Showing papers on "Sowing published in 2017"

Effects of Drought, Heat and Their Interaction on the Growth, Yield and Photosynthetic Function of Lentil (Lens culinaris Medikus) Genotypes Varying in Heat and Drought Sensitivity.

Abstract: Rising temperatures and drought stress limit the growth and production potential of lentil (Lens culinaris Medikus), particularly during reproductive growth and seed filling. The present study aimed to (i) investigate the individual and combined effects of heat and drought stress during seed filling, (ii) determine the response of lentil genotypes with contrasting heat and drought sensitivity, and (iii) assess any cross tolerance in contrasting genotypes. For this purpose, eight lentil genotypes (two drought-tolerant, two drought-sensitive, two heat-tolerant, two heat-sensitive) were either sown at the normal time (second week of November 2014), when the temperatures at the time of seed filling were below 30/20°C (day/night), or sown late (second week of February 2015) to impose heat stress (temperatures > 30/20°C (day/night) during reproducive growth and seed filling. Half of the pots in each sowing environment were fully watered throughout (100% field capacity) while the others had water withheld (50% of field capacity) from the start of seed filling to maturity. Both heat and drought, individually or in combination, damaged cell membranes, photosynthetic traits and water relations; the effects were more severe with the combined stress. RuBisCo and stomatal conductance increased with heat stress but decreased with drought and the combined stress. Leaf and seed sucrose decreased with each stress in conjunction with its biosynthetic enzyme, while its (sucrose) hydrolysis increased under heat and drought stress, but was inhibited due to combination of stresses. Starch increased under heat stress in leaves but decreased in seeds, but drastically declined in seeds under drought alone or in combination with heat stress. At the same time, starch hydrolysis in leaves and seeds increased resulting in an accumulation of reducing sugars. Heat stress inhibited yield traits (seed number and seed weight per plant) more than drought stress, while drought stress reduced individual seed weights more than heat stress. The combined stress severely inhibited yield traits with less effect on the drought- and heat-tolerant genotypes. Drought stress inhibited the biochemical processes of seed filling more than heat stress, and the combined stress had a highly detrimental effect. A partial cross tolerance was noticed in drought and heat-tolerant lentil genotypes against the two stresses.

Translocation of the neonicotinoid seed treatment clothianidin in maize

Abstract: Neonicotinoid seed treatments, typically clothianidin or thiamethoxam, are routinely applied to >80% of maize (corn) seed grown in North America where they are marketed as a targeted pesticide delivery system. Despite this widespread use, the amount of compound translocated into plant tissue from the initial seed treatment to provide protection has not been reported. Our two year field study compared concentrations of clothianidin seed treatments in maize to that of maize without neonicotinoid seed treatments and found neonicotinoids present in root tissues up to 34 days post planting. Plant-bound clothianidin concentrations followed an exponential decay pattern with initially high values followed by a rapid decrease within the first ~20 days post planting. A maximum of 1.34% of the initial seed treatment was successfully recovered from plant tissues in both study years and a maximum of 0.26% was recovered from root tissue. Our findings show neonicotinoid seed treatments may provide protection from some early season secondary maize pests. However, the proportion of the neonicotinoid seed treatment clothianidin translocated into plant tissues throughout the growing season is low overall and this observation may provide a mechanism to explain reports of inconsistent efficacy of this pest management approach and increasing detections of environmental neonicotinoids.

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.

Planting of neonicotinoid-treated maize poses risks for honey bees and other non-target organisms over a wide area without consistent crop yield benefit

