Phytomass Production Research Articles

Winter cover crops grown in low altitude condition

The purpose of the study was to evaluate dry matter phytomass production, percentage of soil cover, and dry matter phytomass decomposition curve of cover crops in single and mix cultivation, in a low-altitude subtropical environment. The study was conducted in Santa Maria - RS, in agricultural years 2019/2020 and 2021/2022. The experimental design used was randomized blocks, with ten treatments and four replications. The experiments were conducted with four winter cover crops: White oat (WO), black oat (BO), forage turnip (FT), and common vetch (CV), in single cultivation and as a mix of cover plants. For the total production of dry matter phytomass, the FT and BO+CV+FT treatments stand out which present the highest averages between the experimental years, with values ​​4365.32 and 4109.87 kg ha-1. FT in single cultivation has a high potential for soil coverage in periods of 45 DAS, and the common vetch crop showed greater soil coverage in the late period, with 84% coverage at 90 days after sowing. The BO and WO treatments showed greater maintenance of dry phytomass in soil cover at the end of the 150-day period, presenting values greater than 40% of the initial volume of dry phytomass present in the production system. Recommending the exclusive cultivation of the species that meets the rural producer's objective.

NITROGEN IMPROVES BIOMASS PRODUCTION AND CHLOROPHYLL SYNTHESIS IN BASIL PLANTS GROWN UNDER SALT STRESS

Basil (Ocimum basilicum L.), a medicinal and aromatic plant extensively cultivated in the Northeast region of Brazil, encounters growth challenges attributed to the salinity of irrigation water and soil. Nitrogen (N) is a crucial macronutrient employed to mitigate salt stress in plants. Therefore, this study aimed to evaluate the production of phytomass and chlorophyll synthesis in purple basil plants grown under salinity stress and nitrogen fertilization. The experiment was conducted in 2021 under protected environmental conditions at the Center for Agricultural Sciences, Universidade Federal Paraíba, Areia-PB, Brazil. Five levels of salt stress (0.0, 0.80, 2.75, 4.70, and 5.50 dS m-1) and five doses of N (0.00, 58.58, 200.00, 341.42, and 400.00 mg L-1) applied via foliar were studied. The results revealed that foliar fertilization with N increases plant tolerance to salt stress, promoting root fresh and dry mass accumulation at 294.96 and 205.36 mg L-1 and under ECw of 1.14 and 0.5 dS m-1, respectively. Applying 217.39 and 231.30 mg L-1 of N improves the production of stem dry biomass and the shoot/root ratio of basil plants subjected to salinity of 0.5 dS m-1. The electrical conductivity of irrigation water above 0.8 dS m-1 adversely affects biomass production. The salinity at 3.8 to 4.0 dS m-1 stimulated chlorophyll synthesis in purple basil plants. However, the foliar application of N proves to be a strategic approach to counteract these effects, resulting in increased total dry mass production and chlorophyll contents.

Оценка перспектив сельскохозяйственного использования биологического ресурса лугово-пастбищных биоценозов Воронежской области

Highly productive meadow grass communities are a valuable biological resource used in agricultural production. To date, there are several main forms of using natural meadows in agriculture – this is haymaking and grazing. The paper presents the results of a comparative analysis of the biological production of aboveground phytomass of four representative sites of floodplain meadows located in Semiluksky, Ternovsky, Talovsky and Bogucharsky districts of the Voronezh region. The study covers a five-year period from 2019 to 2023. The results of the study show differences in the peak values of the aboveground plant biomass of meadows in different regions of the region, as well as the difference in the timing of the formation of the maximum biomass from the beginning of spring vegetation. Based on the results of the study, conclusions are drawn about the prospects of using the biological resource of meadow phytocenoses in the agricultural production of the region, as well as its scaling. Keywords: BIOLOGICAL RESOURCE OF MEADOW BIOCENOSES, DYNAMIC OF PRODUCTIVITY OF MEADOW BIOCENOSES, REMOTE MONITORING, FEED AND ENERGY VALUE

