Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 25, 1998
Publication Date: N/A
Interpretive Summary: A farmer may not have the same type of soil throughout the fields that he farms. One area may be sandy, which doesn't hold much water for the crop to use; another might have clay, which holds water but may not release it to the crop easily; or there may be silt, which holds water and releases it easily. With the control provided by Global Positioning System (GPS) technology, information about the best management strategies to deal with field variability would be invaluable. We grew corn in three different soil types under the same environmental conditions for three years. The soils were a sandy loam, a clay loam, and a silt loam. The corn received different amounts of water, ranging from applications less than the normal rainfall amount received during the growing season to applications slightly greater than the amount of water being used by the crop. The corn in the silt loam produced the highest grain yields under all water applications. If the corn in the clay loam received a lot of water, it would also produc high grain yields, but greatly reduced its yields when water was limited because it didn't use all the water stored in the soil. The corn in the sandy loam did not produce as high of grain yield as the crops in the other two soils, even when it received a lot of water. This may be due to the coarse sand structure which affected its rooting, and the low water holding capacity of the soil. This information will help farmers decide how to vary irrigation applications, enhance soil quality, and possibly modify fertilization to produce the highest yields.
Technical Abstract: Different soil types that occur within a farming unit present a management challenge to producers. We conducted three experiments (1994-96) to determine the influence of soil type and different irrigation levels on short season corn (Zea mays L.) water use and yield. Corn was planted in 0.75-m spaced rows with 4 plants (pl) m**-2 (1994, 1995) and 5.3 pl m**-2 (1996) at Bushland, TX. The crops were grown in lysimeters containing monolithic soil cores of silty clay loam, silt loam, and fine sandy loam that were located at a rain shelter facility. In 1994, the soils were at field capacity initially and received irrigation treatments equivalent to 75% or 25% of normal rainfall (200 mm) for the cropping period. In 1995, the soils contained about 280 mm plant available water (PAW) at planting, and received irrigation treatments equivalent to 100% to 60% of normal rainfall. In 1996, the soils contained about 250 mm PAW initially, and received supplemental weekly irrigation applications equivalent to 110, 80 50, and 20% of measured evapotranspiration (ET). The crops in the silt loam had significantly higher ET, grain yield, total biomass, and seed number in all three years compared with the crops in the two other soil types, for which grain and biomass yields were similar. The soil type/irrigation treatment interaction was significant for ET in 1996, because the crop in the clay loam extracted less water from the lower soil profile under reduced irrigation compared with the other two soils. Even under well-watered conditions, the crop in the sandy loam had 10% lower leaf area index compared with the other two soils. Soil type affected both water use and yield of short season corn.