Best Management Practices for Growing Maize on Dairy Farms

7. Crop monitoring• Monitoring is an important partof good management to maximiseyield• A good monitoring programmeshould include:- Weeds, pests and diseases- Soil N sampling- Soil moisture if irrigating- Crop maturity• Contractors and technicaladvisors can undertake someor all of this monitoringapplication, delayed application or perennialweeds can mean that further post emergenceapplications are required. Choice ofchemical will depend on what weeds arepresent and their growth stage, there<strong>for</strong>emonitoring is vital. Paddocks out of longterm pasture often have a greater broadleaf weed seed bank than grass weeds andthere<strong>for</strong>e omitting a grass weed herbicide(chloroacetamide) from the mix might beworthwhile. However, run out pastures oftenhave (<strong>for</strong> example) summer grass weedseed present and there<strong>for</strong>e the addition of achloroacetamide would be necessary.3. Emergence to four leaves (V4)In order to anticipate or rectify problemsand maximise yield it is necessary tomonitor crops regularly, particularly in thefirst two months of growth. For the busydairy farmer, technical advisors and somecontractors will provide this service.1. EmergencePaddocks need to be checked <strong>for</strong> slugs,bird, rabbit and rat damage. Slugs aregenerally not a problem where intensivecultivation has been carried out but cando serious damage during wet weatherand if reduced tillage practices have beenused. Leaf damage and slime trails are agood confirmation of slug presence. Birdand rat damage is characterised by plantspulled and the seed embryo eaten. Missedplanted rows or poor population areasshould be noted at this time and if practical,rectified.2. WeedsWeeds in maize crops can cause significantyield loss and moisture activated preemergenceherbicides generally per<strong>for</strong>mvery well. However, dry conditions afterNote four leaves with clearly visible collars.Continue monitoring <strong>for</strong> slug and birddamage but also to check <strong>for</strong> greasycutworm and weeds. Greasy cutwormfeed at night by typically cutting and fellingmaize plants. Their presence can be confirmedby digging around the base of freshlyfelled plants or examining plants near dusk.Spraying with a synthetic pyrethroid insecticideat dusk gives good control.Greasy cutworm15