Soil moisture, nutrients, and weeds –

we have the No-Till situation

Olga Walsh, PhD

Cropping Systems Agronomist & Extension Specialist

Parma Research & Extension Center, Parma, ID

OUTLINE

• Tillage

• Dust bowl and soil erosion

• No-till:• Adoption• Soil moisture• Nutrients (Carbon, Nitrogen)• Weed control

***All processes are interconnected

TILLAGE

• Tillage = mechanical manipulation of soil for the purpose of enhancing the growth of crops. • Archaeologists discovered wooden plows which

were used in Egypt as early as 3000 B.C. • Preparing an improved environment for seed

germination was the objective of soil tillage for thousands of years.

Early wooden plow;

Egypt, 3000 BC

http://www.bae.uky.edu/lwells/BAE513/Lectures/Chap1new2.pdf; http://www.crustbuster.com/no-till-drills-and-planers

TO TILL OR NOT TO TILL?

• 1850-1900’s – transition from animal power to mechanical

• 1920’s – the Great DustBowl

• 1950’s – beginning of conservation tillage

• 1980’s – 50% of arable land in US is under conservation tillage

• Major drives: to reduce soil erosion and degradation and to reduce energy inputs

http://www.kshs.org/p/forces-of-nature-part-3/16690; http://capita.wustl.edu/namaerosol/Dust%20Bowl%20map.htm

SOIL WIND EROSION

Wind erosion has

removed the surface soil

from this field, exposing

the less fertile subsoil

Eroding soil filling furrows;

Wheat plants blown out by a storm

http://www.weru.ksu.edu/new_weru/multimedia/storms/storms1.html

NO-TILL ACREAGE (2004)

http://www.washingtonpost.com/blogs/wonkblog/files/2013/11/spread-of-no-till.png

% NO-TILL FOR ALL CROPS, 2004

http://water.usgs.gov/nawqa/home_maps/images/no-till.png

NO-TILL ADOPTION

http://www.ringingcedarsofrussia.org/anastasia/ringing-cedars-settlements.html

NO-TILL:

• Apply herbicide

• Plant

• Apply herbicide

• Harvest

CONVENTIONAL TILL:

• Till with moldboard plow, burying up to 90% of residue

• Till with disk to smooth the ground

• Till with field cultivator to prepare the seedbed for planting

• Till with harrows to smooth seedbed

• Plant

• Apply herbicides

• Till with row cultivator

• Harvest

CONVENTIONAL VS NO-TILL

NO-TILL CHARACTERISTICS

http://cropwatch.unl.edu/tillage/advdisadv; http://store.msuextension.org/publications/AgandNaturalResources/EB0182.pdf

• Excellent erosion control.

• Soil moisture conservation.

• Minimum fuel and labor costs.

costs.

• Builds soil structure and

health.

• Increased dependence on

herbicides.

• Slow soil warming on poorly

drained soils.

No-till systems influence:

• water infiltration

• soil moisture

• soil temperature

• nutrient distribution

• soil aeration

• microbial populations and activity.

TILL VS NO-TILL

http://semillanueva.org/saving-soils/

SOIL MOISTURE

• No-till farming can be considered as the most important tool to

prevent loss of soil moisture, especially during the drought

conditions (Barb Stewart, state agronomist with the USDA-

Natural Resources Conservation Service (NRCS) in Iowa)

• Soil tillage reduces soil moisture in several ways:

• Residue prevents soil crusting due to rain drop effect

• Reduces water infiltration by breaking up the large pores in the

soil structure, which act as large diameter pipelines for water to

soak into the soil profile

• Removes residue through tillage => soil erosion => eroded

particles of soil clog the smaller pores => prevent infiltration =>

cause soil runoff.

SOIL MOISTURE

Dry cloddy seedbeds severely restricted

soybean stand establishment in some

conventional tillage fields where no

substantial rain fell after planting (Columbia

City on June 21, 2012) (©2012 Purdue

Univ., T.J. Vyn) "

No-till soybean are more likely

to result in higher yields when

drought begins after good

early root system establishment,

even if relative no-till yields were

disappointing in years with a

very serious early drought

SM: CONVENTIONAL VS NO-TILL

http://soil5813.okstate.edu/Articles/NT%20in%20Argentina%20-%20A.Bianchini%20-%20V3.pdf

NO-TILL SM FACTS

• Every tillage pass can cause available plant moisture to drop .25 inch.

• Crop residue moderates soil temperatures, reducing soil moisture evaporation, especially in the top two inches.

