Cash crops system: sufficient water available
Precipitations or irrigation
• This is a typical example of crops with different requirements concerning nutrition and tillage: sugar beet is more demanding for P and K, and requires deeper tillage practices, when corn and wheat are more demanding for N and can be cropped with less expensive tillage systems. Soybean, if properly grown, does not requires N, conversely increases the content of soil in N through symbiosis with fixing N Azotobacter strains.
• Weed control in these crop is also different: in sugar beet and soybean grass weeds are easy to control, when broad leaves are difficult: the contrary for corn and wheat. So, by rotating the crops, the results of weeds control improves significantly.
• Different strains of fungi damage these crops, so such a sequence makes more difficult the building up of spores in the soil: as a result, the pathogens’ pressure on crops decreases during the years. This is (relatively) true also for insects’ pressure.
• Life cycles of different plants are different, so field operations are spread on a broader period. Timeliness of operations and distribution of workloads on machinery during the season improves.
• Tillage operation are deeper for sugar beet, when minimum tillage can be applied for other crops: the overall results is an improved soil tilth, due to different working depths.