Phytomass productivity of cutting and grazing grasslands with special reference to small-scale spatial variation in plant nutrient resources

Sown grasslands are generally managed via one of two methods: cutting or grazing. In cutting grassland (CG), fields are uniformly plowed, and subsequently, one or several mixed pasture plant species are uniformly seeded, managed, and cut. In grazing grassland (GG), several pasture plant species are uniformly seeded at the establishment stage of grassland, and livestock is introduced to the grassland after a certain volume of vegetation is achieved. In GG, nutrient cycling occurs via grassland vegetation, intake and excretion by animals in grassland, and grassland soil. The objective of this study was to build a mathematical model to investigate which of CG or GG produces more phytomass under an equal level of plant nutrient resources (PNR) such as mineral nitrogen, available phosphorous, potassium in soil and the derivatives in plant bodies. In the model, we assumed that the relationship between PNR and plant production per unit ground area (plot) in CG and GG would follow the Mitscherlich law; the frequency distributions of the PNR level in soil and vegetation per plot would follow a gamma distribution in GG, but a spatially uniform distribution in CG; PNR level in soil of CG would be equal to the mean PNR in soil of GG; and additional PNR in the form of fertilizer would be applied to achieve equal PNR levels between CG and GG ecosystems after cutting and grazing. The model outputs indicated that (1) under conditions in which mean PNR levels were equal between CG and GG, phytomass in GG after grazing was greater than that after cutting in CG if the spatial variation in PNR is not highly heterogeneous in GG, however, smaller than that just before cutting in CG for any spatial heterogeneity in GG; (2) resupply of PNR (i.e., fertilizer) after cutting or grazing practices (to maintain equivalent PNR levels between both grassland ecosystems) produce a higher phytomass in CG compared to GG. The reason is that CG receives much resupply of PNR to supplement losses by natural (such as runoff and infiltration) and artificial (cutting/carrying-out of phytomass) losses, but in GG only the natural loss is resupplied because there is no artificial loss; (3) the high spatial variations in PNR generally play a negative role to determine phytomass production (phytomass productivity, or phytomass yield) in GG; (4) the efficiency of PNR resupply to phytomass production (output/input ratio of PNR) is higher in GG, particularly under the condition with highly spatial variation in PNR, than that in CG.

Água residuária e substratos no crescimento de mudas de angico

ABSTRACT The production of seedlings of forest species for reforestation of biomes is a practice that restores the conditions of the environment, but water and substrates that favor the growth of seedlings are required. However, in the semi-arid region, water is a limiting factor, requiring the use of alternative sources such as treated domestic sewage. In this context, the objective was to evaluate the growth of Anadenanthera colubrina L. seedlings produced in substrates (soil + bovine manure and soil + coconut fiber) fertilized with treated domestic sewage effluent diluted in public-supply water in proportions (100, 75, 50 and 25% of domestic effluent) and using water from the supply network as a control. The treatments were arranged in a completely randomized design, in a split-plot with three replicates. The treated domestic effluent (TDE) used in the experiment came from the domestic sewage treatment plant of the decanter-digester type of the Projeto de Assentamento Milagre Apodi/RN. The study was conducted in a seedling production nursery at UFERSA, with growth and vigor evaluations at 30, 60, 90 and 120 days after transplanting. The production of seedlings fertigated with domestic effluent caused differences in all growth variables, with improvement in phytomass production. Seedlings fertigated with a dilution of 50% TDE and 50% water supply showed better results when produced with substrate composed of soil and coconut fiber. The seedlings showed good quality, and those cultivated with 50% and 75% of wastewater showed better quality after 120 days of cultivation.

