Wood Ash Fertilization on Structural Characteristics and Chlorophyll Index of Tropical Forage Grasses

The appropriate nutrient supply via fertilization is essential for an adequate plant growth and development. The objective of this study was to evaluate the structural characteristics and chlorophyll index of Marandu and Xaraes grasses fertilized with wood ash. The experiment was conducted in a greenhouse;the experimental design was entirely randomized, with 12 treatments and six replications arranged in a 2 × 6 factorial scheme: two forage grasses (Marandu and Xaraes) and six wood ash doses (0;3;6;9;12;and 15 g·dm-3). Each plot was composed of pots with 7 dm3 soil and five plants. Soil moisture was maintained by the gravimetric method at 60% of the maximum soil water retention capacity. Three harvests of the plant aerial part were performed at 30-day intervals. The evaluated characteristics were plant height, leaf number, tiller number, and chlorophyll index. Results were submitted to the variance analysis by F test and, after verification of the significant effects on Marandu and Xaraes characteristics, were also submitted to Tukey test;the wood ash doses were evaluated according to the regression analysis at 5% probability. Wood ash doses ranging from 10.15 to 15 g·dm-3 resulted in quadratic responses of plant height, leaf number, and tiller number for both Marandu and Xaraes grasses. The highest values of chlorophyll index derived from wood ash doses of 9.44 and 10.92 g·dm-3, with increments greater than 50%, 25%, and 9% at the first, second, and third harvests, respectively. The wood ash, when used as a fertilizer, improves structural characteristics and increases chlorophyll indices of Marandu and Xaraes grasses cultivated in Cerrado Rhodic Hapludox.

Reproductive Components of Safflower Genotypes Submitted of Bulk Density Levels in the Brazilian Cerrado

Nutrient absorption in crops can decline and their development can be hindered by increased bulk density. This study aimed at assessing the manner in which bulk density levels affect the reproductive structures of the safflower genotypes in the Brazilian Cerrado. The completely randomized design was adopted with four replications for the experiment, which was conducted in a greenhouse using Oxisol collected from 0.0 to 0.2 m depth from the region supporting Cerrado vegetation. The treatments included ten safflower genotypes (PI 237538, PI 248385, PI 250196, PI 301049, PI 305173, PI 305205, PI 306520, PI 306603, PI 560202 and PI 613366) and five bulk density levels (1.0, 1.2, 1.4, 1.6 and 1.8 Mg·m-3). Evaluations were done at 90 days after emergence, in terms of the number, diameter and dry mass of the heads. The data were submitted to the analysis of variance. The means were grouped using the Scott-Knott test at 5% probability. The diameter and dry mass of the chapters were influenced by the mean bulk density of 1.10 Mg·m-3. A notable interaction was evident between the safflower genotypes and bulk density levels for the diameter and dry mass of the head alone, revealing the high degree of genetic variability that environmental changes induce among the genotypes. The PI 250196, PI 301049, PI 305173 and PI 305205 genotypes exhibited greater stability to the bulk density variations compared with the others. Mean bulk density of 1.2 Mg·m-3 was found to impair the development of the reproductive components of the safflower genotypes.

Potential of Wood Ash as a Fertilizer in BRS PiatãGrass Cultivation in the Brazilian Cerrado Soil

Utilizing wood ash as a fertilizer in agriculture is a viable alternative to the soil nutrients absorbed by the crops. The aim of this study was to assess the phytometric and productive features of Brachiaria brizantha (cv. BRS Piatã) fertilized with wood ash in the Brazilian Cerrado. The experiment was performed in a greenhouse, adopting a completely randomized design, and applying five rates of wood ash (0, 5, 10, 15 and 20 g·dm-3) with five replicates. The shoot plant parts were subjected to three successive cuts 30-day intervals each. The results were submitted to the analysis of variance and regression analysis at 5% probability. The wood ash rates between 13 to 17 g·dm-3 clearly produced the best results for plant height (102.24, 84.42 and 63.27 cm), leaf/stem ratio (1.61, 1, 78 and 1.94), and chlorophyll index (46.66, 41.93 and 38.39), respectively, during the first, second and third evaluations. A 94% increase in the shoot dry mass (2nd and 3rd evaluations) and root parts was noted for the wood ash rate of 20 g·dm-3, compared with the treatment involving wood ash fertilization. Wood ash affects the phytometric features, increases the chlorophyll concentration and thus the BRS Piatãgrass production in the Oxisol of the Brazilian Cerrado.

