Reduced water consumption of dormant-seeded sugar beet in a semiarid climate
Dormant seeding refers to sowing spring crop species in fall. In the spring, seedlings start growing and the crop is established before spring sowing is normally completed. A dormant-seeded crop can establish quickly in spring and may escape from early season drought. A study was conducted to compare performances of dormant seeding with early and late spring seeding of sugar beet. Field experiments were carried out in the Khorasn province (NE of Iran) in 2002 and 2003 by growing a bolting resistant variety (BR1). The experiment consisted of a randomized complete block design with four replications. Dormant seeding was subjected to six irrigation treatments in addition to an early and late spring seeding. The first irrigation was applied 0, 10, 20, 30, 40 and 50 days after 60% soil moisture depletion. After harvest, root yield, sugar concentration, white sugar yield, and non-sugar components of the root samples were measured and analyzed. The results of the dormant seeding showed that root yield of sugar beet decreased with increasing delay of irrigation at the early stages of plant growth. High white sugar yield was obtained at dormant seeding without irrigation delay compared to the early seeding. No significant differences were observed for white sugar yield until three and five water withholdings in 2002 and 2003, respectively. In the second year of the experiment (2003), a relatively cold winter induced about 4.5% bolters and reduced plant population with 33% compared to the early and late spring sowing treatments. In general, white sugar yield produced in response to specific irrigation amounts for dormant-seeded treatments was higher compared to early and late seeding. However, dormant seeding cannot yet be recommended as a comprehensive agricultural practice for sugar beet and, therefore, further investigations are required to improve the quality of the beet by both agronomic techniques and new improved varieties.
Effect of different tillage methods on the nutritional status, yield and quality of sugar beets.
Optimal nutrition of sugar beets at critical growth stages is one of the crucial factors for the achievement of their highest yield potential. In the present study, it was presumed that reduced systems of sugar beet cultivation had no effect on the plants’ nutritional status at critical growth stages, on their yield or technological quality. In 2012-2013, two series of one-factorial field experiments with different beet crop husbandry were carried out in order to verify this hypothesis. The cultivation systems of sugar beet crops differed in the postharvest cultivation technology, mulch types and seedbed tillage. Conservation tillage systems were compared with the control treatment, which represented the conventional cultivation system with an application of manure and 35 cm deep autumn ploughing. The plant nutritional status assessment was carried out at two dates corresponding to the following growth stages: BBCH 16/17 (6-8 fully unfolded true leaves) and BBCH 39/40 (row closing). Regardless of the methods of tillage or the year of observation, the results showed that the plants at BBCH16/17 stage were well-nourished with macroelements but malnourished with microelements, mainly iron and zinc. The microelement deficiency in the plants was a result of adjusted soil reaction, which varied from slightly acidic to neutral. At the BBCH 39/40 stage, there was a decreasing trend in the content of leaf macronutrients in the no-tillage systems treatments compared to the conventional tillage with the ploughing depth to 35 cm and manure application. The reduced tillage systems in sugar beet cultivation did not result in either a yield decrease or a worse technological quality of roots. The experimental factor had no significant effect on the content of molassegenic compounds in beet roots. A decreasing trend was observed in the content of α-amino nitrogen and potassium when compared to the traditional cultivation system. The study showed that the choice of a cultivation technology is of secondary importance as long as the plant grows in optimal conditions resulting from an appropriate site selection.
Canola seed survival over winter in the field in Alaska.
Factors affecting seed survival of spring canola (Brassica campestris L. ’Tobin’), over two winters in the field at Delta Junction, Alaska were studied. In October, seeds were placed in polypropylene mesh envelopes and buried. The packets were exhumed the next spring and seed viability was determined. Factors studied included seed age, seed treatment, protection by snow-fence enclosures, burial depth, and spring retrieval date. During the first winter, survival of seeds near the soil surface until March was 65%, but many died during spring. During the second winter, seed viability in March was much lower than it had been in the previous March, but no significant mortality occurred during spring. Freshly harvested seeds generally survived better than seeds which had been stored for 1 yr. Seeds buried well below the soil surface and seeds placed inside snow-fence enclosures survived better than seeds placed near the soil surface outside enclosures. Results indicate that factors such as seed storage and prot...