-N, amino acid-N, unidentified hydrolyzable-N, and acid insoluble-N) were markedly influenced by climate. The most striking difference in the amounts of these fractions in various soils was obtained in the acid insoluble-N fraction. Volcanic ash soils developed under high moisture (150 to 250 inches mean annual rainfall) were found to have high nitrogen contents but contained small amounts of acid insoluble-N. In contrast, the acid insoluble-N content of soils occurring under lower rainfall (20 to 40 inches) was considerably higher. Soils derived from crystalline basalt exhibited similar trends. The Lualualei soil developed from alluvium however contained negligible amounts of acid insoluble-N. Changes In the amounts of the organic nitrogen forms after incubation (12 to 18 months) were determined to pinpoint the mineralizable nitrogen fraction. The amounts of hydrolyzable ammonium-N, amino sugar-N, unidentified hydrolyzable-N, and acid insoluble-N slightly increased or decreased with time. Amino acid-N consistently decreased with incubation time. The decrease in amino acid-N was significantly correlated to the increase in mineralized nitrogen content. Distribution of humic and fulvic nitrogen in volcanic ash soils varied markedly with climate. Humic acids predominated in soils developed under low rainfall while fulvic acids were high in soils developed under high rainfall. Basalt-derived soils behaved similarly except for Waialua and Lualualei soils. The Lualualei soil yielded no humic acid and the Waialua soil possessed a low proportion of this fraction. The trend in humic acid distribution followed the distribution pattern of acid insoluble-N. The chemical nature of acid insoluble-N is still unknown. In order to provide more information on the nature of nitrogen in particular fractions of organic matter, the proportions of acid insoluble and hydrolyzable nitrogen in humic acids were determined. It was found that the amount of acid insoluble-N is significantly correlated to the amount of humic acid in soils. Infrared data showed that humic acids of soils developed under high rainfall had lower amounts of aromatic groups than those from soils formed under lower rainfall. Fulvic acids were found to have a more intense absorption band for carboxylic groups than the humic acids. Adsorption of humic and fulvic acids on organic matter-free soils showed that adsorption was strongly concentration and pH dependent. More organic acids were adsorbed in the acid range, and for a given pH adsorption increased exponentially with concentration.
  • Item
  • Item