Ary de Arruda Veiga

Efeitos da densidade de plantio e da aplicação de CCC, em algodoeiro

Excessive growth of the cotton plants Gossypium hirsutum L. in some regions causes laying and deficient luminosity, and a consequent lowering in yield and type of cotton. Such problems are specially serious in the case of mechanical picking where between-row spacing is fixed at about 40 inches. Combined effects of the use of growth limitant chemical CCC (Chlorocholine Chloride) and population density were studied in 1972/73 and 1975/76 in four localities of the State of Sao Paulo. Near Campinas and Sumare, the effects of 4, 8 and 16 plants/meter (respectively 40,000, 80,000 and 160,000 plants/ha) with and without CCC were studied. At Tiete and Piracicaba, 4, 8, 16 and 32 plants/meter were used (respectively 40,000, 80,000, 160,000 and 320,000 plants/ha). Only the treatments of 16 and 32 plants/meter were combined with CCC application. The concentration of CCC used was of 50 g a.i../ha applied from 50 to 70 days after emergence of the plants. The results showed that CCC limited the growth of plants, increased earliness of yield, decreased lint percentage and increased fiber length, boll and seed weight. There was no effect observed on cotton yield, fiber length uniformity, Micronaire, Pressely and fiber maturity. Higher density resulted in higher yield. High density also caused better length of fiber and lower boll weight.

Adubação do trigo VII: Experiências com N, P, K e S em diferentes tipos de solos do estado de São Paulo

No periodo de 1969 a 1973 foram realizados ensaios de adubacao N, P, K e S em cultura de trigo (Triticum aestivum L.) na Estacao Experimental de Tiete, na Estacao Experimental de Capao Bonito, na Fazenda Santa Isabel localizada no municipio de Itabera e na Estacao Experimental de Itarare. Os dados medios obtidos em Tiete e Capao Bonito nao mostraram respostas significativas a nitrogenio, fosforo, potassio e enxofre. Nos experimentos plantados em Itabera e Itarare, os dados medios mostraram efeitos lineares de fosforo e adubacao mineral completa altamente significativos.

Effect of weed competition on cotton

The effect of weed competition on cotton (Gossypium hirsutum L.) was evaluated in the Centro Experimental de Campinas and the Estacao Experimental de Tiete during the 1970/71, 1971/72 and 1972/73 agricultural seasons. In the first season, competition periods of 10, 20, 30, 40, 60, 90 or 120 days, after emergence were studied, compared to checks always either with or without weeds. In the next seasons, competition was studied during the first 10, 20, 30 or 40 days after emergence, or after these periods, until harvest, maintained previously weed free for these different periods and afterwards competition was allowed until harvest. The experimental plots had four rows of five meters, distributed in randomized blocks with five or six replications. For evaluation of the competition effects the following parameters were considered: number, fresh and dry weights of weeds, after each competition period; fiber percentage, boll and seed weight, cotton yield, fiber length uniformity, Micronaire, Pressley and maturity, at harvest. The results showed a lower yield of cotton when the competition period was longer than 20 days after emergence. When the crop was maintained weed free for the first 30 to 40 days yield was similar to the completely weed free treatment. Competition periods of 90 days or longer determined negative effect on yield. In some cases a negative effect of weed competition was observed on fiber percentage, boll and seed weight, Micronaire, fiber uniformity and Pressley.

Estudo comparativo de métodos de deslintamento de sementes de algodoeiro

A comparative study of cotton seed delinting methods was carried out during the years of 1973/74 to 1975/76, in the State of Sao Paulo, using the commercial variety IAC 13-1. Mechanical, acid, gas, and flame delinting were compared, with or without fungicide application. The percentages of seedlings obtained were computed. The best results corresponded to acid and gas delinting associated to treatment with fungicide. The lowest percentages were obtained with mechanical delinting. The best time for counting seedling stands showed to be from twelve to nineteen days afteremergence.

Indução de mutação no melhoramento do trigo

Experiments were carried out during three years with two representative wheat cultivars in the State of Sao Paulo, in order to investigate the effects of gamma-irradiation on mutation for rust resistance (in BH-1146) and short culm (in IAC-5). The original seeds were treated with gamma rays in the source of Centro de Energia Nuclear na Agricultura, Piracicaba, and sowed in the field at the Estacao Experimental de Tiete, in April, 1974. Some progenies, practically free rust disease, and some with earliness (8 days) and with short culm (60 cm), comparated with the control (120 cm), were obtained from the M3 plants of BH-1146 and IAC-5, respectively.

Efeitos da época de incorporação, ao solo, de restos vegetais de soja comum (Glycine max (L.) Merril), sobre a produção de feijoeiro

Experiencias conduzidas em diversas localidades do Estado de Sao Paulo, em dois anos agricolas, visaram estudar os efeitos da epoca de incorporacao ao solo de restos vegetais de soja comum, sobre a producao do feijoeiro. O estudo conjunto das experiencias realizadas em 1967/68 mostrou que a incorporacao de restos vegetais de soja provocou aumento de 196 kg/ha na producao, sendo que em Jau o aumento devido a incorporacao foi de 665 kg/ha. Quanto as epocas de incorporacao, todas provocaram aumentos na producao, destacando-se entre elas o mes de maio. Para o mes de setembro, a adicao de nitrogenio provocou aumento de 239 kg/ha na producao. Em 1969/70, no conjunto da experiencia, a incorporacao dos restos de soja provocou aumento de 340 kg/ha, na producao, sendo que em Sao Simao e Tiete esses aumentos foram de 417 e 738 kg/ha, respectivamente. Todas as epocas de incorporacao provocaram aumentos na producao, podendo-se destacar os meses de maio, julho e setembro, em que os aumentos provocados foram de 351, 394 e 375 kg/ha, respectivamente. No mes de setembro o nitrogenio acusou efeito medio positivo de 93 kg/ha, enquanto o potassio provocou decrescimo de 25 kg/ha, na producao.