Red Loam Soil Research Articles

Declines in Vegetation Patches, Plant Diversity, and Grasshopper Diversity Near Cattle Watering-Points in the Victoria River District, Northern Australia.

In this study, we quantify the density, cover and obstruction width of vegetation patches, the roughness of landscape surfaces, and the diversities of plants and grasshoppers with distance from cattle watering- points. We used distance from water as a surrogate for a gradient in grazing pressure. Fourteen study sites were located in the Victoria River District of northern Australia, seven from a water point on Kidman Springs Station on calcareous red loam soils and seven from a water point at Mount Sanford Station on craclcing-clay black soils. At each study site transect lines were oriented within the landscape to run downslope (i.e. in the direction of flows of run-off). We measured the intercept length and obstruction width of perennial vegetation patches along these lines. Plant diversity was measured in quadrats positioned along each line and grasshopper diversity was determined by species counts on each site. We also surveyed the roughness of the landscape surface along each line. A rough surface will tend to slow run-off. hence increase time for water infiltration and soil-water storage. Surface roughness declined near water, as did the density, cover and obstruction width of perennial vegetation patches. Grasshopper and plant species richness also declined near water. These declines suggest strong linkages between landscape filmtion. biodiversity and inipacts of cattle grazing and trampling. Cattle will always create 'sacrifice zones' around watering-points. However, the area of this impact on function and diversity can be minimised by managing the timing and intensity of paddock use. Key words: grazing gradients. Kidman Springs, landscape function. Mount Sanford, piosphere, surface roughness, tropical grasslands, tropical savannas

Improvement of Dry Tropical Rangelands on Hainan Island, China. 3. Legume Response to Initial Fertilizer

During 1981-83, we identified nutrient requirements and fertilizer strategies for the development of legume-based pastures in dry tropical rangelands of Hainan Island, China. Nutrient requirements for pastures grown on sandy and red loam soils were established using soil tests and missing element experiments with 3 test legumes. An acute P deficiency ( 20 mg kg-1. In contrast, application of P fertilizer proved both profitable and essential for development of legume-based pastures on P-deficient sandy soils. It is recommended that a rate of about 40 kg of P ha-1 should be applied at establishment of stylo pastures on sandy soil. At this rate both legume yield and P content of tops should be maintained at levels needed to sustain a beef production enterprise and return about $1.5 per dollar invested in fertilizer.

Influence of different factors on the adsorption of carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl- N-methyl carbamate) on soils

The effects of exchangeable cations (H + and Na +), autoclaving, organic matter, cationic and anionic surfactants, and temperature on the adsorption of carbofuran on two different types of soils were studied. The adsorption isotherms for all effects/treatments were in close agreement with the Freundlich equation and yielded S-shaped isotherms. The amount of carbofuran adsorbed in all cases was higher in Jhansi red loam soil than in Pilibhit sandy loam soil and was related to organic matter content, clay content, CaCO 3 content, surface area, and cation-exchange capacity of the soils. The adsorption on soils from both sites follows the order H soil → Na soil → natural soil at 25°C → autoclaved soil → soil from which organic matter had been removed → cationic surfactant → anionic surfactant → natural soil at 50°C and was in accordance with Freundlich constant K values and distribution coefficient K d values. The adsorptive capacity of carbofuran for organic matter and clay content for both the Jhansi and the Pilibhit soils was also evaluated by calculating K om and K c values, and it was found that the carbofuran adsorption was better correlated with clay content than with organic matter content of soils. On the basis of adsorption isotherms, various thermodynamic parameters such as the thermodynamic equilibrium constant K 0, standard free energy ( ΔG°) changes, standard ethalpy ( ΔH°) changes, and standard entropy ( ΔS°) changes have been calculated in order to predict the nature of isotherms.

Improvement of Dry Tropical Rangelands in Hainan Island, China: 2. Evaluation of Pasture Grasses

During 1981-83, we studied 19 grasses for potential improvement of dry tropical (1,001 mm annual rainfall) rangelands in Hainan Island, China. The productivity and persistence of the grasses were tested on sandy ( 5 plants/m2), but only 6 cultivars produced yields > 1.5 metric tonne (t)/ha. Melinis minutiflora Beauv., Brachiaria decumbens Stapf. and Chloris gayana Kunth. yielded more than 1.5 t/ha in 3-year-old swards on both soils, whereas Panicum maximum Jacq. and Setaria sphacelata (Schum.) Stapf. ex Massey only performed well on fertile loam soil. Grass establishment was superior on sandy soil, but plant density did not correlate well with production which was higher on red loam soil due to better waterholding capacity and nutrient status. Compatibility of these successful grasses with companion legumes was low with legumes contributing 4 t/ha. S. sphacelata was the only grass to form a stable mixture with companion legumes. [Macroptilium atropurpurem (D.C.) Urban and Stylosanthes guianensis (Aubl.) Sw.], which yielded more than 1.1 t/ha in 3-year-old swards on loam soil. This combination was recommended for improvement of loam soil rangelands. It is concluded from this study that range improvement with perennial grasses is confined to fertile soils, while direct broadcast of Stylosanthes legumes only into grazed native pastures is the practice recommended for improvement of infertile sandy soil until persistent low P tolerant grasses are found for the dry tropics.

