Agronomy Journal
0002-1962
1435-0645
Mỹ
Cơ quản chủ quản: John Wiley & Sons Inc. , WILEY
Lĩnh vực:
Agronomy and Crop Science
Phân tích ảnh hưởng
Thông tin về tạp chí
After critical review and approval by the editorial board, AJ publishes articles reporting research findings in soil–plant relationships; crop science; soil science; biometry; crop, soil, pasture, and range management; crop, forage, and pasture production and utilization; turfgrass; agroclimatology; agronomic models; integrated pest management; integrated agricultural systems; and various aspects of entomology, weed science, animal science, plant pathology, and agricultural economics as applied to production agriculture. Notes are published about apparatus, observations, and experimental techniques. Observations usually are limited to studies and reports of unrepeatable phenomena or other unique circumstances. Review and interpretation papers are also published, subject to standard review. Contributions to the Forum section deal with current agronomic issues and questions in brief, thought-provoking form. Such papers are reviewed by the editor in consultation with the editorial board.
Các bài báo tiêu biểu
Periodic Flooding and Water Table Effects on Two Sugarcane Genotypes Sugarcane (Saccharum spp.) in Florida is increasingly exposed to periodic floods and high water tables for extended durations. We evaluated the effects of periodic flooding, followed by drainage, on morphological characteristics and cane and sugar yields of two sugarcane genotypes. From 2000–2002, experiments were conducted in lysimeters filled with Pahokee muck soil. Flooding was imposed for 7 d during five, nine, and nine 21‐d cycles in 2000, 2001, and 2002, respectively. Cycles commenced when sugarcane leaves covered the rows and were discontinued in mid‐October. Water table depths during the 14‐d drainage period of each cycle were 16, 33, or 50 cm. A fourth treatment was maintained continuously at a 50‐cm water table depth. Genotype CP 95‐1429 yields were not affected by water table or flooding. For CP 95‐1376 in periodic‐flooding treatments, lowering the water table in 1‐cm increments increased cane and sugar yields by 0.16 and 0.02 kg m−2 , respectively, in 2000 and 0.25 and 0.03 kg m−2 , respectively, in 2001. Water table depth during drainage did not affect CP 95‐1376 yields in 2002, perhaps because of a longer duration between planting and initial flooding in 2002. Each day of flooding reduced cane and sugar yields of CP 95‐1376 by 0.17 and 0.02 kg m−2 , respectively, in 2000 and by 0.21 and 0.03 kg m−2 , respectively, in 2002. Flooding might not have reduced yields of CP 95‐1429 because of its ability to form aerenchyma in the stalks before exposure to flooding. Such genotypes should be able to tolerate flooding for at least 1 wk.
Tập 96 Số 3 - Trang 832-838 - 2004
Sugarcane Responses to Water‐Table Depth and Periodic Flood Sugarcane (Saccharum spp.) is exposed to periodic floods and shallow water tables in Florida due to practices that reduce P discharge to the Everglades. This study examined the yields and juice quality of four sugarcane cultivars (CP 88‐1762, CP 89‐2143, CP 89‐2376, and CP 96‐1252) maintained at constant water‐table depths near 20 (20CWT) and 45 cm (45CWT) and with periodic summer flooding. Prescribed lysimeters were flooded for the first 7 d of five, five, and four 21‐d cycles in 2005 (plant‐cane crop), 2006 (first‐ratoon crop), and 2007 (second‐ratoon crop), respectively. These treatments generally remained flooded during the next 7 d while they received no irrigation or drainage, and were drained to 20 (20FWT) or 45 cm (45FWT) for the final 7 d of each cycle. Water treatment affected CRS only in the plant‐cane crop, where 45CWT had lower CRS than 20CWT, 20FWT, and 45FWT. Yields of cane and sucrose of CP 89‐2143 were least affected by water treatments. Reductions in cane and sucrose yields at a 20 compared with a 45 cm water‐table depth were common for the other three cultivars, but yields under the 20CWT vs. 20FWT or 45CWT vs. 45FWT treatments were generally similar. These results suggest that sugarcane roots function well in flood for up to 14 d, but do not grow well into saturated soil. This provides new options for sustaining high yields of sugarcane exposed to shallow water tables and floods; verification of root responses could enhance strategies to sustain yields while reducing P discharge.
