Residual and annual potassic fertilization for soybeans

There is a lack of long-term research on potassium fertilization for soybean in the tropical and subtropical soils of Brazil and the residual effect of the fertilizer has generally not been considered. An experiment was conducted in plots that had been fertilized with 0, 40, 80, 160 and 240 kg ha(-1) of K2O for 3 years on a Dark Red Latosol, loamy sand (Acrortox). The effects of annual or residual fertilization with those rates of K were studied for three additional years. Potassium was supplied as potassium chloride or potassium sulphate. Soil and leaf samples were taken annually. There was a residual effect of the nutrient, which provided for high yields up to the 3rd year with the highest rate of K. In order to maintain the K contents of the soil in the medium range and obtain at least 90% of the maximum grain yield, an annual application of 80 kg ha(-1) of K2O was necessary, irrespectively of the source. The highest soybean yields were always associated with K levels above 15 mg kg(-1) in the leaves and 1.2 mmol(c) dm(-3) in the soil.

Root-system of peanuts as affected by phosphorus fertilization

There have been some responses of peanut roots to phosphorus. An experiment was carried out to study peanut root growth and distribution as related to P in the soil. The cultivars Tatu, Oira and Tup4 and the lines FCA 170 and FCA 265 were grown with or without P fertilization with 80 kg P2O5/ha, as triple superphosphate. The fertilizer was applied in the seed furrows. There was higher P contents in the 0-10 cm layer of the soil 36 days after P application. At 66 and 98 days after application, P contents of the soil were increased by fertilization down to 15 cm. There was no response of peanut roots to P fertilization. Oira showed the highest root lenght density and Tatu the lowert. There was a root concentration the first 15 cm of the soil. Oira with the largest root system showed the lowest P absorption, and Tatu, with the smallest root system absorbed as much P as the others.

THE EFFECT OF SERUM ON IN-VITRO MATURATION, IN-VITRO FERTILIZATION AND STEROIDOGENESIS OF BOVINE OOCYTES COCULTURED WITH GRANULOSA-CELLS

The influence of fetal calf serum alone (FCS) or associated with proestrous (FCS+PCS), estrous (FCS+ECS) or metaestrous (FCS+MCS) cow serum added to the culture medium and of the steroids produced by co-cultured granulosa cells were evaluated in terms of the in vitro maturation (TVM) and fertilization (IVF) of bovine oocytes. Supplementation of the medium with FCS+ECS and FCS+MCS resulted in higher proportions of oocytes that reached metaphase II (96.0% and 93.3%, respectively) and in higher proportions of embryos that reached the four- and eight-cell/morula stages (51.9% and 65.6%, respectively), whereas the supplementation with FCS and FCS+PCS resulted in only 79.2% and 67.5%, respectively, of matured oocytes and 26.7% and 34.3%, respectively, of cleaved embryos. These findings show that the best IVM and IVF were obtained at lower concentrations of estradiol produced by co-cultured granulosa cells (supplementation with FCS+ECS: 10.3 ng/ml and FCS+MCS: 2.1 ng/ml), whereas the worst-results in IVM and IVF occurred at higher concentrations of estradiol that were obtained with FCS (33.1 ng/ml) and FCS+PCS (19.9 ng/ml) supplementation. These data suggest an inhibitory effect of estradiol on resumption of oocyte meiosis in vitro.

Effect of potassium fertilization in 'Rica' guava (Psidium guajava) cultivation

A field experiment was conducted from 1989-90 to 1991-92 to study the effect of potassium fertilization on guava (Psidium guajava L.). using 1-year-old plants of 'Rica', grown in a Kanhapludalf soil in the Jaboticabal region in Brazil. During the first year the K doses used were: 0, 24.9, 49.8, 99.6, 149.4 and 199.2 g K/plant, which were doubled during the second year and tripled during the third. In the third year the increase in g level showed positive response in yield. About 90% of the maximum yield observed was associated with 527 g K/plant and with a leaf content of 18.9 g K/kg.

