Green Gold Report â May 24, 2016 â WESTERN / INTERLAKE
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PLATINUM SPONSOR
Green Gold Report – May 24, 2016 – WESTERN / INTERLAKE Here is the second release for the Optimum Alfalfa Harvest Date for 2016. SITE Arborg Oak Point Roblin NORTH AVERAGE
RFV NIR 197
Brandon McAuley Virden Virden North SOUTHWEST AVERAGE
Height 16 13 15 15
CP 28
188 192.5
RFV PEAQ 237 260 244 247
224 165
252 210
14 19
24 25
203 197
197 220
20 18
26 25
19 24
The results from the North indicate that we are dropping about 7 pts/day. Looking at the crop growth it isn’t surprising with the alfalfa growing 1 inch per day from the 18th. The SW is at a similar RFV and therefore the alfalfa that is taller will likely be at the RFV of 170 around the 30th of May. Most of the alfalfa in late veg. with the McAuley area reporting early bud (accounts for the RFV)
Access all 2016 Green Gold Reports For more information contact: John McGregor, MFGA Extension Support e: [email protected], website: www.mfga.net or follow us on Twitter!
SILVER SPONSORS
BRONZE SPONSORS
2016 MFGA Green Gold Report
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MANITOBA FORAGE & GRASSLAND ASSOCIATION
Alfalfa Weevil Feeding In Manitoba, we are getting reports of adult weevils feeding in alfalfa. Adult alfalfa weevil feeding has been observed at low amounts in the Virden and New Bothwell area. Adults are about ¼ inch long and brown-golden with a blunt snout and dark brown longitudinal stripe in the center of the back. Antennae are elbowed and clubbed. They overwinter in debris and alfalfa stubble. Eggs are laid inside the stems of alfalfa, and are small and cream colored. Mature larvae are about ⅜ inch long with a black head capsule and a green-wrinkled body. A white stripe, running lengthwise, can be observed across the top. The degree days for alfalfa weevil use a base development temperature of 10C and show that adults are active mainly in areas with 42 accumulated degree days (DD). Egg hatch begins at 167 accumulated DD. Presently as of the 24th of May we are at 120 DDs Although adult weevils will feed on the foliage causing defoliation, most of the economic defoliation is caused by larval feeding. Peak feeding occurs about mid-June (or 280 - 330 accumulated DD) when larvae are in the 3rd to 4thinstar. For alfalfa grown for hay, the most cost-efficient method is to cut the alfalfa early before feeding damage occurs. A treatment threshold of 40% tip feeding is recommended. What is PEAQ Over the years that I have been sending out the Green Gold reports I have had 2 columns that mention RFV (relative feed value). These are the numbers that are used to determine when to cut alfalfa to obtain the quality that you require for your livestock. Most of you that feed or sell alfalfa understand NIR which is a laboratory estimate of RFV. What I have come to realize is that as we get more subscribes to the Green Gold reports not all of you understand PEAQ (predictive equation of alfalfa quality). Back in 1991 researchers were looking for a mathematical model to estimate fibre content of alfalfa. Among the models tested were simple equations (referred to as PEAQ) based on length of the tallest stem and stage of the most mature stem in the sample. These were considered the best compromise between accuracy and ease of use for routine estimation of alfalfa fiber composition. Around that time Manitoba Agriculture tested out this equation and compared it to NIR results and determined that it provided a good guesstimate (my interpretation) of estimating RFV. As with scissors-cut sampling, method used for Green Gold RFV, results are highly dependent on good sampling technique. This includes careful attention to finding and measuring the length of the tallest stem in the sample and correctly identifying what is the most advanced maturity stage present in the sample. The equation is calibrated only for pure alfalfa stands, so estimates are less reliable for weedy fields and alfalfa-grass fields. It does not work well in fields with poor stands, or in alfalfa suffering from stress. It does not provide reliable estimates of RFV in alfalfa that is very short (longest stem less than 16 inches) or very tall (longest stem more than 40 inches). Nevertheless, the 16- to 40-inch height limit represents a much broader range in growth than the normal harvest range for alfalfa. If you would like to try out this method on your operation to see how it works click on PEAQ for information on crop stage and height tables.
