S. saponaria L. is a Brazilian native arboreal species, with relevant ecological importance in the recovery of degraded and marginal areas. The objectives of the present study were to characterize morphometrically Sapindus saponaria L. seeds, to extract and to quantify oil content, establish the percent composition of fatty acids; to describe their different post-seminal stages; to describe the different post-seminal stages, as well as to evaluate the germinative performance of the seeds as a function of different treatments to overcome dormancy. Seeds were evaluated as to water content and biometric length and width. The extraction and quantification of the seed oil was obtained by the solvent extraction method using the Soxhlet extractor system. Regarding the post-seminal development, some processes triggered during growth and development of the seedlings were evaluated. The treatments for dormancy overcoming were: mechanical scarification, chemical scarification with sulfuric acid for 5, 10, 20, 30 and 40 minutes, immersion in hot water (80 ºC) until reaching room temperature, immersion in distilled water at room temperature for 24 hours and intact seeds (control). The seeds were evaluated for germination, velocity, medium time, synchrony and germination uncertainty. The design was a completely randomized design with four replicates of 25 seeds per treatment. The seeds present on average 10.3 mm in length and 10.2 mm in width with hygene-cryptocoledonar germination. The oil content found in the seeds was 7.25%, most of which was composed of unsaturated fatty acids (78.9%). The highest values of germination occur when the seeds are immersed in sulfuric acid for 30 minutes.

Drought associated with soil acidity and exchangeable Al3+ in depth are one of the main limiting factors in agricultural production in Northeast Brazil. Acidity correctives such as limestone, metallurgy slag, and gypsum are alternatives to minimize the effects of seasonal droughts on the crop. A field study was carried out to evaluate the effect of the slag and gypsum on the morphological aspects and productivity of sugarcane during two crop cycles. A randomized block design in subdivided plots scheme with four replications was used. The plot consisted of five rows of 10 m length each, spaced 1 m from each other. Treatments consisted of five levels of metallurgy slag (0; 1; 2; 3 and 4 Mg ha-1) and two levels of gypsum (0 and 1.9 Mg ha-1). Slag and gypsum had no effect on sugarcane plant yield. However, regarding sugarcane ratoon, slag increased the yield per hectare by 1.96 Mg ha-1 and sugar yield by 0.33 Mg ha-1 per Mg of applied slag. Slag and gypsum provided better biomass allocation to the root system and improved root distribution along the soil profile.

Sugarcane produces a large amount of biomass, extracts and accumulates high amounts of nutrients. In the literature the nutritional requirements for most cultivated varieties in the past are found, however there is little information on the new varieties currently planted. The objective of this study was to evaluate the nutritional requirement of four sugarcane varieties, currently very planted, in the cycles of plant-cane, first and second ratoon. The study was installed in a Yellow Oxisol. The experimental design was a randomized block design, with five replications, and four treatments: RB867515, RB92579, SP813250 and VAT90212. During maturation of the cane, in the three evaluation cycles, the productivity of natural biomass and the nutritional requirement of macronutrients of the varieties were determined. It was evidenced that the cultivars of sugarcane are of high productive potential and resemble the accumulation of biomass, observing a yield of 158, 128 and 107 t ha-1 in the cycles of plant-cane, first and second ratoon. Regarding the nutritional requirement, the varieties did not differ among them and expressed the following order of need in the plant-cane K > N > Ca > Mg > S > P, in the first and second ratoon, the sequence observed was K > N > Ca > S > Mg > P.

Sugarcane extracts and accumulates high amounts of soil nutrients, because it produces large amounts of biomass. Nutrient contents for varieties widely used in the past can be found in the literature, but there is little information on current cultivars. In view of these considerations, the study aimed to determine the nutrient concentration in the shoot biomass of sugarcane varieties in the first regrowth cycle. The study was conducted at a Latossolo Amarelo in Fazenda Jequiá, located in the state of Alagoas, Brazil. The experiment was a randomized block design with five replicates, consisting of four sugarcane varieties: SP813250, RB867515, RB92579 and VAT90212. At maturity of the first regrowth sugarcane, nitrogen (N), phosphorus (P), potassium (K), Ca (calcium), Mg (magnesium), S (sulfur), zinc (Zn), iron (Fe), copper (Cu), manganese (Mn) and Boron (B) contents were determined. Varietal differences were found in nutrient contents. However, no variety showed higher concentration for all the elements. The varieties showed the following order of macronutrient concentrations: K > N > Ca > Mg > S > P. The average values were 0.47, 0.08, 0.66, 0.15, 0.13 and 0.11 dag kg-1 of N, P, K, Ca, Mg and S, respectively. Concentrations of 9.9, 98.7, 29.2, 1.9 and 4.4 mg kg-1 of Zn, Fe, Mn, Cu and B were found for the micronutrients, respectively.

The soil mulch is an agricultural practice that can benefit soil fertility and can be effective in suppressing weeds. The objective this research was to evaluate the mulching from legumes in weed control and sugarcane (first harvest/cut) productivity, comparing the results with the conventional application of herbicides. This research was carried out under field conditions. Five legumes were managed in two ways to form the soil cover: (1) mechanical topple, and (2) chemically desiccated. To compare the results, used treatments with herbicides applied in pre and pre + post emergence. The soil mulch from mechanical topple of Crotalaria spectabilis, C. juncea, C. ochroleuca, C. breviflora and Cajanus cajan presented lower efficiency in suppressing weeds than the treatment with herbicides applied in pre + post-emergence, however, were more efficient in controlling weeds in relation to the use of herbicides in pre-emergence, a fact observed at 60 days of sugarcane cultivation.