Improvement of Dry Tropical Rangelands in Hainan Island, China: 1. Evaluation of Pasture Legumes

During 1981-83, we studied 19 grasses for potential improvement of dry tropical (1,001 mm annual rainfall) rangelands in Hainan Island, China. The productivity and persistence of the grasses were tested on sandy ( 5 plants/m2), but only 6 cultivars produced yields > 1.5 metric tonne (t)/ha. Melinis minutiflora Beauv., Brachiaria decumbens Stapf. and Chloris gayana Kunth. yielded more than 1.5 t/ha in 3-year-old swards on both soils, whereas Panicum maximum Jacq. and Setaria sphacelata (Schum.) Stapf. ex Massey only performed well on fertile loam soil. Grass establishment was superior on sandy soil, but plant density did not correlate well with production which was higher on red loam soil due to better waterholding capacity and nutrient status. Compatibility of these successful grasses with companion legumes was low with legumes contributing 4 t/ha. S. sphacelata was the only grass to form a stable mixture with companion legumes. [Macroptilium atropurpurem (D.C.) Urban and Stylosanthes guianensis (Aubl.) Sw.], which yielded more than 1.1 t/ha in 3-year-old swards on loam soil. This combination was recommended for improvement of loam soil rangelands. It is concluded from this study that range improvement with perennial grasses is confined to fertile soils, while direct broadcast of Stylosanthes legumes only into grazed native pastures is the practice recommended for improvement of infertile sandy soil until persistent low P tolerant grasses are found for the dry tropics.

Response of vulpia [Vulpia bromoides (L.) S. F. Gray and V. myuros (L.) C. C. Gmelin] and subterranean clover to rate and time of application of simazine

The responses of vulpia [Vulpia bromoides (L.) S. F. Gray and V. myuros (L.) C. C. Gmelin] and subterranean clover (Trifolium subterraneum L.) to rate and time of application of simazine were compared on a red loam soil containing 1.8% organic matter and on sands containing 0.4 and 0.8% organic matter. In 1988 and 1989, applications of 0.50, 0.75 and 1.00 kg a.i./ha of simazine in late May-early June resulted in 96.4, 99.8 and 99.6% control of vulpia, respectively. Later applications in July-August, or earlier applications in April, were less effective. There were no differences in the levels of control obtained on the 2 soils, nor were there any differences in the susceptibility of V. bromoides or V. myuros to simazine. On the red loam soil simazine did not reduce subterranean clover plant density or dry matter production; however, severe reductions of both were recorded on the sandy soils. Reasons for the different responses, along with the potential for the use of simazine to control vulpia in subterranean clover pastures, are discussed in detail.

A COMPARATIVE STUDY OF THE FORMS OF PHOSPHORUS IN TWO RED LOAM SOIL SERIES OXISOL OF KERALA STATE

A study of the different forms of P in the Vellayani and Neyyattinkara series of the red loam soils (oxisols) of Kerala indicated that organic P constituted about 48-51 % of the total P in both soil series. The different fractions of inorganic P were in the order, Red-P Fe-P Saloid-P AI-P Occl-P Ca-P in the Vellayani series; whereas in the Neyyattinkara series it was in the order Red-P Saloid-P Fc-P Ocel-P AI-P Ca-P. Available P showed significant positive correlation with Al-P and Organic-P and no significant correlation was obtained with Saloid-P and Fc-P.

LABORATORY SIMULATION FOR EVALUATING THE EFFECT OF DROPLET SIZE ON PESTICIDE PERSISTENCE IN DRY SOILS

Residual quantities of methyl salicylate, sprayed on sand, red loam, and heavy loam soils, were estimated by measuring evaporation rates in a laboratory simulation setup. Methods for homogeneous dissemination of liquid on the surface and for controlling and measuring droplet size and surface concentration were developed. A flow system was built for measuring the time dependence of the vapor concentration in a wind tunnel, at various flow rates. Our experiments have demonstrated that the efficiency of soil spraying is affected by droplet size—the highest residuals were obtained with the biggest droplet diameter. It is clear, however, that the final determination of the optimal droplet size is a function of soil type and agricultural requirements.

