**Author details**

produce Tutaekuri under partial irrigation and low high N, and Moe Moe under full irrigation with low N. It is not advisable for growers to produce Agria under partial irrigation and low N, because this production system has negative NPV. Economic water productivity is expected to be high in Taewa because of the premiums at market. Premiums, socially and economically forces production of Taewa among the highest producer but low valued. It is evidenced that issue of water footprint requires financial attachment to attract farmers.

In the field, water regimes differently influence crop production and the value of water footprint for both heritage and modern crop cultivars, depending on the crop water use characteristics and field management. Pumpkin squash, Kamokamo, has a low water footprint, since it genetically uses water more sparingly, compared to all the other crop cultivars studied. In spite of this, the yield response to irrigation is highest in modern potato, while Kamokamo is comparable to Moe Moe and Buttercup squash and dark orange oca. It can be concluded that pumpkin squash requires only a small amount of water, in order to produce total fruit yield compared to potatoes and oca. Potatoes, except Tutaekuri, are more responsive to irrigation compared to pumpkin squash and oca. The yields and water footprint of heritage potato is greatly affected by cultivars used and water regimes, unlike the case of oca. It can be concluded that there are water footprint differences between cultivars of different crops and within crops in New Zealand. Knowledge of these water footprint differences can assist growers to manage their crops and water resources sparingly. It is therefore recommended that growers should be properly selecting crops and crop varieties according to their water availability, market price, properly schedule irrigation and nitrogen application as well as pests and disease control in order to reduce water footprint of growing their crops

It is recommended that farmers should strive to reduce water footprint either by avoidance of using two much of other inputs or by replacement of inefficient technologies by very efficient

**1.** Farmers should be advised to strive to reduce grey water footprint in their fields. Grey water footprint would be decreased if application of chemical fertilisers, pesticides and herbicides to the field is avoided or reduced or by following efficient ways of using fertilisers as well as applying better application techniques or use of organic fertilisers and proper

**2.** Farmers should also be advised to decrease green water footprint and blue water footprint. The green and blue water footprints would be greatly lessened by enhancing green and blue water productivity. Our study indicates that application of less water through smart irrigation scheduling (replacing full irrigation by partial irrigation) and selection of water efficient crop cultivars (replacing heavy water users by efficient water users) would help to maximise water productivity (striving for higher yield per cubic of water used for production) thereby

**5. Conclusion and recommendations**

at field level.

100 Irrigation in Agroecosystems

technologies as detailed below:

timing of fertiliser and irrigation application.

reducing both green and blue water footprint.

Isaac R. Fandika1,2\*, Peter D. Kemp<sup>1</sup> , James P. Millner<sup>1</sup> and Davie Horne1

\*Address all correspondence to: fandikai@yahoo.co.uk; fandika68@gmail.com

1 Institute of Natural Resources, Massey University, Palmerston North, New Zealand

2 Kasinthula Agricultural Research Station, Department of Agricultural Research Services, Chikwawa, Malawi
