Mamor Fujiwara

Root-system depth of field beans and wheat under center pivot

O estudo foi realizado na Estacao Experimental de Votuporanga, do Instituto Agronomico, em solo podzolizado com as culturas de feijao e trigo irrigadas por pivo central no inverno de 1989. O objetivo for a determinacao da profundidade efetiva do sistema radicular, como um dos parâmetros fundamentais no manejo das irrigacoes. Estas eram realizadas quando a tensao da agua no solo atingia 0,05 a 0,06 MPa, controlada por tensiometro a 15cm de profundidade. Foram feitas tres medicoes quinzenais de raizes em cada cultura, utilizando-se trado tipo caneca de 7cm de diâmetro. As amostragens foram tomadas na linha de plantio, de 10 em 10cm ate a profundidade de 60cm. Os resultados indicam que, para o manejo adequado da irrigacao, a profundidade do sistema radicular a ser considerada deve ser de 30 e de 40cm, respectivamente, nas culturais de feijao e de trigo no solo em questao.

Fontes e doses de nitrogênio na adubaçâo química do cafeeiro I: latossolo roxo transição para latossolo vermelho-amarelo, orto

The following sourcesof nitrogen were studied in a field experiment with coffee plant: Ammonium nitrate with lime (AND, Ammonium sulphate, Chilean nitrate and urea, in doses corresponding to 75, 150, 225, and 300 kilograms of element per hectare. The soil was a Red Latosol transition to Clay Red - Yellow Latosol from the area of Campinas County, State of Sao Paulo. The experiment was installed in March, 1957 and the yield records collected from 1959 to 1969. The total annual doses were splited into 2, 4, 5, and 9 applications until 1963/64, and into 1, 2, 3, and 4 applications from that year on to the end of the experiment. Shortly after the 1969 picking, the plants were cut down to the height of about 50 centimeters, for renewing of the aereal parts. In 1972 a series of soil and leaf samples were taken for analysis and study of the residual effects of the fertilizers. The yields showed a very significant increase with increasing doses of nitrogen. ANL and ammonium sulphate were significantly superior to the urea and Chilean nitrate. The ammonium sulphate was superior to ANL during several years but in the last few years of the experiment this situation was reversed, with ANL giving higher yields. The mineral analysis of the fruits showed that the nitrogen, iron, and manganese contents varied with the source of nitrogen employed. The use of ammonium sulphate, urea and ANL lowered the pH of the soil; the manganese and aluminum content of the leaves increased when ammonium sulphate or urea was used.

Métodos mecânicos e químico no controle de ervas daninhas em cafezal

Mechanical (disc harrow, rotary cultivator, off-set rotary shredder), chemical (herbicide) and hand hoe weeding are compared in a coffee crop grown on a latosol. After ten years there was no significant yield difference among the treatments. There was however, visible signs of erosion due to the use of disc-harrow, rotary cultivator, and herbicide.

Utilização do etefom e do tidiazurom na desfolha do algodoeiro e na deiscência de seus frutos

The defoliation and fruit dehiscence of cotton plants were evaluated by applications of Ethephon (rates: 0.96, 1.44 and 1.92kg/ha). Thidiazuron (0.075kg/ha) and the mixture of both Ethephon plus Thidiazuron (0.48 + 0.05, 0.96 + 0.05, and 1.44 + 0.05kg/ha, respectively). The mixture of the products was done in the sprayer tank. Observations of the cotton plants were carried out at seven and fourteen days after application of the products. Except for the application of Ethephon at the rate of 0.96kg/ha, it was observed that the three treatments were effective in promoting cotton defoliation. It was also verified that Ethephon at the rates of 1.44kg/ha accelerated fruit dehiscence while Thidiazuron did not. Antagonic action of the products was observed when applied in mixture. The isolated application of the products or the mixture had no effect on cotton yield.

Uso alternado de métodos mecânicos e químicos de controle de ervas daninhas em cafezal

The use of several methods of weed control (disc-harrow, rotary cultivator, off-set rotary shredder and herbicide) was studied and compared with hand cultivation. The treatments were made alternatively, trying to prevent the inconveniences observed when certain machines were sistematically used. After five years of observations, no significant statistical difference was noticed among several combinations: a) off-set rotary shredder versus herbicide; b) off-set rotary shredder versus rotary cultivator; c) off-set rotary shredder versus disc harrow; d) off-set rotary shredder (in the rain season) versus herbicide (in the dry season).

Esforços tratórios no arrancamento de cafeeiros

A new method for removing perennial plants is presented in this paper. It consists of using a clamp type of tool that is attached to a plant and pulled by a tractor. A study was conducted in Campinas, State of Sao Paulo, Brazil, in February of 1984 with a 12 year old coffee plantation on Dusk Red Latosol. The average effort required for coffee plants uprooting was 2,127kgf/plant for C. canephora L. cv. Robusta and 1,158kgf/plant for C. arabica L. cv. Mundo Novo. Among the several systems tested, the best was the use of three clamps applying individual effort in a successive remotion of three plants in one unique operation. This system had the advantage of smaller soil movement than the traditional use of bulldozer. The use of a 100hp wheel tractor was feasible for this system, and it presented a good performance of operation.