ABSTRACT
Corn (Zea mays) silage is an important and popular feed for dairy production in the Amazon region, so it is necessary to evaluate the agronomic performance of forage varieties of corn for cattle feeding in Amazonas. For this purpose, three corn varieties were evaluated (variety 1: Yellow Starchy Corn, variety 2: Chuska INIA 617, and variety 3: DOW 2B710), with two planting densities (density 1: 30 × 80 cm and density 2: 35 × 75 cm) and two fertilization conditions: with fertilization (F1) and without fertilization (F2). The parameters evaluated were plant height, number of leaves, leaf length and width, stem diameter, fresh forage, and dry matter. Student t-tests, correlation analysis of variables, and principal component analysis using R software version 4.1.3 were used for data analysis. The results indicated that variety 2 obtained the best values for the variables leaf width (12.33 cm) and stem diameter (3.25 cm), fresh forage (17.77 kg/m2), and dry matter (4.8 kg/m2), which would explain the directly proportional correlation found between leaf width and stem diameter with fresh forage and dry matter. The principal component analysis showed constant height and leaf length increases, and the best-evaluated parameters were associated with applying fertilizer. The variety that showed the best agronomic performance under Chachapoyas conditions was Chuska INIA 617, emerging as a potential feed for cattle.
ABSTRACT
It is important to carry out the morphological characterization of coffee parent plants and the physicochemical properties of the associated soils in the Amazon region, Peru, in order to achieve germplasm conservation. One hundred coffee mother plants were identified and located in five provinces of the region and evaluated according to morphological descriptors such as stipula shape, young leaf color, leaf shape, leaf apex shape, young shoot color, leaf color, fruit color, fruit shape, mature leaf color, and rust incidence percentage. In the plots where the parent plants were located, soil sampling was carried out to determine the physical and chemical properties. The varieties with the greatest presence in the five provinces were Típica and caturra roja, with the greatest number of specimens reported for the province of Bagua. The predominant stipule shape was triangular (91%), lanceolate leaf shape (60%) and red fruit color (90%). Bongará reported the lowest incidence of yellow rust, as well as the Mundo Novo Rojo variety. Soil pH ranged from acidic to neutral values, low electrical conductivity, high organic matter content, low phosphorus content, high potassium levels and medium cation exchange capacity. The predominant textural class was sandy loam. The physical and chemical characterization of the soils under study show favorable ranges to encourage the best development of coffee cultivation.
ABSTRACT
Silvopastoral systems (SPS) are presented as an alternative for the protection and recovery of soils; however, the relationship between the tree component and the physical-chemical characteristics of the soil is unknown. Thus, the objective of this study was to evaluate the physical-chemical characteristics of the soil under four silvopastoral systems (SPS), alder (Alnus acuminata), pine (Pinus patula), cypress (Cupressus macrocarpa), and pona (Ceroxylon quindiuense), and a treeless system (TS) in the Amazonas region. A completely randomized design (CRD) with five treatments and three replicates was used. The experimental units were sampled at two depths, 0-15 and 15-30 cm. The parameters evaluated were pH, electrical conductivity (dS/m), organic matter (%), phosphorus (ppm), potassium (ppm), cation exchange capacity (meq/100 g), porosity (%), mechanical resistance (kg/cm2), bulk density (gr/cm3), moisture (%) and total carbon (t/ha). The results were analyzed by analysis of variance (α = 0.05 %) and Tukey's test of means (p ≤ 0.05). The systems presented strong acidic pH values (4.11-5.61), which resulted in high organic matter contents in all systems (6.74-9.99 %). The highest phosphorus content was in the SPS with alder (12.64 ppm), and the highest potassium content was in the SPS with cypress (382.33 ppm). Porosity in all systems was higher than 60 %. The highest bulk density was between 15 and 30 cm, and the highest percentage of moisture was in the surface layer (0-15 cm). The mechanical strength was higher in the SPS with cypress (2.62 kg/cm2). For all the systems evaluated, the highest carbon stock was found in the first 15 cm. The SPS with pine had the best soil characteristics and carbon sequestration (149.05 t/ha).
