The monitoring of plants growth constitutes an important activity during the crops formation, including the yellow passion fruit. In this direction, an experiment was carried out in Remigio, Paraiba State, Brazil, to evaluate the effects of saline water irrigation, bovine biofertilizer and potassium on yellow passion fruit growth plants and soil salinity. Treatments were arranged in randomized block with three replications and 12 plants per plot, using factorial design 2 x 2 x 2, relative electrical conductivity of irrigation water of 0.35 to 4.00 dS m-1, in soil with and without biofertilizer and potassium chloride (KCl) conventional and coated with polymers. The variables studied were electrical conductivity of the soil at depths of 0-20 and 21-40 cm, plant height at 30 days after transplanting (DAT), period of the seedlings transplanting to pruning of the main haste and lateral branches, number of productive branches and stem diameter at 30, 90, 150, 210 and 270 DAT. The interaction between water salinity, biofertilizer and potassium increased the soil salinity. The biofertilizer and the slow release of KCl increased the plant growth in height, anticipating the main stem pruning and productive side branches, productive branches number and stem diameter of the plants. Key words: Passiflora edulis, electrical conductivity, organic input.

The response of plants to salt stress is an extremely complex phenomenon that involves morphological, physiological and biochemical changes, modifying the leaf contents of chlorophyll and carotenoids, among others and affecting plant growth, development and production. An experiment was carried out from July 2010 to June 2011, in order to evaluate the contents of chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, the chlorophyll a/b ratio and biomass accumulation of shoots and roots of noni plants, when subjected to irrigation and leaching with water of increasing salinity. The experiment was carried out in a greenhouse, at the Center of Agricultural Sciences of the Federal University of Paraíba, in the municipality of Areia-PB, Brazil. Treatments were distributed in randomized blocks, in a 5 × 2 factorial scheme with four replicates and two plants per plot, and corresponded to levels of electrical conductivity of irrigation water (0.5; 1.5; 3.0; 4.5 and 6.0 dS m^-1) in pots with and without leaching. The increase in irrigation water salinity impairs the leaf contents of chlorophyll a, b, total chlorophyll, carotenoids and biomass production of noni plants, but to a lesser extent in all the treatments in which same irrigation water was used for leaching.

The objective of this study was to evaluate the use of sorghum silage, Buffel grass hay and forage palm fodder in the diet of dairy goats by means of performance tests and economic viability of different roughage sources. Eight Anglo-Nubian goats, multiparous, weighing around 40.13 ± 2.76 kg of live weight were used. The experiment lasted 84 days, consisting of four periods of 21 days, distributed in two Latin squares (4x4). The treatments represented by diets with different volumetric sources: SSCF: (sorghum silage+ forage palm+ concentrate); BHCF: (Buffel grass hay + cactus forage+ concentrate); SS: (sorghum silage+ concentrate) and BH: (Buffel grass hay + concentrate). Nutritional intake, digestibility, feed behavior, milk production and chemical composition and economic analysis were evaluated. Animals fed the BHCF diet had higher nutrient intakes and consequently were more productive in fat, protein, lactose, fat free solids and total solids. The BHCF diet led to a higher gross income in Brazilian currency. The safety margin of the SSCF diet presented the highest percentage, with 43.06%, and the BHCF diet, the lowest percentage, of 14.89. The association of forage palm with sorghum silage and Buffel grass hay can be used as a bulky source in lactating goat diets.

The conversion of caatinga vegetation areas into pastures in the Brazilian semiarid region has depleted soil fertility due to degradation. The natural regeneration of the caatinga has been the alternative adopted to restore soil fertility. However, the real effectiveness of this practice in recovering organic carbon (SOC) and nutrient stocks is unknown. This work evaluated the effect of natural regeneration of the caatinga vegetation on the restoration of levels and stocks of SOC, N, and P as a strategy to maintain the sustainability of the environment. We collected soil samples every 5 cm, up to 20 cm deep, in areas of degraded pasture, caatinga in regeneration (10 years), and regenerated caatinga (35 years) to evaluate the levels and stocks of SOC, N, and P. The depth significantly affects the levels and stocks of SOC, N, and P. Stocks and levels of SOC, N, and P were higher in regenerated caatinga > regenerating caatinga > degraded pasture. The regenerated caatinga increased SOC, N, and P stocks by 115%, 110%, and 117%, respectively, compared to the degraded pasture. Although 35 years of regeneration of the caatinga has improved soil fertility, the levels and stocks of SOC, N, and P remain low.

The Caatinga biome has been severely devastated over the years due to the replacement of native dry forests with grassland areas in the Brazilian semiarid region. Despite this, variations in key soil quality indicators still need to be fully elucidated. We evaluated soil and root respiration dynamics in grassland (GR), agroforestry (AS), and Caatinga forest (CA) areas, during dry and rainy seasons. In situ, monthly ${\mathrm{CO}}_2$ flux (total, root, and heterotrophic respirations), soil moisture ($\theta$v), and temperature (${\mathrm{T}}_{soil}$) were measured. Soil samples were collected every 5 cm layer up to 20 cm depth to analyze total organic carbon (TOC) and microbial activities. The highest parameter values occurred during the rainy season. Total soil respiration was highest in AS, followed by CA and then GR, with 19.3, 13.4, and 8.4 ton C h${\mathrm{a}}^{-1}$ y${\mathrm{r}}^{-1}$, respectively, and root respiration contributed 33.2 and 32.9% to total soil respiration in CA and AS, respectively. However, TOC concentrations and microbial activity were significantly higher in AS than in GR and similar to CA, more than compensating the C losses by respiration. Therefore, agroforestry systems have a high potential for semiarid lands because they preserve soil carbon and microbial activity comparable to Caatinga forests.