Interpretation and Use of Penetrometer Data to describe Soil Compaction in Vineyards.

A portable recording penetrometer was used for in situ field measurements of soil strengths in existing experiments with known profile characteristics. The data reported include effects of soil preparation methods, tractor wheel compaction and soil moisture on soil strength, as well as a case study in a productioll'vineyard. The penetrometer proved to be a useful instrument in identifying and quantifying soil compaction problems and the effects of soil management systems in vineyards. The data revealed that serious subsoil compaction can exist which may result in very poor vine performance and even death of the vines

Comparative Studies on Wine Grapes on Different Trellising Systems: I. Consumptive Water Use

A field trial involving four trellising systems viz.( a) Bush vines, (b) Perold,( c) Lengthened Perold, (d) 1,7 m Slanting trellis, showed differences of the utmost importance with regard to rooting densities, consumptive water use and the incidence of Botrytis rot. Soil physical conditions were dominant in determining root distribution patterns. The slanting trellis had significantlymore roots than the other systems. The consumptive water use, however, was not affected by amount of roots but mainly by the micro-climate. Contrary to expectation, the largest trellising system did not show the highest consumptive water use, but under the experimental conditions the bush vines had the fastest evapotranspiration rate. Average crop factors of 0,313; 0,260; 0,241 and 0,205 were found from bud burst to harvesting for bush vines, slanting trellis, lengthened Perold and Perold systems respectively. The high evapotranspiration rate of the bush vines is attributed to higher ambient air temperatures, more air movement as well as less shading of the soil surface than in the case of the slanting trellis.Crop factors varied according to soil moisture content, indicating the need to determine these parameters for specific irrigation frequencies. The low crop factors determined in this experiment emphasize the high water useefficiency of vineyards and stress the need to adopt existing crop factors to recent findings. Significant differences which cannot be attributed to micro-climate conditions occurred among trellising systems. Grape juice analyses, carried out throughout the growing season, indicated a relationship between total nitrogen and arginine status and Botrytis cinerea determined immediately prior to harvesting. More Botrytis rot was found at lower cropping levels. More investigations as to the relationship among the incidence of Botrytis rot, cropping level and nitrogen status of the plant are needed

Irrigation Systems - Their Role in Water Requirements and the Performance of Grapevines

Irrigation systems were evaluated in three major viticultural areas in South Africa as regards grapevine performance, must and wine quality and the saving of irrigation water. Furrow irrigation saved more than 50% on irrigation water compared to full surface flooding without affecting grape yield, pruning mass and must composition. The irrigation frequency, however, had to be adapted to the volume of soil wetted. Tricklers gave results comparable to that of furrows. In another viticultural region, tricklers saved 25-30% water and the vines yielded a more favourable sugar/acid ratio compared to micro-jets, sprinklers and flood irrigation. In a third trial on a compact silty soil, tricklers gave results similar to that of flooding. Grape yield was not affected by the irrigation system in any one of the trials. Crop factors to be used for irrigation planning and scheduling are presented

Comparative Studies on Wine Grapes on Different Trellising Systems: II. Micro-climatic Studies, Grape Composition and Wine Quality

In a field experiment the micro-climate and grape composition of four trellising systems viz., (a) Bush vines, ( b) Perold system, (c) Lengthened Perold, and (d) Slanting trellis were investigated and compared. Significantly more air movement, higher bunch and ambient air temperature as well as higher soil temperatures at 200 mm depth were recorded in the bush vines compared to the lengthened Perold and slanting trellis. Bunch temperature differences among trellising systems became most pronounced at 12h00 to 14h00

The Efficiency of Different Methods of Lime Application During Soil Preparation

The efficiency of a newly developed lime applicator, mounted on different soil preparation implements and in combination with different methods of lime application, was studied. The distribution and placement of lime were tracked by using fluorescent pigments mixed with the lime, and subsequent photography under UV light. It was found that lime, applied on the surface before the deep-ploughing operation, gave surprisingly good results in comparison .to blown-in lime, or conventional methods, but that the lime applicator in combination with a winged plough, needs modification. Double ploughing the soil seems to be an efficient method of ensuring proper mixing of lime and soil

Preliminary Studies on the Effect of a Permanent Cover Crop and Root Pruning on an Irrigated Colombar Vineyard

