Introduction, Allen V. Barker and David J. Pilbeam Essential Elements-Macronutrients Nitrogen, Allen V. Barker and Gretchen M. Bryson Phosphorus, Charles A. Sanchez Potassium, Konrad Mengel Calcium, David J. Pilbeam and Philip S. Morley Magnesium, Donald J. Merhaut Sulfur, Silvia Haneklaus, Elke Bloem, Ewald Schnug, Luit J. de Kok and Ineke Stulen Essential Elements-Micronutrients Boron, Umesh C. Gupta Chlorine, Joseph R. Heckman Copper, David E. Kopsel and Dean A. Kopsell Iron, Volker Roemheld and Miroslav Nikolic Manganese, Julia M. Humphries, James C.R. Stangoulis, and Robin D. Graham Molybdenum, Russell L. Hamlin Nickel, Patrick H. Brown Zinc, J. Benton Storey Beneficial Elements Aluminum, Susan C. Miyasaka, N.V. Hue, and Michael A. Dunn Cobalt, Geeta Talukder and Archana Sharmaz Selenium, Dean A. Kopsell and David E. Kopsell Silicon, George H. Snyder, Vladimir V. Matichenkov and Lawrence E. Datnoff Sodium, John Gorham Vanadium, David J Pilbeam and K Drihem Conclusion, Allen V. Barker and David J Pilbeam

Handbook of plant nutrition

Increasing concern about the need to provide high-quality food with minimum environmental impact has led to a new interest in crop rotations as a tool to maintain sustainable crop production. We re...

The role of crop rotations in determining soil structure and crop growth conditions

Potato roots are concentrated mostly in the plow layer up to 30 cm in soil depth. Some roots extend up to 100 cm depth and the total root length throughout the soil profile reaches about 10–20 km m−2 area. There are large differences in root mass (dry weight and length) in the plow layer between cultivars, breeding lines and wild relatives. The differences are generally stable across different environmental conditions, such as locations with different soil types, fertilizer rates and planting densities. Under favourable environmental conditions without severe shortage of water and nutrients, root mass differences between genotypes are related to maturity class: late genotypes continue root growth longer, and attain larger root mass and deeper rooting than early genotypes. Differences in root mass become clear at the start of flowering, much earlier than differences in shoot mass. Root mass is negatively correlated with early tuber bulking. However, root mass generally shows positive correlations with shoot mass and final tuber yield. Differences in root mass also exist amongst genotypes of the same maturity class. Using root mass in the plow layer and tuber yield as selection criteria, Konyu cultivars were bred in Japan. They showed significantly less reduction of leaf conductance and photosynthesis, leaf area and tuber yield than commercial cultivars under dry soil conditions. To assist breeding for root characters, new methods have been developed to assess the ability of roots to penetrate into hard soil layers using pots with paraffin-vaseline discs and the ability to absorb under low water potential in vitro. Physiological research on root characteristics contributed in the past, and will continue to do so in the future, to the development of new cultivars with high drought tolerance and to the improvement of irrigation practice.

Physiology of the Potato: New Insights into Root System and Repercussions for Crop Management

There is concern that modern cultivars and/or agronomic practices have resulted in reduced concentrations of mineral elements essential to human nutrition in edible crops. Increased yields are often associated with reduced concentrations of mineral elements in produce, and a number of recent studies have indicated that, when grown under identical conditions, the concentrations of several mineral elements are lower in genotypes yielding more grain or shoot biomass than in older, lower-yielding genotypes. Potato is a significant crop, grown worldwide, yet few studies have investigated whether increasing yields, through agronomy or breeding, affects the concentrations of mineral elements in tubers. This article examines the hypothesis that increasing yields, either by the application of mineral fertilizers and/or by growing higher-yielding varieties, leads to decreased concentrations of mineral elements in tubers. It reports that the application of fertilizers influences tuber elemental composition in a complex manner, presumably as a consequence of soil chemistry and interactions between mineral elements within the plant, that considerable variation exists between potato genotypes in the concentrations of mineral elements in their tubers, and that, like in other crops, higher-yielding genotypes occasionally have lower concentrations of some mineral elements in their edible tissues than lower-yielding genotypes.

/pdf/relationships-between-yield-and-mineral-concentrations-in-370vxpfuet.pdf

Relationships Between Yield and Mineral Concentrations in Potato Tubers

The challenge to produce more food for a rising global population on diminishing agricultural land is complicated by the effects of climate change on agricultural productivity. Although great progress has been made in crop improvement, so far most efforts have targeted above-ground traits. Roots are essential for plant adaptation and productivity, but are less studied due to the difficulty of observing them during the plant life cycle. Root system architecture, made up of structural features like root length, spread, number, and length of lateral roots, among others, exhibits great plasticity in response to environmental changes, and could be critical to developing crops with more efficient roots. Much of the research on root traits has thus far focused on the most common cereal crops and model plants. As cereal yields have reached their yield potential in some regions, understanding their root system may help overcome these plateaus. However, root and tuber crops such as potato, sweetpotato, cassava, and yam may hold more potential for providing food security in the future, and knowledge of their root system additionally focuses directly on the edible portion. Root-trait modeling for multiple stress scenarios, together with high-throughput phenotyping and genotyping techniques, robust databases, and data analytical pipelines, may provide a valuable base for a truly inclusive ‘green revolution’. In the current review, we discuss root system architecture with special reference to root and tuber crops, and how knowledge on genetics of root system architecture can be manipulated to improve their tolerance to abiotic stresses.

/pdf/root-system-architecture-and-abiotic-stress-tolerance-z20j7rdt1o.pdf

Root System Architecture and Abiotic Stress Tolerance: Current Knowledge in Root and Tuber Crops

In a 2-year field experiment with potatoes measurements were made at successive harvests of the dry-matter yield of leaves and tubers and of the length of the root system. Experimental treatments were 150 kg N/ha, control plots receiving no N, and each with or without irrigation. In both years the crop gave increased yields with fertilizer N and irrigation. Fertilizer N increased the weight of leaves and embryonic tubers as early as 6 weeks after planting; it had little effect on water use. Irrigation, which was applied only in the mid-season after water deficits of about 100 mm had developed, increased yields and water use. Highest uptake rates of N, P and K (g/m 2 /day) occurred 4–6 weeks after crop emergence when they reached 0·62, 0·071 and 0·88 respectively. At harvest the tubers contained (g/m 2 ) N: 8·7–21·1, P: 1·5–2·8 and K: 11·7–27·2. Uptake of all three nutrients was increased by application of N fertilizer and by irrigation. The average root length for all treatments throughout the season in both years was 12 km/m 2 of soil surface, with 84% in the top 30 cm of soil. From values of inflow of water and NO 3 –-N 1 calculated from depletion of successive 15 cm deep soil horizons, roots below 30 cm depth were substantially more active than those nearer the soil surface. During most of the growing season about half the nitrate reached the roots by mass flow. During crop growth NO 3 –-N concentration in the soil decreased to less than 10 μg/cm 3 to 30 cm depth. Summation of crop N and soil NO 3 ·N indicated net mineralization rates of soil N of between 0·07 and 0·17 g/W/day (average 012 g/m 2 /day). At final harvest the residue of N of about 9–10 g/m 2 on plots that received N fertilizer, included crop residues, NO 3 –·N left in the soil and leaf fall.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0021859600032470

A. F. Asfary

Papers

Growth, mineral nutrition and water use by potato crops