potassium ( K ). Farmers apply fertilizer using the 4R method : right source , right rate , right timing , and right placement . Farmers never want to apply more fertilizer than what is needed because of environmental factors and the cost associated to apply additional fertilizer . They only apply fertilizer where the plants are not getting sufficient nutrients . Fertilizer can come in many forms . Some forms , like anhydrous ammonia ( for nitrogen ) are purchased from a cooperative . Other forms , like manure from livestock , may be something the
Vegetative Stages ( growth of the plant )
VE = emergence
Days After Emergence Can take 5 to 14 days
Calendar Day
May 1 to 14
V1 = first leaf collar 1 May 15
V2 = second leaf collar 4-6 May 19-21
V3 = third leaf collar 9-12 May 24-27
V5 = fifth leaf collar 14-21 May 29-June 5 V9 = ninth leaf collar 28-35 June 12-June 19 V15 = 15th leaf collar 56-63 July 10-17
VT = Tasseling 60-67 July 14-21
Reproductive Stages ( development of the kernels on the ear )
Days After Emergence
Calendar Day farmer already has on hand . Manure is very high in nitrogen , and contains high levels of phosphorus and potassium .
Insects are another factor that farmers must deal with . There are a variety of insects that feed on corn plants . There are insects that feed on the roots , the stalk , the leaves , or elsewhere on the plant . A precaution a farmer can take prior to planting is selecting a certain type of seed that is resistant to insects . This is known as a genetically modified organism ( GMO ). Another way to deal with pests like insects is to
Concerns apply an insecticide . A farmer will only apply an insecticide
Seed needs proper moisture and if he / she notices a pest / warmth to germinate and emerge insect in the corn field that
Moisture and weather conditions is destructing the crop . are critical for continued growth Moisture and weather conditions are critical for continued growth Late frost will not damage plant potential yield Cooler soil temperatures will slow growth and cause a later harvest
Flooding up until this stage can kill a plant in a few days
Drought conditions from V6-V15 can reduce yields up to 25 %
Water is still critical and hail can lead to pollen damage
Concerns
R1 = silking |
63-68 days |
July 17-22 |
Water is critical |
R2 = blister |
73-78 days |
July 27-Aug . 1 |
Drought conditions from V15 to
R2 can reduce yields up to 50 %
|
R3 = milk |
83-88 days |
Aug . 6-10 |
Water is critical |
R4 = dough |
89-94 |
Aug . 11-16 |
Frost can reduce yields by 35-50 % |
R5 = dent |
99-104 |
Aug . 21-26 |
Drought and frost conditions from
R2 to R5 can reduce yield up to 25 %
|
R6 = maturity |
118-123 |
Sept . 9-14 |
|
After maturity , the corn ( plant and kernels ) begins to dry before it is harvested . |
As the growing season comes to an end , corn begins to dry and hold less moisture . A farmer knows that the corn is ready when the plant stops filling the kernel with starch , and the tip cap of the kernel is closed off from the cob . This can be seen when the tip is broken off the kernel , and is called the black layer . The kernel is about 30 percent moisture at this time , and the corn is dead and continues to dry in the field . This is when the corn plant turns brown . By using a moisture tester , farmers determine when the corn is ready to harvest . Corn can be harvested at moisture levels between 15 and 30 percent .
www . GrowingYourFuture . com - 5