Digital soil mapping: strategy for data pre-processing

The region of greatest variability on soil maps is along the edge of their polygons, causing disagreement among pedologists about the appropriate description of soil classes at these locations. The objective of this work was to propose a strategy for data pre-processing applied to digital soil mapping (DSM). Soil polygons on a training map were shrunk by 100 and 160 m. This strategy prevented the use of covariates located near the edge of the soil classes for the Decision Tree (DT) models. Three DT models derived from eight predictive covariates, related to relief and organism factors sampled on the original polygons of a soil map and on polygons shrunk by 100 and 160 m were used to predict soil classes. The DT model derived from observations 160 m away from the edge of the polygons on the original map is less complex and has a better predictive performance.

Strategy of specification of management areas: rice grain yield as related to soil fertility

It is well-known nowadays that soil variability can influence crop yields. Therefore, to determine specific areas of soil management, we studied the Pearson and spatial correlations of rice grain yield with organic matter content and pH of an Oxisol (Typic Acrustox) under no- tillage, in the 2009/10 growing season, in Selvíria, State of Mato Grosso do Sul, in the Brazilian Cerrado (longitude 51º24' 21'' W, latitude 20º20' 56'' S). The upland rice cultivar IAC 202 was used as test plant. A geostatistical grid was installed for soil and plant data collection, with 120 sampling points in an area of 3.0 ha with a homogeneous slope of 0.055 m m-1. The properties rice grain yield and organic matter content, pH and potential acidity and aluminum content were analyzed in the 0-0.10 and 0.10-0.20 m soil layers. Spatially, two specific areas of agricultural land management were discriminated, differing in the value of organic matter and rice grain yield, respectively with fertilization at variable rates in the second zone, a substantial increase in agricultural productivity can be obtained. The organic matter content was confirmed as a good indicator of soil quality, when spatially correlated with rice grain yield.

Endosperm genotyping as a strategy to differentiate the allele source in maize heterozygous progeny

The objective of this work was to distinguish the parental source of alleles in heterozygous progeny using semiquantitative polymerase chain reaction (PCR) in maize endosperm. Endosperms derived from direct and reciprocal single-cross hybrids between maize inbred lines L3 and L1113-01 were genotyped by semiquantitative PCR methodology (SQ-PCR) using fluorescent microsatellite primers. The amplification products were evaluated by the ratios of fluorescence intensity (RFI), calculated between the peaks corresponding to the alleles derived from each parental line. Based on the statistically significant contrast between RFI mean values of direct and reciprocal single-cross hybrids, it was possible to distinguish the number of alleles received from each parental line and, ultimately, to determine the origin of the alleles of each cross. Thus, endosperm genotyping using SQ-PCR is a promising strategy to map QTL in maize outbred populations.

Quantification of the diversity among common bean accessions using Ward-MLM strategy

The present work aimed at evaluating the divergence among common bean accessions by their agronomic, morphological and molecular traits, based on the Ward-MLM procedure. A collection of 57 accessions from the gene bank of Universidade Federal do Espírito Santo was used in this study, from which: 31 were landraces belonging to the community Fortaleza, in the municipality of Muqui, ES, Brazil; 20 accessions were provided by Embrapa Trigo; and 6 were commercial cultivars. Five agronomic traits (plant cycle, number of seeds per pod, number of pods per plant, weight of 100 seeds, and grain yield), five morphological traits (growth habit, plant size, seed shape, seed color, and commercial group) and 16 microsatellite primers were evaluated. High genetic variability was detected considering morphological, agronomic and molecular traits in the 57 common bean accessions studied. The Ward-MLM procedure showed that the ideal number of groups was five, according to the pseudo F and pseudo t² criteria. The accessions from Andean origin had heavier seeds than others and formed a cluster. The Ward-MLM statistical procedure is a useful technique to detect genetic divergence and to cluster genotypes by simultaneously using morphological, agronomic and molecular data.

Hematological profile of beef cattle with divergent residual feed intake, following feed deprivation

The objective of this work was to characterize the hematological profiles of steers and bulls, according to residual feed intake (RFI), after feed deprivation. Twenty‑month‑old Nellore steers and bulls were fed feedlot diets for 70 and 56 days, respectively. RFI was calculated as the difference between actual feed intake and expected feed intake. More and less efficient steers and bulls, according to RFI, were subjected to 24 hours of food deprivation. Blood was sampled prior to and following the withdrawal period. Hematological analyses included total and differential white blood cell count, red blood cell count and morphology, and plasma glucose concentration. Variation in RFI did not influence plasma glucose concentration or blood cell profiles. Glucose concentrations in bulls decreased from 114 to 97 mg dL‑1, but remained unchanged in steers, and the neutrophil:lymphocyte ratio increased from 0.39 to 0.57 following deprivation. Hematological profiles do not differ between more and less efficient steers and bulls, according to RFI.

Feed intake and growth performance of goats supplemented with soy waste

The objective of this work was to evaluate the effects of supplemental feeding of soy waste on the feed intake and growth rate of goats. Twenty male crossbred (Boer x local) goats were assigned to two isonitrogenous diet groups: one of commercial pellet and the other of soy waste. The commercial pellet (1.0%) and soy waste (0.8%) were provided on the dry matter basis of body weight (BW) per day, to the respective group of each diet. The soy waste group had lower daily intakes of total dry matter (0.79 vs. 0.88 kg) and organic matter (665.71 vs. 790.44 g) than the group fed pellet; however, the differences on daily intakes for grass (0.62 vs. 0.64 kg), crude protein (96.81 vs. 96.83 g), and neutral detergent fibre (483.70 vs. 499.86 g) were not significant. No differences were observed between groups for BW gain. The feed conversion ratio and feed cost per kilogram of BW gain were lower for the group fed soy waste than for the one fed pellet. Goats fed supplemental soy waste have a lower total dry matter intake, feed conversion ratio, and feed cost per kilogram of body weight gain than those fed commercial pellets.