Tập 102 Số 2 - Trang 372-380 - 2010
Analysis of Fallow‐Farming Systems in Semi‐Arid Africa Using a Model to Simulate the Hydrologic Budget<sup>1</sup> Abstract A model was developed to predict bare soil evaporation, crop water use, and the distribution of water in the soil. Comparisons with hydrologic budget data obtained in the field with bare soil, cowpeas (Vigna unguiculata (I.,) Walp.), and millet (Pennisetum typhoides (Burm. f.) S. and W.) indicated that the models performed adequately for the conditions and objectives of the study. Simulations of annual fallow, predicted that the amounts of water conserved in the soil would rapidly decrease with decreases in annual rainfall. Simulations of partial year fallow, achieved by weed removal after harvest of 90‐day or 75‐day millets were evaluated through an 8‐ year period of wet, dry, wet, and dry years having an average, monomodal rainfall of 502 mm. The simulations predicted that substantial quantities of water may be conserved in the soil by partial fallow during wetter years. More soil moisture would be conserved with the shorter cycle variety, but the longer cycle variety would have greater need for this moisture in this climatic zone during dry years, indicating a possible advantage of rotations involving short cycle, and long cycle crops. Shorter cycle varieties and partial fallow could also increase ground water recharge. The simulations predicted that present varieties may only use a small proportion of the moisture that may be stored below 150 cm depth in the soil by partial fallow, indicating a possible need for developing varieties with faster growing, deeper, root systems.
Tập 70 Số 5 - Trang 816-823 - 1978
Crop Rotation and Nitrogen Input Effects on Soil Fertility, Maize Mineral Nutrition, Yield, and Seed Composition Knowledge of complex relationships between soils, crops, and management practices is necessary to develop sustainable agricultural production systems. Objectives were to determine how maize (Zea mays L.) would respond to monoculture (C‐C), 2‐yr rotation (C‐S) with soybean [Glycine max (L.) Merr.], or 4‐yr rotation (C‐S‐W/A‐A) with soybean, wheat (Triticum aestivum L.), and alfalfa (Medicago sativa L.) under different N input levels. We evaluated N fertilizer input (8.5 or 5.3 Mg/ha yield goal, or no N) and crop rotation (C‐C, C‐S, or C‐S‐W/A‐A) treatment effects on soil minerals (N, P, K, S, Ca, Mg, Fe, Mn, and Zn) and their subsequent effect on shoot dry weight and mineral concentrations, grain yield, and grain composition (oil, starch, and mineral concentrations) using univariate and multivariate statistical tests. Soil under C‐S‐W/A‐A rotation had greater NO3 –N and less extractable P than other rotations. Significant input × rotation interactions revealed that shoot concentrations of N, Ca, and Mg were less while P, K, and Zn were greater at no N input for the C‐C rotation compared with other N input/rotation treatments. Increased soil NO3 –N, increased plant Ca concentration, and increased grain N and grain S concentrations were most important in differentiating C‐S‐W/A‐A rotation from C‐C and C‐S rotation treatments. No N input resulted in less yield and kernel N concentration within the C‐C and C‐S rotations but not C‐S‐W/A‐A. Thus, growing maize in extended rotations that include forage legumes may be a more sustainable practice than growing maize in either monoculture or 2‐yr rotation with soybean.
Tập 101 Số 4 - Trang 870-879 - 2009
Plant‐to‐Plant Variability in Corn Production Corn (Zea mays L.) grain yields are known to vary from plant to plant, but the extent of this variability across a range of environments has not been evaluated. This study was initiated to evaluate by‐plant corn grain yield variability over a range of production environments and to establish the relationships among mean grain yield, standard deviation, coefficient of variation, and yield range. A total of forty‐six 8‐ to 30‐m corn transects were harvested by plant in Argentina, Mexico, Iowa, Nebraska, Ohio, Virginia, and Oklahoma from 2002 to 2004. By‐plant corn grain yields were determined, and the average individual plant yields were calculated. Over all sites in all countries and states, plant‐to‐plant variation in corn grain yield averaged 2765 kg ha−1 (44.1 bu ac−1 ). At the sites with the highest average corn grain yield (11478 and 14383 kg ha−1 , Parana Argentina, and Phillips, NE), average plant‐to‐plant variation in yield was 4211 kg ha−1 (67 bu ac−1 ) and 2926 kg ha−1 (47 bu ac−1 ), respectively. As average grain yields increased, so did the standard deviation of the yields obtained within each row. Furthermore, the yield range (maximum corn grain yield minus the minimum corn grain yield per row) was found to increase with increasing yield level. Regardless of yield level, plant‐to‐plant variability in corn grain yield can be expected and averaged more than 2765 kg ha−1 over sites and years. Averaging yield over distances >0.5 m removed the extreme by‐plant variability, and thus, the scale for treating other factors affecting yield should be less than 0.5 m. Methods that homogenize corn plant stands and emergence may decrease plant‐to‐plant variation and could lead to increased grain yields.