Phytomass and essential oil of basil (cv. Basilicão) under periods of induced salt stress

Research results reporting the effect of under periods of induced salt stress on biomass production, yield and composition of the essential oil of rosemary are scarce. The aim of this study was to evaluate phytomass production and essential oil yield of basil plants (Ocimum basilicum L. ‘Basilicão’) in soilless cultivation under different levels of salt stress, in addition to analyzing their phytochemistry. Four periods of salt stress were evaluated in summer and winter experiments: 0, 10, 20 and 30 days. The analyzed variables were fresh mass (FM), dry mass (DM), number of inflorescences (NI), essential oil yield (EOY), and phytochemistry. A completely randomized design was used, and the data were submitted to analysis of variance and evaluated by polynomial regression. Salt stress reduces leaf and stem FM and DM and the FM of total aerial part, in summer and in winter; it increases FM, DM, and NI in summer; there is no difference in FM, DM or NI in winter; and no difference in DM of total aerial part in both seasons. Leaf EOY reduces under salt stress during both seasons, as well as total EOY in winter. Inflorescence EOY increases in summer. Linalool, the main component of the oil, increases under salt stress.

Photochemical and phytomass aspects of pomegranate seedlings grown under water salinity and foliar nitrogen fertilization

Pomegranate is a fruit with potential for exploitation in the Brazilian Northeast as medicine and food. However, the qualitative and quantitative scarcity of water resources is common in this region, requiring the use of water with high salt contents in irrigated agriculture. The adoption of strategies to reduce the harmful effects of salt stress in plants is therefore necessary, and foliar nitrogen (N) fertilization is a promising alternative. The objective of the work, therefore, was to evaluate the photochemical and phytomass aspects of pomegranate seedlings grown under irrigation water salinity and foliar nitrogen fertilization. The experiment was performed in a randomized block design, in an incomplete factorial scheme, with five levels of electrical conductivity of irrigation water - ECw (0.50, 1.15, 2.75, 4.35 and 5.00 dS m-1) and five nitrogen doses - N (0.0, 0.33, 1.15, 1.97 and 2.30 g L-1), totaling nine combinations, generated by the Central Composite Design, with four repetitions and two plants per repetition. Foliar N application at a dose of 1.37 g L-1 increased the production of leaf and root dry phytomass at 90 days after emergence. Salt stress reduced the photochemical activity and phytomass production of pomegranate seedlings, while there was a stimulus by increasing N application up to 2.3 g L-1.
 Keywords: nitrogen, photochemical efficiency, Punica granatum L., salt stress.

Analysis of Interrelations Structure in Agro-Systems Using the Factor Analysis Technique (FA)

A model is not an exact copy of its original, but only its idealised reproduction that is simpler, more understandable, more accessible and easier, safer and more effective to work with. In the presented study, we used the technique of factor analysis (FA). We used 44 parameters to describe an agroecosystem, which proportionally describe the main components of the study agroecosystem. Based on Malinowsky error analysis, we extracted a 6-factor solution. We found out that Factor 1 [Climate factor] had primary factor loads in [average temperatures TIII-TIX (0.99) and [average atmospheric precipitation ZIII-ZIV (0.99)] variables. Factor 2 [Chemical parameters of geological foundation] was mainly saturated by [SiO2-G (0.92), Al2O3-(0.82), (CaO-G (0.83)] variables and secondary loads were observed in soil [SiO2-P (0.61], [CaO-P (0.64], [Al2O3-P (0.32)], [soil skeleton SKEL (0.47)] and [granularity GRN (0.39)] variables. Factor 3 [Phytomass production potential factor] had primary factor loads in [depth of soil profile DSP (0.76)], [quality of organic substances Q4/6 (0.63)], [slopeness SL (0.67)] and [potential phytomass production PROD (0.65)] variables. In factor 4 [Physical-chemical soil properties factor] variables [Al2O3, (0.81)], [granularity GRN (0.69)] and [SiO2 (0.61)] have significant loads. Factor 5 [Erosion by water potential factor] has the highest primary loads in [large-scale arable land ALL (0.70)] and [soil loss as a result of erosion EROS (0.67)] variables, and secondary loads in the [continuous length of plot of land slope LS (0.53)] variable. Factor 6 [Biochemical properties factor] has the highest factor load values in the content of organic substances in soil [content of organic substances in soil H (0.69)]. Secondary loads can be seen in the properties of soil [GRN (0.35)], [SiO2 (0.32)], [Al2O3-P (0.38)] and [depth of groundwater surface GWS (0.39)]. We determined the weight coefficients for the individual factors with the aim of quantifying ecological criteria with the obtained factor structure. The factor score F0 determines the projections of the extracted factors for the individual elements of the selection (it is the value soil-ecological units—VSEU). Row vectors in this matrix represent the distribution of the individual factors for the specific realisation of the selection (spatial distribution). We re-scaled the obtained values of the factor score into seven categories and projected them into VSEU units. We could propose a sustainable agroecosystem management based on quantifying the ecological criteria for each VSEU unit.

