ISSN:
1573-0867
Keywords:
Phosphate leaching
;
drip irrigation
;
phosphate availability
;
iron phosphates
;
soil fertility
;
irrigated soils
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract The effect of fertilization on the distribution of Bray No. 1 phosphate, total soil phosphate, iron, calcium, manganese and aluminium were studied in a trickle irrigated vineyard. Placement of superphosphate (9% P, 12% S, 20% Ca) at the trickle outlet increased phosphate availability to at least 22 cm depth, and the volume of soil containing more readily available phosphate increased with increasing application rate (18, 36.5 and 73 g per vine). Adding lime to the superphosphate increased P availability below the trickle outlet, but had little effect elsewhere. Placement of 73 g of P at the trickle outlet more than doubled total phosphate to between 20 and 40 cm below the surface. There was a significant linear relationship between P application rate and P concentration in vine leaves. The distribution of aluminium and manganese around the outlet did not change, and most of the calcium from the superphosphate was retained within 5 cm of the application point. Applying P reduced total iron in a region extending to at least 35–40 cm below the surface and to between 15 and 45 cm from the outlet. Reducing conditions in the soil during the irrigation cycle probably caused dissolution of iron which then moved into the profile in association with the P. Loss of iron would also have reduced the capacity of the soil to absorb phosphate, increasing its availability and enhancing its penetration to 25–35 cm. The results show placement of small quantities of superphosphate near the trickle outlet is a satisfactory alternative to broadcasting.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01054457
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