Tập 97 Số 6 - Trang 1603-1611 - 2005
Seeding Rate Effects on Rough Rice Yield, Head Rice, and Total Milled Rice Abstract Without an adequate and uniform rice (Oryza sativa L.) stand, optimum rough rice yields are difficult to attain. Most seeding rate research has emphasized optimizing rough rice yields, with little consideration given to the effect of seeding rate on head rice (percentage of whole milled kernels) and total milled rice (percentage of whole milled kernels plus milled broken kernels). Thus, our objective was to assess the effect of seeding rate on head rice and total milled rice of two very early‐season rice cultivars (Millie and Adair) and two midseason rice cultivars (Katy and Kaybonnet). The experiment was conducted at the Pine Tree Experiment Station near Colt, AR, during 1992 and 1993. The cultivar (maturity group) × seeding rate interaction was significant for head rice and total milled rice, suggesting that, for head rice and total milled rice, the four cultivars responded differently to seeding rate. There was a linear decrease in head rice as seeding rate decreased for Millie, a quadratic decrease in head rice as seeding rate decreased for Adair, and a linear increase in head rice as seeding rate decreased for both Katy and Kaybonnet. We surmise that increased tillering and decreased kernel weights at the lower seeding rates decreased the head rice for Adair and Millie. Total milled rice decreased linearly with decreasing seeding rate only for Adair. When evaluating thin rice stands for potential performance or replanting, both cultivar and head rice and total milled rice losses should be considered.
Tập 88 Số 1 - Trang 82-84 - 1996
An Integrated Approach of Breeding and Maintaining an Elite Cultivar of Snap Bean This study is an attempt to describe a functional breeding and maintaining program of intraselection in a traditional snap bean (Phaseolus vulgaris L.) cultivar. The program was applied in three stages. The first thing examined was the existing genetic variability of source material for earliness and pod yield potential. Single‐plant frequency distributions with positive skewness for earliness showed that the frequency of unfavorable alleles was high. For total pod yield, distribution was found normal. Thus, the end‐target should be selection for early maturity, keeping, and stabilizing high yield. The seed shape uniformity was added as third criterion of selection. Secondly, combined pedigree intraselection, based on widely spaced single‐plant performance, for the prementioned traits was applied for three successive generations. The evaluation of the third‐generation families revealed progenies with high yield, earliness, and stability of performance. Thirdly, the end‐product of the program applied was to restore or even improve the cultivar. The evaluation of improved selections of fourth‐generation families and of the source material, at dense stand, showed that all families were the only ones producing high and stable early fresh pod harvest, even 53 d after planting (53.25–80 g/plant, compared with 0 g/plant of the control). The total pod yield of all the families was 219 to 276% superior compared with source material. Conclusively, the widely spaced single‐plant combined pedigree intraselection was proved reliable and effective in restoring or even improving the local cultivar of snap bean according to update demands.
Tập 92 Số 5 - Trang 1020-1026 - 2000
Furrow Seeding with Plastic Mulching Increases Stand Establishment and Lint Yield of Cotton in a Saline Field Uniform stand establishment is essential for profitable cotton (Gossypium hirsutum L.) production in saline fields. This study was conducted during 2003 and 2004 to determine if furrow‐bed seeding and plastic mulching improve stand establishment and cotton lint yield in a saline field. The experiment was arranged in a split‐plot design with seeding patterns (flat‐seeded and furrow‐seeded) as main plots and mulching (with or without plastic mulching) as subplots. The effects of seeding patterns, mulching, and their interactions on root‐zone salinity, soil temperature, stand establishment, and lint yield were monitored. Furrow seeding reduced the root‐zone salinity, while plastic mulching both reduced salinity and increased soil temperatures. As a result, furrow‐seeded cotton under plastic mulching increased stand establishment and lint yield by 103 and 25% in 2003, and 92 and 22% in 2004, compared with flat‐seeded cotton without mulching, respectively. Plastic mulching and furrow seeding also enhanced earliness as indicated by the percentage of the first two harvests. Physiological assay 30 d after seeding (DAS) showed that plastic mulching and furrow seeding substantially reduced Na+ accumulation both in root and leaf tissues, inhibited peroxidation of lipids, and improved leaf photosynthesis (Pn) and dry matter production. The overall results suggest that use of plastic mulching plus furrow‐bed seeding would be a suitable cultural practice for enhancing cotton production in saline soils.
