No-Till and Conventional Tillage Fallow Winter Wheat Production Comparison in the Dryland Cropping Region of Eastern Washington

Esser, A.D.; Jones, R.

Journal of the NACAA
ISSN 2158-9429
Volume 6, Issue 1 - May, 2013

Editor:

No-Till and Conventional Tillage Fallow Winter Wheat Production Comparison in the Dryland Cropping Region of Eastern Washington

Esser, A.D., Extension Agronomist, Washington State University
Jones, R., Wheat Producer

ABSTRACT

A 2-year rotation of winter wheat (WW) (Triticum aestivum L.) on tillage-based summer fallow (SF) has been a standard practice for producers in the dryland (< 14 inch annual precipitation) cropping region of eastern Washington for more than 100 years. This practice has been profitable but it comes at a cost of soil loss through wind and water erosion. Producers have examined alternative methods including no-till farming systems for maintaining or increasing profitability and reducing soil erosion. A series of on-farm tests in a 12-to 14-inch precipitation zone were completed over a 5-year period examining WW established under three fallow treatments: (i) conventional, (ii) no-till early (planted at the same time as the conventional treatment), and (iii) no-till late(planting was delayed one month). Conventional tillage encompassed a glyphosate application, a chisel sweep, and two cultiweeding operations for fertilization and weed control and planting with deep furrow hoe drills. No-till included as many as four herbicide applications for weed control and seeding and fertilization with a no-till hoe drill. Conventional tillage increased seed zone water (0-8”) but no differences were detected between treatments in total water to a depth of 3 feet. Less soil compaction was detected in the no-till treatments at a depth of 10-16 inches compared to conventional tillage. There were differences in grain yield between conventional and no-till early, averaging 70 bu/acre. No-till late produced 20% less yield. Economic return above variable costs was similar to yield with no differences between conventional and no-till early and lower when seeding was delayed. This study shows that producers in the 12-to 14-inch precipitation zone of eastern Washington could convert to a soil-saving no-till early planting system with no economic hardship compared to their conventional tillage-based system.

INTRODUCTION

The main purpose of SF is to store a portion of the winter precipitation in the soil for early establishment of WW (Feng, et. al., 2011). Tillage during the spring of the fallow year breaks soil capillary continuity from the subsoil to the surface and creates a 4-6 inch deep dry soil mulch that helps conserve moisture in the seed zone. Conventional tillage based WW-SF often offers economic advantages and minimizes risks compared to no-till WW-SF (Zaikin, et al., 2007). However, it comes with a cost of elevated wind and water erosion and degrades soil quality, and also contributes to lower air quality (Saxton et al. 2000).

Producers have examined alternative methods to conventional tillage based SF, including no-till SF systems. Interest in no-till has increased because it provides optimum control of soil erosion and may potentially reduce fuel, labor and machinery costs (Schillinger and Bolton, 1993). However, farmers have not widely adopted this system because of increased evaporative loss of seed-zone moisture during the dry summer months reduces the potential to achieve adequate WW stand establishment needed to optimize yield (Schillinger and Young, 2004). The objective of this project was to better understand, both agronomically and economically, no-till SF-WW system in comparison to a conventional minimum tillage SF-WW system in the 12-to 14-inch annual precipitation zone of eastern Washington. A second objective was to determine what happens in no-till SF if seeding date or emergence is delayed because of insufficient seed zone moisture conditions.

MATERIAL AND METHODS

An on-farm test (OFT) was designed to examine WW production under three fallow treatments: (i) conventional tillage,(ii) no-till early, or seeded at the same time as the conventional treatment, and (iii)no-till late’, or planting was delayed one month. Conventional methods included a glyphosate application, a chisel sweep operation, two cultiweedings for fertilization and weed control, and seeding with deep furrow hoe drills (Table 1). No-till included up to four glyphosate herbicide applications as needed for weed control and seeding and fertilization with a no-till hoe drill with Anderson® paired row openers.Glyphosate was applied at 16 oz/ac (6 lb formulation). All three treatments were harrowed in mid-May following a glyphosate application. All three treatments were seeded with ‘Eltan’ WW at 60 lbs./ac in 2004-06 and ‘Bruehl’ WW at 60 lbs./ac in 2007. The trial was fertilized each year with 52 lbs. N/ac in the form of aqua NH₃and a dry fertilizer was applied with the seed at a rate of 8-10-0-7 lbs./ac. Table 1 outlines the treatments timeline and operations.