Effect of foliar and substrate fertilization on lady palm seedling growth and development

Lady palm, [Rhapis excelsa (Thunberg) Henry ex. Rehder] is one of the most cultivated ornamental palms in the world, for use as a vase plant or in shaded landscapes. Because limited information exists on lady palm response to fertilizers, the objective of this study was to evaluate the effect of different types of fertilization and substrates on lady palm seedling growth and development. Three year old lady palms were planted in 8-L pots, filled with a mix of soil, manure, and sand 1:1:1 (v:v:v), placed under a 50% shade, and irrigated with microspray. Treatments were substrate fertilization with 500 g P(2)O(5) and 100 g K(2)O per m(3); fertilization with 1.8 kg of P(2)O(5) (simple superphosphate) per m3; 50 g of nitrogen (N), P(2)O(5), and K(2)O of a granulated fertilizer (10:10:10) per m(3), control (without fertilization), and a foliar fertilization in addition to these treatments using the commercial product Biofert (8:9:9). Treatments were replicated four times in a randomized block design. Each treatment plot consisted of four plants. Data were collected at 140, 170, 200, 230, 260, and 290 days after transplanting (DAT) for plant heights, stem diameter at substrate level, number of leaves, shoots, and canopy, roots fresh and dry matter samples were harvest at 290 days. Foliar fertilization resulted in significantly greater plant height in a 140, 120, 200, and 230 DAT and plant diameter on the 140, 260, and 290 DAT. There was interaction among factors for number of leaves with fertilization based on P(2)O(5) and K(2)O when leaf fertilizer was added that resulted in a greater number of leaves.

The effect of serum on in vitro maturation, in vitro fertilization and steroidogenesis of bovine oocytes co-cultured with granulosa cells.

The influence of fetal calf serum alone (FCS) or associated with proestrous (FCS+PCS), estrous (FCS+ECS) or metaestrous (FCS+MCS) cow serum added to the culture medium and of the steroids produced by co-cultured granulosa cells were evaluated in terms of the in vitro maturation (IVM) and fertilization (IVF) of bovine oocytes. Supplementation of the medium with FCS+ECS and FCS+MCS resulted in higher proportions of oocytes that reached metaphase II (96.0% and 93.3%, respectively) and in higher proportions of embryos that reached the four- and eight-cell/morula stages (51.9% and 65.6%, respectively), whereas the supplementation with FCS and FCS+PCS resulted in only 79.2% and 67.5%, respectively, of matured oocytes and 26.7% and 34.3%, respectively, of cleaved embryos. These findings show that the best IVM and IVF were obtained at lower concentrations of estradiol produced by co-cultured granulosa cells (supplementation with FCS+ECS: 10.3 ng/ml and FCS+MCS: 2.1 ng/ml), whereas the worst results in IVM and IVF occurred at higher concentrations of estradiol that were obtained with FCS (33.1 ng/ml) and FCS+PCS (19.9 ng/ml) supplementation. These data suggest an inhibitory effect of estradiol on resumption of oocyte meiosis in vitro.

Effects of rooting media, indolbutyric acid and fertilization on the rooting of rose (Rosa sp. 'Dalas') leafy cuttings

The objectives of this study were to evaluate the effects of rooting media (vermiculite, carbonized rice bark, fenolic spume and sand), presence of IBA (indole-3-butyric acid) and presence of fertilization during the rooting of rose (Rosa sp.) leafy cuttings, Dalas cultivar. This investigation was carried out in Jaboticabal (Sao Paulo State - Brazil) during the period of March to April 1997. The experimental design was a randomized block in a factorial arrangement. It consisted of 16 treatments (the 4 rooting media combined with IBA concentrated solutions - 0 and 1.000 ppm and fertilizer - 0 and commercial product with macro and micronutrients, applied weekly) with 3 replicates. The evaluations were 30 days after cuttings showed that the best rooting percentage occurs in sand (98%), followed by vermiculite (90%) and fenolic spume (87%) and cuttings treated with IBA (95%), while the fertilization showed no promoting effects. The number of cuttings roots wasn't affected with rooting media or DBA treatment, while the fertilization showed effective.

