The study aims to establish a simple method for testing varieties for aluminum tolerance and to screen the acid tolerant varieties. The sheat varietal differences were greatest in the nutrient solutions containing 0.6/mM A1. Sprouted seeds transplanted 3.4 days after such as: Atlas 66, Chokwang, Geurumil, Suweon 205, Naemil, Suweon 185, Suweon 89, and Changkwang were Al-tolerant

The ability to elongate with rising floodwaters determined the success or failure of different genotypes and elongation was affected by nutrient availability. For survival in deep water the promising lines required a higher fertilizer level than the traditional floating varieties and the latter performed better at a low fertility level. However, once the new rices, such as RD19 had sufficient fertilizer for survival they appeared able to respond to further increments of fertilizer better than the traditional varieties

An experiment was conducted with three soybean varieties, Bragg, Lee-74 and Improved Pelican; and four N-doses, 33.64, 44.86, 56.07 and 67.28 Kg N/ha, to study the effect of variety and nitrogen on the growth, yield and nutrient content of soybean. Improved Pelican produced significantly more branches and pods per plant and gave the highest seed yield. Oil, protein and carbohydrate contents were the maximum in the seeds of the varieties Bragg, Pelican and Lee-74 respectively. The highest seed yield was obtained by applying 56.07 Kg N/ha. The oil content increased with the increase in the amount of nitrogen. The highest protein and carbohydrate contents were recorded with the application of 44.86 kg N/ha

The purpose of this research was to study the effect of NH4/NO3 ratio, on the growth, foliar surface and chemical composition of two different varieties of corn (ETA, FAO210 and PROTADOR, FAO 250). The experiment was carried out in a greenhouse. All nutrient solutions contained the same amount of N, but five NH4+/NO3 ratios (100/0; 75/25; 50/50; 25/75 and 0/100). The results had shown that both varieties, produced more shoot and root dry matter when grown in NO3 medium. Foliar surface followed the same trend as the dry matter, showing the detrimental effect of high NH4 levels. There were increases in the uptake of N, P and Zn with high NH4+ supply. The tops of plants grown in NH4+, contained higher Fe levels than those in NO3 cultured in NO3. Increasing NH4+ in the ratios decreased the K, and Ca percentages on tops and roots

A pot experiment was conducted in the greenhouse during the dry and rainy seasons to determine and compare the response of rice (IR 36), corn (DMR-2), and soybean (Clark 63) to soil water stress. Water was withheld 19, 12, and 15 days after planting (DAP) for rice, corn, and soybean, respectively. These are the ages of the crops when their total leaf area per plant were identical. Water stress significantly decreased leaf elongation, leaf water potential, transpiration, and nutrient uptake of the crops, except K in corn. The response of the crops to water stress differed during the dry and rainy seasons. Crops grown during the rainy season had longer period of tolerance to water stress. With the varieties tested, the tolerance of the plant species studied to imposed water stress may be described as follows: cornsoybeanrice

The results show that Faraon clay gave the highest yield for both varieties with 576.63 g/hill or 5.77 tons/ha for the purple variety and 573.03 g/hill or 5.73 tons/ha for the white variety. The purple variety had significantly higher values than the white variety in terms of N, P, K, Ca and Mg content. Highest amount of N and K taken up were observed in tubers from Bolinao clay, Ca and Mg from Faraon clay and P from Ubay clay

Maximum soil pH of 4.38 was obtained at 3 months after the application of lime. Different varieties of cabbage matures at different time irrespective of liming levels. Highest yield was obtained from treatments with the highest lime application. At 2.5 m tons lime per hectare only 50% of the cabbage heads were properly formed. The liming level should not be less than 7.5 m tons per hectare in order to get a profitable yield. The optimum level obtained from differentiation of the regression equation was at 11.5 m tons per hectare. The best lowland cabbage varieties were K.K. Cross and U.S. Hybrid. The N, P, K and Ca contents of the leaf responded either linearly or quadratically to the different levels of lime

