ARS | Publication request: EFFECT OF MULCH, IRRIGATION, AND SOIL TYPE ON WATER USE AND YIELD OF MAIZE

Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 28, 1999
Publication Date: N/A

Interpretive Summary: Maintaining a good water supply for crop use is a very important challenge to farmers in semi-arid climates. Farmers must either add supplemental irrigation to the natural rainfall or, if irrigation is not available, reduce water losses such as evaporation from the soil. Tillage practices that maintain crop residues on the soil surface help reduce soil water evaporation, which can benefit high water use crops such as corn (Zea mays L.). We grew short season corn for two years in a rain shelter facility which allowed us to control the amount of rainfall the crop could receive. In the first year, the soil surface was covered with a flat mulch of 4 Mg ha**-1 and the crop received infrequent irrigations totaling either 50 mm or 150 mm. The second year, mulch mass on the surface was 6.7 Mg ha**-1 and the crop received more frequent irrigations totaling either 120 mm or 200 mm. Total water use was similar for the residue and non-residue surfaces each year. Mulch did not affect yield or yield components in 1994. Mulch increased grain yield by 17% and crop biomass yield by 19% in 1995. Mulched treatments also maintained significantly greater soil water compared with unmulched treatments during the vegetative growth stages in 1995 but not in 1994. During those growth stages, maximum air temperatures were above average in 1994 and below average in 1995. A complex interaction between mulch mass, irrigation frequency, and evaporative potential of the climate most likely determined the effectiveness of mulch in increasing crop yields.

Technical Abstract: Tillage practices that maintain crop residues on the soil surface help reduce soil water evaporation, which can benefit high water use crops such as corn (Zea mays L.). Management practices, climatic conditions, and soil type may affect how well a crop responds to surface residue. We grew short season corn for two years utilizing a rain shelter facility that has lysimeters containing monolithic cores of the Pullman, the Ulysses, and th Amarillo soil series. In 1994, treatments were a flat straw and coconut fiber mulch of 4 Mg ha**-1 with infrequent irrigations totaling 25% and 75% of normal rainfall (200 mm). The 1995 treatments were 6.7 Mg ha**-1 of mulch and more frequent irrigations totaling 100% and 60% of normal rainfall. Total water use was similar for the residue and non-residue surfaces each year. Mulch did not affect yield or yield components in 1994. Mulch increased grain yield by 17%, biomass yield by 19%, and grain water use efficiency (WUE) by 14% in 1995. Mulched treatments also maintained significantly greater soil water compared with unmulched treatments during the vegetative growth stages in 1995 but not in 1994. During those growth stages, maximum air temperatures were above average in 1994 and below average in 1995. Mulching increased grain WUE for the crop in the Pullman soil compared with the corn in the other two soils. A complex interaction between mulch mass, irrigation frequency, and evaporative potential of the climate most likely determined the effectiveness of mulch in increasing yield.