Update on Using No-Till

Increased yields coupled with decreases in erosion, water runoff, and fuel use support the premise that growing soybeans in Mississippi with conservation tillage is more economically and environmentally sustainable than with any other tillage system. In fact, conservation tillage is the tillage approach that realistically supports environmentally sustainable soybean production in the Midsouth.

Information in a recent publication in Agronomy Journal (Vol. 104, 2012: pp. 530-541) entitled “Effects of No-Till as Influenced by Crop and Environmental Factors” provides additional information related to the use of no-till vs. tillage for crop production in the US and the Midsouth.

The objective of the research reported in this study was to evaluate the impacts on expected yields of sorghum, wheat, corn, cotton, and soybeans, and the downside risk, or the probability of having lower yields after converting from tillage (conventional tillage, strip tillage, ridge tillage, or mulch tillage) to no-till. The authors used data from 442 paired tillage experiments across the US.

The impacts were evaluated in relation to the year the conversion took place, the crop produced, annual rainfall, soil texture, and geographic location in the US.



The major findings and their relation to Midsouth soybean production are:

  • Lack of data for corn and sorghum in the lower Mississippi Delta (Midsouth) precludes any conclusions about using no-till vs. tillage for these two crops in the region. This is a research gap that deserves attention since these two crops are good candidates for rotation with soybeans in the Midsouth.

  • No-till performs better on well-drained soils, or conversely, does not perform as well on finely-textured or poorly-drained soils. An area not addressed in this study was that of using efficient surface drainage or raised beds to overcome some of the negative properties of fine-textured soils that will contribute to poor performance of no-till.

  • On coarse-textured or sandy soils that have a low water holding capacity that is especially problematic in dry years, no-till soybean provides no benefit. Growing no-till soybeans on sandy soils increases the probability of producing lower no-till than tillage yields. Thus, growing no-till soybeans on these soils is probably not risk-efficient.

  • Higher relative no-till yields in the southern US than in the northern US confirm that no-till is a favorable practice in the warmer climate of the region.

  • In regions where sufficient data were available, yields from no-till sorghum were better than yields from tillage sorghum in dry years vs. wet years. Also, the downside risks for no-till sorghum were smaller than the downside risks for no-till corn. This has implications for a Midsouth soybean/grain crop rotation in a dryland system vs. an irrigated system.

  • No-till tended to produce similar to greater yields than tillage for crops grown on loamy soils in the Midsouth. Again, a warmer climate and warmer soils appear to favor no-till on these soils.

  • Time after conversion from tillage to no-till improved the probability of higher no-till soybean and cotton yields in the Midsouth. Therefore, the downside risk from using no-till was reduced with time for these two crops. Again, this has important implications for a rotation system using these two crops in the Midsouth.

  • Increased annual rainfall negatively impacts no-till yields from high-residue crops such as corn and sorghum, but does not impact no-till yields from low-residue crops such as soybean and cotton.

  • Downside risks for no-till soybeans are less than the downside risks for no-till corn in the warmer climates of the southern US.

  • Favorable average yields and low predicted downside yield risk probability for no-till vs. tillage production of soybeans in the warmer southern US climate favors no-till when all factors are considered.

  • To repeat the above first point, the lack of data for no-till vs. tillage production of corn and sorghum in the lower Mississippi Delta (Midsouth) precludes any conclusions about using no-till vs. tillage for these two crops in the region. This is a research gap that deserves attention since these two crops are good candidates for rotation with soybeans in the Midsouth.

  • Key findings of this study strongly indicate that soil and climate factors influence no-till yields relative to tillage yields. This should be a major consideration when contemplating the decision to convert from a tillage to a no-till system of production in the Midsouth because of the full range of soil textures and sizable acreage of both flat and rolling topography in the region.


In my opinion, the above points highlight two major research needs in the Midsouth.

  • Studies that utilize both corn and sorghum rotated with soybeans in both dryland and irrigated no-till production systems, and

  • Studies conducted to determine the effect of the major soil series and topography differences in the Midsouth on no-till soybeans grown in both monocrop and rotated systems.


 

MSSOY Update

Check the Irrigation Category in the Production Resources section of this website for a recently posted MAFES Bulletin that Dr. Harry Hodges and I wrote in 1983.  The information in that bulletin is just as pertinent today as it was when we wrote it nearly 30 years ago.  You will find information on soil-water relations, how soil texture affects soil water retention and its availability for plant use, and how plants respond to water deficit.



Composed by Larry G. Heatherly, May 2012, larryheatherly@bellsouth.net

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