Row Spacing and Nitrogen Fertilizer Effect on No‐Till Oat Production

By G. Lafond, W. May, C. Holzapfel. 2013

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Published in Agron. J. 105:1–10 (2013) doi:10.2134/agronj2012.0221 Available freely online through the author-supported open access option. Copyright © 2013 by the American Society of Agronomy, 5585 Guilford Road, Madison, WI 53711. 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. T global arable land base is estimated at 1.351 billion hectares which amounts to about 0.19 ha per person based on a population of 7 billion (World Fact Book, 2012). With the projected population increase to 9 billion by 2050, the per capita arable land amount will be 0.15 ha per person but in actual fact much less because an extra 2 billion people will require additional land for infrastructure. Also, the fact that 93 to 99% of the food consumed by humans comes from the land (Pimentel and Pimentel, 2000; Smil, 2000) implies that food production per unit area will have to increase. However, 45% of global arable soils are aff ected by degradation (Lal, 2007). Th e Food and Agriculture Organization endorses conservation agriculture as the key step to meeting the long-term global demand for food, feed, and fi ber for the projected 9 billion people by 2050 (Mackenzie, 2009). Irrigated land comprises about 7% of the total arable land area (World Fact Book, 2012) and land under irrigation will probably not increase to make up for short falls in food production because of competing fresh water needs by a growing population. Th erefore dry land farming systems will need to become more productive which means more water effi cient. Th e positive benefi ts of no-till production systems on crop production (Lafond et al., 1996, 2006b), economic performance (Gray et al., 1996; Zentner et al., 2002; Holm et al., 2006) and energy use effi ciency (Zentner et al., 2004) are well recognized in the Northern Great Plains. More recent no-till studies have demonstrated additional yield increases in spring wheat (Triticum aestivum L.) and canola (Brassica napus L.) as length of time under no-till increases (Lafond et al., 2011). Additional benefi ts from no-till can be obtained if crops are seeded into tall stubble. Increases in grain yield and water use effi ciency have been observed for spring wheat (Cutforth and McConkey, 1997), canola (Cutforth et al., 2006), fi eld pea (Pisum sativum L.), lentil (Lens culinaris Medik.), and chickpea (Cicer arietinum L.) (Cutforth et al., 2002) when seeding into >30 cm tall stubble. Tall stubble reduces water loss from evaporation at the soil surface and increases water available for transpiration, thereby explaining the greater reported crop water use effi ciencies and grain yields when compared to shorter or no stubble. Growing crops into tall stubble combined with long-term no-till represents an important approach to increasing crop production under semiarid dryland farming conditions. Given the reported benefi ts of no-till production systems, seeding into standing stubble and through surface residues has challenges. One solution to reduce plugging is to increase the row spacing. Th e common accepted knowledge is that narrow row spacing gives greater grain yields in cereal crops (Austenson and Larter, 1969; Briggs, 1975; Bauder, 1990; Chen et al., 2008). However, other studies have shown that it is possible to use wider spacing without experiencing grain yield losses. Research with no-till winter wheat showed equivalent yields between 18 and 36 cm under semiarid conditions (McCleod et al., 1996) and among 10-, 20-, and 30-cm row spacing under subhumid conditions (Lafond and Gan, 1999). With spring wheat, no diff erences in yield were observed among 10-, 20-, and 30-cm row spacing under no-till (Lafond, 1994; Bailey et al., 1998) and conventional till systems (Lafond and Derksen, 1996) and between 23 and 30 cm with no-till (Johnston and Stevenson, 2001) under subhumid conditions. No grain yield diff erences were observed among 10-, 20-, and 30-cm spacing in barley with no-till (Lafond, 1994; Bailey et al., 1998) and conventional till (Lafond and Derksen, 1996) under subhumid ABSTRACT

Subfields: Agronomy and Crop Science, Plant Science

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