Handbook for Irrigation of Wine Grapes in South Africa

0 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 1 0

3 0

A

2 5

2 0

Na ex (cmol (+) /kg)

1 5

1 0 Na (%)

c

Figure 5.27 0 0 0 5

No Na Pl

No Na Plus Na No Na Plus Na

Leaves

Tubers

Without fodd

0 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 1 0

B

a

Na ex (cmol (+) /kg)

b

c

c

No Na Plus Na No Na Plus Na

No Na Plus Na Tubers

Without fodder beet

With fodder beet

Soil microbial activity in different soil depth layers was assessed by (i) enzyme analysis using a colorimetric assay, (ii) coarse-level comparisons of total heterotrophic and actinomycete populations by dilution plating on growth media monitoring shifts in microbial communities using the ARISA method and (iii) measuring soil glomalin by a simple Bradford assay (Myburgh & Howell, 2014b FIGURE 5.27. The effect of irrigation with Na-enriched water on (A) the Na in fodder beet leaves and tubers and (B) the Na ex in soil with and without fodder beet (Myburgh & Howell, 2014a). Vertical bars indicate standard deviation, and columns designated by the same letter do not differ significantly (p ≤ 0.05).

140 CHAPTER 5 – IRRIGATION WATER QUALITY