An experiment was conducted in the Olifantsrivier irrigation area to assess the effect of different cultivation treatments, such as clean cultivation, a permanent cover crop and of root pruning by means of deep ripping, on the growth and yield of a flood irrigated, ungrafted Colombar vineyard. The best vine performance was obtained with clean cultivation. Although a cover crop plus deep cultivation improved water infiltration, competition of the permanent cover crop seriously suppressed vine growth and yield, and also caused a notable decrease in the nitrogen status of the vines. There were indications that severe root pruning by means of deep ripping increased the negative effect of the permanent cover crop on vine performance. Clean cultivation remains an effective way of weed control provided there is no soil compaction hazard and it is economically feasible

The Effect of Conventional and Minimum Tillage Practices on some Soil Properties in a Dryland Vineyard

Preliminary results of a long-term viticultural tillage experiment comprising two groups of treatments, are reported. These groups are (i) a group of "minimum" tillage practices having received no mechanical soil tillage at all, and (ii) a group of "conventional" tillage treatments according to long-established local practices by disc-harrow. The "minimum" group consists of: (a) a permanent straw mulch cover, (b) chemical weed control, and ( c) a permanent cover of indigenous weeds frequently cut by a bush-cutter. The "conventional" group consists of: (a) deep and (b) shallow trench furrow systems, and (c) the locally customary "clean cultivation" system. A comprehensive investigation into the changes of sleeted soil properties after a period of eight years revealed significant differences between properties of the soil under minimum tillage (group (i)) and under clean cultivation (group (ii)). Soil parameters, such as pore volume distribution, compaction indices, activity of micro-organisms and availability of plant nutrients, were found to be more favourable in some minimum tillage treatments than on the conventionally tilled plots

The Effect of Cover Crop Management on Soil Conditions and Weed 6ontrol in a Colombar Vineyard in Oudtshoorn

Wimmera and vetch were used as vineyard cover crops in the hot and dry Klein Karoo region. The effect of different masses of dry cover crop residues used as mulches, as well as that of a growing crop, on soil moisture conservation was compared with the effect of a "bare soil" treatment. Data obtained comrrmed the common notion that in vineyards under dry-warm conditions any growing plants other than vines removed water from the soil which should have been available to the vines. Accumulative water consumption over the whole season on the mulched plots was 50 mm less than the total of 530 mm on plots with a growing cover crop. The mulch played an important role in moisture conservation, especially in the early and critical growth phase of the vines. The higher moisture content on the mulched plots was determined not only in the top layers, but also down to a depth of 120 cm. Under these climatic conditions a crop factor of0,50 for vineyards with growing cover crops is suggested. The implications of growing a cover crop in dry areas for organic matter production, weed control and moisture conservation are discussed. It was concluded that biological weed control by means of mulches, produced by growing cover crops in the vineyard, can replace pre-emergence herbicides

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The effect of conventional and minimum tillage practices on some soil properties in a dryland vineyard

CITATION: Van Huyssteen, L. & Weber, H. W. 1980. The effect of conventional and minimum tillage practices on some soil properties in a dryland vineyard. South African Journal of Enology & Viticulture, 1(1):35-45, doi:10.21548/1-1-2412.The original publication is available at http://www.journals.ac.za/index.php/sajevPreliminary results of a long-term viticultural tillage experiment comprising two groups of treatments, are reported. These groups are (i) a group of "minimum" tillage practices having received no mechanical soil tillage at all, and (ii) a group of "conventional" tillage treatments according to long-established local practices by disc-harrow. The "minimum" group consists of: (a) a permanent straw mulch cover, (b) chemical weed control, and ( c) a permanent cover of indigenous weeds frequently cut by a bush-cutter. The "conventional" group consists of: (a) deep and (b) shallow trench furrow systems, and (c) the locally customary "clean cultivation" system. A comprehensive investigation into the changes of sleeted soil properties after a period of eight years revealed significant differences between properties of the soil under minimum tillage (group (i)) and under clean cultivation (group (ii)). Soil parameters, such as pore volume distribution, compaction indices, activity of micro-organisms and availability of plant nutrients, were found to be more favourable in some minimum tillage treatments than on the conventionally tilled plots.http://www.journals.ac.za/index.php/sajev/article/view/2412Publisher's versio