2016 MFGA Green Gold Report
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~
MANITOBA FORAGE & GRASSLAND ASSOCIATION
PLATINUM SPONSOR
Green Gold Report – May 24, 2016 – WESTERN / INTERLAKE Here is the second release for the Optimum Alfalfa Harvest Date for 2016. SITE Arborg Oak Point Roblin NORTH AVERAGE
RFV NIR 197
Brandon McAuley Virden Virden North SOUTHWEST AVERAGE
Height 16 13 15 15
CP 28
188 192.5
RFV PEAQ 237 260 244 247
224 165
252 210
14 19
24 25
203 197
197 220
20 18
26 25
19 24
The results from the North indicate that we are dropping about 7 pts/day. Looking at the crop growth it isn’t surprising with the alfalfa growing 1 inch per day from the 18th. The SW is at a similar RFV and therefore the alfalfa that is taller will likely be at the RFV of 170 around the 30th of May. Most of the alfalfa in late veg. with the McAuley area reporting early bud (accounts for the RFV)
Access all 2016 Green Gold Reports For more information contact: John McGregor, MFGA Extension Support e: [email protected], website: www.mfga.net or follow us on Twitter!
SILVER SPONSORS
BRONZE SPONSORS
2016 MFGA Green Gold Report
~1
~
MANITOBA FORAGE & GRASSLAND ASSOCIATION
Alfalfa Weevil Feeding In Manitoba, we are getting reports of adult weevils feeding in alfalfa. Adult alfalfa weevil feeding has been observed at low amounts in the Virden and New Bothwell area. Adults are about ¼ inch long and brown-golden with a blunt snout and dark brown longitudinal stripe in the center of the back. Antennae are elbowed and clubbed. They overwinter in debris and alfalfa stubble. Eggs are laid inside the stems of alfalfa, and are small and cream colored. Mature larvae are about ⅜ inch long with a black head capsule and a green-wrinkled body. A white stripe, running lengthwise, can be observed across the top. The degree days for alfalfa weevil use a base development temperature of 10C and show that adults are active mainly in areas with 42 accumulated degree days (DD). Egg hatch begins at 167 accumulated DD. Presently as of the 24th of May we are at 120 DDs Although adult weevils will feed on the foliage causing defoliation, most of the economic defoliation is caused by larval feeding. Peak feeding occurs about mid-June (or 280 - 330 accumulated DD) when larvae are in the 3rd to 4thinstar. For alfalfa grown for hay, the most cost-efficient method is to cut the alfalfa early before feeding damage occurs. A treatment threshold of 40% tip feeding is recommended. What is PEAQ Over the years that I have been sending out the Green Gold reports I have had 2 columns that mention RFV (relative feed value). These are the numbers that are used to determine when to cut alfalfa to obtain the quality that you require for your livestock. Most of you that feed or sell alfalfa understand NIR which is a laboratory estimate of RFV. What I have come to realize is that as we get more subscribes to the Green Gold reports not all of you understand PEAQ (predictive equation of alfalfa quality). Back in 1991 researchers were looking for a mathematical model to estimate fibre content of alfalfa. Among the models tested were simple equations (referred to as PEAQ) based on length of the tallest stem and stage of the most mature stem in the sample. These were considered the best compromise between accuracy and ease of use for routine estimation of alfalfa fiber composition. Around that time Manitoba Agriculture tested out this equation and compared it to NIR results and determined that it provided a good guesstimate (my interpretation) of estimating RFV. As with scissors-cut sampling, method used for Green Gold RFV, results are highly dependent on good sampling technique. This includes careful attention to finding and measuring the length of the tallest stem in the sample and correctly identifying what is the most advanced maturity stage present in the sample. The equation is calibrated only for pure alfalfa stands, so estimates are less reliable for weedy fields and alfalfa-grass fields. It does not work well in fields with poor stands, or in alfalfa suffering from stress. It does not provide reliable estimates of RFV in alfalfa that is very short (longest stem less than 16 inches) or very tall (longest stem more than 40 inches). Nevertheless, the 16- to 40-inch height limit represents a much broader range in growth than the normal harvest range for alfalfa. If you would like to try out this method on your operation to see how it works click on PEAQ for information on crop stage and height tables.
2016 MFGA Green Gold Report
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MANITOBA FORAGE & GRASSLAND ASSOCIATION
