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.

Prospects for Brassica carinata as an oilseed crop in India.

Abstract: Twenty one strains of Brassica carinata were tested under irrigated, rainfed and saline soil conditions and five strains under late sowing conditions along with five varieties each of B. juncea, B. napus and B. campestris var. yellow sarson, brown sarson and toria. Brassica juncea had the largest seed and oil yield under irrigated conditions but B. carinata performed much better than other species under late sowing, rainfed and saline soil conditions.

Improving weed management and crop productivity in maize systems in Zimbabwe

Abstract: Keywords: Intercropping, narrow planting, precise fertilizer placement, radiation interception, leaf stripping, detasselling, Land Equivalent Ratio, maize, pumpkin, dry beans, reduced herbicide dosages In the tropics, weeds cause more crop losses and farmers spend more of their time weeding crops than in any other part of the world. Weeds form a major factor which contributes to the miserable quality of life of smallholder farmers, especially of women and children, in rural areas of sub-Saharan Africa . The effects of maize-pumpkin and maize-bean intercropping and, narrow row planting and precise basal fertilizer placement in monocrop maize, on crop and weed radiation interception (RI), crop yields, weed emergence, growth and fecundity were investigated in this study. The effects of leaf stripping (removal of the lowest 2-6 leaves) and detasselling maize at anthesis on the radiant environment and crop yields in a maize monocrop and maize-pumpkin and maize-bean intercrops were also studied to determine the impact of these interventions on yield of component crops. The aim of the studies was to generate technologies that could be integrated into the production practices of smallholder farmers to suppress weeds and alleviate the severe weeding burden faced by these farmers while ensuring high crop productivity. Maize-pumpkin and maize-bean intercropping reduced weed biomass by 50-66% when established at a density of 12,300 plants ha - 1 for pumpkins equivalent to 33% of the maize density (37,000 plants ha - 1 ), and 222,000 plants ha - 1 for beans. Lower densities of pumpkins than 33% of the maize density failed to reduce weed biomass more than that achieved by sole maize. Sole maize crops were weeded twice or thrice to achieve the same weed biomass as intercrops weeded once showed that intercropping could reduce the weeding requirements of maize by 33 to 67%. Maize grain yield was reduced by 20% in one out of four seasons in the first study on maize-pumpkin intercropping. Maize grain yield was not reduced in three seasons when the maize-pumpkin intercropping treatments were leaf stripped and/or detasselled and the trend of leaf stripping and detasselling alleviating the effects of companion crop competition on maize grain was shown in the maize-bean intercrop experiments as well. Intercrop productivity increased with leaf stripping and detasselling as a result of greater penetration of radiation to the companion crop and their effects of increasing dry matter distributed to the maize cob (indicated by 1000-grain weight, cob weight, and kernel weight cob - 1 ). Leaf stripping maize at anthesis focused on the removal of leaves that were beginning to senesce. If they would remain on the plant they would compete with the cob for assimilates as they senesce further, until necrosis. Detasselling is known to remove apical dominance and to increase radiation penetration to the middle leaves on the maize plant that produce most assimilates destined for the cob. Leaf stripping did not affect the ability of the intercrop to suppress weed growth and seed production. In maize monocrops more weed biomass and weed seeds were produced with leaf stripping and detasselling. Maize grain yield decreased with an increase in maize density from 30,000 plants ha - 1 to 36,000 and 42,000 plants ha - 1 and weed growth suppression increased with an increase in maize density in a semi arid location in Zimbabwe. Planting maize using narrow row (60 cm × 45 cm) and (75 cm × 36 cm) spatial arrangements increased radiation interception by maize plants by 16 to 24% and maize grain yields by 15 to 26% compared to wide row (90 cm × 30 cm) spatial arrangement commonly used by smallholder farmers. Weed biomass was reduced by 20 to 80%, dependent on weed species, in narrow row spatial arrangements compared to normal farmer planting patterns. The duration of the weed free period required to attain maximum yield increased from 6 weeks after emergence (WAE) in the 60 cm × 45 cm spatial arrangement to 9 WAE in the wider row spatial arrangements. It is, therefore, risky for smallholder farmers to increase maize density to suppress weeds as this will lead to maize grain yield reductions. The use of narrow rows proved to be a better option. Precise fertilizer placement (banding and spot placement) resulted in higher rates of early growth and by 4 WAE these treatments intercepted 20% more of the incoming radiation than a broadcast placement method. Weed emergence, growth and seed production was higher in the broadcast placement treatment as a result of weeds intercepting more incoming radiation and greater access to applied fertilizer nutrients. High fertilizer rates of 225 kg ha - 1 of a compound fertilizer (8% N, 14% K 2 O, 7 % P 2 O 5 ), reduced maize grain yield by 15% compared to 150 kg ha - 1 in a season characterized by drought. It was hypothesized that high concentrations of fertilizer around the root zone predisposed the maize plants to more severe effects of drought than lower fertilizer application rates. Reduced dosages of atrazine and nicosulfuron (25% of the Label Recommended Dosages, LRDs) protected maize from weeds as well as the full LRDs of each herbicide. The reduced dosages suppressed weed competition during the critical period for weed control in maize. However, the tolerant weed species Eleusine indica (L.) Gaertn., Setaria verticillata (L.) Beauv., Setaria homonyma (Stead.) Chiov. for atrazine and E. indica , Galinsoga parviflora Cav. and Portulaca oleracea L. for nicosulfuron, tended to escape the herbicide effects and survive as dosages were reduced. Reduced dosages of these herbicides have to be combined with hoe weeding or ox-cultivation to prevent the inadvertent selection of these species by the reduced dose strategy. Recalcitrant species recovering from tillage were shown to be more vulnerable to reduced herbicide toxicity in a greenhouse experiment. It was concluded that cultural weed management techniques that enhance radiation capture by the crop were effective in suppressing weed growth and seed production and increasing crop yields and should be incorporated into smallholder farmer's production practices in a systematic manner as part of Integrated Weed Management and cropping system design.

