*3.2.1. Blue, green and grey water footprint on total yield*

The green, blue and grey water footprint components varied with both crop cultivars and water regimes as presented in **Tables 2** and **3** and **Figure 2**. The total water footprint of consumptive


pumpkin squash was 425 and 398 m<sup>3</sup> ha−1, respectively (**Table 1**). An increase in N rate application raised the grey water in potato and oca compared to pumpkin squash. The actual crop water use for rain-fed crop in oca, potato and pumpkin squash was 74.9, 65.1 and 69% of the irrigated crop, respectively (**Table 1**). The total consumptive water use (m3 ha−1) was greatest in oca and lowest in pumpkin squash, while potato was intermediate, despite variation within cultivars. Heritage crops (Maori potato, Kamokamo) used more water because of its long growing season. Differences in yields were observed to be influenced by water regime and crop cultivars among the eight selected crop cultivars. With exception of Tutaekuri, average yields continuously increased from rain-fed (16.7–67.7 t ha−1) to irrigated conditions (23.2–78 t ha−1). Kamokamo had the greatest yields while dark orange had the lowest yields under both water regimes. Average yields for other crops' varieties such as Agria, Moonlight and Moe Moe were similar but greatly lower than Kamokamo. Out of the crop cultivars, oca varieties and Tutaekuri proved to have lowest yield levels. Agria, Moonlight and Moe Moe also demonstrated an ability of partitioning more dry matter to economic yields basing on its harvest index (HI). In summary, the heritage crop cultivars extremely partition more to biomass unlike most of the

**Figure 2.** Blue, green and grey water footprint on total yield of potato, oca and pumpkin squash crop cultivars under

modern cultivars which partition more to economic yields (**Table 1**).

irrigation and rain-fed condition in New Zealand, 2010. Error bar represents LSD0.05.

92 Irrigation in Agroecosystems

*3.2.1. Blue, green and grey water footprint on total yield*

**3.2. Water footprint differences of cultivars of selected heritage and modern crops**

The green, blue and grey water footprint components varied with both crop cultivars and water regimes as presented in **Tables 2** and **3** and **Figure 2**. The total water footprint of consumptive **Table 1.** Date of planting and harvesting, harvestable yield, total biomass yield and consumptive water use for heritage and modern potato, oca and pumpkin squash crop cultivars in New Zealand, 2010.

water use (blue plus green water footprint or pure green water footprint) of total yield ranges was high in irrigated field and low in rain-fed field (**Table 2**). **Figure 1** evidently show that the blue water footprint in rain-fed crop was zero while the green water footprint of total yield and total biomass yield related to rain-fed environment were high compared to the green water footprint of the irrigated field.

In the irrigated crops, the blue water footprint comprised 27–39% while the grey water footprint made up to 6–9% of the total water footprint of total yield (**Figure 2**). The total water footprint of consumptive water use increased with irrigation in Moe Moe, Tutaekuri, Ebisu, Kamokamo and scarlet oca whilst Agria, Moonlight and dark orange oca decreased total


**Table 2.** Total water footprint of heritage and modern potato, oca and pumpkin squash crop cultivars on total yield basis in New Zealand, 2010.

water footprint of consumptive water use with irrigation (**Table 2**). The dilution requirement for the applied nitrogen in potato, oca and pumpkin squash, had the equivalency of 424.8 and 398.2 m<sup>3</sup> ha−1, grey water footprint, respectively (**Table 1**). The green, blue and grey water footprint reflected the inverse trend observed in total yield and total biomass yield above. All water footprint components above were largest in dark orange oca and smallest in pumpkin squash, Kamokamo (**Figure 2**).

from 64.3 to 337.3 m3

basis in New Zealand, 2010.

143 m3

**Water regime/ cultivar**

*Irrigation*

*Rain-fed*

*Significance*

LSD0.05

**Green water footprint (m<sup>3</sup>**

 **ton−1)**

**(m<sup>3</sup> ton−1)**

Agria 57.5 34.6 7.3 99.4 Moonlight 43.7 26.8 5.7 76.3 Moemoe 48.8 26.5 5.6 80.9 Tutaekuri 68.2 37.2 7.9 113.2 Buttercup 23.8 17.9 4.1 45.9 Kamokamo 16.5 12.1 2.8 31.4 Dark orange 94.6 39.9 8.5 143.0 Scarlet 71.4 29.6 6.3 107.3

Agria 82.9 — 10.2 93.1 Moonlight 69.2 — 8.4 77.6 Moemoe 66.5 — 7.1 73.6 Tutaekuri 79.8 — 8.6 88.4 Buttercup 30.2 — 4.7 34.9 Kamokamo 19.7 — 3.0 22.7 Dark orange 141.8 — 11.8 153.6 Scarlet 105.2 — 8.8 114.0

Cultivars p < 0.0001 p < 0.0001 p < 0.0001 p < 0.0001 Water regime p < 0.01 p < 0.0001 p < 0.01 Ns

