The experimental unit is being conducted at the Research and Training Center of the Agrarian Development and Rural Extension Agency ( Cepaer/Agraer ) in Campo Grande/MS at latitude 20º 25' 23” S, longitude 54º 40' 03”, altitude of 556 m and local climate Aw, from May 2022 to November 2024. The project is financed by FUNDECT in partnership with Edem, UEMS and UCDB . Being headed by Professor Dr. Sandro Cardoso.
Researchers:
Eng. Agr. doctor Sandro Cardoso – AGRAER/CEPAER
Eng. Agr. doctor Edimilson Volpe – AGRAER/CEPAER
Eng. Agr. M.Sc Antonino H. Dias Neto – AGRAER/CEPAER
Eng. Agr. Prof. doctor Jolimar Antônio Schiavo – UEMS/AQUIDAUANA-MS
Zoot. Dr. Prof. Tatiana da Costa Moreno Gama – UCDB
The experimental design used is the factorial in randomized blocks (DBC). The treatments were predefined with 04 doses 0, 75, 150 and 300 kg ha -1 of P 2 O 5 (FNRB), 04 doses 0, 100, 200 and 400 kg ha -1 of K 2 O (KMC), and a chemical treatment with 150 kg ha -1 of P 2 O 5 (Super Triple) and 200 kg ha -1 of K 2 O (Potassium Chloride), totaling 17 treatments, four replications and 68 plots. Each plot measures 5 mx 5 m or 25 m 2 ; totaling 425 m 2 per block with a total experimental area of 1700 m 2 .
Initially, soil samples (Dystrophic Red Latosol) of 0 – 20 cm were collected, chemically analyzed in the laboratory ( EMBRAPA , 2011), for soil corrections according to the requirement of the forage species, except for phosphorus and potassium that were pre-defined .
Urea will be used as a nitrogen source in the amount of 100 kg ha -1 year -1 . The limestone used was dolomitic limestone, agricultural gypsum for sulfur and FTE BR-12 for micronutrients. With the exception of urea, which will be distributed 50% of the dose at the beginning of the rainy season (after the animals leave in the first standardization grazing) and 50% near the end of the rainy season each year, the other inputs were incorporated in a single application initially with a leveling grid in the implementation in November 2022.
On November 16, 2022, shortly after preparation (Plowing; Plowing Harrow and Leveling Harrow) and soil corrections, the plots were demarcated and sown manually in line with cv. Piatã with 20 cm spacing between rows and approximately 4 cm deep.
Then the seeds were manually covered in all plots, in amounts of 4.0 kg ha -1 of pure viable seeds. Weed control is being carried out manually in the plots and mechanically and chemically in the corridors.
After sowing, a fence was built around the experiment and water was conducted through hoses to a pileta (water tank) for pasture management with the use of animals.
On February 6, 2023, 80 days after sowing, small animals (heifers and calves) were introduced into the area in order to standardize and lower the pasture, in a fast grazing to break apical dominance and stimulate rooting and growth. tillering.
Approximately 20 days after the animals leave, a new batch of animals (heifers and lactating cows) will be introduced to lower the pasture to approximately 20 cm in height from ground level.
Then the animals will be removed from the area and the first dose (50%) of nitrogen fertilization will be performed. Whenever the forage plants reach an average of 35 to 40 cm in height, green dry mass (MSV) evaluation cuts will be carried out in all plots with subsequent entry of the animals until lowering to 20 cm in height.
If the plants in the experimental area are not completely homogeneous (20 cm) after removing the animals, a backpack cutter will be used for standardization, and the residual material will be later removed from the plots.
Annual production assessments will be carried out during the water and drought cycle starting in 2022/2023 and ending in 2023/2024. The interval between cuts will not be pre-established, therefore, weekly analyzes of the canopy will be carried out, and the ideal height/interval for cutting will be considered when the average sample of plants from one of the experimental treatments (carrying out eight readings at points representative of the average condition of the vegetation in each plot) reach a height of approximately 40 cm above ground level.
The future of the project
On this occasion, a random sample of 2.5 m 2 of grass will be collected in each plot, disregarding 1 m of borders, using a motorized backpack pruner with a cut at 20 cm above ground level to determine the dry mass production green (MSV). Of this total, after being weighed in the field, a sub-sample of forage collected from each plot will be taken, in a portion of approximately 500 g, which will be packed in plastic bags for later weighing in the laboratory. After weighing, the material will be packed in paper bags (identified) and taken to dry in an oven with forced air circulation at a temperature of 65-70ºC, for 72 hours, to estimate the total dry mass (TSM) of the forage produced.
For the determination of phosphorus (P) and potassium (K) in the leaf blades, material will be collected one day before making the cuts in March/April 2023 and 2024 (period representative of the waters), material composing a sample. Approximately 100 leaf blades will be collected in each plot (MONTEIRO, 2005), which after pre-drying (55ºC) to constant weight, will be ground and submitted to analysis according to SARRUGE & HAAG (1974) in a private laboratory.
Soil samples from 0 to 20 cm deep will also be collected annually at the end of the rainy season (2023 and 2024) using the STIHL BT 45 soil driller with drill and collector in all plots for chemical and physical analysis in a private laboratory , to evaluate the soil concentration of “P” FNRB and “K” KMC (EMBRAPA, 2011). In each plot, 20 sub-samples will be collected, which after being homogenized will compose a duly identified sample. Phosphorus will be analyzed in the laboratory by the Mehlich and Resin method.
The collection of soil samples for microbiological analyzes will be carried out at the implantation and in the wet and dry periods (2023 and 2024), at depths of 0 - 10 cm, in each plot, with the aid of the STIHL BT 45 soil driller, in a number of six repetitions per treatment, composed of six subsamples collected in zig-zag. An undisturbed area with original vegetation will also be sampled to be used as a reference. Soil samples will be taken to the laboratories of the State University of Mato Grosso do Sul (UEMS), Aquidauana unit, and stored in a refrigerated environment at 4 °C until the moment of analysis, in order to stabilize the microbiological activities.
Soil microbial biomass carbon, phosphorus and nitrogen will be analyzed according to VANCE et al . (1987). Soil microbial respiration (C-CO 2 ) will be determined by the methodology described by SILVA et al . (2007). The metabolic ( q CO 2 ) and microbial ( q Mic) quotient of the soil will be determined by the CCO 2 ratio of the soil by the C-BMS content (ANDERSON & DOMSCH, 1993). The enzymatic activities will be determined according to TABATABAI (1994). Data will be analyzed in a completely randomized design, with the statistical program R Studio, ExpDes.pt package. Data will be submitted to analysis of variance, and when significant, means will be compared with Tukey's test (P≤ 0.05).
The other data obtained will be submitted to analyzes of variance, in which the PROC GLM of the Statistical Analysis System (SAS, version 8.0) will be chosen for analysis of variance (ANOVA), and, when significant (P
