Trial location: Trenque Lauquen (Buenos Aires)
Land belonging to Mr Eduardo Firpo. Plot Nº 57
Trial carried out within the INTA-BIAGRO Technological Agreement.

Professionals in charge: Lic. Eduardo Firpo (Owner) Ing. Alejandro Perticari, Ing. Juan C. Pacheco Basurco. (IMYZA-INTA-Castelar), Ing. Roberto Echegaray (Biagro). Special collaboration in the studies related to the occupation of strains introduced in nodules: Dr. María Florencia Del Papa, Dr. Antonio Lagares. (IBBM UNLP).

History and characteristics of the plot: Previous crops: 1996-1997 agricultural cycle: Wheat, with localized fertilization at the sowing line, simultaneously PDA 50 Kg/ha. When the seeds began to sprout, Urea 100/ha was applied by broadcasting. 1997-1998 agricultural cycle: Corn, fertilised with 120 Kg/ha of PDA using the same system applied to wheat. 1998-1999 agricultural cycle: inoculated soybean. 1999-2000: sunflower. Population of specific bacteria soybean nodulation: > 1,000 bac/g. of soil (NMP).

Soil characterisation:

Compound samples were taken and sent to the Soil Institute of the INTA Castelar. Results: OM = 2.34%. CO = 1.36%. NO = 0.14%. C/N = 9.1 Passim = 14.3 ppm. CE = 0.16 mS/cm pH = 6.1 The soil is a typical mollisol of the sandy west, with sand levels of 65-70% (thin-medium and thick fractions), A-AC-C profile with a high risk of wind erosion and low structure stability. Agricultural potential: Class III SC.

Sowing method: no-tilling. Seed: GM 4. VC DM 3800 RR. Planting date: November 13th, 2000. Inoculating method: INTA-BIAGRO preinoculation (Nodulest 10 inoculant + Biagro S1 sticker + Biagro S2 additive). Weed and plague control: April 5th, 2000: 3 l/ha of Glyphosate to the sunflower stubble. Crop pre-emergency: 3 l/ha of Glyphosate. January 25th,2001: 2 l/ha of Glyphosate combined with 0.7 l/ha of metamidofos and 0.1 l/ha of cypermetrine. The products applied were formulated.

Experimental design:
Randomised blocks. Six (6) repetitions in plots 6.6 yards long and 4 rows with 20 inches of row spacing. Plots and blocks separated by less than 40 inches.

Nodule observation: 8 plants in R2-R3 were taken from each plot. For the analysis of the percentage of occupation in the nodules of the strains introduced by the inoculant, samples of 8 nodules of the main root were taken from each plant (about 64 nodules per plot). Around 300-400 nodules were processed for treatment and sent to the IBBM-UNLP.

Strains used: The strains used for the trial from the IMYZA-INTA-Castelar collection were specially prepared by Laboratorios Biagro S.A. and formulated following the protocol for Nodulest 10 inoculant to be used with the INTA-BIAGRO preinoculation technology.

Strains: E109, S5079, S5080, Tucumán 1, Salta 1.

Treatments:
1- Uninoculated
2- Uninoculated and fertilised with 400 N units (divided in 5 applications of 80 UN: planting, V2, V4, R1, R3).
3, 4- E109 single and double dose.
5, 6- Tucumán 1 single and double dose.
7, 8- Salta 1 single and double dose.
9, 10- S5079 single and double dose.
11, 12- S5080 single and double dose. Rainfall: November, 2000: 0mm. From planting. December, 2000: 35mm. January, 2001: 81mm. February, 2001: 196mm. March, 2001: 178mm. April, 2001: 108mm. until harvest.

Harvest date: April 17th, 2001.

Harvest: (see comments) 40 plants were harvested in each plot. Cultivable surface = 13.5 ft2. 2 Field-edge margins were eliminated and 40 inches in each headland. Mobile plot harvester was used.

Comments: at planting time there was low soil moisture and steady winds followed by a prolonged drought. This may have limited an adequate emergency.

Summary chart with up-to-date analysed data (the data is expressed as an average for each strain):

The bar chart describes the level of response for the preinoculated treatments vs. uninoculated in a soil with a naturalised population of specific soybean nodulating bacteria that will be identified and characterised at the IBBM.     Trenque Lauquen 2000/2001: Nodulest 10 INTA-BIAGRO Preinoculation Strains