Soil Water Availability on Growth and Development of Safflower Plants

Safflower (Carthamus tinctorius L.) is a promising culture to be widespread in Brazil. However, the lack of basic knowledge about cultivation techniques, such as water demand by the culture, is still obstacle to the expansion of safflower in that country. The objective was, then, to evaluate the effect of the soil water availability on growth and development of safflower in the Cerrado soil of Mato Grosso, Brazil. The experiment was conducted in a greenhouse, in a completely randomized design with five water availabilities (25%, 50%, 75%, 100% and 125% of the maximum water holding capacity in the soil) and four replications. Maintenance soil moisture was performed by gravimetric method with daily weighing of experimental units. The variables analyzed were: plant height, stem diameter, number of leaves, number of heads, heads diameter, dry mass of shoots, heads, and roots. The results were submitted to analysis of variance and regression test at 5% probability by SISVAR program. All variables set to the quadratic regression model, showing the best results in the water availability between 64% and 76%. Safflower is shown to be more sensitive to water stress with increased tolerance to water deficit in the soil than to flooding.

Initial Development of Cowpea Bean Fertilized with Natural Phosphate in the Brazilian Cerrado Soil

Cowpea, string Bean, or Macassar bean [Vigna unguiculata (L.) Walp] presents a short life cycle, low water requirement, develops in soils of low fertility, and has the ability to fix nitrogen from the air. In the Cerrado, the oxisols occupy practically all the flat to soft-wavy areas with little reserve of nutrients for the plants, in general, they are soils with great limitations of fertility. A source of alternative phosphate fertilization is the use of reactive natural phosphates. The reactive natural phosphate of Bayóvar presents intermediate solubility between the sources of soluble phosphates and the natural phosphates. In this context, the objective was to evaluate the initial development of Cowpea beans fertilized with the natural Bayóvar phosphate used for cultivation of the Brazilian Cerrado Oxisol. The experimental design was completely randomized, with six doses of phosphorus (0, 100, 200, 300, 400, 500 mg·dm-3) using natural Bayovar phosphate as a source in four replications. The species used in this study was the legume cowpea bean [Vigna unguiculata (L.) Walp] cultivar Tumucumaque. The treatments were applied using the natural phosphate Bayóvar as a source of phosphorus (29% of P2O5). At 33 DAS (days after sowing), the variable number of leaves of the Cowpea bean was analyzed and at 40 DAS, the variables plant height, SPAD chlorophyll index (Soil Plant Analysis Development) and stem diameter were analyzed. For all variables analyzed there was a significant effect. The initial development of the cowpea bean cultivated in the Brazilian Cerrado Oxisol was significantly influenced by the Bayóvar natural phosphate fertilization with the best phosphorus (P2O5) doses in the range of 200 to 350 mg·

Soil Water Availabilities in the Content and Accumulation of Nitrogen and Chlorophyll Index in the Safflower

The safflower (Carthamus tinctorius L.) is adapted to grow in adverse conditions, is tolerant to salinity and water deficit, however, its productivity increases when grown in areas with greater availability of water and in fertilized conditions, showing that the knowledge of crop management can bring income gains for producers. It is known that extreme conditions of soil moisture damage the crop development. Given this context, the objective was to evaluate the influence of water availability on the nutritional characteristics of the safflower. The experiment was conducted in a greenhouse in a completely randomized design with five water availabilities (25%, 50%, 75%, 100% and 125% of the maximum water holding capacity of the soil) in four replications. Maintaining soil moisture was performed by gravimetric method with daily weighing of experimental units. The variables analyzed were SPAD reading (chlorophyll content), concentration and accumulation of nitrogen in the shoot and in the sections. The results were submitted to analysis of variance and regression test at 5% probability by Sisvar program. There was adjusting of variables to linear and quadratic regression models. Water availabilities between 65% and 75% have greater potential to promote better nutrition for safflower plants. Both deficit and excess of water in the soil are detrimental to the absorption of nitrogen and reduce the chlorophyll content. Safflower is less tolerant to excess than to deficit of water.

