Sweet sorghum [SS; Sorghum bicolor (L.) Moench] is a potential biofuel crop for the Great Plains. Sweet sorghum was compared with corn [Zea mays (L.)] and grain sorghum for potential ethanol yield, energy use efficiency, and greenhouse gas (GHG) emissions at seven dryland site‐years in Nebraska. Seasonal rainfall ranged from approximately 340 to 660 mm. Soils were deep with medium texture at all site‐years. The effects of seeding rate, N rate, and cultivar on SS performance were evaluated. Sweet sorghum sugar yield was not affected by seeding rate and N application at six of seven site‐years, but yield was increased by 19% at one site‐year. Calculated ethanol yield and net energy yield were 33 and 21% more, respectively, with the grain crops compared with SS, but mean net energy yield of an earlier‐maturing SS cultivar was comparable with the grain crops. The mean ratio of energy produced in ethanol per total energy invested was 23% less for grain crops compared with SS. Mean life cycle GHG emissions were 53% and 66 to 69% less compared with gasoline for SS and grain crops, respectively. Very efficient use of the ethanol coproducts was assumed for the grain crops while SS bagasse was assumed to be returned to the field. At least one SS cultivar is competitive with grain crops for some biofuel criteria, but SS is not competitive with grain crops for total or net liquid transportation fuel produced per hectare.
rotation is also more effective in preventing deep leaching of nitrate N than continuous corn (Katupitiya et al., Reduced tillage, including no-till, and crop rotation are common 1997;Varvel and Peterson, 1990). Reduced stress from practices for corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] production in the Midwest. Benefits of no-till vary with latitude pests may be one of the reasons for improved yield with and cropping system. This study was conducted to evaluate the influ-crop rotations (Boosalis and Doupnik, 1976). ence of seasonal temperature and precipitation on the effects of pri-Reports on the effects of tillage and crop sequence mary tillage (plow, disk, chisel, subsoil, ridge-till, and no-till) and (rotation) on grain yield of both corn and soybean in the rotated and continuous corn and soybean production under rainfed Corn Belt vary considerably. Planting corn and soybean conditions over 16 yr in southeastern Nebraska. Corn and soybean without tillage results in increased yield in some enviproduced less grain with greater summer temperatures. Corn yield ronments but less in other environments. Several reincreased with less spring and more summer rainfall. Tillage and searchers have shown that the crop rotation benefit is rotation practices affected corn grain yield; but only rotation affected greater with no-till than with tillage (Griffith et al., 1988; soybean yield. Corn produced less grain with no-till than with plow. Lund et al., 1993). The summary statement that yieldThe tillage ϫ year interaction was significant for both crops; the yield advantage for plow was less during seasons with warmer springs.increase with no-till compared with tillage is less likely Soybean grain yield was less responsive to favorable environments for continuous corn compared with corn in rotation on with the chisel than other tillage treatments. Grain yield was greater poorly drained soils in northern latitudes is supported with rotation than continuous cropping for both corn (7.10 vs. 5.83 by results of tillage studies conducted on both poorly Mg ha Ϫ1 ) and soybean (2.57 vs. 2.35 Mg ha Ϫ1 ). The benefit of rotationand well-drained soils in Ohio (Dick et al., 1991) and in terms of grain yield was greatest for corn during years with cool on poorly drained soils in Illinois (McIsaac et al., 1990) springs. The benefit of rotation for soybean grain yield did not vary and Iowa (Brown et al., 1989). with weather conditions. Seasonal temperature and rainfall patternsOn well-drained soils, crop yields were less with noinfluenced the effects of tillage and rotation on corn yield. In contrast, NE, under natural rainfall conditions.
Efficient use of N by corn (Zea mays L.) is financially and environmentally important, and may be improved with higher plant density and reduced row spacing. Hypotheses were tested that irrigated corn yield in northeast Nebraska is increased by reducing row spacing from 0.76 m and increasing plant density above 61 800 plants ha 21 , and that grain yield response to applied N is greater with reduced row spacing and increased plant density. Field experiments were conducted for 3 yr comparing the effects 0.76-vs. 0.51-m row spacing, three plant densities, and four N rates on crop performance. The soil was a silty clay loam (mesic Cumulic Haplustoll). Nitrogen rates ranged from 0 to 252 kg N ha 21 . Plant N concentration and biomass and grain yield were not affected by plant density. Decreasing row spacing from 0.76 to 0.51 m resulted in 4% more grain yield. Grain yield response to applied N and N rates for optimum yield were not affected by row spacing. Nitrogen application resulted in mean increases of 22% more biomass production and 24% more grain yield. The N response function was linear in 1996, quadratic in 1997, and quadratic with decreased yields at the high N rate (252 kg N ha 21 ) in 1998. Grain yield was not affected by increasing plant density above 61 800 plants ha 21 but was greater with narrow row spacing. Yield response to applied N was similar for all planting arrangements. Optimal N rate cannot be better predicted by considering plant density and row spacing.
All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. N itrogen fertilizer will continue to be indispensible for meeting global food, feed, and fi ber needs. Voroney and Derry (2008) estimated that 340 million Mg yr −1 N is fi xed by natural means, including lightning and biological N fi xation, and 105 million Mg yr −1 is fi xed by human activities, including burning of fossil fuels and N fertilizer production, with N fi xation by human activities expected to continue to increase. Townsend and Howarth (2010) estimated the amount of N fi xed by human activities to be about 180 million Mg yr −1 , with most used as mineral fertilizer. Fertilizer N production has important environmental implications with an average of ~2.55 kg CO 2 emitted per kg fertilizer N fi xed and transported (Liska et al., 2009). Th e amount of N applied is associated with emission of N 2 O (IPCC-OECD, 1997) and N accumulation in sensitive aquatic, marine, and terrestrial ecosystems (Groffman, 2008; Malakoff , 1998). Th e challenge is to produce more grain to meet growing global needs with high NUE. Nitrogen use effi ciency, or grain production per unit of available N in the soil, is composed of the effi ciency of N uptake and of conversion of total UN to grain (Moll et al., 1982). Corn NUE has an impact on energy effi ciency, profi tability, water protection, and CO 2 and N 2 O emission. High N requirement for high yield cereal systems can lead to substantial N losses to the environment and low NUE with suboptimal management and yields well below the attainable yield potential (Cassman et al., 2002). Globally, 46% of the N input for crop production is from inorganic fertilizers with biological N fi xation, atmospheric deposition, animal manure, and crop residues being major sources (Smil, 1999). Th e main factor aff ecting NUE is N application rate with excess N supply causing reduced NUE (Meisinger et al., 2008). Effi cient N recovery with minimal losses of N to denitrifi cation, leaching, and volatilization is important to NUE which in turn will improve natural resource protection and profi tability (Raun and Schepers, 2008). Th e potential for N loss increases as inorganic N, and especially NO 3-N in the soil profi le increases (Cassman et al., 2002). Crop NUE is a function of effi ciency of recovery of indigenous soil nitrogen and applied nitrogen (RE), and internal effi ciency of nitrogen use within the plant (IE), specifi cally conversion of UN to grain. Uptake of indigenous soil N by the crop is important to NUE and includes uptake of N from RSN, net mineralization of N from soil organic matter (SOM) and crop residues, atmospheric N 2 fi xation, wet and dry deposition of atmospheric NH 4 , and NO 3-N in irrigation water. Considering RSN in formulating N recommendations for corn is common in subhumid corn production areas w...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.