Agricultural bacteriology, by Joseph E. Greaves ... illustrated with 48 engravings.

copy 1

Fertilizer policy in the developing countries: the case of Brazil

This paper deals initially with the role of mineral fertilizers in increasing agricultural production: the relationship between the two variables is illustrated within global, regional national and local contexts. The pattern and trends in fertilizer usage in Brazil are presented next, namely: increase in consumption in the period 1950/72; regional distribution; consumption as related to crops and cultivated land. It is shown that in less than a quarter or century fertilizer use has increased in the country nearly 12 fold, whereas world consumption was raised 7 fold, thus exceeding estimates based in several criteria. Steps taken to secure the raise in fertilizer consumption above the historical trend are discussed: research experience for outlining fertilization recomendations; the transfer of the knowledge to the farmer by the extension work both official and private; the credit policy and special incentives for the purchase of fertilizer; the national policy for minumum proces of agricultural products; the implantation of a national fertilizer industry. It is considered that the Brazilian experience adapted to similar local conditions in other developing countries, presents a possibility for achieving beneficial results without inflationary reflexes in the economy.

The forests and flora of British Honduras / by Paul C. Standley and Samuel J. Record ; in cooperation with the Conservator of Forests and the Agricultural Officer of the Colony.

v.12(1936)

Increasing the efficiency of utilization of soil and fertilizer phosphorus in the subtropical and tropical agricultural systems C

As a rule, soils of the subtropical and tropical regions, in which rainfall is not limiting, are acidic, and low in phosphorus, and, to a less extent, in other macro and micronutrients as well, such a sulfur, boron and zinc. The establishment of a permanent agricultural prac. tice therefore, demands relatively high usage of liming and phosphatic fertilization, to begin with. Several approaches, not mutually exclusive, could be used in order to increase the efficiency of utilization of soil and fertilizer phosphorus so that, goal of diminishing costs of production is reached. The use of liming materials bringing up pH to 6.0-6.5 causes the conversion of iron and aluminum phosphates to more available calcium phosphates; on the other hand, by raising calcium saturation in the exchange complex, it improves the development and operation if the root system which allows c or a higher utilization of all soil nutrients, including phosphorus, and helps of stand water deficits which may occur. The role of mycorrhizal fungi should be considered as a way of increasing soil and fertilizer P utilization, as well as the limitations thereof. Screening of and breeding for varieties with higher efficiency of uptake and utilization of soil and fertilizer phosphorus leads to a reduction in cost of inputs and to higher benefit/cost ratios. Corrective fertilization using ground rock phosphate helps to saturate the fixation power of the soil thereby reducing, as a consequence, the need for phosphorus in the maintenance fertilization. Maintenance fertilization, in which soluble phos-phatic sources are used, could be improved by several means whose performance has been proved: limimg, granula tion, placement, use of magnesium salts. Last, cost of phosphate fertilization could be further reduced, without impairing yields, through impairing yields, through changes in technology designed to obtain products better adapted to local conditions and to the availability or raw materials and energy sources.

Chaetognatha of the Brazil-Malvinas (Falkland) confluence: distribution and associations

The planktonic chaetognaths from the Brazil-Malvinas (Falkland) confluence, extending between 36º 30' - 50º 5' S and 60º 33' - 41º 7' W, were studied. Ten species were found: Eukrohnia hamata (Möbius, 1875) (Eukrohniidae), Pterosagitta draco (Krohn, 1853) (Pterosagittidae), Sagitta enflata Grassi, 1881, Sagitta gazellae Ritter-Zahony, 1909, Sagitta hexaptera d´Orbigny, 1834, Sagitta lyra Krohn, 1853, Sagitta minima Grassi, 1881, Sagitta planctonis Steinhaus, 1896, Sagitta serratodentata Krohn, 1853, and Sagitta tasmanica Thomson, 1947 (Sagittidae). Sagitta gazellae was the most abundant species followed by E. hamata, S. tasmanica and S. serratodentata. The association analysis among the different species, salinity and temperature revealed two groups of species, one related to higher salinities and warmer waters (P. draco, S. hexaptera and S. serratodentata) and the other to lower salinities and colder waters (E. hamata, S. gazellae and S. tasmanica). The fact that P. draco and S. hexaptera, formerly defined as warm-water species, appeared further south than previously reported might be related to the existence of warm core eddies up to 46º S in September and October 1988.

Composition and diversity of bees (Hymenoptera) attracted by Moericke traps in an agricultural area in Rio Claro, state of São Paulo, Brasil

The composition and diversity of bees in an agricultural area in Rio Claro, state of São Paulo, Brazil, were studied from May 2003 to June 2004, using Moericke traps. The collection site, an area with 58.08 hectares, is characterized by grain production and direct planting, with 70% of the surrounding area planted with sugar cane. During the study, 456 bees were collected, distributed among 20 genera, pertaining to the families Andrenidae (4.8%), Apidae (40.8%) and Halictidae (54.4%). Specimens of genera Dialictus (38%) and Diadasia (30%) predominated in this area. The species diversity, assessed using the Shannon and Simpson indices, were H’=1.88 and 1/ D= 4.15, respectively, and the Evenness index was 0.61.

Transactions of the Department of Agriculture of the State of Illinois with reports from county and district agricultural organizations for the year ...

38

Transactions of the California State Agricultural Society.

1863

Transactions of the California State Agricultural Society.

1880

Transactions of the Highland and Agricultural Society of Scotland.

ser. 4 vol. 11

Annual report of the Agricultural Experiment Station / Cornell University, College of Agriculture.

1890

Bird-habitat associations in coastal rangelands of southern Brazil

Nearly all remnants of temperate grasslands in southeastern South America are used for livestock ranching and are subject to habitat degradation resulting from this activity. Exploring how habitat features affect the composition of grassland avifaunal communities is a first step to understand how current cattle-ranching management practices impact avian diversity. We used canonical ordination to test for relationships between five habitat variables and the composition of the bird community in coastal grasslands in southern Brazil. We sampled pastures with different heights, from overgrazed short-grass to tall herbaceous vegetation. We recorded 1,535 individuals and 27 species of birds. The first ordination axis indicated a strong contribution of mean vegetation height on the composition of the bird community, whereas the second axis revealed the influence of herbaceous vegetation patchiness and woody vegetation cover. Three groups of species were revealed by the ordination: one more diffuse associated with intermediate and tall herbaceous vegetation, another with short grass, and a third with vegetation patchiness and woody vegetation. Species restricted to tall herbaceous vegetation are negatively impacted from habitat degradation resulting from overgrazing and trampling by livestock, and mowing and burning of tall plants. Occurrence of these species in our study area is related with the presence of swales immediately behind the dune system and where remnants of tall vegetation persist. Birds of pastures with ample cover of short herbaceous plants, including one globally threatened species and six other restricted to short-grass habitat, apparently benefit from local livestock management practices. Woody vegetation possibly functions as a keystone structure, enabling the occurrence in grasslands of avian species that rely on shrubby habitat. Although livestock ranching promotes the diversity of habitats by creating distinct patches of vegetation height in grasslands, current management practices directed to the maintenance of short grass pastures may eliminate an entire subset of species, including regionally threatened taxa, and reduce avian diversity. The maintenance of large patches of tall herbaceous plants is needed to ensure the survival of species reliant on this type of grassland structure in our study area.

Transactions of the Wisconsin State Agricultural Society ...

1, 1851

Transactions of the Highland and Agricultural Society of Scotland.

ser. 4 vol. 8