Christi Falen Extension Educator

 Critical for dairy cattle rations  Necessary for phosphorous (P) uptake  Need yield maximized for feed production and maximum P uptake

 Examination of 26 different studies showed decrease in yield  Corn yield reduced 5 to 15% for corn following corn compared to the first year corn  op_Rotation_Lit_Review.pdf

 Choose the corn seed hybrid most desired for your farm – considering soil, rotations, insect/disease pressures, residues, manure or compost applications, emergence concerns etc.  7/Text.htm has corn hybrid performance for grain and silage in Wisconsin 7/Text.htm

 Dale Baker has variety trial on corn grain from Kimberly  Then look at cost and necessity of seed treatments included on the seed for insect and disease control.

 We need to minimize insect and disease concerns to maximize corn yield and P uptake  Crop rotation is an effective management tool for reducing hosts for pathogens

 Eggs laid in soil during the fall – hatch in spring  Larvae feed on corn roots  Adults emerge from soil  Adults beetles feed on female flowers (silks) and soft kernels

 Repeated efforts to control rootworm has led to resistance to methyl parathion and carbaryl   Crop rotation is an important option to prevent large rootworm infestations  Consider chemical and transgenic control when it is economically required

HostEnvironment Pathogen Disease Risk of disease severity higher with continuous corn, but weather conditions in-season still affect disease severity

 Long term buildup of soil born pathogens can reduce corn stands, vigor, yield, plus decrease nutrient uptake potential.  Pathogens survive on corn residues and/or in the soil.  Crop rotation beneficial to break the cycle

 Increased corn acreage = more stubble, roots, and crowns = potential for increasing Fusarium graminearum, which causes primarily scab (head blight) in wheat and barley, stalk and ear rot of corn

 Gibberella ear rot is caused by the fungus Gibberella aeae, also known as Fusarium graminearum. It usually appears at the ear tip and is red or pink. A vomitoxin can be produced that causes vomiting in monogastrics.

 To stop, look, and carefully evaluate the best corn hybrid and insect/disease control for your farm  Practice good crop rotation to minimize costs and mgmt. intensity for corn production in Idaho, while maximizing P uptake  Keep accurate records when using transgenic seed and chemicals

Christi Falen Extension Educator

Where do we go with the …  Environmental concerns for livestock operations are critical to everyone. *nutrient and waste mgmt.  *water quantity and quality  *air quality and odor mgmt.

B. Brown, UI Parma

Crop% P% H 2 OYield lb P Removed Canola seed lb/A8 Peas lb/A7 Beans cwt/A10 Potatoes cwt/A20 Sugar beets tons/A21 P Content and Removal with Crops Information from National Research Council (NRC) with modifications for Idaho where data is available from Dr. Brad Brown, UI in Parma

Crop% P%H 2 OYield lb P Removed Wheat grain bu/A28 Barley grain bu/A20 Oat grain bu/A18 Corn grain bu/A25 Corn silage tons/A51 P Content and Removal with Crops Information from NRC with modifications for Idaho where data is available from Dr. Brad Brown, UI in Parma

Soil Test P Decline John Brown's annual corn removes 36 lb P per acre. For his soil, the soil test declines 1 ppm for every 12 lb of P removed each year. His manured field has a soil test P value of 84 ppm. How many years will it take with his current cropping system to lower soil test P to 40 ppm based just on the crop P removal with no additional P applied?

Soil Test P Decline Question STP change in one year 36 lb P a year / (12 lb P/ppm) = 3 ppm P Difference in ppm P 84 ppm - 40 ppm = 44 ppm Years to change STP 44 ppm 44 ppm / 3 ppm = 14.6 years

Predicted Soil Test P Increase A new dairy wants to apply composted manure at the rate of 10 tons per acre annually to a field. The compost is 70% dry matter and 0.92% P (dwt basis). Initial soil test P for the field is 20 ppm. He can remove 37 lb P annually with corn silage but is wondering about a double cropping system that would remove 55 lb P per acre annually. Assume soil test P changes 1 ppm for every 12 lb P applied per acre. How many years for STP to reach 40 ppm P?

Predicted Soil Test P Increase Question Net P added per acre? 10 tons x 2000 lb per ton = 20,000 lb 20,000 lb x 0.70 = 14,000 lb dry matter 14,000 lb x = lb compost P per acre lb P added - 37 lb P removed = 91.8 lb P = net P gained annually with single crop corn lb P added - 55 lb P removed = 73.8 lb P gained annually with double cropping

Predicted Soil Test P Increase Question Soil test P change? 40 ppm P - 20 ppm P = 20 ppm P Annual soil test change 91.8 lb net P added/ (12 lb P/ppm) = 7.65 ppm 73.5 lb net P added/ (12 lb P/ppm) = ppm Time required? 20 ppm P change / 7.65 = 2.6 yrs with SC 20 ppm P change / = 3.26 yrs with DC

 Hauling hay from east Idaho here and exporting compost back  High fertilizer prices making the export farther away more economical  High quality compost marketed for organic producers  Lime, struvite cystalization, anaerobic digesters, nursery industry – continue the quest for ways to export P!

 Produced by mold fungi – Aspergillus falvus and Aspergillus parasiticus  Aflatoxins are harmful or fatal to livestock and are considered carcinogenic  No aflatoxins allowed for milk from dairies  See Aflatoxins in Corn, PM1800 Iowa State University, for sampling procedures and control methods

 Highly effective compounds like the triazoles and Qol fungicides (e.g. strobilurins) with specific modes of action developed  These affect one specific site in one metabolic pathway of fungus  Fungi only have one barrier to overcome

 FRAC = Fungicide Resistance Action Committee  Goal is to provide fungicide resistance mgmt guidelines to prolong effectiveness of “at risk” fungicides.

 Look on label for group number-easier to alternate chemistry  M is when a fungicide acts onmultiple sites and resistance is low

ProductRate (fl oz/acre)REI (hours)PHI (days) Headline a 7 Quadris a4a 7 Quilt a After brown silk Statego a After silking Tilt2-424 a After silking a REI is 7 days for bare-hand detasseling activity *Headline and Quadris are strobilurin fungicides *Considered “high risk” for fungicide resistance *May result in yield increases, even in supposed absence of any disease pressure, in short term *Exercise caution-use only when required to minimize selection of fungicide-resistant strains of fungal pathogens. *