Australian Farming Assignment

Australian Farming Assignment

Question 1

Use the information in the following table to discuss why controlled traffic systems are replacing conventional (cultivated) systems and zero till systems on Australian farms.

Wheel Traffic and Stubble Effects on Steady Infiltration Rate for a Self Mulching Black Earth at Gatton (Li et al.2001)

Wheeled

Untrafficked

(mm/hr)

Bare soil

11

48

Stubble covered

16

102

The controlled traffic systems are replacing conventional systems primarily due to the lower absorption rate of water. The self mulching black earth is effectively utilizing in agricultural farming for crops such as tomatoes and sweet corn. When large amounts of water during rainy season sink into the earth, the mulch disappears. The mulch is the ideal substance for raising the crops so farmers are trying to reduce the absorption rate of water.

As illustrated in the table above, utilizing wheel traffic, the absorption rate of water is 11 millimetres per hour for bare soil and 16 millimetres per hour for stubble covered. This data suggests that utilizing controlled traffic systems, the self mulching black earth can be utilized and not wasted. The conventional method statistics state the high absorption rate of water which is unfavourable for the mulch. Further from the study while utilizing stubble treatment, the access of water into untrafficked soil was 77% of rainfall while for wheeled it was 25%. The difference in infiltration for wheel traffic is accountable by compaction on cropped soils.

The compaction found in majority cultivation and trafficking is implemented when the soil is moist in order to monitor weeds and sow crops. It is observed that compaction performed through machinery minimizes infiltration of water by limiting or inhibiting pores in the soil. The maximum utilization of compaction appears to be during the initial passage of the tractor. During a single season, wheel tracks spread on 100% of traditional cultivated paddock, 60% of minimum tilled paddock, and 30% of randomly trafficked zero till paddock. The study also states that although vertosol for the past 2 years created higher effectiveness in soil fertility, a single wheel pass in a season could minimize the infiltration significantly.

Question 2

The following graph shows crop yields against water available to the crop in the growing season.

Explain the relevance of the slope of the line shown, and its intercept with the x axis.

The slope indicated by the graph above illustrates that the trend observed between crop yield and water over one hundred years follows a system of y = 11.73x - 1186. The slope defines that with a single unit increase in water, the crop will rise by 11.73 kilograms per hectare. At the same time the minimum threshold for crops to yield is about 101.11 mm of water. This value is the point where the line cuts the x-axis (x-intercept). The values located are only positive since you cannot have negative crops yield; minimum is none produced. It can also be noted that majority of the observations plotted on the graph are located below the trend line. When an average estimate is taken and plotted, the ...