Development of Safflower Subjected to Nitrogen Rates in Cerrado Soil

In a context in which the nitrogen fertilizer recommendations in the literature for safflower crop show up conflicting, it was aimed by the present study to evaluate the development of safflower when subjected to nitrogen rates in an Oxisol collected under Cerrado vegetation. The experiment was conducted in a greenhouse using pots filled with Oxisol collected in area under Cerrado vegetation in the layer from 0.0 to 0.20 m. Each experimental unit was represented by a plastic pot of 5 dm-3, the experimental design was completely randomized, consisting of six nitrogen rates (0, 60, 120, 180, 240 and 300 mg&degdm-3) and six repetitions. It were assessed plant height, number of leaves, chlorophyll content, number of heads, dry mass of shoot and dry mass of root. The results were submitted to variance analysis and, when significant, to regression analysis, both at 5% probability by SISVAR program. Nitrogen rates positively influence the development of safflower, and the one that best promotes this development is between 160 and 190 mg&degdm-3.

Correction of Acidity of a Brazilian Cerrado Oxisol with Limestone and Wood Ash on the Initial Growth of Cowpea

Among Brazilian soils orders, there are some of it classified as acid soils, which need correction to guarantee crop productivity. Currently, limestone is the most used soil corrective and wood ash has been a sustainable alternative to this process. Thus, the objective was to evaluate the effect of two correctives of soil acidity on an Oxisol collected in the Brazilian Cerrado area using limestone and wood ash and the effect of soil correction on initial growth of cowpea. Two greenhouse experiments were carried out: 1) with limestone, using base saturation levels (V%) of 0, 20, 40, 60 and 80;and 2) wood ash, with doses of 0, 8, 16, 24 and 32 g⋅dm−3, both in five randomized blocks. At 40 days after sowing, it was verified that pH values were within the range considered ideal for soil (pH of 5 to 7), according to the increase of base saturation levels and wood ash doses, but limestone provided faster results. Initial growth of cowpea was positively influenced by soil correction with use of both correctives. Wood ash and limestone increased soil pH to adequate values and resulted in better initial crop development.

Effects of Inoculation of Rhizobium on Nodulation and Nitrogen Accumulation in Cowpea Subjected to Water Availabilities

With high protein content, the cowpea is one of the most widely consumed legumes in northeastern Brazil. This study was aimed to evaluate the rhizobia inoculation effect on nitrogen accumulation and nodulation in cowpea subjected to water availability. The experiment was conducted in a greenhouse, in a completely randomized design, with six water availabilities (40%, 60%, 80%, 100%, 120% and 140% of maximum soil water retention capacity), with four replications. Soil moisture maintenance was performed by gravimetric method. The BR3267 strain (Bradyrhizobium japonicum) recommended for cowpea grown in Brazil was used. At thirty-five days after treatments implementation, the nitrogen nutritional status was assessed through SPAD reading, shoot nitrogen concentration and total accumulation. Nodulation was assessed by nodules number and dry matter. The increased water availability provided negative effect on SPAD reading and shoots nitrogen concentration. Shoot nitrogen accumulation was favored to up to 78.8% water availability, with subsequent decline. Nodulation was favored when soil water availability was between 85% and 87%. Water availability affects nodulation and cowpea nutritional status, although negative effects are more pronounced when there is soil water excess.

Bulk Density in Jack Bean’s Development Grown in Cerrado Oxisol

The use of cover plants promotes the recycling of nutrients and the increase in organic mass, and minimizes the effects of erosion. The objective was to evaluate the effect of bulk density in the development of jack bean (Canavalia ensiformis) in Cerrado Oxisol. The experiment was conducted in a greenhouse at the Federal University of Mato Grosso, Rondonópolis-MT, in the period from June to September 2013. Oxisol was used from a Cerrado reserve area, collected at 0 - 0.20 m depth. The experimental design was completely randomized, corresponding to bulk density levels (1.0, 1.2, 1.4, 1.6 and 1.8 Mg&middotm-3), and five replications. The experimental plot consisted of three PVC rings (polyvinyl chloride) with 150 mm internal diameter, 300 mm total height, where the upper and lower rings of pots were filled with 1.0 Mg&middotm-3 density soil and intermediaries according to bulk density treatments. The results were submitted to variance analysis and, when significant, to regression analysis, both with a 5% probability, using SISVAR software. At 60 days after germination, number of leaves, stem diameter, plant height, dry mass of leaves, stem dry mass, dry mass of roots, dry mass of nodules, number of nodules and chlorophyll index (SPAD index) were evaluated. The increase in bulk density negatively influences the development of jack bean, showing little efficiency as a decompacting plant in Cerrado Oxisol.