Author
WILLIAMS, ALWYN - University Of Minnesota | |
Davis, Adam | |
EWING, PATRICK - University Of Minnesota | |
Forcella, Frank | |
GRANDY, STUART - University Of New Hampshire | |
KANE, DANIEL - Michigan State University | |
MORTENSEN, DAVID - Pennsylvania State University | |
SMITH, RICHARD - University Of New Hampshire | |
Spokas, Kurt | |
JORDAN, NICHOLAS - University Of Minnesota |
Submitted to: Soil and Tillage Research
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/14/2016 Publication Date: 3/24/2016 Citation: Williams, A., Davis, A.S., Ewing, P., Forcella, F., Grandy, S., Kane, D., Mortensen, D., Smith, R., Spokas, K.A., Jordan, N.R. 2016. A comparison of soil hydrothermal properties in zonal and uniform tillage systems across the northern U.S. corn belt. Soil and Tillage Research. 273:12-1. Interpretive Summary: Zonal tillage practices (e.g. ridge and strip till) aim to integrate the benefits of conventional tillage and no-till by separating management of crop rows and inter-rows to create contiguous yet complementary functional zones. We examined the effects of zonal versus uniform tillage on soil moisture and temperature over two growing seasons at four sites across the northern US Corn Belt. Ridge tillage (RT) was used as a model zonal system and chisel plough (CP) a model uniform system. In addition, we investigated whether differences in soil moisture and temperature between tillage systems could significantly affect weed seedling emergence in the period following crop planting. Soil moisture and temperature were similar in RT and CP row positions from time of planting to the V6 stage of corn development. uring this period, inter-row positions were significantly wetter and cooler in RT than CP. This led to small but significant reductions in predicted weed emergence in RT. Later in the season (V6 to harvest), RT rows and inter-rows were significantly warmer and moister than CP rows and inter-rows. The results demonstrate that zonal systems are capable of integrating the benefits of conventional tillage for early soil warming and drying with the moisture retention benefits of no-till. This may improve soil buffering capacity against climate variability, aid weed management and increase resource-use efficiency. Technical Abstract: A primary goal of tillage is to improve seedbed temperature and moisture (hydrothermal) conditions to maximise crop emergence and development. Uniform tillage practices (e.g. conventional tillage and no-till) apply management uniformly across a field. Conventional tillage attempts to optimise spring seedbed conditions and can increase soil warming and drying, but over time can deplete soil quality. In contrast, no-till aims to maintain or enhance soil quality, but on certain soils can produce suboptimal spring seedbed conditions by maintaining cool, wet soil. However, no-till can help conserve soil and improve soil moisture retention later in the season, minimising risk of summer drought. Zonal tillage practices (e.g. ridge and strip till) aim to integrate the benefits of conventional tillage and no-till by separating management of crop rows and inter-rows to create contiguous yet complementary functional zones. We examined the effects of zonal versus uniform tillage on soil hydrothermal conditions over two growing seasons at four sites across the northern US Corn Belt. Ridge tillage (RT) was used as a model zonal system and chisel plough (CP) a model uniform system. In addition, we investigated whether differences in hydrothermal properties between tillage systems could significantly impact weed seedling emergence in the period following crop planting, and whether zonal management could stimulate greater nitrogen (N) availability during the period of corn peak N demand. Continuous measurements of soil moisture and temperature were taken in row and inter-row positions in each treatment. Soil temperatures were used to estimate weed emergence using the WeedCast model. Soil cores collected shortly after corn six leaf stage (V6) were analysed for plant-available N and potentially mineralisable N (PMN). Hydrothermal properties were similar in RT and CP row positions from time of planting to V6. During this period, inter-row positions were significantly wetter and cooler (accumulated fewer growing degree days) in RT than CP. This translated into small but significant reductions in predicted weed emergence in RT. Later in the season (V6 to harvest), RT rows and inter-rows were significantly warmer and moister than CP rows and inter-rows. Plant-available N and PMN were significantly greater in RT rows compared with CP rows between V6 and tasselling, suggesting closer coupling of soil N turnover with crop requirements under zonal management. The results demonstrate that zonal systems are capable of integrating the soil hydrothermal benefits of conventional tillage with the moisture retention benefits of no-till. This may improve soil buffering capacity against climate variability and increase resource-use efficiency. |