Abstract: Summary Neonicotinoid insecticides are routinely used as seed treatments on most grain and oilseed crops in the USA, yet the extent and likelihood of spread of insecticide residues during planting has not previously been quantified Honey bees, Apis mellifera, are highly mobile and highly sensitive to neonicotinoid residues, presenting an opportunity to estimate non-target exposures to neonicotinoids in mobile insects We measured neonicotinoid dust drift during maize sowing and used sites of maize fields, apiary locations and honey bee foraging radii to estimate likelihood of forager exposure We performed a concurrent multi-year field assessment of the pest management benefits of neonicotinoid-treated maize Our results indicate that over 94% of honey bee foragers throughout the state of Indiana are at risk of exposure to varying levels of neonicotinoid insecticides, including lethal levels, during sowing of maize We documented no benefit of the insecticidal seed treatments for crop yield during the study Synthesis and applications We demonstrate movement of neonicotinoid residues well beyond planted fields occurs during maize sowing in Indiana Based on locations of maize fields and apiaries in the state, the likelihood of neonicotinoid exposure for foraging honey bees is high Other non-target organisms are also likely to encounter neonicotinoid residues; we conservatively estimate that deposition of neonicotinoid residues on non-target lands and waterways will occur on over 42% of the state of Indiana during the period of maize sowing However, we also demonstrate that the risk to pollinators and other non-target organisms may be rapidly and dramatically reduced without yield penalties, by aligning use rates of neonicotinoid insecticides with pest incidence

Analysis on Fungal Diversity in Rhizosphere Soil of Continuous Cropping Potato Subjected to Different Furrow-Ridge Mulching Managements.

Abstract: Knowledge about fungi diversity following different planting patterns could improve our understanding of soil processes and thus help us to develop sustainable management strategies. The objective of this study was to determine the impact of different furrow-ridge mulching techniques on fungal diversity in rhizosphere soil under continuous cropping system. The investigated treatments were: flat plot without mulch (CK); flat plot with mulch (T1); on-ridge planting with full mulch (T2); on-furrow planting with full mulch (T3); on-ridge planting with half mulch (T4); and on-furrow planting with half mulch (T5). NGS (Illumina) methods and ITS1 sequences were used in monitoring fungi diversity of the potato rhizosphere soil. The fungi diversity in the rhizosphere soil was ranked in the order T5 > T2 > T4 > T1 > CK at the early growth stage and T2 > T3 > T1 > T4 > CK at the late growth stage of potato. The fungal communities found in the rhizosphere soil were Ascomycota, Zygomycota, Basidiomycota, Chytridiomycota, and other unidentified fungal communities. Among the fungal community in the rhizosphere soil, Ascomycota was found to be dominant fungi population, with the highest percentage (89%) in the T5 soil whereas the T2 soils had the lowest percentage (67%). The Fusarium abundance in fully-mulched treated soils was higher than in half-mulched treated soil. The dominant genus in the T4 soil was Mortierella, whereas lower populations (1-2%) of Scutellinia, Cryphonectria, Acremonium, and Alternaria were found in that treatment. Among the eumycetes, the dominant fungal class in all treated soils was the Sordariomycetes, which ranged from 57 to 85% in T2 and T5 soils, respectively. The Fusarium percentages in half-mulched treated soils (T4 and T5) were 55 and 28% lower than that of complete mulched treated soils (T2 and T3), respectively. The cluster analysis results showed that, CK, T4, and T5 treated soils and T1, T2, and T3 treated soils had similarities in microbial compositions, respectively. Potato tuber yield was greater under the on-ridge planting with full mulch (T2) treated soil, followed by on-ridge planting with half-mulch (T4) treated soil. The rhizosphere soil under the on-ridge planting with full-mulch (T2) soil had the highest fungal diversity, suggesting that this management was the best environment for fungi, whereas the on-ridge planting with half-mulch (T4) soil had the minimum abundance of Fusarium.

Time Interval Between Cover Crop Termination and Planting Influences Corn Seedling Disease, Plant Growth, and Yield

Abstract: Experiments were established in a controlled-growth chamber and in the field to evaluate the effect of the length of time intervals between winter rye cover crop termination and corn planting on corn seedling disease, corn growth, and grain yield in 2014 and 2015. Rye termination dates ranged from 25 days before planting (DBP) to 2 days after planting (DAP) corn in the field and from 21 DBP to 1 DAP in controlled studies. Results were similar in both environments. In general, shorter intervals increased seedling disease and reduced corn emergence, shoot growth, and grain yield of corn following winter rye compared with corn planted 10 or more days after rye termination or without rye. Incidence of Pythium spp. increased with shorter intervals (less than 8 DBP); incidence of Fusarium spp. was not consistent between runs and experiments. In 2014, in the 1-DAP treatment, number of ears and grain yield were reduced (P = 0.05 and 0.02, respectively). In 2015, all termination intervals reduced plant population, number of ears, and yield (P = 0.01), with the 2-DBP treatment causing the biggest decrease. A 10- to 14-day interval between rye termination and corn planting should be followed to improve corn yield following a rye cover crop.

