No cenário olerícola nacional, a produção de batata está em crescimento. Nas áreas produtoras de batata das regiões Sul e Sudeste é comum encontrar essa cultura em rotação com milho e trigo. O uso de alguns herbicidas do grupo químico das sulfoniluréias nas culturas anteriores tem causado sintomas de fitointoxicação nas lavouras de batata. As deformações dos tubérculos ocorrem no inicio da fase de tuberização, quando se nota numerosas rachaduras relacionadas à contaminação por sulfoniluréias. O objetivo deste trabalho de pesquisa foi avaliar a resposta de plantas de batata das cultivares Atlantic e Lady Rosetta, quanto à produtividade e qualidade dos tubérculos, submetidas a aplicação de subdoses dos herbicidas metsulfuron-methyl e nicosulfuron, utilizados nas culturas do trigo e milho respectivamente. O experimento foi instalado em condições de campo. Os herbicidas foram aplicados nas plantas de batata no início da fase de tuberização. A fitointoxicação causada pelos herbicidas foi avaliada na parte aérea, na produtividade e qualidade dos tubérculos. Ambas as sulfoniluréias, metsulfuron-methyl e nicosulfuron, causaram injúrias foliares nas cultivares de batata, sendo que na cultivar Atlantic esses sintomas não predizem os danos nos tubérculos, que foram inferiores aos esperados. As sulfoniluréias reduziram a produção de tubérculos de maior diâmetro em ambas as cultivares. A cultivar Atlantic teve redução na produção e produtividade causadas pela pulverização de nicosulfuron na dose recomendada para a cultura do milho, e não foi afetada pelas pulverizações de metsulfuron-methyl. A cultivar Lady Rosetta foi afetada por ambas as sulfoniluréias nas maiores doses e pelo nicosulfuron também em dose 10 vezes menor àquela recomendada para a cultura do milho. A produção de tubérculos inviáveis na cultivar Atlantic foi devido à incidência de rachaduras, podendo chegar a 16,11% com a pulverização de metsulfuron-methyl e até 91,33% com nicosulfuron. Na cultivar Lady Rosetta a produção de tubérculos inviáveis caracterizou-se por sintomas de distúrbios fisiológicos, chegando até 78,26% e 88,44% com pulverização de metsulfuron-methyl e nicosulfuron respectivamente. As cultivares Atlantic e Lady Rosetta não perderam produtividade nem qualidade dos tubérculos após aplicação de metsulfuron-methyl ou nicosulfuron nas subdoses testadas. / Potato production increases in the brazilian horticultural scene. Its common to find this crop in rotation with wheat and maize in the south and southeast production areas in Brazil. The use of some sulfonylureas herbicides in previous crops might cause phytotoxicity symptoms in potato. Tuber malformation take place in the beginning of tuberization, when can be noted tuber cracking related to sulfonylureas contamination. This trial aimed to assess the tuber quality and productivity of potato cultivars Atlantic and Lady Rosetta, subjected a application of low ates of metsulfuron-methyl and nicosulfuron, used previously in wheat and maize crops respectively. The trial was carried out in field conditions. The herbicides were sprayed in potato plants in the beginning of the tuberization phase in different rates. The sulfonylureas phytotoxicity was evaluated in the vegetative part and in the tuber quality and yield. Sulfonylureas, metsulfuron-methyl and nicosulfuron, caused foliar injuries in the potato cultivars, being that in Atlantic cultivar these symptoms do not predict tuber damages, that was below expectations. The sulfonylureas also reduced the production of tubers with larger caliber. The Atlantic cultivar decreased the production and the yield because of the nicosulfuron sprayed in maize recommended dose but was not affected by metsulfuronmethyl treatments. The Lady Rosetta cultivar was affected by both of sulfonylureas in the highest doses, such recommended for other crops, and also by nicosulfuron ten times diluted. The production of tuber unachievable for commercialization by the Atlantic cultivar was due to cracking, leading to 16.11% of cracked tubers after metsulfuronmethyl spray and 91.33% with nicosulfuron. In the Lady Rosetta cultivar it was characterized by malformation and second growth, achieving 78.26% and 88.44% of deformed tubers after metsulfuron-methyl and nicosulfuron sprays respectively. Both of the cultivars did not reduce tuber quality and yield after pulverization of metsulfuronmethyl or nicosulfuron in those low rates tested.

