AGRICULTURAL
Theme : Harvest
The financial impact of harvesting efficiency
A good crop is the result of interaction of various factors of which ( precision ) technology , dedication and hard work throughout the production cycle are controllable by the producer .
By Petrus van Staden , Lourens Janse van Rensburg , Boet van Zyl & DW de Villiers
The harvesting process demands efficient planning , good service and tuning capabilities to complete the process efficiently . The time spent on it can limit losses and maximise profits .
� WHAT ARE THE CONSEQUENCES OF INEFFICIENT HARVESTING ?
Loss of income : Estimation of the losses are as follows :
• 21 kernels / square metre = ± 60 kg / ha . It equates to approxi - mately R 100 / ha which is equiva - lent to diesel consumption for 2 cultivations with a 6-row interrow cultivator , or 3 actions with a 12-row interrow cultivator .
• 43 soybean pips / square metre = ± 64 kg / ha , which equates to R302 / ha
• 1 maize cob / 43 m of 0.76m rows = ± 50 kg / ha
Volunteer plants : A dense stand of volunteer plants is an indication of significant combine losses . Volunteer plants have advantages and disadvantages .
Advantages - organic material for the cattle component , increase in soil carbon and surface protection against erosion . Disadvantages - increased input costs for control of volunteer plants ; negative effect of volunteer plants on the next crop ; volunteer plants serve as green bridge for insects , bacterial or fungal diseases or viruses .
� FACTORS WHICH CONTRIBUTE TO CROP LOSSES
Diseases : Diseases such as Diplodia or Gibberella can cause light kernels that can be lost during threshing . These diseases can also weaken the ear shank which can often result in ears dropping off the plant prior to entering the combine .
Harvesting losses : The combine has three major actions : picking , threshing , and cleaning . Losses occur in all three stages . Matching the groundspeed to crop throughput and harvesting conditions , is among the most important factors over which the combine operator has control . Faster is not always better . Optimal threshing and cleaning action usually decrease groundspeed . High groundspeed will increase grain losses , while low groundspeed will result in underutilisation of combine capacity . When operated at less than full capacity , threshing efficiency decreases while fuel consumption increases .
Header Losses Header loss results when kernels don ’ t make it into the machine . The cause may be due to biological and / or mechanical factors . Corn that has lodged or is excessively dry may shatter , causing whole ears to be lost . Deck plates set too widely may cause excessive shelling of the ears .
Threshing losses Cylinder or rotor adjustment determines corn quality . Up to 80 percent of kernel damage occurs during the shelling process . Over shelling the grain ( by having the cylinder or rotor speed too high , or the clearance too tight ) not only produces excess fines , but also consumes excessive power and fuel .
Careful management at this point will produce dividends throughout storage and drying . Moisture content has a huge effect on the amount of damage .
Sieve and chaffer settings Grain losses at the sieve and chaffer involve cobs or parts of cobs with kernels , or kernels which leave the machine with the chaff . If there is too much trash , the kernels stay in the trash through the straw walkers in a conventional combine or over the cleaning shoe in a rotary design . The kernels are then thrown out of the machine in the tailings . This can result in a “ windrow ” effect when the corn kernels germinate .
� SUGGESTIONS TO LIMIT LOSSES
The objective is to get grain through the combine and not all the trash or organic material . Adjustments will differ between crops , combines , type of concave and corn header . Calibration is very important and the time spent in this regard is a good investment .
Corn header
• Proper adjustment of the gathering snouts , gathering chains , snapping rolls , deck plates and thrash knives is very
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SENWES SCENARIO | AUTUMN 2018