Cultivar 25.57 5.08 2.32 30.48 Water regime 12.78 2.54 1.16 15.24

**Blue water footprint** 

**Grey water footprint** 

**Total water footprint** 

95

**(m<sup>3</sup> ton−1)**

http://dx.doi.org/10.5772/intechopen.77509

**(m<sup>3</sup> ton−1)**

Water Footprint Differences of Producing Cultivars of Selected Crops in New Zealand

ton−1 under irrigation and from 47.3 to 343.6 m3

ton−1 under irrigation, and 22.7 to 153.6 m<sup>3</sup>

dition (**Table 2**). The total water footprint on total biomass yield basis was between 31.3 and

**Table 3.** Total water footprint of heritage and modern potato, oca and pumpkin squash crop cultivars on total biomass

of a remarkable crop water use increase with irrigation, the total water footprint on total yield and total biomass yield basis under irrigation and rain-fed regimes were much different.

**Figure 3** shows that dark orange oca had the largest average total water footprint of total yield and total biomass while pumpkin squash, Kamokamo had the least. The total water footprint on total yield exceeded total water footprint on total biomass basis in all crop

ton−1 under rain-fed con-

ton−1 under rain-fed (**Table 3**). Regardless

#### *3.2.2. Total water footprint of total yield and total biomass yield*

Total water footprint of potato, oca and pumpkin squash on total yield and total biomass yield basis varied with crop cultivars. The total water footprint on total yield basis ranged


**Water regime/ cultivar**

94 Irrigation in Agroecosystems

*Irrigation*

*Rain-fed*

*Significance*

LSD0.05

in New Zealand, 2010.

squash, Kamokamo (**Figure 2**).

*3.2.2. Total water footprint of total yield and total biomass yield*

**Green water footprint (m<sup>3</sup>**

 **ton−1)**

**(m<sup>3</sup> ton−1)**

Agria 65.5 39.4 8.4 113.3 Moonlight 55.8 34.3 7.3 97.4 Moemoe 70.1 38.0 8.1 116.2 Tutaekuri 139.8 76.2 16.2 232.2 Buttercup 42.8 32.2 7.3 82.3 Kamokamo 33.8 24.8 5.7 64.3 Dark orange 223.2 94.1 19.9 337.3 Scarlet 190.3 78.9 16.8 285.9

Agria 106.5 — 13.03 119.5 Moonlight 90.4 — 10.92 101.3 Moemoe 99.4 — 10.69 111.1 Tutaekuri 144.6 — 15.62 160.2 Buttercup 55.6 — 8.68 64.3 Kamokamo 44.3 — 6.78 51.1 Dark orange 331.8 — 27.67 359.5 Scarlet 244.8 — 20.55 265.4

Cultivars p < 0.0001 p < 0.0001 p < 0.0001 p < 0.0001 Water regime p < 0.0001 p < 0.0001 p < 0.001 Ns

**Table 2.** Total water footprint of heritage and modern potato, oca and pumpkin squash crop cultivars on total yield basis

water footprint of consumptive water use with irrigation (**Table 2**). The dilution requirement for the applied nitrogen in potato, oca and pumpkin squash, had the equivalency of 424.8 and 398.2 m<sup>3</sup> ha−1, grey water footprint, respectively (**Table 1**). The green, blue and grey water footprint reflected the inverse trend observed in total yield and total biomass yield above. All water footprint components above were largest in dark orange oca and smallest in pumpkin

Total water footprint of potato, oca and pumpkin squash on total yield and total biomass yield basis varied with crop cultivars. The total water footprint on total yield basis ranged

Cultivar 44.3 10.7 4.10 54.6 Water regime 15.5 3.7 2.02 27.3

**Blue water footprint** 

**Grey water footprint** 

**Total water footprint** 

**(m<sup>3</sup> ton−1)**

**(m<sup>3</sup> ton−1)**

> **Table 3.** Total water footprint of heritage and modern potato, oca and pumpkin squash crop cultivars on total biomass basis in New Zealand, 2010.

> from 64.3 to 337.3 m3 ton−1 under irrigation and from 47.3 to 343.6 m3 ton−1 under rain-fed condition (**Table 2**). The total water footprint on total biomass yield basis was between 31.3 and 143 m3 ton−1 under irrigation, and 22.7 to 153.6 m<sup>3</sup> ton−1 under rain-fed (**Table 3**). Regardless of a remarkable crop water use increase with irrigation, the total water footprint on total yield and total biomass yield basis under irrigation and rain-fed regimes were much different.