Influence of organic and chemical fertilization on the yield of flowers, contents and composition of essential oil of (Chamomilla recutita (L.) Rauschert)

A field experiment was conducted with chamomile (Chamomilla recutita [L.] Rauschert), in an area of the Olericulture and Medicinal Plants of the Horticulture Department at UNESP - Jaboticabal Campus, with the aim to evaluate the influence of organic and chemical fertilization on the yield of flowers, and content and composition of the essential oil of chamomile. The experimental design for the yield of flowers consisted of randomized blocks with 7 treatments and 4 replications, for the analysis of the contents and composition of the oil, the completely randomized block was used and for analysis of the correlation between harvesting and treatment, the split-plot design into randomized blocks was used. The treatments tested were: no fertilization, green manure (Mucuna aterrima + Crotalaria spectabilis), green manure (plant cocktail), organic fertilizer (farmyard manure), N as urea, N as ammonium sulphate, NPK with N supplement as ammonium sulphate. There was no influence of the treatments on the yield of flowers nor on the essential oil content; on the other hand both characteristics did show significant differences in harvesting times (Tukey 5%). The main yield was 885.90 kg/ha dry flowers and the mean oil content was 0,86%. The green manure treatment (M. aterrima + C. spectabilis) showed a higher percentage of chamazulene content, with a highly significant difference in harvesting times (Tukey 1%). The a-bisabolol percentages did not evidence significant differences between treatments. However, among harvesting times, there was a variation. A negative correlation was verified between the chamazulene and abisabolol percentages; the first increasing - from 21.02 to 36.17% - and the latter decreasing - from 14.12 to 8.72 % - from the first to the sixth harvest. The observed mean content of chamazulene was 14.64 % and a-bisabolol was 16.72 %.

Nitrogen and potassium fertilization of 'Nanicao' banana (Musa AAA Cavendish subgroup) under irrigated and non-irrigated conditions

A field experiment was carried out in São Paulo State, Brazil, with the objective of investigating the response of 'Nanicao' banana (Musa AAA Cavendish subgroup) to nitrogen and potassium fertilization under irrigated and non-irrigated conditions during two crop seasons. The effects of cropping on some soil chemical properties were also investigated. A split-plot design was used with irrigation (micro-sprinkler) and no irrigation applied to main plots, and a combination of four rates of N (0, 200, 400 and 800 kg N ha-1) and K (0, 300, 600 and 900 kg K2O ha-1) as the sub-plot treatments. Irrigation caused a significant increase in fruit yield and determined the response to N and K fertilizers. In spite of a high level of exchangeable K, a positive response to K application was observed on the plant crop in non-irrigated plants. Fruit yield was impaired by N application in the plant crop (1st cycle). A positive response to N application was observed in the 2nd cycle. Soil pH decreased with increasing N rates. Exchangeable K was significantly reduced due to crop exhaustion.

Phosphorus foliar fertilization in guava trees

Currently there is very little information on the response of fruiting perennial plants to applied P. This is especially true for tropical production areas where soils have a high capacity of P fixation, and are poor in native phosphorus. An alternative to soil P fertilization, which is inefficient in fixing soils, is to apply phosphorus as a foliar spray. P is quickly absorbed by leaves, and is redistributed quite well through the plants because its phloem mobility, and foliar application may be a viable practice. The purpose of this present work, is to determine the effectiveness of foliar P application on the nutritional status and yield of guava. The experiment was done in a Typic Hapludox, for three consecutive agricultural years, in an adult orchard of 'Paluma' guava. Five treatments were tested: four rates leaf applications of P (0-0.5-1.0 and 2.0% of P2O5) and a control where P was applied to soil (200 g of P2O5/plant). Through the results it was verified that the foliar application of P altered the concentration of the nutrient in the soil (13 to 48 mg dm-3 P-resin), and in the guava leaves (1.2 to 1.8 g of P kg-1), but did not affect the production of fruits. In conclusion, in field conditions, it is viable to combine the phosphorus foliar fertilization with disease control, without increasing the operations and, consequently, the production cost.