Tập 100 Số 6 - Trang 1640-1646 - 2008
In Situ Nuclear Magnetic Resonance Imaging of Roots: Influence of Soil Type, Ferromagnetic Particle Content, and Soil Water<sup>1</sup> Abstract The paucity of root information combined with the difficulty in obtaining it make new approaches imperative. The observation of roots is essential to the understanding of plant growth and productivity. Proton (1 H) nuclear magnetic resonance (NMR) imaging offers a noninvasive method for the study of both root morphology and function in situ. Herein, NMR imaging of plant root systems was evaluated for southeastern U.S. agricultural soil series from 30 different sites, and eight common artificial soil substrates, as a function of soil type, ferromagnetic particle content, and soil water, using a 1.5‐tesla medical research NMR imaging system and Vicia faba L. seedlings grown in the soils. Roots of about 1 mm in diameter and 1‐mm‐diam capillaries of water were undetectable by NMR imaging and conventional NMR in soils with ferromagnetic particle contents of greater than about 4% by weight. Below 4%, ferromagnetic particle content did not correlate well with NMR image quality, but the presence or absence of NMR signals from water‐containing capillaries embedded in soil samples in a conventional NMR experiment reliably reflected soil suitability for NMR root imaging. Images of seedlings in four of the artificial soils (perlite, Ottawa sand, peatlite, and peat) and seven of the native soils (Wynnville fine sandy loam, Lucy loamy sand, Dothan sandy loam, Lakeland sand, Kinston loamy sand, Blanton loamy sand, and Eustis fine sandy loam) showed excellent spatial resolution and accurate reproduction of the root systems when they were extricated from the soils. However, the results from three of the artificial soils (perlite, Ottawa sand, and peat) were significantly compromised by background NMR signals that derived from soil water. In the seven native soils, soil water to near saturation was rendered essentially invisible by the NMR imaging sequence employed, thereby demonstrating excellent root‐to‐soil image contrast. Several root pathologies apparent in the images were identified. The results reveal that 1 H NMR imaging is a practical tool for the nondestructive, noninvasive investigation of plant root systems in many natural agricultural soils at virtually any stage of a water stress cycle.
Tập 79 Số 6 - Trang 957-965 - 1987
Nitrapyrin Impacts on Maize Yield and Nitrogen Use Efficiency with Spring‐Applied Nitrogen: Field Studies vs. Meta‐Analysis Comparison In maize (Zea mays L.), low N use efficiency (NUE) is observed when a high proportion of the fertilizer N is not recovered by the crop. Combining different management practices can improve maize NUE. The objectives were to assess the impacts of integrated N management practices on grain yield (GY), plant N uptake (PNU), and NUE (and its components, N recovery efficiency [NRE] and N internal efficiency [NIE]) from three maize site‐years (Indiana). The factors evaluated were: (i) N rate (0, 90, and 180 kg N ha−1 ), (ii) nitrapyrin (presence or absence), and (iii) N timing (at planting or V6 stage). Grain yields for the field research study ranged from 6.3 to 12.1 Mg ha−1 . The main results indicated: (i) PNU increased with N rates and with delayed N timing, (ii) the use of nitrapyrin increased NUE (∼ 17%), primarily via improving NRE (∼ 25%), and (iii) NUE increased by delaying the timing of N application. In addition to the field experiments, a meta‐analysis studying the effect of nitrapyrin on maize GY, PNU, and NUE was performed. Highlights from the meta‐analysis were: (i) positive impacts of nitrapyrin application on both GY and PNU, but (ii) those impacts were neither reflected in gains for NUE nor for NRE and NIE. The positive impacts of nitrapyrin on NUE (and components) found in the field research study were not consistent with the outcomes documented in the meta‐analysis. This emphasizes that the potential maize NUE benefits of nitrapyrin addition to spring N applications are not always realized.
Tập 106 Số 2 - Trang 753-760 - 2014