A Rice-Based Intercropping Sequence for Vindhyan Red Loam Soils of Eastern Uttar Pradesh

A Rice-Based Intercropping Sequence for Vindhyan Red Loam Soils of Eastern Uttar Pradesh

Distribution of herbicides in soil in a simulated drip irrigation system

The behavior of two herbicides (bromacil and napropamide) applied to a Mediterranean red loam soil (hamra) from a point source is presented. Neither herbicide was degraded during the period of the study. Bromacil was only slightly adsorbed by the soil (K d − 0.1 ml/g; Fig. 1) and was evenly distributed in the soil volume when applied at a constant concentration (Fig. 3). The distribution of napropamide, which was adsorbed by the soil (K d − 1.2 ml/g; Fig. 1), was restricted to the zone immediately around the emitter (Fig. 3). Application of the herbicides to previously wetted soils increased the vertical and lateral movement of both herbicides (Fig. 4). Leaching of the chemicals was more pronounced for bromacil than for napropamide (Fig. 5). Cycles of irrigation and evaporation at two irrigation frequencies demonstrated that bromacil can be leached quickly from the emitter zone whereas naproparnide will move only slowly into the soil volume (Fig. 8).

The yield response of bananas to supplementary watering

The Giant Cavendish banana variety Williams growing on a red clay loam (krasnozem) soil, was used to study yield response to sprinkler irrigation from 1967 to 1970, at the Alstonville Tropical Fruit Research Station. Irrigation treatments were applied when moisture deficits fell to 90, 80, 60, and 30 per cent of available water capacity (AWC). Non-irrigated control plots were also included in the experiment. Bunch number, fruit weight, hand and finger number and finger length all increased significantly (P < 0.001 ) with decreased moisture deficit. The most effective treatment (minimum of 90 per cent AWC) involved the application of 7.7 mm of water every three to five days during dry periods and produced about double the yield of the non-irrigated treatment.

Calcium nutrition of the tomato as influenced by total salts and ammonium nutrition

Calcium deficiency in tomatoes was induced by adding ammonia nitrogen to the rooting medium. Ammonia was found to inhibit the absorption of calcium by the plant. When total soil nutrient concentration was varied, but the ratio of calcium to other ions held constant, blossom-end rot incidence was inversely related to the calcium level in fruits but was not necessarily associated with low calcium levels in leaves or whole plants. In the presence of high total salts, the incidence of the disorder could not be explained by a reduction in calcium content of whole plants and factors affecting distribution of the calcium within the plant were involved. The physiological disorder pith rot is described and evidence presented suggesting it is caused by a deficiency of calcium. Ammonia increased the incidence of the disorder but was not essential for its occurrence. In field trials on a red loam soil, ammonium sulphate reduced the pH values from 6.0 to 4.7, which prevented nitrification and induced pith rot and blossom-end rot through an accumulation of ammonia nitrogen. Calcium foliar sprays were able to offset yield reductions that were induced by moderate fertilizing with ammonium sulphate even where blossom-end rot did not occur. High total plant calcium was associated with reduced fruit yields.

Experiments on the effects of phosphate applied to a Buganda soil: I. Pot experiments on the response curve

SUMMARYIn a pot experiment providing for rapid growth of sorghum plants in the red clay loam soils of the Cotton Research Station, Namulonge, in the Buganda Province of Uganda, large yield increases were obtained from added phosphate. In an uncultivated soil which had carried undisturbed natural vegetation (Pennisetum purpureurn)for at least 10 years the response curve had negative curvature throughout. In an arable soil, yields without added phosphate were very poor and the response curve was sigmoid in form. With the arable soil, liming did not modify the form of the response curve for added phosphate but at the heaviest dressing lime decreased yield.

Corrigendum - Frequency of annual species of Medicago on the major soil groups of the Mcquarie region of New South Wales

The frequency of eight annual species of Medicago was determined on 10 soil groups in a region climatically favourable for medics. They occurred on nine of these, the overall frequency being in the order M. minima (L.) Bart. > M. denticulata Willd. > M. laciniata (L.) Mill., M. praecox DC., M. tribuloides Desr., and M. orbicularis (L.) Bart. > M. arabica (L.) Huds. and M. confinis Koch. M. minima was more tolerant of variation of soil habitat than any other medic in the region. M. denticulata was most commonly found on the soils of high soluble salt content and showed the greatest tolerance of poor drainage conditions. M. laciniata occurred in greatest abundance on soils of the well-drained brown acid group. M. praecox was most commonly found on soils with a compact gravelly surface. M. tribuloides was recorded on five soil groups but was common only on the black earths. M. orbicularis was confined to the black earth and red loam soils. M. arabica was rarely found, being restricted to lower, fertile, well-drained parts of the landscape, and M. confinis occurred only occasionally and then in association with M. denticulata.

