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.

Nitrogen Fertility and Planting Date Effects on Lint Yield and Cry1Ac (Bt) Endotoxin Production

Abstract: Early planted cotton (Gossypium hirsutum L.) and varieties expressing the Bacillus thuringiensis (Bt) gene offer improved yield potential. It is not dear whether the current N recommendations remain appropriate for these new production options. The objectives were to determine how varying rates, application timing, and sources of N affected cotton dry matter partitioning, leaf chlorophyll (Chl) concentration, leaf Bt (CrylAc) endotoxin concentration, lint yield, and fiber quality. Four N treatments (112 kg N ha -1 anhydrous; 112 kg N ha -1 liquid; 112/56 kg N ha -1 split; 56/56 kg N ha -1 split) were applied to three cotton varieties (PM 1218BR, STV 4691B, and FM 832) planted on either an early or normal planting date from 2001 through 2004. The N response was consistent across planting dates and varieties for all data collected as shown by the lack of any interactions with these variables. Although N treatments had no effect on lint yield or any dry matter partitioning components, plants receiving the 112/56 kg N ha -1 split application treatment exhibited 14% greater leaf CrylAc concentration and a 3% greater leaf Chl concentration than the other N treatments. Early planted cotton had 5% greater leaf Chl concentration but a 12% lower leaf CrylAc concentration than normal planted cotton. Lower CrylAc levels may reflect enhanced remobilization of the leaf protein to feed the faster developing boll load of the early planted cotton. Early planted cotton yielded 10% more than normal planted cotton because it produced 9% more bolls. Current N recommendations for normal planted cotton also appear sufficient for early planted cotton.

Agricultural practices altered soybean seed protein, oil, fatty acids, sugars, and minerals in the Midsouth USA.

Abstract: Information on the effects of management practices on soybean seed composition is scarce. Therefore, the objective of this research was to investigate the effects of planting date (PD) and seeding rate (SR) on seed composition (protein, oil, fatty acids, and sugars) and seed minerals (B, P, and Fe) in soybean grown in two row-types (RT) on the Mississippi Delta region of the Midsouth USA. Two field experiments were conducted in 2009 and 2010 on Sharkey clay and Beulah fine sandy loam soil at Stoneville, MS, under irrigated conditions. Soybean were grown in 102 cm single-rows and 25 cm twin-rows in 102 cm centers at seeding rates of 20, 30, 40, and 50 seeds m–2. The results showed that in May and June planting, protein, glucose, P, and B concentrations increased with increased SR, but at the highest seeding rates (40 and 50 seeds m–2), the concentrations remained constant or declined. Palmitic, stearic, and linoleic acid concentrations were the least responsive to SR increases. Early planting resulted in higher oil, oleic acid, sucrose, B, and P on both single and twin-rows. Late planting resulted in higher protein and linolenic acid, but lower oleic acid and oil concentrations. The changes in seed constituents could be due to changes in environmental factors (drought and temperature), and nutrient accumulation in seeds and leaves. The increase of stachyose sugar in 2010 may be due to a drier year and high temperature in 2010 compared to 2009; suggesting the possible role of stachyose as an environmental stress compound. Our research demonstrated that PD, SR, and RT altered some seed constituents, but the level of alteration in each year dependent on environmental factors such as drought and temperature. This information benefits growers and breeders for considering agronomic practices to select for soybean seed nutritional qualities under drought and high heat conditions.

Influence of birds, stones and soil on the establishment of pasture juniper, juniperus communis, and red cedar, j. virginiana in new england pastures'

Abstract: In New England the pasture juniper, Juniperus communis var. depressa Pursh, usually occurs in pastures adjacent to stones, whereas the red cedar, J. virginiana var. crebra Fern. & Grisc., occurs either at stoneside or in interstonal areas. In non-stony pastures red cedar is often dominant and pasture juniper absent. Accordingly, attempts were made to determine the effects of the stoneside position. During their fall migrational flights, robins, Turdus migratorius Linnaeus, feed heavily on the berries of both pasture juniper and red cedar, and are effective disseminators of the seed. During feeding periods the robins come to rest on exposed field stones and the seed in their droppings becomes concentrated on the stones. The seeds are subsequently washed and planted into frost-heave cracks adjacent to the stones. The burial of pasture juniper seed assures their retention in a moist condition during the long, double stratification period required for their germination. Red cedar seed requires only a single cold stratification period, however, and this may be encountered even when seeds are planted on soil surfaces. Seedlings developing in the stoneside frost-heave crack are protected from trampling or grazing, and they receive extra moisture from their stone micro-watershed. Yet, all items in the system are not favorable. Seedling junipers make their best growth in compacted soils, like those away from stoneside, and although birds are effec- tive disseminators of their seed, the passage of seed through the birds gut inhibits germination.. Nevertheless the fortuitous planting of seed on exposed stones introduces pasture juniper and red cedar to a micro-habitat that more than compensates for reduced germination and slower growth.