**3. Results**

#### *3.1. Costs and Incomes*

Comparing the cost of the considered mulches, biodegradable materials are between 25% and 188% more expensive than PE while paper mulches are between 153% and 236% more expensive (see Table 3). Among biodegradable materials, Ecovio ® is the cheapest one and Arrosi ® 69 and Arrosi ® 240 are the cheapest papers.

Table 4 shows the aggregated costs by operations calculated in the trials. The name "field preparation" includes subsoiler, cultivator tillage, rotatory tillering, and the application and burial of pre-transplanting manure. "Crop season operations" comprised irrigation, herbicide application and chemical dressing among others. "Plastic and paper mechanical mulching" includes the costs of materials and mechanical installation on the field. Finally, the concept of "field conditioning" includes irrigation system and crop removal, waste managemen<sup>t</sup> for the non-biodegradable scenarios, and, finally, a cultivator pass.



a For a plastic consumption of 160 kg ha−1. Management of plastic, transport time, and landfill and recycling costs included.

If the use of PE with no waste managemen<sup>t</sup> is considered as a benchmark, then mulching represents 6.3% of the total costs for pepper production. The biggest expenditure of these operations corresponds to crop season operations (mainly transplant and pepper seedlings costs) with 45.3% and the following is the harvest with 27% because it is a manual task. For the rest of the cases, mulching materials represents between 7.5% and 14.1% of the total costs in biodegradable and between 13.1% and 16.2% in paper types (Table 4). Regarding irrigation costs, although we expected to save water with plastics with respect to papers, water consumption was very similar for both types of materials.

The analysis of field conditioning costs for PE scenario shows that this cost represents 4.7% of the total when no waste managemen<sup>t</sup> is carried out. This cost increases to 4.8% when the farmer transports the waste to the recycling point (landfill scenario) and up to 4.9% if the complete recycling cost is assumed. By contrast, using biodegradable mulches allows a saving in field conditioning of a minimum of 54.7% and a maximum of 56.7% with respect to PE.

Table 5 shows the results obtained for yield, subsidies, and incomes. Despite no statistically di fferences are found among mulching materials, PE obtained one of the lowest yields. Mater-Bi ® and Arrosi ®240 obtained amounts close to 30 t ha−1, which are similar to the average yields recorded in Spain (29 t ha−1). Final incomes were calculated including the subsidies available to cover 35% of the biodegradable plastic cost.


**Table 5.** Experimental yield (t ha−1), subsidies, and total income obtained for mulching materials in open-air conditions in 2014.

> Same letters in yield mean no statistical differences among treatments (*p* = 0.45).

#### *3.2. Net Margins*

Table 6 summarizes the main economic variables analyzed. Net margins are calculated under the three waste managemen<sup>t</sup> scenarios considered for PE and under the two scenarios for biodegradable materials (with and without subsidies). In addition, the percentage with respect to PE without waste managemen<sup>t</sup> (baseline scenario) is calculated in order to present a comparative analysis of alternative materials.

For biodegradable materials, the total costs are between 2.2% and 9.3% higher than those of PE. The only exception is Ecovio®, which is cheaper than PE because the additional material cost is less than disposal costs. Regarding final profitability, two bio-degradable materials (Mater-Bi® and Sphere®) present higher profitability than PE (with and without subsidies) while Bioflex® and Ecovio® are the worse options, with reductions of 1.6% and 6.9% with respect to the benchmark due to low yields obtained in the trials. Mater-Bi® is the best biodegradable option, with an increase of 29.9% with respect to PE.


**Table 6.** Incomes, costs, and net margins of different mulching materials (€ ha−1).