Effect of phosphorus concentration on mineral nutrition and growth phenology in Pistacia vera L. and Pistacia atlantica Desf.

• The treatment 5 ppm enhance P. atlantica establishment. • Increasing phosphorus concentrations in the soil enhanced P, K, Fe, Mg, Na and Cu uptakes in both species. • High P level reduced Zn uptake. • P. atlantica can rehabilitate the exploited phosphate zones. This study was performed to evaluate the effect of phosphorus (P) on two pistachio species Pistacia vera L. ( P. vera L.) and Pistacia atlantica Desf . ( P. atlantica Desf.) growth, phytomass production and nutrient uptake, recorded 82 days after treatment. The plants were grown in pots containing soil supplied with six levels of phosphorus 0, 5, 15, 30, 60 and 120 mg/L as phosphoric acid (P 2 O 5 ). Results showed that P has a major effect on minerals uptake, leaf area and relative growth rate of (shoot, root and root/shoot phytomass ratio) in P. vera and P. atlantica . The two species showed different patterns. P level (5 mg/L) increased significantly P. atlantica leaf area and relative growth rate compared to low phosphorus level (0 mg/L) and high P level 60 and 120 ppm. Indeed, high P level 60 and 120 mg/L reduced significantly these parameters in both species. This study suggested that P applications at 5 mg/L enhance P. atlantica establishment. Also, P. atlantica maintained growth at 15, 30 mg/L. Increasing phosphorus concentrations in the soil enhanced P, K, Fe, Mg, Na and Cu uptakes in both species. In contrast, high P level reduced Zn absorption. Added to P. atlantica adaptation to water and salinity stress, this finding has major implications in arid land rehabilitation, where many soils have high P levels and suffering from aridity.

Aerial Phytomass Production and Growth Performances of Five Common Tall Species in Andean Grasslands at Harvesting and Application of Natural Fertilizers

The objective of the research was to evaluate: aerial cover, canopy height and aerial phytomass production in five of the most common tall species in the area, in order to articulate it to a plant fiber production project. For the evaluation, 5 plots of 900 m2 were fenced, including 50 subplots of 32 m2, which were fertilized with cattle manure and phosphate rock. Monthly measurements were made from October 2020 to June 2021. At the end of the control, significant differences were observed for P = .01. Between plots they ranged from 1533±508 to 2909±192 cm2 in canopy cover (CC), from 36.9±0.89 to 38.3±2.31 cm in canopy height (CH) and 44±9.11 to 129±9.11 g DM/plant in Aerial Phytomass Production (AFP). Between species, they ranged from 2067±876 to 2975±200 cm2 in CC, from 33.2±3.86 to 40.3±1.24 cm in CH, and from 49.4±11.52 to 162.4±8.49g DM/plant in AFP. By fertilization effect the AFP varied as follows: those fertilized with phosphate rock reached 109.5±6.72 g DM/plant (14.7%), with cattle manure 88.8±6.72 g DM/plant (-5.3%), and finally the control plants with 93.5±15.03 g DM/plant, which means. A high canonical correlation was also observed between biological variables (canopy cover, canopy height, and dry matter production) and climatic variables (maximum temperature, minimum T. in °C, and rainfall in liters/m2). It was shown that tussock species respond quickly to cutting and natural fertilization has beneficial effects on biological indicators, despite the altitudinal difference between the plots and the particular species.

