Colombia – Sentencia T-360 de 2010

The typical orchard production practices of the two model organic apple systems were described in section 6.3. From the information gathered from the growers, it was noted that some of the key management practices were different from orchard to orchard, which might have an effect on sustainability. The effect of the key differences, in management practices on sustainability indicators in the semi- intensive and intensive organic apple systems, is described below.

6.5.1.1 Management scenario analysis of the semi-intensive organic apple system

The only key difference, within the management inputs in the semi-intensive organic apple systems, was the application of brought in (purchased from outside) compost. Compost was usually brought in and applied to the orchard at the rate of 8 t/ha, once every four years. Hence, compost application is not considered as a production practice within the model organic semi-intensive system. However, application of compost is considered by considering the „what if‟ management scenario, as below.

What if the grower applies brought in compost?

Compost is applied once in every four years at the rate of 8 t/ha. Energy is required to prepare compost and transport it to the orchard. The energy in compost transportation is considered to be 3 MJ/t-km (Bone et al., 1996). Simultaneously, CO2-equivalent emissions take place from the embodied energy used in the compost preparation and transportation. As a result, the energy ratio for the year when the compost is applied lowers from 1.57 to 1.38 and the CO2 ratio lowers from 1.24 to 1.20. In this scenario, however, additional carbon is added to the soil from outside the orchard, in addition to carbon being added through prunings and roots. The total carbon added to the soil through prunings, roots and the addition of compost is 6,482 kg. Most of this carbon is returned to the atmosphere as carbon dioxide, through decomposition. It is estimated that about 5,315 kg is lost to the

atmosphere as CO2 and the remainder can be expected to be stored in the soil. As a result, 1,167 kg of carbon can be expected to be sequestered in the soil, compared to 897 kg of carbon when no brought in compost was applied. Also, as a result of additional N surplus through the application of brought in compost, the N-leaching losses went up from 14 to 17 mg N/L.

6.5.1.2 Management scenario analysis of the model intensive organic apple system

The description of the model intensive apple system, presented in section 6.3, represented the typical situation of intensive organic apple orchards. Compost is only applied in the model intensive organic apple system once in four years and therefore, compost application was not considered as a management practice, within the model intensive organic apple system. Similarly, a frost-fighting system is not included as an input in a typical model intensive organic apple system, because it is not used on all blocks. However, one of the blocks, in one particular orchard, was equipped with a wind machine to fight the frost. The wind machine is usually used for 70 hours in one season. Also, it is known, from the literature, that a smaller powered tractor consumes less amounts of diesel, compared to a high powered tractor, which carries out the same operations. A management scenario analysis was undertaken to identify the effect of these variations respectively on the model results. These management scenarios are presented below.

Scenario 1: What if the grower applies brought in compost?

Compost is purchased from commercial suppliers and applied once every four years at a rate of 8 t/ha. Energy is expended for compost preparation, in addition to transporting the compost to the orchard. The growers estimate that the compost is transported from 100 km away. With this scenario, the energy ratio is lowered from 1.84 to 1.66 and the CO2 ratio from 1.23 to 1.20, compared to the base model which does not apply compost. When the compost is purchased, additional carbon is added to the orchard soil from outside the orchard. As a result, the total carbon added to the soil is increased from 981 kg/ha when the compost is not applied to 1269 kg/ha when the compost is applied. Also, due to the application of the

compost, the N surplus increased which increased the N-leaching losses from 5 to 8 mg N/L.

Scenario 2: What if the grower uses a smaller tractor?

The literature suggests that diesel usage can be expected to be lower in denser plantings, because of smaller tree size that facilitate the passage of smaller equipment within the orchard, compared to semi-intensive apple system which requires larger tractors (Funt, 1980). However, no difference was found in the machinery/equipment used in the two model organic apple systems in this study. In fact, the diesel usage of the model intensive system was higher than the model semi-intensive system, due to frequent spraying and a higher work rate, necessitated by higher number of rows, than in the semi-intensive system.

The fact that similar sized machinery/equipment was used between the two model systems, in this study, can be explained by the number of trees and tree spacing. For example, the difference between the row spacing of the model semi-intensive and intensive orchard was only one metre (semi-intensive orchards had 5m between the rows, whilst intensive orchards had 4m between the rows). The semi- intensive orchard, in the study carried out by Funt (1980), had only 165 trees/ha and the intensive system had 1,512 trees/ha. In this study, the model semi-intensive system had 800 trees/ha and the intensive system had 1,250 trees/ha. There is not such a large difference in the number of trees/ha between semi-intensive and intensive apple orchards, compared to those studied by Funt (1980). The other reason, for the fact that the model intensive system had similar machinery/equipment size to those of the semi-intensive system, is the philosophy of the grower.

To see the effect of using a smaller tractor on the total energy use and CO2 emissions, a hypothetical scenario was considered, in which the model intensive system used a 40 kW tractor instead of a 50 kW tractor: the time required to carry out the same operation was increased by 10% more than the based model. Under this scenario, the diesel consumption/hr is estimated as:

40 kW*0.35 L*0.6 = 8.4 L (as per equation 4.6)

Accordingly, the diesel requirement for individual operations is presented in Table 6.16.

Table ‎6.16 Fuel consumption in individual operations with a 40 kW tractor in the model intensive organic apple system

Operation Fuel used L/hr Work rate hr/ha Fuel use L/pass No of passes Fuel use (L/ha) Spraying* 8.4 0.86 7.22 35 253 Mowing 8.4 1.10 9.24 4 37 Mulching 8.4 2.75 23.1 1 23 Fertilisation 8.4 0.86 7.22 3 22 Harvest tractor 8.4 4.40 37.00 1 37 Total 372

* Number of sprayings excludes aerial sprays

As a result of using a smaller tractor, the total fuel consumption of the model intensive organic apple systems, per ha per year, is reduced from 596 to 559 L/ha/yr. Also, the embodied energy invested in the tractor is lowered from 1,440 MJ to 1,170 MJ/ha/yr. As a result, the energy ratio elevated from 1.84 to 1.88 whilst the total energy input per ha reduced from 64.00 to 62.00 GJ/ha.

Scenario 3: What if the location of the orchard required the installation of the wind-machine?

A frost protection system was used by only one grower, on one of the blocks which was prone to the occurrence of frosts. On this block, a wind-machine, run for an average of 70 hours a year to minimise frost damage, was installed. The embodied energy in the frost fighting machinery was estimated to be 2,133 MJ/ha/yr, with a working life of 15 years (Appendix VI). It is assumed that, had the frost protection system not been installed in this particular block, then there would have been no marketable yield, since the majority of the fruit would have been frost damaged. Therefore, installing a frost protection system ensured that the yield from this block

would be similar to those of the orchards, which do not have the problem of frost. In this scenario, the energy ratio lowered from 1.84 to 1.49 and the CO2 ratio lowered from 1.23 to 1.16. This suggests that frost fighting consumes significant proportions of energy and contributes associated CO2-emissions.