Table 1 Description of the filtering operations performed on Census elementary data

Filter 1: excluding from P-NT the holdings who declare A-UAA under different tillage schemes in addition to NT and keeping holdings practicing only NT as simplified soil farming technique.

We filtered P-NT (52.218 agricultural holdings) keeping the agricultural holdings only declaring NT as tillage practice and excluding the ones declaring also MT and CT on a certain share of the A-UAA. After applying this first filter, the total population of holding decreased to 27.338 (“P-NT ONLY”).

It is reasonably possible that farmers practicing NT, but also other soil tillage techniques in their holdings, are not operating under CA principles, but simply adopting NT as an occasional practice on a share of the A-UAA.

Filter 2: excluding from P-NT the holdings with NT A-UAA < 100% of the total A-UAA.

Many of P-NT ONLY holdings have a total A-UAA greater than the area under NT. Thus, we filtered P-NT ONLY excluding those holdings for which total A-UAA resulted > of the A-UAA declared under NT. After this second filter, we obtained a total of 21.033 holdings (“P-NT100%”).

It is reasonably possible that holdings practicing NT only on a share of the total A-UAA are not fully operating under CA principles, but simply adopting NT as an occasional practice.

Filter 3: excluding from P-NT the holdings with A-UAA devoted to the cultivation of corn and open-field vegetables.

We filtered 21.033 P-NT100% excluding holdings cultivating corn/maize and open-filed vegetables in A-UAA: this third filter reduced our P-NT100% population to a total of 19.498 holdings (“P-NT100%NoC-V”);

Corn is a very profitable crop in Italy and requires irrigation to be productive. The same happens with open-field vegetables in arable land. Where irrigation is available, corn and open-field vegetables tend to be mono-cultivated or, anyway, tend to require soil tillage operation to compensate soil compaction determined by heavy machineries traffic. Moreover, vegetables are normally transplanted (not drilled) and this requires dedicated soil tillage operations. In this frame, it is reasonably possible that holdings cultivating corn and open-field vegetables tend to adopt NT as an occasional practice more than as a part of a consolidated CA system.

Filter 4: excluding from P-NT the holdings with A-UAA cultivated for forage/hay production.

We filtered P-NT100%NoC-V population excluding holdings cultivating exclusively hay/forage (even if in rotation with other crops) on the 100% of the declared A-UAA and keeping all the other holdings with the ratio hay-forage A-UAA/total A-UAA < 1). This last filter was very restrictive since the final number of holdings is composed by 5.328 remaining agricultural holdings (“P-CA”). After all these filtering operations, we assume that this P-CA population of agricultural holdings could represent the population of farms practicing in Italy NT under the real principles of CA.

Production of forage is quite common in Italy, especially in more marginal areas. Cultivation of hay normally do not require any specific or heavy preliminary soil tillage operations. For this reason, it is reasonably possible that holdings declaring to hold A-UAA for the production of forage/hay in rotation with other arable crops tend to adopt NT as an occasional practice more than as a part of a consolidated CA system.