Frequency of annual species of Medicago on the major soil groups of the Mcquarie region of New South Wales

The frequency of eight annual species of Medicago was determined on 10 soil groups in a region climatically favourable for medics. They occurred on nine of these, the overall frequency being in the order M. minima (L.) Bart. > M. denticulata Willd. > M. laciniata (L.) Mill., M. praecox DC., M. tribuloides Desr., and M. orbicularis (L.) Bart. > M. arabica (L.) Huds. and M. confinis Koch. M. minima was more tolerant of variation of soil habitat than any other medic in the region. M. denticulata was most commonly found on the soils of high soluble salt content and showed the greatest tolerance of poor drainage conditions. M. laciniata occurred in greatest abundance on soils of the well-drained brown acid group. M. praecox was most commonly found on soils with a compact gravelly surface. M. tribuloides was recorded on five soil groups but was common only on the black earths. M. orbicularis was confined to the black earth and red loam soils. M. arabica was rarely found, being restricted to lower, fertile, well-drained parts of the landscape, and M. confinis occurred only occasionally and then in association with M. denticulata.

Fertilizer studies on Basaltic red loam soil form the Lismore District, NSW.

A pot-culture study was made -to examine the effects of nutrient elements on the growth of white clover (Trifolium repens L.) and Paspulum dilatutum Poir. on a basaltic red loam soil known to contain a high percentage of phosphorus and free iron vide. The response of paspalum to phosphorus was limited by deficiency of nitrogen. The results indicate that the native phosphorus in the soil is of very low availability, but that the added phosphate is not rapidly converted in the soil to unavailable forms. They suggest also that the response to superphosphate on this soil is restricted by other deficiencies rather than by phosphate fixation. The paspalum responded most to nitrogen on the soil where the lowest yields occurred without added nitrogen. However, the percentage nitrogen in the stunted untreated plants on this soil was higher than in less responsive plants on other soils. The results indicate that the percentage total nitrogen in paspalum is not a satisfactory index of the likely response of the plants to nitrogen. High levels of manganese were found in the paspalum plants which were examined. In an experiment with white clover, molybdenum, deficiency was induced by a light dressing of manganese sulphate. Responses of clover to phosphorus, molybdenum, and sulphur were obtained, and some evidence of calcium and magnesium deficiency is presented. The importance of elements concerned in protein formation in plants in relation to the general problem of pasture improvement on these soils is discussed.

Bioassay of available trace metals from Australian soils

A study was made of various factors influencing the microbiological assay of available iron, zinc, copper, manganese, and molybdenum. Aspergillus niger (M.) was chosen as the best test organism from a group of 9 fungi, 1 alga, 1 yeast, and 6 bacteria. The composition of the basal medium could be altered markedly without affecting the availability figures. A new method of purifying the medium with A1203, gave good deficiency symptoms for Fe, Zn, Cu, and Mn, but Nicholas's method was superior for removing Mo. It was found necessary to sterilize the soil, preferably by autoclaving. The availability of 15 micronutrients was determined by bioassay from 278 surface and 164 subsoil samples from eastern Australia. Seven soil groups, viz. 3 pedalfers, "red loam", acid humic, and podzol, and 4 pedocals, rendzina and terra rossa, chernozem, red-brown earth, and desert soil, showed more deficiencies than all other soil groups bioassayed. Even within these seven groups non-deficient soils also occurred. The commonest deficiency detected was that of Zn, followed by Cu, then by Mo, hut deficiencies of Fe and Mn were rarely found. Usually surface soils with a well-developed root zone were less deficient than subsoils. Fewer deficient samples were obtained from meadow soil, alkaline humic, volcanic tuff, and brown earth than from all other soil groups. There was a fair correlation between the availability of Zn, Cu, and Mo to A. niger (M.) and availability to plants, but none for Fe and Mn. The fungus was able to obtain adequate amounts of micronutrients from a variety of insoluble salts or oxides of Fe, Zn, Cu, Mn, and Mo, some of which were known to be unavailable to plants. A number of soils, e.g. red loam, laterite, and desert soil, inhibited the growth of the mould in complete medium. This effect was due to active fixation of added micronutrients, especially in soils rich in calcium carbonate and in red loams. No evidence was obtained that microbial fixation of trace elements occurred in deficient soils; but most major and minor elements were fixed by microorganisms in very deficient, acid-washed, quartz crystals, with the exception of Ca, which was not significantly affected, and of Fe and Zn, which were released by microbial activity from the minute amounts of contaminants present.