> **Figure 3** shows that dark orange oca had the largest average total water footprint of total yield and total biomass while pumpkin squash, Kamokamo had the least. The total water footprint on total yield exceeded total water footprint on total biomass basis in all crop

shows how the crop coefficient (or growing stages) overlapped during the growing season between different crops leading to different water use. Application of one irrigation schedule in crops with different kc would result in over-irrigating pumpkin squash. Thus, irrigation scheduling (timing) based on soil water monitoring rather than some approximate modelling approach can significantly improve the water management [25], that is, the total water footprint. Differences in growth stages and date to maturity might contribute to great differences in crop water requirement and water footprint among the selected crops cultivars [15]. From the study, it is definite that Taewa and oca have the longest duration of growth to maturity

Water Footprint Differences of Producing Cultivars of Selected Crops in New Zealand

http://dx.doi.org/10.5772/intechopen.77509

97

Most of heritage crop cultivars used more water than modern cultivars. Likely, the large biomass and longer growth cycle in heritage crop cultivars (Kamokamo, Tutaekuri, oca and Moe Moe) made them use more water than modern cultivars. This study considered actual evapotranspiration and other discharges in determining the water footprint, as suggested by Maes [23]. In this case, the water requirement was not equal to the actual total consumptive water use, thus remedying the over-estimation. This is in contrast to water footprint determination in other studies, where hypothetical crop yield and evapotranspiration were used [26]. Apart from, expected enormous variability in crop water use within the area in future, the current results provide a great benchmark of heritage and modern crop water requirement and water

**4.2. Water footprint differences of cultivars of selected heritage and modern potato,** 

Water footprint components differ with crop type or cultivars and water regimes as also reported in energy crops [27]. Pumpkin squash, Kamokamo, was the most efficient crop cultivar, while dark orange oca was the least efficient crop. Equivalency in water footprint could be noticed between pumpkin squash cultivar and Moonlight. Nevertheless, both were five times slighter than water footprint of oca. Likewise, Moonlight, Agria and Moe Moe equaled in water footprint. Tutaekuri has largest water footprint almost double that of other potato cultivars. There more benefits to grow Tutaekuri and pumpkin squash cultivars under rainfed than under irrigated conditions. If not, there is no gain in growing oca under irrigation, excluding in the case of a likely premium price, which would offset low water productivity,

The average water footprint of growing potato reported in this study (ranging from 46 m3

and Brazil, except for Tutaekuri, which was equal to the water footprint of growing potato in

Besides, our study demonstrates that water footprint of growing potato and pumpkin squash in New Zealand is either average, or smaller than that of crops with smallest water footprint in referred regions. Oca was found to have largest total water footprint. However, oca average water footprint in this study is within the range of smallest water footprint reported in Netherlands, USA, Brazil and Zimbabwe among sugar beet, sugarcane and maize [27].

An average of 12, 10, 11, 20, 7, 5, 35 and 28 l of water (in virtual water content form) would be required to produce 100 g of Agria, Moonlight, Moe Moe, Tutaekuri, Buttercup squash,

ton−1) were greater than that for the Netherlands and almost equal to USA

ton−1 was reported in Netherlands, 111 m3

ton−1 in Zimbabwe [27] for producing potatoes.

ton−1

compared to the other selected crop cultivars [13].

footprint for the studied area.

**pumpkin squash and oca**

ton−1 to 335 m3

in USA, 106 m<sup>3</sup>

compared to potato and pumpkin squash.

Zimbabwe [27]. The water footprint of 72 m<sup>3</sup>

ton−1 in Brazil and 225 m<sup>3</sup>

**Figure 3.** Average water footprint of total yield and total biomass in oca, potato and pumpkin squash cultivars. Error bar represents LSD0.05.

cultivars (**Figure 3**, **Tables 2** and **3**). The pumpkin squash cultivars and Moonlight were not much different on total water footprint of total yield but were considerable different to Moe Moe, Agria, Tutaekuri and oca cultivars. Tutaekuri had the greatest total water footprint of total yield and total biomass among potato cultivars though extremely lower to oca cultivars. Nevertheless, the total biomass water footprint for Tutaekuri was not much different from Agria. Moonlight and Moe Moe were second from pumpkin squash in low water footprint of total biomass (**Table 3** and **Figure 3**).

#### **3.3. Social-economic of the selected crop cultivars**

Gross revenue on investment income; present value per ha from irrigation in 1st year; net present value was highest in Moe Moe among potato cultivars. Moe Moe also displayed shortest repayment period. The high market value and its intermediary yield response to full irrigation and low N-assisted Moe Moe to have high economic value among the selected potato cultivars. Agria, despite its highest yield response to full irrigation and nitrogen, ended up being the least economic crop enterprise. Agria gross revenue on investment income was NZ\$8740; present value per ha from irrigation in the 1st year was NZ\$7159; net present value was NZ41,764.5; and its repayment period was longer (0.92 years) than other enterprises. Low market value in Agria compared to Taewa contributed to its lowest economic status. An intermediary economic value was reported in Tutaekuri which had intermediary gross revenue on investment income; present value; net present value and intermediary repayment period. Tutaekuri outperformed modern potatoes in economic terms regardless of its low yield response to irrigation and N just because of its novelty value and reduced water and nitrogen fertiliser requirement.