No cenário olerícola nacional, a produção de batata está em crescimento. Nas áreas produtoras de batata das regiões Sul e Sudeste é comum encontrar essa cultura em rotação com milho e trigo. O uso de alguns herbicidas do grupo químico das sulfoniluréias nas culturas anteriores tem causado sintomas de fitointoxicação nas lavouras de batata. As deformações dos tubérculos ocorrem no inicio da fase de tuberização, quando se nota numerosas rachaduras relacionadas à contaminação por sulfoniluréias. O objetivo deste trabalho de pesquisa foi avaliar a resposta de plantas de batata das cultivares Atlantic e Lady Rosetta, quanto à produtividade e qualidade dos tubérculos, submetidas a aplicação de subdoses dos herbicidas metsulfuron-methyl e nicosulfuron, utilizados nas culturas do trigo e milho respectivamente. O experimento foi instalado em condições de campo. Os herbicidas foram aplicados nas plantas de batata no início da fase de tuberização. A fitointoxicação causada pelos herbicidas foi avaliada na parte aérea, na produtividade e qualidade dos tubérculos. Ambas as sulfoniluréias, metsulfuron-methyl e nicosulfuron, causaram injúrias foliares nas cultivares de batata, sendo que na cultivar Atlantic esses sintomas não predizem os danos nos tubérculos, que foram inferiores aos esperados. As sulfoniluréias reduziram a produção de tubérculos de maior diâmetro em ambas as cultivares. A cultivar Atlantic teve redução na produção e produtividade causadas pela pulverização de nicosulfuron na dose recomendada para a cultura do milho, e não foi afetada pelas pulverizações de metsulfuron-methyl. A cultivar Lady Rosetta foi afetada por ambas as sulfoniluréias nas maiores doses e pelo nicosulfuron também em dose 10 vezes menor àquela recomendada para a cultura do milho. A produção de tubérculos inviáveis na cultivar Atlantic foi devido à incidência de rachaduras, podendo chegar a 16,11% com a pulverização de metsulfuron-methyl e até 91,33% com nicosulfuron. Na cultivar Lady Rosetta a produção de tubérculos inviáveis caracterizou-se por sintomas de distúrbios fisiológicos, chegando até 78,26% e 88,44% com pulverização de metsulfuron-methyl e nicosulfuron respectivamente. As cultivares Atlantic e Lady Rosetta não perderam produtividade nem qualidade dos tubérculos após aplicação de metsulfuron-methyl ou nicosulfuron nas subdoses testadas. / Potato production increases in the brazilian horticultural scene. Its common to find this crop in rotation with wheat and maize in the south and southeast production areas in Brazil. The use of some sulfonylureas herbicides in previous crops might cause phytotoxicity symptoms in potato. Tuber malformation take place in the beginning of tuberization, when can be noted tuber cracking related to sulfonylureas contamination. This trial aimed to assess the tuber quality and productivity of potato cultivars Atlantic and Lady Rosetta, subjected a application of low ates of metsulfuron-methyl and nicosulfuron, used previously in wheat and maize crops respectively. The trial was carried out in field conditions. The herbicides were sprayed in potato plants in the beginning of the tuberization phase in different rates. The sulfonylureas phytotoxicity was evaluated in the vegetative part and in the tuber quality and yield. Sulfonylureas, metsulfuron-methyl and nicosulfuron, caused foliar injuries in the potato cultivars, being that in Atlantic cultivar these symptoms do not predict tuber damages, that was below expectations. The sulfonylureas also reduced the production of tubers with larger caliber. The Atlantic cultivar decreased the production and the yield because of the nicosulfuron sprayed in maize recommended dose but was not affected by metsulfuronmethyl treatments. The Lady Rosetta cultivar was affected by both of sulfonylureas in the highest doses, such recommended for other crops, and also by nicosulfuron ten times diluted. The production of tuber unachievable for commercialization by the Atlantic cultivar was due to cracking, leading to 16.11% of cracked tubers after metsulfuronmethyl spray and 91.33% with nicosulfuron. In the Lady Rosetta cultivar it was characterized by malformation and second growth, achieving 78.26% and 88.44% of deformed tubers after metsulfuron-methyl and nicosulfuron sprays respectively. Both of the cultivars did not reduce tuber quality and yield after pulverization of metsulfuronmethyl or nicosulfuron in those low rates tested.

