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

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, compared to potato and pumpkin squash.

The average water footprint of growing potato reported in this study (ranging from 46 m3 ton−1 to 335 m3 ton−1) were greater than that for the Netherlands and almost equal to USA and Brazil, except for Tutaekuri, which was equal to the water footprint of growing potato in Zimbabwe [27]. The water footprint of 72 m<sup>3</sup> ton−1 was reported in Netherlands, 111 m3 ton−1 in USA, 106 m<sup>3</sup> ton−1 in Brazil and 225 m<sup>3</sup> ton−1 in Zimbabwe [27] for producing potatoes. 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, Kamokamo, dark orange and scarlet oca, respectively. Efficient crop water management and crop cultivar choice might contribute to lower virtual water content of producing potato and pumpkin squash than 25 l/100 g for potato tuber [28] and 23.8 l/100 g for pumpkin [22], which were reported as average global and Indian virtual water content, respectively. On the other hand, oca virtual water content is still falling outside the 25 l/100 g for potato tuber. These disparities in water footprint are within or above those reported in the 1995–2006 global water footprint of pumpkin squash (336 m<sup>3</sup> ton−1) and potato (287 m<sup>3</sup> ton−1) [12].

in potato 622 and 654 m<sup>3</sup>

ranged from 95 to 111 m3

crop husbandry is appropriate.

**4.3. Social-economics of the selected crop cultivars**

tion), 173–406 m<sup>3</sup>

(160 m<sup>3</sup>

ton−1 in maize and 2651 and 2667 m<sup>3</sup>

ton−1 (modern potato); 110–220 m<sup>3</sup>

2010/2011 the water footprint for water regimes ranged from 163 to 586 m<sup>3</sup>

ton−1 (partial irrigation) and 198–505 m<sup>3</sup>

Farmers need to keep fields weed free to reduce pests and diseases incidences.

a water footprint approaching the global water footprint of 160 m<sup>3</sup>

irrigation and uniform rate irrigation, respectively. It is noted that the total water footprint of growing potato by Hedley et al. [29, 30], was higher than those reported by Hoekstra [31] and the water footprint for this study, except for Tutaekuri. Similarly, the study under this report vividly shows that water footprint differed between full irrigation and rain-fed that

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

footprint was found in Agria and the highest in Tutaekuri. From this discussion and **Figure 3**, it is well illustrated that water management within different crop cultivars influences levels of water footprint. Apart from differences in water footprint caused by varieties differences, water footprint may also extensively differ in their water footprint due to pests' infestation.

Pests and diseases affect water footprint of producing selected crop cultivars because they reduce yields without affecting water input. In case of this study, water footprint of Taewa between seasons differed due to pests' infestation. As weather variations between seasons Water footprint was greatly higher in 2011 than in 2010 (**Figure 3**). Potato psyllid infestation influenced the increase in water footprint in 2011. However, the water footprint of producing potato without psyllid infestation, in 2009/2010, was smaller than the global water footprint

 ton−1) for producing potato. Potato infested with psyllid in 2010/2011 behaved differently, only a well-managed full irrigation regime of modern potato and Moe Moe, obtained

proper management of irrigation under pests' infestation can help to reduce water footprint.

The water footprint indicator suggests there are numerous disparities, with global averages and within country or seasons, arising from irrigation management and methodological differences when estimating crop water use, climate variability, cultivars and pest and disease infestation [22, 28]. However, the water footprint for crops grown in New Zealand can be reduced through good management [12]. For instance, pumpkin squash (especially Kamokamo) had the lowest water footprint, compared to oca, potato, maize and pasture in New Zealand, and compared well with small water footprint crops such as sugar beet and sugarcane, at the global level [26]. This observation suggests that some heritage crop cultivars can compare with (or outperform) modern cultivars in relation to water footprint, when the

