ENERGY AND LABOR EFFICIENCY FOR 3 PAIRS OF CONVENTIONAL AND ALTERNATIVE MIXED CROPPING (PASTURE ARABLE) FARMS IN CANTERBURY, NEW-ZEALAND

The major energy inputs and outputs and labour inputs for each year of the rotation from three pairs of farms were measured. One of each pai r was under conventional agriculture and the other under an alternativ e (organic or biodynamic) system. In the study locality, a mixed cropp ing system of farming is practised in which grazed grass/white clover pastures and/or grass and white clover seed crops are grown in rotatio n with arable crops. The energy input for sheep meat production was ap preciably lower than that normally observed in intensive production in the Northern Hemisphere. This is principally because livestock graze outside throughout the year on forage that has been supplied with litt le energy-intensive fertiliser-N. Energy input was lower under alterna tive than conventional sheep meat production at two of the sites and s imilar at the third. For cereal crops (wheat and barley), energy input s and grain yields were greater under conventional than alternative ma nagement owing mainly to fertiliser-N inputs under conventional manage ment. These accounted for 23-63% of total energy inputs. Sown seeds an d field operations contributed substantially to energy inputs under bo th farming systems. Fertiliser-N inputs under conventional management were low compared with those used in Europe and North America since ce real crops relied partially on N-2 fixed biologically during pasture a nd seed crop phases of the rotations. As a result, the energy efficien cy ratio (energy output over input) was considerably higher than that commonly observed in intensive agriculture in the Northern Hemisphere. The energy efficiency ratio for cereal production was higher under al ternative management at two sites but higher under conventional manage ment at another. Over the entire rotation, the mean annual energy inpu t was considerably lower under alternative than conventional managemen t. Labour input was higher for production of individual cereal crops u nder alternative management but mean annual labour inputs over the who le rotations were slightly lower under alternative than conventional m anagement.