Statistical Databases

Temperature and Crop Development

Agriculture in the southeastern USA can be highly productive (i.e., high photosynthetic fixation of atmospheric CO2) due to warm-moist climatic conditions. However, its impacts on greenhouse gas emissions and mitigation potential have not been thoroughly characterized. This paper is a review and synthesis of literature pertaining to soil organic C (SOC) sequestration and greenhouse gas emissions from agricultural activities in the southeastern USA. Conservation tillage is an effective strategy to regain some of the SOC lost following decades, and in some areas centuries, of intensive soil tillage and erosion. With conventional tillage (CT) as a baseline, SOC sequestration with no tillage (NT) was 0.42 � 0.46 Mg ha � 1 year � 1 (10 � 5 years). Combining cover cropping with NT enhanced SOC sequestration (0.53 � 0.45 Mg ha � 1 year � 1 ) compared with NT and no cover cropping (0.28 � 0.44 Mg ha � 1 year � 1 ). By increasing cropping system complexity, SOC could be increased by 0.22 Mg ha � 1 year � 1 , irrespective of tillage management. Taking into account an average C cost of producing and transporting N fertilizer, SOC sequestration could be optimized at 0.24 Mg ha � 1 year � 1 with application of 107 kg N ha � 1 year � 1 on Nresponsive crops, irrespective of tillage management. In longer-term studies (5‐21 years), poultry litter application led to SOC sequestration of 0.72 � 0.67 Mg ha � 1 year � 1 (17 � 15% of C applied). Land that was previously cropped and converted to forages sequestered SOC at a rate of 1.03 � 0.90 Mg ha � 1 year � 1 (15 � 17 years). Limited data suggest animal grazing increases SOC sequestration on upland pastures. By expanding research on SOC sequestration into more diverse pasture and manure application systems and gathering much needed data on methane and nitrous oxide fluxes under almost any agricultural operation in the region, a more complete analysis of greenhouse gas emissions and potential mitigation from agricultural management systems would be possible. This information will be necessary for developing appropriate technological and political solutions to increase agricultural sustainability and combat environmental degradation in the southeastern USA. # 2005 Elsevier B.V. All rights reserved.

Soil organic carbon sequestration and agricultural greenhouse gas emissions in the southeastern USA

A better understanding of how drought stress affects soybean [Glycine max (L.) Merr.] seed-yield determination would aid in the development of improved cultivars for the southeastern Coastal Plain and better production systems aimed at ameliorating the effects of drought stress. The objective of this field study was to examine the effects of drought stress on both soybean branch vegetative growth and the distribution of seed yield and yield components between the main stem and branches. Soybean was grown on an Eunola loamy sand in 1998 and 1999 with three levels of drought-stress treatment: (i) irrigation and no deep tillage, (ii) deep tillage but no irrigation, and (iii) no deep tillage or irrigation. Total seed yield, branch seed yield, and the percentage of total seed yield on the branches were highest with irrigation, followed by the in-row subsoiled/no deep tillage treatment and the no irrigation/no deep tillage treatment. Drought-stress treatment had no effect on mainstem seed yield. Branch seed number per square meter was highly correlated with branch seed yield (r = 0.994; P < 0.0001) and total seed yield (r = 0.989; P < 0.01) over both years and all levels of drought-stress treatment. A close relationship was found between branch seed number per square meter and branch dry weight at harvest maturity (r = 0.963; P < 0.05), final branch length per square meter (r = 0.994; P < 0.05), and final branch number per square meter (r = 0.995; P < 0.05). Most branch growth occurred between initial flowering and the beginning of seed fill. Less association was found between individual seed weight and seed yield from the mainstem or branch fractions. These data indicate that drought stress occurring between initial flowering and seed fill decreases total seed yield primarily by reducing branch vegetative growth, which reduces branch seed number and branch seed yield.