Com os objetivos de: - Determinar a concentração e acumulação de B, Cu, Fe, Mn e Zn nos cultivares Brasil 48 e Clause's Aurélia em função da idade. Foi conduzido um ensaio de campo em Piracicaba, São Paulo sobre o solo Terra Roxa Estruturada, série "Luiz de Queiroz" que vem sendo cultivado com hortaliças há mais de 50 anos. Mudas com 20 dias foram transplantadas para um espaçamento de 0,30 x 0,25 m. A adubação constou em aplicação de 200 g por metro quadrado da fórmula 4-14-10. Aos 20 e 40 dias após o transplante foi aplicado 5 g de sulfato de amônio por planta. A cultura foi irrigada sempre que necessário. As amostragens foram feitas por ocasião do transplante e depois a intervalos de dez dias aproximadamente. As plantas foram cortadas rente ao solo, lavadas, secas e analisadas para B, Cu, Fe, Mn e Zn de acordo com as instruções contidas em SARRUGE & HAAG (1974). Houve diferenças na concentração de nutrientes, mostrando-se o cultivar Brasil 48 mais exigente. Os cultivares Brasil 48 e Clause's Aurélia acumularam ao final do ciclo respectivamente, 896 g e 958 µg de B, 196µg e 168 µg de Cu, 6800 µg de Fe, 3534 µg e 1025 µg de Mn, 4462 µg e 2425 µg de Zn. | This research was carried out in order to determine the concentration and the amount of micronutrients extracted by to varieties of lettuce plants during a life cycle. The lettuce plants were collected at the age of 20, 30, 40, 50, 60 and 70 days old from a commercial field and separated into new and old leaves and stems; then the concentrations of B, Cu, Fe, Mn and Zn were determined. There were differences in the nutrient concentrations between the two varieties, and the cultivar Brasil 48 has presentend the highest levels. The amount of Fe 6,800 µg, Mn 3,534 µg, Zn 4,462 µg; Clause's Aurélia: B 958 µg, Cu 165 µg, Fe 5,446 µg, Mn 1,025µg, Zn 2,425 µg.

Rice, varieties IAC-165 and IAC-165, both upland, were grown in nutrient solution (Hoagland's nº 2) complete, with deficiency of N, P, K, Ca, Mg, S, B, Cu and Zn, and with excess of Al, CI, and Mn. Symptoms od feficiency and toxicity were observed according to the treatments. Dry matter production by var. IAC-164 was affected by the treatments in the following order: - N, -K, -P, -Mg, -B, -Ca = -Zn, -S, and -Cu; in the case of var. IAC-165, the sequence was -B, -N, -P, -K, -Mg, -Ca, -Cu, -S, and -Zn. There was no grain yield in treatments -Ca and -B. The toxicity of Al, CI, and Mn significantly decreased dry matter formation; Mn was more detrimental than Al. Variety IAC-164 was more sensitive to the toxic levels of Al and CI. At full tillering the following tissue levels in the freshly mature leaves are considered as adequate, respectivelr the varieties IAC-164 and IAC-165. N - 2.32-2.70%, P - 0.28-0,49, K - 2.83-4,21, Ca - 0.94-0,94, Mg - 0.73-0.88, S - O.13-0.16%. | O arroz das variedades IAC-164 e IAC 165, foi cultivado em solução nutritiva (Hoagland nº 2) completa, com deficiência de N, P, K, Ca, Mg, S, B, Cu e Zn e com excesso de Al, Cl e Mn. Foram observados sintomas associados aos desequilíbrios nutricionais provocados pelos tratamentos. A produção de matéria seca na var. IAC -164 foi afetada pelos tratamentos na seguinte ordem: -N, -K, -P, -Mg, -B, -Ca -Zn, -S e -Cu; no caso da var. IAC-165 observou-se: -B, -N, -P, -K, -Mg, -Ca, -S e -Zn. Não houve produção de grãos nos tratamentos -Ca e -B. Os excessos Al, Cl e Mn afetaram significativamente a produção de matéria seca, sendo o efeito prejudicial do Mn maior que o do Al. A variedade IAC-164 foi mais afetada pela toxidez de Al e Cl. Consideram-se adequados os seguintes teores, encontrados na lâmina das folhas medianas por ocasião do perfilhamento pleno, respectivamente para as variedades IAC-164 e IAC-165: N -2,32 e 2,70%; P -0,28 e 0,49; K -2,83 e 4,21; Ca -0,94 e 0,94; Mg -0,93 e 0,88; S -0,13 e 0,16%.