Precision farming for increased land and labour productivity in semi-arid West Africa. A review

Abstract: Farmers in the semi-arid regions of West Africa face challenges related to poor crop establishment, variable rainfall, low soil fertility and a shortage of labour at times of peak demand Farmers are generally low on resources Given these conditions, it is important to develop farming practices that make efficient use of the available resources and reduce risks Here, we review agricultural intensification in semi-arid West Africa using the principles of precision farming to assess the possibilities they offer The basic idea is to create a favourable micro-environment in the planting pocket and to ensure timely sowing and weeding In the context of precision farming in the semi-arid West Africa, this means (1) large seeds are selected, primed and treated with a mix of pesticides/fungicides Seed priming increases yields in the order of 20 to 30%, while seed treatment increases yields by 15% (2) Mineral fertilizers are applied; at doses as low as 03 g of fertilizer per pocket, they have been found to increase yields by half or more (3) Seeds and fertilizers are distributed accurately by means of a combined planter-weeder, which can be motorized (4) Mechanized sowing and weeding enable timely farm operations and reduce the workload (5) Water loss is prevented by using zai and stone bunds on soils with high run-off rates (6) Care is taken to make use of farm resources in a targeted and efficient way This can imply adjusting micro-doses of manure and fertilizer to crops (sorghum needs less than millet) and soil types, sequenced sowing of crops according to their vulnerability to delayed sowing and applying organic input to soils This paper is the first to review agricultural intensification in semi-arid West Africa within the context of precision farming It shows how a low-cost package for precision farming can be developed, which can help to increase land and labour productivity, and works with all the major field crops in the region

Can Growing Degree Days and Photoperiod Predict Spring Wheat Phenology

Abstract: Wheat (Triticum aestivum) production in the rainfed area of Pothwar Pakistan is extremely vulnerable to high temperature. The expected increase in temperature due to global warming should result in shorter crop life cycles, and thus lower biomass and grain yield. Two major factors control wheat phenological development: temperature and photoperiod. To evaluate wheat development in response to these factors, we conducted experiments that created diverse temperature and daylength conditions by adjusting the crop sowing time. The study was conducted during 2013-14 and 2014-15 using five spring wheat genotypes, four sowing times, at three sites under rainfed management in Pothwar, Pakistan. Wheat crops experienced more cold days with early sowing, but later sowing dates resulted in higher temperatures, especially from anthesis to maturity. These treatments produced large differences in phenology, biomass production, and yield. To investigate whether growing degree days (GDD) and photoperiod algorithms could predict wheat phenology under these changing conditions, GDD was calculated based on the method proposed by Wang and Engel while photoperiod followed the approach introduced in the APSIM crop growth model. GDD was calculated separately and in combination with photoperiod from germination to anthesis. For the grain filling period, only GDD was calculated. The observed and predicted number of days to anthesis and maturity were in good agreement, showing that the combination of GDD and photoperiod algorithms provided good estimations of spring wheat phenology under variable temperature and daylength conditions.

Effect of Organic Mulching on Soil Moisture, Yield, and Yield Contributing Components of Sesame (Sesamum indicum L.)

Abstract: Sesame (Sesamum indicum L.) is one of the chief foreign exchange earning oil crops in Ethiopia. However, its productivity remains low due to lack of appropriate agronomic practices. The aim of this research was to study the effect of organic mulches on sesame productivity and in situ moisture conservation. This experiment was carried out in Humera Agricultural Research Center, Western Tigray, during 2015 growing season. The experimental design was Randomized Complete Block Design with three replications. There were four types of organic mulches; rice straw, sorghum straw, sesame straw, and Sudan grass were compared with control. Sesame, variety Setit-1 was used in the experiment. The organic mulching rate of application was 10 ton ha−1 and this was applied evenly to the soil immediately after germination. Soil water content, phonological characteristics yield, and yield components of sesame were collected. The analyzed results indicated that organic mulching had significant effect on soil moisture content at 0–0.2 m, 0.21–0.4 m, and 0.41–0.6 m in every two-week interval after sowing and grain yield of sesame. Sesame straw conserved highest soil moisture content as compared with respective mulch material. The highest yield (664 kg ha−1) was recorded with Sudan grass while the lowest grain yield (190 kg ha−1) was recorded with no mulch.