• Corn stalks can help trap snow, which can add up to 2 inches of soil moisture after snow melt in the spring.

http://www.nrcs.usda.gov/wps/portal/nrcs/detail/ia/home/?cid=nrcs142p2_011847;

http://www.prairiefirenewspaper.com/files/201004-no-till-chloe.jpg

RESIDUE AND WATER

• Effect of stubble height on soil water

content change from fall to spring for a

4-foot depth in wheat-fallow at Mandan,

North Dakota (Kanwar, R.S., A. Kumar, and

D. Baker. 1998)

NUTRIENT LEACHING VS

RETENTION

http://semillanueva.org/wp-content/uploads/2013/09/Notill-infographic.png

ORGANIC CARBON

• Is a fraction of the soil solid components, crucial for soil productivity

• Organic matter participates in the cycle of several nutrients, like N and S, impacting in the soil chemical fertility

• Organic carbon enters the soil through the decomposition of plant and animal residues, root exudates, living and dead microorganisms, and soil biota.

• Indicator of soil quality

SOIL ORGANIC CARBON

http://www.cropscience.org.au/icsc2004/symposia/2/2/459_malikrk-5.gif

Organic carbon (%) in no-till and conventional tillage in 0-6 in layer

of soil, after 4 years of continuous no-till or continuous

conventional tillage wheat, India.

SOIL ORGANIC CARBON

• Soil organic matter

in the 0 to 8 inch soil depth,

6 to 10 years after the

conversion to no-till, Montana

• No-till systems maintain and build soil organic matter

• The process requires nitrogen!

http://store.msuextension.org/publications/AgandNaturalResources/EB0182.pdf

NITROGEN IN NO-TILL (N)

• To gain 1% SOM in the upper 6 inches of soil, it takes ~1,000 lb N/a above crop need; N needs to be added over time, likely decades.

• If no additional N added => lower crop yields due to inadequate N => less roots and stubble added to the soil => lower the amount of SOM accumulation, reducing N mineralization => reduced available N in future years

• Also: crop residue left on the surface affects soil temperature and moisture content => affects N mineralization and efficiency of N fertilizer use.

http://store.msuextension.org/publications/AgandNaturalResources/EB0182.pdf

NITROGEN ACCUMULATION

N MANAGEMENT IN NO-TILL

• More N (~40 lb N/a) is required due to lower N mineralization rates and greater potential for nutrient stratification.

• N rates need to be slightly increased for several years, depending on the field, to maximize yield and build SOM to save on N in the long-term. More soil water increases N availability due to increased N mineralization

• On-farm studies showed that long-term no-till (>6 years) should get 50 lb N/a credit, due to improved N availability and plant/microbe balance

http://store.msuextension.org/publications/AgandNaturalResources/EB0182.pdf

PRECISION WEED CONTROLBackground:

Cross and multiple herbicide-resistant weeds are evident in Montana farm fields.

Herbicide resistance management programs often use multiple modes of action, which involve additional cost.

WeedSeeker® sprayer could be a cost-effective technology for precision weed control in chem-fallow.

Operates on differential red and near infrared light absorption by a green plant relative to bare ground or residue cover and activates a solenoid switch above a spray nozzle.

In collaboration with Prashant Jha, Weed Scientist, MSU

PRECISION WEED CONTROL

Objectives:

• Compare weed control efficacy

between WeedSeeker® and

conventional broadcast sprayer in

post-harvest wheat stubble.

• Determine the herbicide savings

using WeedSeeker® sprayer vs.

conventional broadcast sprayer.

PRECISION WEED CONTROL

Methods:

• Experimental Site: Southern Agricultural Research Center, Huntley, MT; Year: 2013

• Target broadleaf weeds: Kochia, prickly lettuce

• Time of Application: Post-harvest wheat (15-30 cm-weed height)

• Sprayer: 5 foot, ATV-mounted, spray boom fitted with five WeedSeeker® sprayer units equipped with flat-fan nozzles spaced 12 in apart, to deliver 20 gal per ac

PRECISION WEED CONTROL

• Saved between 45 and 62 % in cost per ac

• WeedSeeker® technology is economically feasible to use high rates of an herbicide or herbicide tank-mixtures.

• Cost-effective control of weed escapes and herbicide-resistant weeds in chem-fallow/post-harvest wheat stubble.

• Greater environmental sustainability (less pesticide use per ac) at the whole farm level.

THE FULL PICTURE - BALANCE

ARGENTINA NO-TILL SUCCESS

- 96% less soil erosion.

- 66% less fuel use.

- Maintenance or improvement of the organic matter.

- Higher water use efficiency.

- Increase in soil fertility.

- Lower production costs.

- Higher production stability and higher yield potential.

NO-TILL, PART OF SUSTAINABLE AG

THANK YOU!

Olga Walsh

Cropping Systems Agronomist and Extension Specialist

Parma Research & Extension Centerowalsh@uidaho.edu

(208)722-6701ID Crops & Soils blog: www.idcrops.blogspot.com

Twitter: @IDCrops