Energy input analysis

According to the results, the energy input per area for maize corn production was the high-est, at 51,500 MJ ha^-1 (figure 10, annex 1.1). For the other products, the energy input ranged between 36,800 MJ ha^-1 (spring maize silage) and 28,000 MJ ha^-1 (alfalfa). For all investigat-ed crops except alfalfa, fertilisation was the single operation with the highest energy input, followed by irrigation. The high energy input from fertilisation was caused by the high energy demand for N fertiliser production. Within the maize corn production, energy input from ferti-lisers and their spread was 34% of the total energy input, of which 88% of the energy input came from the consumption of 200 kg ha^-1 N fertiliser. Irrigation made up 22% and spraying operations accounted for 10% of the total energy input, which were the operations with the next highest energy input for maize corn production. In the spring maize silage, harvest and transportation of the highest amount of fresh matter yield (75 t ha^-1) had 19% of the total en-ergy input. In addition, two instances of ploughing and three rounds of using of cultivator caused a high energy input in the form of machinery operations. In wheat, 150 kg ha^-1 N ferti-liser consumption (50% more than that of spring maize silage) and the spraying requirement caused the same extra energy input as from repeated machinery operations in spring maize silage. Summer maize silage or secondary maize silage cultivation had a short growing peri-od (July-October) and was cultivated in a 2,000 ha quantity after the cereal or rapeseed har-vest. The reduced energy input in summer maize silage in comparison to spring maize silage resulted from the exclusion of manure spreading, less repetition of the cultivator operation (only one) and a nearly 50% reduction in fresh matter yield and ensuing energy input from the transportation of summer maize silage production. Because summer maize silage was cultivated after a different prior crop, no energy input from manure spreading from the previ-ous cultivation was allocated to summer maize silage. For all feedstuffs other than summer maize silage and barley, the energy input from manure spreading ranged between 4%

(maize corn) and 8% (alfalfa) of the total energy input with the same amount per area (2,240 MJ ha^-1).

Figure 10 Energy input in the investigated crop production (MJ ha^-1 yr^-1) from machinery op-erations including energy from materials, fuels and machines. ^{a b}

a Operations with an energy input of less than 5% of the total energy input were shown as Other”.

b For summer maize silage, the yield was not yearly because it was cultivated as a secondary product.

No manure spreading was reported for barley production. Barley fertilisation comprised 48%

of the total energy input. In alfalfa production, the energy input from irrigation was the high-est, with 40% of the total energy input. This high share of the energy input came from high water consumption (18,000 m³ ha^-1) as a result of flooding irrigation system. A harvest opera-tion with 25% of the total energy input was the next biggest share of energy input, which re-sulted from five harvests per year and required three individual machinery operations (mow-er, rake, and baler). Operations with a share of less than 5% of the total energy input for each product were merged together as “Other” operations to limit the number of operations.

Therefore, as an example, the spraying operation in this figure is only visible for alfalfa and maize corn production, with 5% and 10% of their total energy inputs, respectively.

The energy input from different sources and their proportion of the total energy input are shown for each investigated product in figure 11 (according to annex 1.2). The energy input

from fertiliser was the biggest or second biggest energy source (maize silage) in total energy input, except for alfalfa, which had the lowest N fertiliser requirements. Fuel consumption during machinery operations was the main source of energy input in the production of maize silage, and it was the second main source of energy input for the other crops. In both maize silage productions, the diversity of machinery operations and the high volume and mass of the fresh matter yield caused high energy consumption during harvest and transfer. Thus, the fuel had the highest share of the energy input for both products.

Regarding the high volume of water consumption, irrigation was the third main source of en-ergy input besides the fertilisers and fuel in most crops. With approximately 18,000 m³ ha^-1 water, irrigation caused the highest single energy input in alfalfa and in maize corn produc-tion, with nearly the same energy input as that of fuel consumption. Irrigation and fuel were the two dominant energy input sources in alfalfa, which were responsible for 73% of the total energy input. The energy inputs from machinery, seed, manure and pesticides were consid-erably less than the three dominant sources, except in alfalfa, in which energy input from fertilisers was very low. The energy input from pesticides was relatively high only in maize corn production. For the other products, energy input from pesticides was very low or zero for both maize silage products.

Figure 11 Energy input in the production of the investigated crops according to different sources (MJ ha^-1 yr^-1).^a

a For summer maize silage, the yield was not reported annually because it was cultivated as a secondary product.