Sowing

About: Sowing is a research topic. Over the lifetime, 33888 publications have been published within this topic receiving 273438 citations. The topic is also known as: seeding.

Winter cover crops to minimize nitrate losses in intensive lettuce production

Abstract: A 2-year study conducted in Salinas, California in 1989–91 showed that soil nitrate (NO3–N) concentrations were reduced by cover crops during a short winter fallow period and that this practice can be compatible with year-round vegetable crop production schedules by planting and incorporating cover crops directly on the beds into which the lettuce crop will be direct seeded in the early spring. Cover crops grown the first year were oilseed radish (Raphanus sativus cv. Renova), white senf mustard (Brassica hirta cv. Martigena), white mustard (Brassica alba), Phacelia (Phacelia tanacetifolia cv. Phaci), rye (Secale cereale cv. Merced) and annual ryegrass (Lolium multiflorum). Only phacelia and Merced rye were included in the second year. In both years, all of the cover crops depleted soil NO3-N and soil moisture relative to the fallow control. Estimates of cover crop root length, based on core sampling to 60 cm soil depth, averaged 18800 m/m2 after 17 weeks of growth the first year and 12500 m/m2 after 13 weeks of growth the second year. Above-ground dry matter production averaged 449 g/m2 (12·8 g N/m2) the first year and 161 g/m2 (61 g N/m2) during a shorter growing period and under the more adverse growing conditions of the second year. Following cover crop incorporation with a rotary tiller, soil ammonium (NH4-N), N03-N and net mineralizable N (anaerobic incubation) peaked after c. 1 week, then gradually declined for 1 month. Cover-cropped plots sustained higher net mineralizable N levels than the fallow control after incorporation. Nitrate concentrations after spring rains were lower in soils left fallow during winter. The subsequent lettuce crop was not affected by cover crop treatment.

Development and Testing of “On‐Farm” Seed Priming

Abstract: Poor germination and emergence of tropical crops under stressful conditions, such as adverse soil temperature, variable soil moisture, and hardening soils, are major obstacles to obtaining adequate stands of vigorous seedlings and hence reasonable yields in marginal areas of the less‐developed world. Representative examples of failures of common tropical crops to establish are reviewed and management techniques appropriate to resource‐poor farmers are discussed, including use of good quality seed, dry planting, timely sowing, control of sowing depth, transplanting of seedlings, and seed priming. It is concluded that successful establishment is associated with rapid emergence. Studies of “on‐farm” seed priming, whereby farmers can prime their own seeds in water, are reviewed in detail with special reference to work done in developing countries. A large body of in vitro, on‐station, and participatory on‐farm research shows that priming seeds of many important tropical crops in water, typically overnight, before sowing can increase the rate and extent of emergence, improve seedling vigor, advance flowering and maturity, and increase yield in most cases. In some instances, priming does not benefit farmers, but negative effects of priming are rare. The consequences of drying seeds after priming are discussed, as are opportunities for farmers to “add value” to their seeds by using priming to deliver nutrient supplements and increase resistance to pests and diseases. Given its low cost, on‐farm seed priming represents good insurance for risk‐averse, resource‐poor farmers.

Analysis of high yielding, early-planted soybean in Indiana.

Abstract: A trend toward early planting of soybean [Glycine max (L.) Merr.] in Indiana results in higher yield, but the limit to which a positive response to early planting occurs has not been evaluated. Our objective was to determine how early planting affects yield components and seed composition of indeterminate soybean planted in late March through early June in Indiana. Three cultivars (Pioneer brand 92M61, Becks brand 321NRR, and Becks brand 367NRR) were sown at six planting dates (late March through early June) in West Lafayette, IN, in 2006 and 2007. Across cultivars, yield in 2006 ranged between 4.24 to 4.43 Mg ha -1 at the planting dates from late March to mid-May, and decreased to 3.36 and 3.56 Mg ha -1 at later planting dates. In 2007, yield ranged from 4.21 to 4.44 Mg ha -1 for the 10 April, 30 April, and 9 May planting dates. Yield was reduced at the late March and early June plantings and ranged from 3.85 to 3.99 Mg ha -1 . Path analysis revealed that pods m -2 had the greatest impact on yield, but seed mass was also an important constituent. Mean oil concentration decreased approximately 12 g kg -1 as planting was delayed in both years. In 2006, average seed protein concentration varied by planting date. In 2007, mean protein concentration increased 14 g kg -1 as planting was delayed. Delaying planting until late May or early June altered seed composition slightly, but significantly reduced yield. Planting in April or early May is an effective management strategy to increase soybean yield in Indiana.

Selenium (Se) Seed Priming Induced Growth and Biochemical Changes in Wheat Under Water Deficit Conditions

Abstract: Insufficient stand establishment at early growth stages in wheat (Triticum aestivum L.) due to drought stress is a major problem that limits overall efficiency and yield of crop. Priming of seed is an effective method for raising seed performance and improving tolerance of crops to abiotic stresses especially drought. The seeds of two local wheat cultivars (Kohistan-97 and Pasban-90) were soaked in distilled water or sodium selenate solutions of 25, 50, 75, and 100 μM for 1/2 or 1 h at 25 °C and later re-dried to their original moisture levels before sowing. One-hour priming significantly increased root length stress tolerance index, dry matter stress tolerance index, and total biomass of seedlings; however, no significant effect of changing duration of Se seed priming was observed on plant height stress tolerance index and shoot/root ratio. Among cultivars, Kohistan-97 was found to be more responsive to Se seed treatment as 1 h priming at 100 μM significantly increased its total biomass by 43 % as compared to control treatment. Although biomass of seedlings was not affected with Se seed priming under normal conditions, but it increased significantly with increase in rates of Se under drought stress conditions. One-hour priming at 75 μM increased the total sugar content and total free amino acids in both wheat cultivars. A more significant decrease in soluble proteins of seedlings was observed by 1 h priming than 1/2 h priming under drought stress conditions.