Effect of different mowing intensities on phytomass production of permanent grassland in a warm and an arid region

The aim of the work was to analyse the impact of different intensities of grassland exploitation on the productive capacity in the context of declining livestock numbers and the need for temporary or permanent extensification. The research was carried out in 2017-2020 in the locality of Žirany in the Nitra district, located in the temperate zone at the boundary between the continental and Atlantic-continental regions. Average annual temperatures are around 9 °C. The original semi-natural vegetation has been used for sheep grazing for many years. There were 8 experimental variants of use/cutting with different intensity of exploitation: var. 1 - abandoned unused, var. 2 - 3x per year, var. 3 - 2x per year, var. 4 - 1x per year, var. 5 - 4x - 3x - 2x - 2x - 1x per year, var. 6 - 1x - 2x - 3x - 4x per year, var. 7 - 3x - 1x - 1x - 3x and var. 8 - 2x - 1x - 1x - 1x - 2x. By comparing the sum of yields for the entire 4-year annual cycle, we concluded that, with the exception of the 1x annually mowed variant, all the others differentiated themselves from the abandoned stand by their increased production capacity. We also observed differentiation between fertilized and exploited variants into groups. The stand mowed 3 times annually (variant 2, 29.07 t ha-1) was shown to be the most productive. The second group consisted of variants with production lower in the sum of 4 years by about 5 t ha-1 (3, 5, and 6). The same level of lower yield was then found on stands with temporarily reduced intensity of use (variants 7 and 8). In the effectiveness of applied nutrients on production growth, it was found that as the number of applications increased, nutrient use also increased. The average of the years in the overall assessment of the 4-year cycle showed the dynamics from the individual years and also confirmed the tendency of the highest nutrient use at a stable 3-cut use.

Application of Callopian clay to improve the productivity of zinc-contaminated soils in lawn ecosystems

Pollution of lawn soils with heavy metals leads to the suppression of life and activity of living organisms inhabiting these ecosystems. The use of various means of soil detoxification will make it possible to neutralize the effect of technogenic pressure on the functional properties of urban ecosystems. The article presents data on the sorption-fertilizing properties of Callovian clay when used in zinc-contaminated soils of lawn ecosystems. The study used a small-plot field experiment, which simulated artificial contamination of agro-gray soil with zinc. The article discusses 2 methods of tillage and 4 doses of fertilizer-sorbent. It was found that the use of Callovian clay led to an increase in the production of raw and dry phytomass of lawn grasses by 3.7 - 33.2%, microbiological activity of soils by 0.9 - 132.5 times, as well as a decrease in zinc toxicity by 10 - 25%. The sorption-fertilizing effect and the optimal doses of the applied Callovian clay were determined by the time when the Callovian clay was introduced into the soil (autumn or spring).

Water availability and seasonality affect phytomass production and photosynthetic pigments of Aloysia citrodora Paláu

Vegetative growth can be affected by different environmental factors. The objective of this work was to evaluate phytomass production and photosynthetic pigments of Aloysia citrodora plants submitted to different irrigation levels and seasons. The experiment was carried out in a protected environment from August 2015 to March 2017, in an experimental randomized blocks design, 4x4 factorial scheme, with four blocks with four plants each. The irrigation levels tested were 25%, 50%, 75% and 100% of the field capacity, in the four seasons of the year (autumn, winter, spring and summer). Plant height, fresh and dry mass of branches, fresh and dry mass of leaves, leaf area and photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids) were evaluated. It was observed that water availability and seasons influence phytomass production as well as the photosynthetic pigment analyzes. Low irrigation levels and cultivation during autumn and winter adversely affect vegetative growth. Furthermore, our results indicate that for higher phytomass production, it is recommended to cultivate Aloysia citrodora during spring and summer under irrigation levels of 75% and 100% of field capacity. Spring season promotes higher content of photosynthetic pigments. This study will open new avenues and perspectives to elucidate possible changes in secondary metabolites of Aloysia citrodora, a medicinal plant, in the presence of changes in the growing seasons and different stress conditions, including water stress.