Adapting to climate change for food security in the Rift Valley dry lands of Ethiopia: supplemental irrigation, plant density and sowing date

Abstract: Studies on climate impacts and related adaptation strategies are becoming increasingly important to counteract the negative impacts of climate change. In Ethiopia, climate change is likely to affect crop yields negatively and therefore food security. However, quantitative evidence is lacking about the ability of farm-level adaptation options to offset the negative impacts of climate change and to improve food security. The MarkSim Global Climate Model weather generator was used to generate projected daily rainfall and temperature data originally taken from the ECHAM5 general circulation model and ensemble mean of six models under high (A2) and low (B1) emission scenarios. The FAO AquaCrop model was validated and subsequently used to predict maize yields and explore three adaptation options: supplemental irrigation (SI), increasing plant density and changing sowing date. The maximum level of maize yield was obtained when the second level of supplemental irrigation (SI2), which is the application of irrigation water when the soil water depletion reached 75% of the total available water in the root zone, is combined with 30 000 plants/ha plant density. It was also found that SI has a marginal effect in good rainfall years but using 94–111 mm of SI can avoid total crop failure in drought years. Hence, SI is a promising option to bridge dry spells and improve food security in the Rift Valley dry lands of Ethiopia. Expected longer dry spells during the shorter rainy season (Belg) in the future are likely to further reduce maize yield. This predicted lower maize production is only partly compensated by the expected increase in CO2 concentration. However, shifting the sowing period of maize from the current Belg season (mostly April or May) to the first month of the longer rainy season (Kiremt) (June) can offset the predicted yield reduction. In general, the present study showed that climate change will occur and, without adaptation, will have negative effects. Use of SI and shifting sowing dates are viable options for adapting to the changes, stabilizing or increasing yield and therefore improving food security for the future.

CERES-Maize Model for Determining the Optimum Planting Dates of Early Maturing Maize Varieties in Northern Nigeria.

Abstract: Field trials were carried out in the Sudan Savannah of Nigeria to assess the usefulness of CERES-Maize crop model as a decision support tool for optimizing maize production through manipulation of plant dates. The calibration experiments comprised of twenty maize varieties planted during the dry and rainy seasons of 2014 and 2015 at Bayero University Kano and Audu Bako College of Agriculture Danbatta. The trials for model evaluation were conducted in 16 different farmer fields across the Sudan (Bunkure and Garun - Mallam) and Northern Guinea (Tudun-Wada and Lere) Savannas using two of the calibrated varieties under 4 different sowing dates. The model accurately predicted grain yield, harvest index, and biomass of both varieties with low RMSE values (below 5% of mean), high d-index (above 0.8) and high r-square (above 0.9) for the calibration trials. The time series data (tops weight, stem and leaf dry weights) were also predicted with high accuracy (% RMSEn above 70%, d-index above 0.88). Similar results were also observed for the evaluation trials, where all variables were simulated with high accuracies. Estimation efficiencies (EF) values above 0.8 were observed for all the evaluation parameters. Seasonal and sensitivity analyses on Typic Plinthiustalfs and Plinthic Kanhaplustults in the Sudan and Northern Guinea Savannas were conducted. Results showed that planting extra early maize varieties in late July and early maize in mid-June leads to production of highest grain yields in the Sudan Savanna. In the Northern Guinea Savanna planting extra-early maize in mid-July and early maize in late July produced the highest grain yields. Delaying planting in both Agro-ecologies until mid-August leads to lower yields. Delaying planting to mid-August led to grain yield reduction of 39.2% for extra early maize and 74.4% for early maize in the Sudan Savanna. In the Northern Guinea Savanna however, delaying planting to mid-August resulted in yield reduction of 66.9% and 94.3% for extra-early and early maize respectively.