Typewritten Includes bibliographical references

This thesis develops two related themes.The first is that participatory approaches to agricultural research and extension can provide a sound process for all stakeholders to learn how to develop more sustainable agriculture. The second is that appropriate levels of participation can be used to link knowledge from three important sources: local knowledge, scientific knowledge and experiential knowledge.The thesis develops these two related themes by examining the inconsistencies between esposed theories of participatory approaches (i.e.intended behaviour) and theories in action (i.e. what is actually practised).The study was based upon the work of a major research, development and extension (R, D and E)project known as the Western Farming Systems Project (WSFP),which was concerned with the development of sustainable rotations and cropping practices in south western Queensland and north western N.S.W. between 1994-1999. The study was conducted in the Balonne Shire, centred on the town of St. George, Queensland, Australia. / Master of Science (Hons)

Indigenous African shifting cultivation production systems, that were developed over many generations and took into account production potential as well as the constraints imposed by natural resources, are no longer practicable for Nigerian smallholder farmers. These systems relied on long fallow for fertility restoration after a period of cropping. Overpopulation has resulted in lower per capita land availability, necessitating a shift to sedentary cultivation systems. In such systems, fallow is short term (months) compared to shifting systems, where it lasted several years. This shift has resulted in overexploitation of land resources and despite intensification of agricultural production methods, non-sustainable demand on the natural resource base has increased and crop and animal production has declined. This study examined the performance of five maize-based cropping systems consisting of cereal-legume, cereal-cereal and cereal bare fallow rotations, to identify systems that have potential for increased agricultural production in the subhumid and mid-altitude zones of Nigeria. The study was conducted at Richmond, near Sydney, in NSW, Australia from 2000 to 2003. The trial investigated the effects of the combined use of legumes and N fertilizer in CSs to maintain or improve soil fertility, maize crop and maize storage silage production and yield and quality of all crop residues. This study showed that inclusion of a legume in the rotation is an important production and income generating strategy. Owing to their potential for increased maize productivity, to build up N-rich systems and to improve small holder levels of farm income, cropping systems with legumes should therefore be given more research attention in Nigeria / Doctor of Philosophy (PhD)

Bibliography: leaves 115-130.

Thesis (Ph. D.)(Plant Production)--University of Pretoria, 2001. / Includes bibliographical references).

No description available.

A study was conducted for two growing seasons in northeastern Syria to evaluate the effect of N and P fertilizers and previous crops--i.e. vetch (Vicia sativa L.), barley (Hordeum vulgare L. cv. Beecher) or fallow--on water consumption, development, growth and yields of barley in a semi-arid, Mediterranean-type climate. / The two seasons contrasted in rainfall and temperature which affected soil N, water use and yields. Fertilizer addition and residual P were the major determinants in barley yield increases. Rotation effects were significant only when fertilizers were added. Fallowing was an inefficient way of storing water, but stored water was used most efficiently by subsequent barley crops when fertilized. / Fertilizers did not increase total evapotranspiration. Water use efficiency was related to dry matter production at stem elongation (DMse). Grain weight was a stable component of grain yields. Grain number was related to crop growth rates during the three week pre-anthesis period and to DMse, in turn affected by temperature, nutrient and moisture conditions. / Vetch yields were in the order of 2.5 t.ha$ sp{-1}$ in the wetter season (1982/83). / Results showed that substantial barley yield increases can be obtained with innovative crop rotations and appropriate use of fertilizers in semi-arid environments.

Thesis (M.Ag.Sc)--University of Adelaide, Faculty of Agricultural Science, 1956. / Typewritten. Includes bibliographical references.