A premium that farmers get at market on crop cultivar has higher influence on smallholder farmer's social-economic status than sole yield and sole irrigation response factors. In our case, fully irrigated Moe Moe and partially irrigated Tutaekuri production systems, were economically viable due to their high value at market. The novel value of most heritage crops are value which have been based on social preferences based on their superiority flavour, texture and colour. Fully irrigated Moe Moe and partially irrigated Tutaekuri production systems, with low N, would be profitable investments for Taewa growers because they have high value and low N use. For growers to maintain these economic benefits they should be advised to

ton−1 in pasture at varied rate

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

ton−1 (Taewa) in 2009/2010. In

ton−1 (rain-fed). The lowest water

ton−1 (full irriga-

99

ton−1. A combination of

The results suggest that there are great disparities in virtual water content and water footprint within global averages, which may be due to climate, cultivars and methodological differences, when estimating crop water use [22, 28]. This study used actual water use and actual yield, as suggested by Maes [22], while the study referred to used hypothetical crop yields and water use [26]. On the other hand, the virtual water content and water footprint in this study, outweigh the global water footprint put forward by Mekonnen [12]. The reason for such disparities with this study is that most referred global water footprint studies theoretically estimated crop water use while this study practically recorded the actual water used. The theoretically estimated water use might have been over-estimated while our study might sparely use the water resulting into lower water footprint. It is globally agreed that smart and efficient practices in agriculture, selection of efficient crop cultivars in water use and good weather patterns do assist in reducing water footprint of producing various crops.

Irrigation increases total water use compared to rain-fed agriculture. In this study blue water raised total crop water use by 34, 48 and 59%, in oca, potato and pumpkin squash cultivars, respectively. Consequently, blue water clearly increased the total water footprint. Total water footprint increased by 5, 45, 28, 25 and 8% in irrigated Moe Moe, Tutaekuri, Buttercup squash, Kamokamo and Scarlet oca. However, irrigation reduced total water footprint in Agria, Moonlight and dark orange oca by 6, 4 and 7%. The earlier trends were reported in wheat whereas the later was reported in sugarcane and soybean, respectively [12]. For crop varieties which positively respond to irrigation, the intervention is indispensable to reduce the total water footprint, by improving the economic yields. Nevertheless, this is contrary to like Moe Moe, Tutaekuri, Buttercup squash, Kamokamo and scarlet because the intervention raised the actual evapotranspiration nearly to potential evapotranspiration resulting into reduced water footprint, even with improved yield. The findings emphasise that irrigation is very important for crop yield quality and yield enhancement as well as reduced water footprint where rainfall is limited. Apart from differences in water footprint influenced by crop varieties and differences and crops, water footprint also extensively differ in their water footprint at different irrigation management.

Irrigation scheduling method would influence the water footprint of producing various crops—however, this is dependent on crop cultivars. Partial irrigation reduced water footprint in Tutaekuri while full irrigation reduced water footprint in Moe Moe and Agria. The differences about crop varieties response to different irrigation schedules are very significant because they indicate disparity of water use among crop varieties. This result is very useful in selection for crop varieties that are sparing in water use or drought tolerant and breeding for water use efficiency.

Hedley proved that the water footprint of modern potato production is slighter small than that of maize and pasture [29]. Hedley report registered water footprint of 308 and 325 m<sup>3</sup> ton−1

in potato 622 and 654 m<sup>3</sup> ton−1 in maize and 2651 and 2667 m<sup>3</sup> ton−1 in pasture at varied rate irrigation and uniform rate irrigation, respectively. It is noted that the total water footprint of growing potato by Hedley et al. [29, 30], was higher than those reported by Hoekstra [31] and the water footprint for this study, except for Tutaekuri. Similarly, the study under this report vividly shows that water footprint differed between full irrigation and rain-fed that ranged from 95 to 111 m3 ton−1 (modern potato); 110–220 m<sup>3</sup> ton−1 (Taewa) in 2009/2010. In 2010/2011 the water footprint for water regimes ranged from 163 to 586 m<sup>3</sup> ton−1 (full irrigation), 173–406 m<sup>3</sup> ton−1 (partial irrigation) and 198–505 m<sup>3</sup> ton−1 (rain-fed). The lowest water footprint was found in Agria and the highest in Tutaekuri. From this discussion and **Figure 3**, it is well illustrated that water management within different crop cultivars influences levels of water footprint. Apart from differences in water footprint caused by varieties differences, water footprint may also extensively differ in their water footprint due to pests' infestation. Farmers need to keep fields weed free to reduce pests and diseases incidences.