Produção de fitomassa por plantas de cobertura e seus efeitos em atributos do solo

Associated with the positive use of particle formation cover plants and improvement of the differentiating objective effect machining attributes of cover mixes compared to single black sphere impact, in soil structure attributes and in the production of phytomass The experiment was located in Jardim Alegre, PR under a randomized block design with 3 treatments and 7 replications. The treatments consisted of two mixes of cover crops (Mix 1 and Mix 2) and black oat cv. Embrapa 139. After 97 days, the production of wet and dry phytomass was evaluated, and at 100 DAS the total density and porosity of the soil at depths of 0.05 to 0.10 and 010 to 0.15 m. The results indicate that the use of a cover crop mix containing buckwheat, sudan grass and forage radish (Mix 1) results in a greater contribution of plant residues to the soil. The use of cover formed by oat, white oat, rye, Japanese radish and forage radish (Mix 2) mixes a smaller amount of residues, compared to single black oat. Soil density and porosity were not presented in width and depths. of soil. In this sense, it appears that at 100 DAS there are no effects on the physical attributes of a long-term study, demonstrating the need for long-term studies on the effect of coverage for these attributes.

Bioenergy potential of agricultural phytomass production in Slovakia

Biomass is a highly versatile renewable energy source used on a global scale. The paper discusses the current state of biomass energy use in the EU and Slovakia. Residual biomass was found as a key feedstock for the European bioeconomy. Slovakia is one of the most forested and rural countries in the EU. Therefore, biomass energy has the highest technical potential from all renewables in Slovakia. The main objective of the paper was to evaluate the phytomass production of the selected crops and their energy potential in individual self-governing regions of Slovakia. It is focused on the production of usable post-harvest residues theoretically used for energy purposes from the following studied main crops: wheat, rye, oats, barley, maize, potatoes, oilseed rape and sugar beet. The results show the estimated production of usable post-harvest residues of the selected crops and their energy potential in individual self-governing regions in Slovakia in 2019. The total production of usable post-harvest residues from the studied crops was 4,854,017 t and their estimated energy potential was 68 PJ. This amount of energy would cover 10% of the total energy consumption in Slovakia. The top three productive crops were maize, wheat, and sugar beet. Maize had the highest energy potential of 28.1 PJ, followed by wheat at 19 PJ and sugar beet at 14.2 PJ. The highest yields of post-harvest residues, as well as energy potential, were found in the Nitra region.

Storage and feeding of karakol sheep in desert and semi-desert pastures

The article discusses seasonal pasture diets and their nutrition, the feeding rates of Karakul sheep, the annual requirement of Karakul sheep for nutrients (per head), the feeding rates of Karakul sheep of different gender and age groups (heads/day), the addition of sheep, the nutritional norms of different gender and age groups are studied. The self-renewal and phytomass production properties of natural pasture plants make pastures a source of biological reserves that provide nutrients. The duration of the year is calculated as 100%, and the spring, summer, autumn and winter seasons are calculated as a percentage.

Mentha spicata L. grown with nitrate: Ammonium proportions in different light environments

Mentha spicata L. is an aromatic and medicinal plant, known as mint and used in the pharmaceutical and cosmetic industry and in phytotherapy. Although the cultivation of medicinal plants is traditional, there are several questions about which practices are most appropriate in the management of these plants, especially regarding nutrition and availability of light. The objective of this work was to evaluate the growth, phytomass production and physiological aspects of M. spicata cultivated in proportions of nitrate (NO3-) and ammonium (NH4+) and light environments. The research was carried out in a greenhouse at the Universidade Federal do Recôncavo da Bahia, Cruz das Almas, BA, Brazil. The experimental design used was completely randomized, in a 5 x 3 factorial scheme, with five proportions of NO3-:NH4+ (0: 100; 25:75; 50:50; 75:25; 100: 0) and three light environments (ChromatiNet® meshes red, black and in full sun), with seven repetitions. There was a significant interaction between the proportions of ammonium and nitrate with the light environments for most of the evaluated parameters. It is concluded that M. spicata plants grown under balanced proportions of nitrate and ammonium in a light environment favorably favored the initial growth and physiological indications of this species.

