A Systematic Approach to Simulating Corn Production Systems

An evaluation of machinery systems for harvesting the total corn plant

“…This discussion suggests that predicting daily rates of moisture loss from daily climatological data, as Carpenter and Brooker (1970) and Holtman et al (1973) did, could introduce an error into the predictions because of daily fluctuations in the predicted rate of moisture loss that would not occur under field conditions. Over a long period of time, daily errors might be cumulative, causing the predicted value to be consistently high or low.…”

“…They concluded that the reduction in moisture before maturity was largely a physiological process, whereas after maturity, moisture reduction was a drying process. Carpenter and Brooker (1970) and Holtman et al (1973) used the results of Schmidt and Hallauer (1966) to relate grain moisture reduction per day to known values of temperature and wet bulb depression for each year being simulated. Carpenter and Brooker (1970) increasing moisture contents, later in the season for grain that was approaching the equilibrium moisture content.…”

“…Carpenter and Brooker (1970) reported no verification of their criteria defining suitable field conditions for harvesting. Morey (1971) and Holtman et al (1973) reported that their choice of 95 percent of field capacity for the limiting value of soil moisture was based on the work of Rutledge and McHardy (1968 (Knight and Freltag, 1962;Gill and Vanden Berg, 1967;Rush, 1968Rush, , 1969. These tests have been conducted on very wet, fine-grained soils and wet sands.…”

“…Activity ratio r^^ would remain the same if turn time was proportional to harvest time. But this activity ratio has been observed to increase as machine size increases (Barnes et al, 1959;Byg et al, 1970;Holtman et al, 1973). A 10 percent increase in r^ was assumed for the 6-row combine.…”

“…and Mbrey (1971) specified a grain moisture content on September 1 as their initial condition and used the same value of grain moisture for each simulation. But grain moisture on any particular day is a random variable, so a constant value cannot be used for the starting day if each simulation represents a different crop year Holtman et al (1973). used known values of grain moisture and potential yield on October 15 as their initial conditions.…”