Pests and diseases affect water footprint of producing selected crop cultivars because they reduce yields without affecting water input. In case of this study, water footprint of Taewa between seasons differed due to pests' infestation. As weather variations between seasons Water footprint was greatly higher in 2011 than in 2010 (**Figure 3**). Potato psyllid infestation influenced the increase in water footprint in 2011. However, the water footprint of producing potato without psyllid infestation, in 2009/2010, was smaller than the global water footprint (160 m<sup>3</sup> ton−1) for producing potato. Potato infested with psyllid in 2010/2011 behaved differently, only a well-managed full irrigation regime of modern potato and Moe Moe, obtained a water footprint approaching the global water footprint of 160 m<sup>3</sup> ton−1. A combination of proper management of irrigation under pests' infestation can help to reduce water footprint.

The water footprint indicator suggests there are numerous disparities, with global averages and within country or seasons, arising from irrigation management and methodological differences when estimating crop water use, climate variability, cultivars and pest and disease infestation [22, 28]. However, the water footprint for crops grown in New Zealand can be reduced through good management [12]. For instance, pumpkin squash (especially Kamokamo) had the lowest water footprint, compared to oca, potato, maize and pasture in New Zealand, and compared well with small water footprint crops such as sugar beet and sugarcane, at the global level [26]. This observation suggests that some heritage crop cultivars can compare with (or outperform) modern cultivars in relation to water footprint, when the crop husbandry is appropriate.

#### **4.3. Social-economics of the selected crop cultivars**

Kamokamo, dark orange and scarlet oca, respectively. Efficient crop water management and crop cultivar choice might contribute to lower virtual water content of producing potato and pumpkin squash than 25 l/100 g for potato tuber [28] and 23.8 l/100 g for pumpkin [22], which were reported as average global and Indian virtual water content, respectively. On the other hand, oca virtual water content is still falling outside the 25 l/100 g for potato tuber. These disparities in water footprint are within or above those reported in the 1995–2006 global water

ton−1) and potato (287 m<sup>3</sup>

The results suggest that there are great disparities in virtual water content and water footprint within global averages, which may be due to climate, cultivars and methodological differences, when estimating crop water use [22, 28]. This study used actual water use and actual yield, as suggested by Maes [22], while the study referred to used hypothetical crop yields and water use [26]. On the other hand, the virtual water content and water footprint in this study, outweigh the global water footprint put forward by Mekonnen [12]. The reason for such disparities with this study is that most referred global water footprint studies theoretically estimated crop water use while this study practically recorded the actual water used. The theoretically estimated water use might have been over-estimated while our study might sparely use the water resulting into lower water footprint. It is globally agreed that smart and efficient practices in agriculture, selection of efficient crop cultivars in water use and good

weather patterns do assist in reducing water footprint of producing various crops.

differ in their water footprint at different irrigation management.

for water use efficiency.