Water stress mitigation by silicon in sweet-potato

The objective was to evaluate the effect of the reduction in the irrigation blades under silicate fertilization via soil on growth, branch emission, production of fresh phytomass of aerial part, yield of marketable tuberous roots, and agricultural water use efficiency by plants of the sweet-potato variety Campina, with purple skin. The treatments were arranged in subdivided plots, distributed into randomized blocks, using a 2x5 factorial scheme with three repetitions, totaling 30 experimental units. The plots were two irrigation blades of 100 and 50% of the crop evapotranspiration – (ETc) and the subplots corresponded to the silicon doses of 0.0, 0.5, 1.0, 1.5, and 2.0 g plant-1. At the end of the experiment, the following variables were evaluated: stem diameter, branch emission, fresh phytomass of aerial part, phytomass of marketable tuberous roots, yield, and water use efficiency by plants. According to the results, the reduction from 100 to 50% of the ETc caused inhibition of growth, production of fresh phytomass of aerial part, and yield of marketable tuberous roots. The crop revealed to be more sensitive to water stress regarding yield than regarding growth or biomass formation by the aerial part and marketable tuberous roots.

Production of forage palm cultivars (Orelha de Elefante Mexicana, IPA-Sertânia and Miúda) under different salinity levels in irrigation water

Brazilian semiarid region is characterized by irregular rainy periods that limits the production of forage feed for the maintenance of agricultural livestock and causes losses in the production. Despite that, semiarid region stands out in the production of forage palm, buffering the impact of drought in the area. Thus, this study aimed at analyzing the effect of different levels of salinity in irrigation water on the production of forage palm in the semiarid region. The experiment was arranged as a complete randomized block, in a 4x3 factorial arrangement and four levels of salinity (0.2, 2.0, 3.8 and 5.6 dS m-1); three cultivars (Miúda, Orelha de Elefante Mexicana and IPA-Sertânia) with 4 replications. The variables evaluated were the following: number of primary, secondary, tertiary and total cladodes, cladode biomass and estimative of threshold salinity (SL). The results showed that irrigation with saline water with an electrical conductivity of 2.0 dS m-1 negatively affected the emission of cladodes of superior orders for all forage palm cultivars. Miúda cultivar presented the best production of fresh phytomass (13.36 kg per plant) under a salinity level of 4.04 dS m-1, followed by Orelha de Elefante Mexicana (12.55 kg per plant) under a salinity level of 2.73 dS m-1 and Baiana (11.56 kg per plant) under a salinity level of 2.17dS m-1.

INITIAL DEVELOPMENT OF CLADODE GIANT SWEET CLONE AS A FUNCTION OF WATER AND SALINE STRESS

Forage plants are considered one of the main factors for the development of livestock worldwide, for presenting high potential for phytomass production, drought tolerance, high energy value, large water reserve and easy propagation. Forage cactus stands out for its tolerance to water deficit. Aimed to evaluate the initial performance of the morphometric characteristics of Giant Sweet clone (N. cochenillifera) submitted to water and saline stresses using response surface analysis. Design used was completely randomized in a 4x4 factorial scheme, composed of four levels of water replacement, based on crop evapotranspiration (ETc): (25%.ETc, 50%.ETc, 75%.ETc and 100%.ETc) and four levels of water salinity (0, 2, 4 and 8 dS/m), with four repetitions totalling 64 experimental units. The following morphometric characteristics were evaluated: plant height, length, width, thickness, number of cladodes and area of cladodes. Eight evaluations were realized during the experimental period. Response surface analysis was used to evaluate the morphometric characteristics of the cladodes. Best water levels were between 55%.ETc and 65%.ETc and saline levels between 3.5 and 5 dS/m, maximizing the morphometric characteristics of Giant Sweet clone.