soil moisture, nutrients, and weeds in no till

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Barley Yellow Dwarf Virus Effects on Barley Water and Nitrogen Use Efficiency

Soil moisture, nutrients, and weeds we have the No-Till situationOlga Walsh, PhD Cropping Systems Agronomist & Extension SpecialistParma Research & Extension Center, Parma, ID outline Tillage

Dust bowl and soil erosion

No-till:AdoptionSoil moistureNutrients (Carbon, Nitrogen)Weed control

***All processes are interconnected2tillage 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; 3To till or not to till?1850-1900s transition from animal power to mechanical1920s the Great DustBowl1950s beginning of conservation tillage1980s 50% of arable land in US is under conservation tillageMajor drives: to reduce soil erosion and degradation and to reduce energy inputs; Soil wind erosion

Wind erosion has removed the surface soil from this field, exposing the less fertile subsoilEroding soil filling furrows;Wheat plants blown out by a storm No-till acreage (2004)

% no-till for all crops, 2004 No-till adoption No-till:Apply herbicidePlantApply herbicideHarvest

Conventional till:Till with moldboard plow, burying up to 90% of residueTill with disk to smooth the groundTill with field cultivator to prepare the seedbed for plantingTill with harrows to smooth seedbedPlantApply herbicidesTill with row cultivatorHarvest

Conventional vs no-tillNo-till characteristics;

Excellent erosion control.Soil moisture conservation.Minimum fuel and labor costs.Builds soil structure and health.Increased dependence on herbicides.Slow soil warming on poorly drained soils.No-till systems influence:water infiltrationsoil moisturesoil temperaturenutrient distributionsoil aerationmicrobial populations and activity. Till vs no-till Soil moistureNo-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 effectReduces 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 profileRemoves 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 likelyto result in higher yields whendrought begins after goodearly root system establishment,even if relative no-till yields were disappointing in years with a very serious early droughtSm: conventional vs no-till No-till sm factsEvery 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.;

Residue and waterEffect 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 Organic carbonIs a fraction of the soil solid components, crucial for soil productivityOrganic matter participates in the cycle of several nutrients, like N and S, impacting in the soil chemical fertilityOrganic 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 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 carbonSoil organic matter in the 0 to 8 inch soil depth, 6 to 10 years after the conversion to no-till, MontanaNo-till systems maintain and build soil organic matterThe process requires nitrogen! 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 yearsAlso: crop residue left on the surface affects soil temperature and moisture content => affects N mineralization and efficiency of N fertilizer use. nitrogen accumulation

N management in no-tillMore 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 mineralizationOn-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 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 controlMethods:Experimental Site: Southern Agricultural Research Center, Huntley, MT; Year: 2013Target broadleaf weeds: Kochia, prickly lettuceTime 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 acPrecision weed controlSaved 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 SpecialistParma Research & Extension Crops & Soils blog: www.idcrops.blogspot.comTwitter: @IDCrops