Quantification of Climate Warming and Crop Management Impacts on Cotton Phenology.

Abstract: Understanding the impact of the warming trend on phenological stages and phases of cotton (Gossypium hirsutum L.) in central and lower Punjab, Pakistan, may assist in optimizing crop management practices to enhance production. This study determined the influence of the thermal trend on cotton phenology from 1980–2015 in 15 selected locations. The results demonstrated that observed phenological stages including sowing (S), emergence (E), anthesis (A) and physiological maturity (M) occurred earlier by, on average, 5.35, 5.08, 2.87 and 1.12 days decade−1, respectively. Phenological phases, sowing anthesis (S-A), anthesis to maturity (A-M) and sowing to maturity (S-M) were reduced by, on average, 2.45, 1.76 and 4.23 days decade−1, respectively. Observed sowing, emergence, anthesis and maturity were negatively correlated with air temperature by, on average, −2.03, −1.93, −1.09 and −0.42 days °C−1, respectively. Observed sowing-anthesis, anthesis to maturity and sowing-maturity were also negatively correlated with temperature by, on average, −0.94, −0.67 and −1.61 days °C−1, respectively. Applying the cropping system model CSM-CROPGRO-Cotton model using a standard variety in all locations indicated that the model-predicted phenology accelerated more due to warming trends than field-observed phenology. However, 30.21% of the harmful influence of the thermal trend was compensated as a result of introducing new cotton cultivars with higher growing degree day (thermal time) requirements. Therefore, new cotton cultivars which have higher thermal times and are high temperature tolerant should be evolved.

Fitomassa e cobertura do solo de culturas de sucessão ao milho na Região do Cerrado

Abstract: The objective of this study was to evaluate the biomass production and soil cover by different crops after maize cultivated in conventional tillage and no-tillage, in Cerrado conditions. The biomass of black oat, sunnhep, canavalia, pigeonpea, mucuna, sunflower and millet was obtained when they showed 50% of flowering. Soil coverage was evalluated at 30 and 60 days after sequential crops sowing, in August (during dry season), in October (at the beginning of the rainy season) and after 15 and 45 days of maize crop sowing. Mucuna showed the highest soil coverage rate during its growing. The biomass produced by sunflower had no efficiency for soil coverage. No-tillage showed the highest productions of biomass by sequential crops, compared to the conventional tillage system.