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Drought-Stress Effects on Branch and Mainstem Seed Yield and Yield Components of Determinate Soybean

Yield reductions from no-tillage cotton (Gossypium hirsutum L.) jeopardized adoption of conservation systems in the Tennessee Valley region of north Alabama in the early 1990s. We conducted a study from 1995 to 1999 on a Decatur silt loam (fine, kaolinitic, thermic Rhodic Paleudults) to develop a practical conservation tillage system with competitive yields for the region. Treatments included a factorial combination of fall ridging (ridged and nonridged) and fall non-inversion deep tillage (none, in-row subsoiling, paratilling), along with spring strip tillage and conventional tillage (fall chisel-spring disk). All treatments, except conventional tillage, were established with a rye (Secale cereale L.) cover crop. Tillage systems were evaluated for soil temperature, penetration resistance, a soil compaction index, soil water, plant population, and seed cotton yield. Paratilling reduced soil compaction index 29 and 31% compared with conventional tillage and no-tillage, respectively. Subsoiling reduced the compaction index 12 and 15% compared with conventional tillage and no-tillage, respectively. Soil water content was decreased with the fall paratilled and subsoiled conservation tillage systems, compared with conventional tillage and no-tillage, suggesting increased rooting. Fall non-inversion deep tillage, either paratilling or in-row subsoiling with a narrow-shanked subsoiler, resulted in the highest seed cotton yields; 16% greater than conventional tillage (2660 kg ha -1 ), and 10% greater than strict no-tillage (2810 kg ha -1 ) across a 4-yr duration. In this region, non-inversion deep tillage under the row in fall, coupled with a rye cover crop to produce adequate residue for moisture conservation and erosion control, is a highly competitive and practical conservation tillage system.

Conservation Tillage Systems for Cotton in the Tennessee Valley

Effects of sowing date and growth duration on growth and yield of groundnut in a Mediterranean-type environment in Turkey

Tillage and Residue Management Effects on Properties of an Ultisol and Double-Cropped Soybean Production1

Effect of Planting Method and Plant Population on Growth and Yield of Sesame (Sesamum indicum L.) in a Mediterranean Type of Environment

Optimizing plant density and seed size are the most important subjects of early potato production systems in mediterranean-type environments due to their effects on seed cost, plant development, yield and quality of the crop. The effects of different in-row spacing (20, 25, 30 and 35 cm) and seed size (small, medium and large) treatments on yield components and tuber yield of early potato were studied in Adana, where is situated in the east mediterranean region of Turkey, during 2006 and 2007 growing seasons. It was determined that closer spacing reduced tuber number per hill, average tuber weight, tuber yield per hill and percentages of large and medium size tubers. Total yields increased as increasing planting density up to 20 cm spacing. Planting larger seeds positively affected all growth and yield components in both years. Tuber yield per hectare was increased up to certain stem density and then started to decline at all seed sizes. However, the optimum stem density for the maximum tuber yield per hectare markedly differed depending on size of seed tubers. The optimum stem density increased with increasing seed size. Our findings indicated that size of seed tuber has further importance for growth of potato plant as well as competition aspect in early potato production in the mediterranean-type environments. Hence it was concluded that using larger tubers had an advantage for vigorous early growth and for obtain high tuber yield in early potato production in the mediterranean-type environments. Seed size should be considered during recommendation for planting density in potato production.  

	 

	Key words: Seed size, in-row spacing, early potato, competition.

Effects of seed size and in-row spacing on growth and yield of early potato in a mediterranean-type environment in Turkey.

Nine introductions of sweetpotato (Ipomoea batatas) of diverse origin and two local genotypes were evaluated for storage root yield and average storage root weight in four locations of Turkey (Diyarbakir and Sanliurfa representing semi‐arid environment and Adana and Hatay representing Mediterranean environment) in 2000 and 2001. The genotype × environment (GE) interaction was evaluated for two yield components (mean storage root weight and storage root yield) using the joint regression analysis and the Additive Main Effects and Multiplicative Interaction (AMMI) analysis. Stability of the genotypes over environments was estimated by using different stability parameters. GE interaction was found to be significant for both yield components, and genotype main effect contributed more than environment and GE interaction to total variability. Total storage root yield varied from 6.72 to 112.60 t ha−1, depending on genotypes and environments. The introduced genotypes produced a higher yield than local ge...

https://www.tandfonline.com/doi/pdf/10.1080/01140670709510172

Halis Arioglu

Papers

Effects of sowing date and growth duration on growth and yield of groundnut in a Mediterranean-type environment in Turkey

Tillage and Residue Management Effects on Properties of an Ultisol and Double-Cropped Soybean Production1

Effect of Planting Method and Plant Population on Growth and Yield of Sesame (Sesamum indicum L.) in a Mediterranean Type of Environment

Effects of seed size and in-row spacing on growth and yield of early potato in a mediterranean-type environment in Turkey.

Genotype x environment interaction and stability analysis of sweetpotato (Ipomoea batatas) genotypes