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.

Using the CROPGRO-Peanut Model to Quantify Yield Gaps of Peanut in the Guinean Savanna Zone of Ghana

Abstract: Peanut (Arachis hypogaea L.) yield in Ghana is limited by variable rainfall, low soil fertility, pests and diseases, and poor crop management. Field experiments were conducted during the 1997 and 1998 seasons at the Savanna Agricultural Research Station in Ghana to evaluate the CROPGRO-peanut model for its ability to simulate growth, yield, and soil water balance of a peanut crop and to quantify yield losses caused by biotic and abiotic factors. Two peanut cultivars, Chinese which matures in 90 d, and F-Mix which matures in 120 d, were grown rainfed on an Alfisol soil at three sowing dates between May and August in 1997 and at four dates in 1998. Soil water and crop growth were measured during the season and compared with crop model simulations to determine yield-limiting factors relative to potential yield. Growth and yield were highest for the early sowing dates and decreased progressively with later sowing, a trend attributed to leaf diseases. After incorporating functions for percentage leaf defoliation and percentage diseased leaf area, the model accurately simulated soil water content fluctuations, crop growth, and yield of cultivars for the sowing dates and seasons. Simulated yield losses caused by water deficits were small (averaging 5–10%) for early sowing dates (late May to mid-July) and increased with later sowing dates (20 and 70% for third and fourth sowings). Yield losses due to diseases and pests were simulated as a percentage of potential yield under water-limited environments and averaged 40%, also increasing with later sowing dates. Using 13 yr of weather data, simulated yields were reduced 10 to 20% by water deficit for the two earlier (normal) sowing dates, but more for the later sowing dates, while additional yield reductions were attributed to biotic stresses. We conclude that the CROPGRO-peanut model can be successfully used to quantify the yield potential and yield gaps associated with yield-reducing stresses and crop management for this region.

Organic no-tillage system effects on soybean, corn and irrigated tomato production and economic performance in Iowa, USA

Abstract: Novel technologies to reduce tillage in organic systems include a no-tillage roller/crimper for terminating cover crops prior to commercial crop planting. The objective of this experiment was to compare: (1) weed management and yield effects of organic tilled and no-tillage systems for corn (Zea mays L.), soybean [Glycine max (L.) Merr.] and irrigated tomato (Lycopersicon esculentum Mill.), using a roller/crimper and two cover crop combinations [hairy vetch/rye (Vicia villosa Roth/Secale cereale L.) and winter wheat/Austrian winter pea (Triticum vulgare L./Pisum sativum L. ssp. arvense (L.) Poir.)]; and (2) the economic performance of each system. Weed management ranged from fair to excellent in the organic no-tillage system for soybean and tomato crops, with the rye/hairy vetch mulch generally providing the most weed suppression. Corn suffered from low rainfall, competition from weeds and hairy vetch re-growth and, potentially, low soil nitrogen (N) from lack of supplemental fertilization and N immobilization during cover crop decomposition. No-tillage corn yields averaged 5618 and 634 kg ha−1 in 2006 and 2007, respectively, which was 42–92% lower than tilled corn. No-tillage soybeans in 2007 averaged 2793 kg ha−1 compared to 3170 kg ha−1 for tilled soybeans, although no-tillage yields were 48% of tilled yields in the dry year of 2006. Irrigated tomato yields averaged 40 t ha−1 in 2006 and 63 t ha−1 in 2007, with no statistical differences among tillage treatments. Economic analysis for the three crops revealed additional cover crop seed and management costs in the no-tillage system. Average organic corn returns to management were US$55,515 in the tilled system. Overall, the organic no-tillage soybean and irrigated tomato system demonstrated some promise for reducing tillage in organic systems, but until economic benefits from soil carbon enhancement can be included for no-tillage systems, soil improvements probably cannot offset the economic losses in no-tillage systems. Irrigation could improve the performance of the no-tillage system in dry years, especially if grain crops are rotated with a high-value irrigated tomato crop.

Seed production and longevity, seasonal emergence and phenology of wild radish (Raphanus raphanistrum L.).

Abstract: Experiments conducted from 1977 to 1979, at Rutherglen, north-eastern Victoria, investigated seed production, seed longevity, seasonal emergence and phenological development in wild radish (Raphanus raphanistrum L.), a weed of field crops. Seed production of wild radish reached 17 275 seeds/m2; seeds retained viability and germinated over a period of three years. The loss of viability was faster at the soil surface or at 1 cm depth than at 5 or 10 cm. Of 1000 wild radish seeds buried at 1 cm depth, 737 emerged after three years, compared with 367, 167 and 5 at 0.5 and 10 cm, respectively. Phenological development of wild radish was affected by time of planting, and the duration of the period from plant emergence to plant senescence ranged from 5 to 10 months. Temperature appeared to influence development up to flowering, but photoperiod affected the length of flowering. Plants emerging at any time during the year were able to flower and seed successfully. The implications of these findings for control programs are discussed.