Irrigated Small-Grain Residue Management Effects on Soil Chemical and Physical Properties and Nutrient Cycling

Abstract

Abstract:The effects of straw removal from irrigated fields cropped to wheat and barley on soil properties and nutrient cycling are a concern because of its potential impact on the sustainability of agricultural fields. The increasing demand of straw for animal bedding and the potential development of cellulosic ethanol production will likely increase the demand in the future. Previous reviews addressing changes in soil properties when crop residues are removed focused primarily on rain-fed systems. This article reviews published research assessing the effects of wheat and barley straw removal on soil organic carbon (SOC) and analyzes changes in nutrient cycling within irrigated wheat and barley production systems. The effects of straw removal on bulk density, saturated hydraulic conductivity, and other properties are reported from selected studies. Six studies compared SOC changes with time in irrigated systems in which wheat straw was removed or retained. These studies indicated that SOC either increased with time or remained constant when residues were removed. It is possible that bclowground biomass was supplying C to soils at a rate sufficient to maintain or, in some cases, slowly increase SOC with time. A separate research review calculated the minimum aboveground annual carbon inputs needed to maintain SOC levels from nine wheat system studies. Calculations of the minimum aboveground annual C source inputs needed to maintain SOC levels were from rain-fed systems and are some of the best information presently available for use in evaluating residue removal effects in irrigated systems. However, long-term studies are needed to obtain reliable data for diverse irrigated systems. Significant amounts of nutrients are removed from the soil/plant system when straw is removed. Producers will need to determine the cost of the nutrient removal from their systems to determine the value of the straw.Key words: Straw, residue, wheat, barley, small grain, soil organic carbon, nutrients, fertilizer (Soil Sci 2009:174: 303-311) R emoval of straw from grain production fields that have historically incorporated the residues with tillage have many interested parties concerned about the effects on soil properties and nutrient cycling. Several changes and potential changes in straw management have led to these concerns, including removal of straw from grain fields for animal bedding and feed, increased costs of fertilizers and fuel, and the potential development of cellulose-based ethanol production. Because of potential increases in biofuel demand, the ethanol industry will likely be a major cause of more residue removal from cropland. The immediate and long-term effects of removing aboveground crop residues from fields on crop productivity and sustainability are a concern. A series of policies have pushed for the increased production of biofuels, including the

Effects of Tillage and Residue Management on Soil Organic Carbon and Total Nitrogen in the North China Plain

“…Crop residue is important to soil nutrient cycling and soil fertility. Crop residue removal will cause the depletion of soil nutrition (such as N, P, K) which could decrease agronomic productivity and increase soil degradation (Blanco‐Canqui et al, 2009; Tarkalson et al, 2009). Lal (2009) estimated that residue contained 18 to 62 kg Mg −1 of agronomically important nutrients, depending on the type of residue produced and its nutrient content, which would be equivalent to 83% global fertilizer consumption in 2001.…”

Small Grain Residue Management Effects on Soil Organic Carbon: A Literature Review

“…Burning of residue was an attractive option because of the lower fuel costs. Results from their study did not show any diff erence in SOC among residue-management treatments in 1967in , 1973in , or 1980in (Tarkalson et al, 2009. Th e rate of SOC change in the 0-to 15-cm soil depth was positive and similar for all residue management treatments (average = 0.40 g kg -1 yr -1 ) (Table 4).…”

“…Th e quantity of aboveground biomass (minus grain) produced will infl uence SOC. Grain and aboveground biomass data from studies listed in Table 2 are not presented in this paper but are summarized in Tarkalson et al (2009). Bordovsky et al (1998Bordovsky et al ( , 1999) conducted a long-term (11 yr) study in the Texas Rolling Plains (North Central Texas) which have soils with poor structure, low organic matter, and low water holding capacity.…”

“…Changes in soil organic carbon (SOC) for residue management practices in irrigated wheat-based production systems for studies listed in Table 2. Actual soil organic C values from reported years are presented in Tarkalson et al (2009 RS-NT -3.50 RB-CT -0.98 † Cont. W = continuous wheat, SW DC = sorghum-wheat double crop, RR-CT = residue removed after harvest followed by conventional tillage, RI-CT = residue incorporated with conventional tillage, RR-RT = residue removed after harvest-reduced tillage, RS-RT = residue left on surface-reduced tillage, RB-CT = residue burned followed by conventional tillage, RS-NT = residue left on surface-no tillage.…”

The Stratification of Organic Carbon and Nitrogen in Top Soils as Affected by the Management of Organic and Conventional Rice Cultivation

“…The organic matter content varies according to the input of crop residues (Franzluebbers et al, 1998). Organic matter is also a source of nutrients (Bhandari et al, 2002;Magdoff and Es, 2009), including nitrogen (Tarkalson et al, 2009). Carbon and nitrogen are important for the condition of agricultural system (Gao et al, 2007), also C/N is important for plant growth (Yang et al, 2011).…”