POTATOHANDBOOK The E of The recently published Potato Handbook, written by Professor Anton Haverkort, covers in around six hundred pages all conceivable aspects that relate to the potato. Never before has a unique and complete reference book about the nutritious tuber been published, intended for everyone in the world who works with the potato in any way whatsoever and/or wants to know more about it. In order to establish a clear line in the format of the extensive manual, Haverkort has used the formula S ociety x P lant = P lanting material x E nvironment x C ultivation as a guideline. This brings together all the factors related to the potato. To give a first impression of all the information that the Potato Handbook has to offer, in a few consecutive editions of Potato World magazine you will find a very brief summary of each chapter in the column ‘Potato Handbook’. Last time Chapter 3 was discussed, this time we will publish two short and topical excerpts from chapter 4. Environment Potato handbook Crop of the future Anton J. Haverkort Environmental dependence on cultivation systems In technologically-advanced conditions, seed inspection and the input of chemicals contribute enormously to the yielding capacity of potato cultivation. In raindependent conditions where irrigation is Variable Insolation, kWh/ m²/day Clearness, 0-1 Temperature, °C I 1.73 0.55 Wind speed, m/s 3.45 Precipitation, mm 3 Wet days, d 5.6 II 2.77 0.60 3.57 5 5.5 III 3.99 0.59 -18.03 -14.11 -5.33 3.71 10 5.2 not common, potato yields are considerably higher in developed than in developing countries. Northern and central Europe (including Ukraine, Russia, the Czech Republic) northeast America/ Canada (Quebec, Neww Brunswick), and Asia (Korea, Japan) are generally dependent on rainfall and farmers use a lot of high quality fertilisers, crop protection chemicals and seed. In most sub-Saharan countries, with rain-dependent potato production, growers rarely intervene with irrigation, fertilisation or disease control. IV 4.92 0.54 5.77 4.20 21 6.3 All growth and development-defining factors at a glance. V 5.70 0.53 4.12 37 10.2 VI 5.85 0.51 3.72 78 12.7 VII 5.09 0.46 3.31 159 15.3 Here crops are subjected to the natural growing conditions as they occur. All over the world, farmers achieve the highest yields in places where they irrigate crops and also optimise other cultivation practices. The South Island of New Zealand and the north-western United States, such as the states of Idaho and Washington, are such regions. The environment in which a potato crop is grown represents the most important climatic growth-determining factors that growers cannot change, even if they wish to do so. These factors are temperature, precipitation, evapotranspiration, solar radiation and day length or photo period. The temperature determines the length of the heat and cold-free growing season between planting and harvesting. Solar radiation is responsible for the daily growth rate, and the length of the day determines the length of the growth cycle of the crop, i.e. the earliness or lateness. Shorter days lead to earlier tuber initiation and an earlier maturing crop. Without irrigation, the crop depends solely on the rainfall and the yields are more or less proportional to the ratio of available water: water requirement during the growing cycle between planting and harvesting. Growth and development as defining factors Growth-defining factors are the environmental factors that the grower cannot VIII 4.59 0.47 3.40 115 13.4 IX 3.98 0.52 3.68 60 10.7 X 2.83 0.52 13.64 19.49 21.77 20.09 13.94 5.32 3.88 23 7.3 XI 1.92 0.54 -5.44 3.64 8 5.8 XII 1.46 0.54 -14.82 3.54 5 6.3 16 Potato World 2019 • number 4 Pagina 15
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