Irrigation increases total water use compared to rain-fed agriculture. In this study blue water raised total crop water use by 34, 48 and 59%, in oca, potato and pumpkin squash cultivars, respectively. Consequently, blue water clearly increased the total water footprint. Total water footprint increased by 5, 45, 28, 25 and 8% in irrigated Moe Moe, Tutaekuri, Buttercup squash, Kamokamo and Scarlet oca. However, irrigation reduced total water footprint in Agria, Moonlight and dark orange oca by 6, 4 and 7%. The earlier trends were reported in wheat whereas the later was reported in sugarcane and soybean, respectively [12]. For crop varieties which positively respond to irrigation, the intervention is indispensable to reduce the total water footprint, by improving the economic yields. Nevertheless, this is contrary to like Moe Moe, Tutaekuri, Buttercup squash, Kamokamo and scarlet because the intervention raised the actual evapotranspiration nearly to potential evapotranspiration resulting into reduced water footprint, even with improved yield. The findings emphasise that irrigation is very important for crop yield quality and yield enhancement as well as reduced water footprint where rainfall is limited. Apart from differences in water footprint influenced by crop varieties and differences and crops, water footprint also extensively

Irrigation scheduling method would influence the water footprint of producing various crops—however, this is dependent on crop cultivars. Partial irrigation reduced water footprint in Tutaekuri while full irrigation reduced water footprint in Moe Moe and Agria. The differences about crop varieties response to different irrigation schedules are very significant because they indicate disparity of water use among crop varieties. This result is very useful in selection for crop varieties that are sparing in water use or drought tolerant and breeding

Hedley proved that the water footprint of modern potato production is slighter small than that of maize and pasture [29]. Hedley report registered water footprint of 308 and 325 m<sup>3</sup>

ton−1

ton−1) [12].

footprint of pumpkin squash (336 m<sup>3</sup>

98 Irrigation in Agroecosystems

A premium that farmers get at market on crop cultivar has higher influence on smallholder farmer's social-economic status than sole yield and sole irrigation response factors. In our case, fully irrigated Moe Moe and partially irrigated Tutaekuri production systems, were economically viable due to their high value at market. The novel value of most heritage crops are value which have been based on social preferences based on their superiority flavour, texture and colour. Fully irrigated Moe Moe and partially irrigated Tutaekuri production systems, with low N, would be profitable investments for Taewa growers because they have high value and low N use. For growers to maintain these economic benefits they should be advised to 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.

**3.** Agricultural Extension Officers need to be guided to assist farmers in defining their target of best agricultural technology practices for reducing water footprint and formulating targets to be achieved in order to contribute to reduction of water footprint. Where possible farmers should be assisted to monitor and measure their water footprint in their environment. This can be achieved by setting environmental and social safeguards plan that would help to reduce risk of water footprint by investing in reasonable water use,

**4.** Governments should formulate policies that include goal of sustainable usage of water resources. The policies should promote smart agriculture: that is, efficient irrigation (drip irrigation), conservation agriculture, system of rice intensification (SRI), crops that are effi-

, James P. Millner<sup>1</sup>

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

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

[1] Hooijdonk B, Behboudian H. Strategies to save water and manage export apple production during seasons of high crop demand and low water availabilty. The Orchards.

[2] Fowler A. Potential climate change impacts on water resources in the Auckland Region—

[3] Halloy SRP, Mark AF, Dickson KJM. Management of New Zealand's terrestrial bidiver-

[4] Francis GS, Trimmer LA, Tregurtha CS, Williams PH, Butler RC. Winter nitrate leaching losses from three land uses in the Pukekohe area of New Zealand. New Zealand Journal

[6] Howell T. Enhancing water use efficiency in irrigated agriculture. Agronmy Journal. 2001;

[7] Roskruge N. Taewa Maori; their Management, Social Importance and Commercial Viability. A Research Report Presented in Partial Fulfillment of the Requirements of

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

New Zealand. Climate Research. 1999;**11**:221-245

of Agricultural Research. 2003;**46**:215-224

sity as a complex adaptive system. Complext International; **200**:8

[5] MAF. Ministry of Agriculture and Forestry Technical Paper N0:04/01. 2000

and Davie Horne1

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

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

101

better-quality catchment water management and sustainable water use.

cient in water use and organic fertilisers.

Isaac R. Fandika1,2\*, Peter D. Kemp<sup>1</sup>

**Author details**

Chikwawa, Malawi

2004:64-67

**93**:281-289

**References**