Table 1. Timeline and operations for winter wheat seeded under a conventional SF system and no-till SF seeded early and late in an on-farm test at near Wilbur, WA.

Roundup was applied at 16 oz/ac. All three treatments were seeded with 'Eltan' WW at 60lbs./ac in 2004-06 and 'Bruehl' WW at 60 lbs./ace in 2007. The trail was fertilzed each year with 52 lbs. N/ac in the form of aqua at the time of fertilization, and had dry fertilizer with the seed applied at a rate of 8-10-0-7 lbs./ac.

The OFT was located six miles northwest of Wilbur, Washington in a 12-14 inch annual precipitation zone (Figure 1). Two sites (SF and crop segments each year) were established on a Bagdad silt loam soil with at least two years of direct seed spring cropping history. Plots were approximately one acre in size, and seeded, maintained, and harvested by the producer. The OFT at both sites was set up using a randomized complete block design with five replications (15 acres at each site). All ANOVA and mean separation computations were carried out using Statistix 9 (Statistix 9, 2008). Treatment means were considered statistically different at P < 0.05.

Figure 1. Location and precipitation zone of the on-farm test sites located 6 miles northwest of Wilbur, Washington.

Gravimetric soil water samples were collected each year prior to seeding in mid-September in four-inch increments (seed zone) in the top foot and one-foot increments to a depth of three feet for total moisture. Soil compaction data was collected (4 samples/plot) in the spring of the year in the 2006 and 2007 WW crops with a Spectrum™ Field Scout SC900 Soil Compaction Meter in one inch increments to a depth of 18 inches. Additional data collected included grain yield, test weight, and protein.

Gross return was calculated using the free-on-board price at Ritzville Warehouse on September 15 each year along with the treatment yield and any grain quality premiums/discounts that apply. Variable operation and input costs were established using 2003 Extension enterprise budgets for Lincoln County, Washington (Platt, et al. 2003; Esser, et al. 2003) and adjusted for the appropriate operation and product applied. Land cost was a ¾-¼ crop share where the landowner pays property tax on the land and ¼ of the cost of fertilizer and receives ¼ of the crop. This is an important cost to separate out as landlords are impacted during the transition to a no-till farming system and is often a major limiting factor stated by growers as a limitation of adoption.

AGRONOMIC AND ECONOMIC PRODUCTION RESULTS

Over the four years, total average soil moisture was the same between treatments (Figure 2). Similar to other studies (Lindstrom, et al. 1974, Hammel et al. 1981, Wilkins et al. 2002), seed zone soil water (0-12 inches) was greater in the conventional tillage system with an average of 1.63 in/ft compared to only 1.49 in/ft in the no-till treatment (Figure 3). However, despite being less, seed moisture levels in no-till were adequate (>12%) each of the four years for satisfactory winter wheat stand establishment.

Figure 2. Average total soilmoisture to a depth of 3 feet in conventional and no-till SF systems prior to early seeding date in an on-farm test near Wilbur, WA.

Figure 3. Average seed zone soilmoisture to a depth of 12 inches in conventional and no-till SF systems prior to early seeding date in an on-farm test near Wilbur, WA.

Growers throughout the region have expressed concerns with potentially increasing soil compaction with no-till systems. Overall the no-till fallow treatments had 10% less soil compaction than the conventional treatment (Figure 4). Soil compaction was not different in the top 9 inches between conventional and no-till treatments, and no-till had significantly less compaction between 10-16 inches.

Figure 4. Soil compaction in conventional and no-till SF-WW systems inin an on-farm test near Wilbur, WA.

† Differences from 10 to 16 inches are significant (P< 0.05).

Yield between conventional and no-till early WW over the 4-years was not significantly different at 71 and 69 bu/ac (Table 2). In a case study in the dryland farming region of eastern Oregon similar results were found as no significant difference in yield were detected between no-till and conventional winter wheat systems (Williams, 2011). No-till late yielded 55 bu/ac and was significantly less than other two treatments.

T

Table 2. Grain yield of winter wheat produced under conventional SF, no-till SF seeded early and no-till SF seeded late in an on-farm test near Wilbur, WA.