Soil studies

Soil studies.

On treating soils with respect. Delving into the vineyard’s deeper-lying soil layers.

By Dr. agr. Andrew Lorand

Almost everything we do in agriculture depends directly on the soil. The health of the soil determines whether plants are able to develop healthily or not – and, consequently, human beings. For this reason Manincor has long placed great importance on a holistic and respectful approach to soil care methods, especially since our vineyards have been transformed along biodynamic cultivation lines. But what does that entail in concrete terms? // In principle the above statement on the importance of the soil is obvious: soils are the basis of life (especially with regard to life in the vineyard). Nevertheless the idea that a modern estate should be able to understand this substratum in all its multi-layered complexity and interrelationships can hardly be taken for granted. The most diverse expedients have been developed to come to grips with the vagaries of nature, mechanical as well as chemical. It is specifically expedients such as these which now hamper rather than favour a deeper understanding of these basic resources upon which life depends. They make the work of the grower deceptively easy but ultimately result in the qualities and forces of the soil being less than fully exploited. // Terroir. This French term has become naturalised into English, originally via the tasting expression ‘goût de terroir’ meaning ‘taste of the soil’ or ‘sense of place’. In winegrowing terms it refers to the local factors above and below ground which influence the character and quality of the wine via the grapes from which it is fermented: soil composition, diversity of flora, climate, geology, aspect, rainfall and myriad other factors which determine a wine’s ‘typicality’. – This concept has been decisive in forming the Manincor wine philosophy from the very beginning. // Of course it needs to be qualified to an extent, given that agriculture is a cultural activity. It modifies the natural surroundings and influences them. ‘Terroir’ is, itself, to a certain extent ‘made’. Even if we work fully respecting the environment, sensitively, carefully and conscientiously, we nevertheless exert an enormous influence on the soil, vine, grapes and wine. Whether through our work we invigorate the soil, improve the retention capacity of water and nutrients, or conserve the micro-organisms in the soil along with beneficial insects, everything we do affects the ecosystem. This means: terroir yes, though not as a passive concept but as a philosophy which stimulates everybody at Manincor to play an active part in supporting the natural cycles. We should really say: ‘terroir soigné’ or ‘well-kept soils’. // Humus. Our first consideration is the humus content of the soil. Humus is the dark, moist, rich layer reminiscent of forest soil which forms when plant and animal remains decompose and under the right conditions become transformed. It is organic matter though also a vital (and stable) layer rich in nutrients, moisture and home to many millions of micro-organisms. Hummus protects against extreme conditions. Its sponge-like quality results in a significant reduction in erosion. It can hold the equivalent of up to 90 % of its weight in moisture, increasing the soil’s (and the vine’s) capacity to withstand drought conditions. In hot weather the plant can draw water and nutrients from the humus when it needs them in stead of all at once and irregularly. // We can build up humus by (1) making compost, i.e., with manure, straw, hay, grass clippings, grape remains etc. – in order to produce fine humus, black with a scent of forest soil; (2) planting cover crops, cereals, flowers and herbs to loosen and vitalise the soil; (3) breaking open the soils deeply from time to time to reverse the effect of many years of their being packed hard through the use of heavy machinery; and (4) by spraying the soils with diverse teas of natural origins in order to additionally foster the natural humification process (decay and regeneration processes). // Soil fauna and flora. Billions of micro-organisms live and ‘work’ in the soils. The main group consists of bacteria, fungi and algae. Soil fauna in an average forest is thought to comprise 1000 to 1500 species. A single gram of soil (around one-fifth of a teaspoon) can contain over 100 million bacteria, one million actinomycetes and 100,000 hyphal fungi. We endeavour to develop a feeling for the way to foster the positive effects of these natural soil organisms in our vineyards, for they contribute substantially towards producing important nutrients for the flora. Furthermore, the formation of humus is impossible without the help of these microscopic friends. Composting, planting of cover crops and spraying the soils all combine to further the development of healthy soil ecology and consequently of these organisms. // We have begun planting our sites with alternating cover crops. They loosen up the soils with their roots and further the development of humus through the decomposition of plant remains. Beneficial insects are attracted by flowers and blossoms, and pests are thereby controlled. Cover vegetation protects against erosion and is a resource of nutrients which are also introduced into the soil via the roots. Therefore cover crops play an enormously important ecological role in vineyard floor management, brighten up our tractor rows and protect in equal measure both soils and vines. // Many insects have been branded as pests simply because they have got out of control through a lack of natural predators. It is well known that nature always strives to achieve equilibrium and under ideal conditions insects balance each other. Since the 1960s and the introduction of aggressive chemical pesticides many insects have become a scourge for wine growers worldwide because natural beneficial predators have frequently also been affected by the same compounds. We have achieved considerable success in striving to re-establish equilibrium among insect species through our targeted programme of planting cover crops which provide beneficial predatory insects with nutrition and shelter. // Last but not least our consistent drive towards employing ever more environmentally sustainable technology is worthy of mention. It is impossible for a modern wine estate to get by without a certain degree of mechanisation. As far as possible we use technology both in the vineyards and in the winery which has minimal environmental impact. For example we spray our vines with teas using an all-terrain quad, a type of four-wheeled motorbike which weights approximately 800 kilos compared with a standard tractor weighing 2 1/2 tonnes. The significantly lower weight vehicle has a much lighter impact on the soil, reducing compaction. // Respect. Bio-dynamics are important to us because they enable us to better understand the entire cycles and interrelationships in nature in our vineyards and in general. We learn to see our soils from a new perspective and how to treat them with care. The notion that our soils are actually alive has enriched us personally and increased our respect for the many ‘assistants’ in the soil. We learn to improve and protect the natural life in our estates through composting, growing cover crops, fostering beneficial predators and employing environmentally sustainable technologies. We can strengthen the natural defences and immune systems of our vines through the study of herbs and then using them to prepare teas. // These ‘soil studies’ are made more complex by the fact that each grape variety thrives best in its own specific environment – which includes the soil, flora and fauna, altitude, aspect, microclimate and husbandry. Therefore it requires enormous skill on the part of the winegrower to determine which grape variety is best suited to which individual site, or put differently, to select the ideal location to produce the type of wine the estate is striving to obtain, and to prepare and cultivate the soil accordingly.