Journal of the NACAA
ISSN 2158-9429
Volume 3, Issue 1 - July, 2010

Effect of Common ‘Mal-Practices’ in No-Till Corn Production Following Soybeans

  

 

   Extension professionals give advice to farmers based on university researched data. To develop appropriate research protocols, agents collect information from observations in the field, develop research criteria, do research, and provide feedback to farmers and consultants. This research emulated this model by designing a research protocol based on unintentional mistakes made by farmers in planting no-till corn after soybeans.

 

   Farmers have grouped ‘mastering no-till operations’ as one of the most difficult management problems (Musser et al., 1994). Usually on moderately to poorly drained soils, crop rotation, type of residue, and amount of residue can be significant factors determining the performance of no-till corn production systems. Corn following corn often produces lower yields than corn following soybean (Griffith et al., 1988). However, differences in yield can be intensified greatly when different planting practices, due to unintentional mistakes (herein called malpractices) play a role. Such yield differences can persist even when soil and drainage improvements are made (Dick et al., 1991). Malpractices may include placing seeds too shallow, little or no starter fertilizer, early planting in wet-cold soils, faulty or loose press wheels, and planting on compacted fields. These malpractices can affect emergence rates, early growth and health of corn plants, and yield.

 

   No-till production presents issues such as uneven seedling emergence resulting from planting early, planting under reduced tillage, compacted soils, shallow planting, and planting in wet or cloddy soils (Lauer et al., 1999, TeKrony et al., 1989). Still, other causes may include; soil crusting, herbicide injury, insect or disease damage, non-adjusted closing wheels, varying seed depth, different soil types within one field, and variation in topography (Beyaert et al., 2002, Carter et al., 1992). For compacted soils, reduced aeration and biotic activities contribute to reduced growth and vigor, resulting in yield loss (Hilton et al., 1994, Kasper et al., 1995, Ngunjiri and Siemens, 1995, Voorhees et al., 1989). Planting shallow may contribute to the rootless corn syndrome where corn is anchored in the soil by a single nodal root or by seminal roots (Scharf, 1999), while planting depth problems are usually associated with inadequate down pressure by the drill that creates poor seed-to-soil contact usually caused by sidewall compaction or coulters running too deep than the double disc openers. On the other hand, starter fertilizers (usually containing N and P) are used to increase early-season growth and final grain yield on soils with adequate P and K (Buah et al., 1999, Scharf, 1999). Starter fertilizers are especially important in cool soils usually associated with early planting in high-residue production systems where seedlings benefit from localized P availability and enrichment with N in the seedling root zone (Carter et al., 1992, Gordon et al., 1997).

 

   Our study was conducted to evaluate the effect on yield when common malpractices on planting corn are taken as limiting factors in no-till corn production following soybeans. We investigated the effect of these factors on final stand count, crop development, and yield components and compared their performance to that of conventional tillage and no-till production. Understanding how these malpractices affect yield should aid in developing sets of criterion for gauging yield losses and the establishment of a checklist system that ensures that planting mistakes are not routinely committed.

 

 

   Studies were conducted in 2000 and 2001 on a moderately well drained Rockfield silt loam (Typic, Argiaqualf) located at the Purdue University Agronomy Research Farm in Indiana (40°, 28’,05’’N and 86°, 59’, 11’’W). The site was continuously cropped to alternating no-till corn and soybean for the last 17 years. The study consisted of corn (Becks 5402) planted in three blocks in a randomized block design of eight treatments and three replications for a total of 24 plots with each plot measuring 10 by 80 feet. The treatments were based on observed planting practices and malpractices for corn and were:

 

(i)                 Conventional tillage (CT)

(ii)               Normal no-till corn planting (NT)

(iii)             Planting on wet-cold soils < 50^oF (TW)

(iv)             Light pressure on press wheels (LPW)

(v)               No starter fertilizer (NS)

(vi)             Double starter fertilizer (DS)

(vii)           Planting depth too shallow (TS)

(viii)         Compacted soil surface (CS).

 

   The TW treatments were planted on May 12, 2000 (wet year - Figure 1) and April 13, 2001 (dry year – Figure 1). The rest of the treatments were planted on May 23, 2000 and April 27, 2001. Target planting depth was two inches, and one inch for TS treatment. Other than the NS treatment, starter fertilizer 19-17-0 was applied to all treatments at the rate of 28 lb N/acre. Side-dressing with urea ammonium nitrate (UAN) was done at 8 weeks to all treatments.

 

   Corn was planted at 30,000 seeds/acre on 30-inch wide row spacing. Precipitation was monitored at the Agronomy Research Center about half a mile from the study site. Data were recorded on final stand count for corn plants, weekly plant heights until silking, and final corn yields (hand harvested) adjusted to 15.5% moisture content. All data were subject to analysis of variance using SAS (SAS, 1997). A Fisher’s protected LSD test procedure was used for mean separations at P<0.05.

 

 

 

   The year 2000 was generally wet but 2001 was drier with respect to the growing season (Figure 1). Final plant stand count for 2000 and 2001 are shown on Table 1. In 2000, there were no significant differences on final stand count for all treatments in the study. Abundant moisture and better soybean residue seedbed could have contributed to this outcome. Lower soil temperatures at planting have been found not to delay seed germination but do reduce rate of emergence compared to conventional tillage (Beyaert et al., 2002). These results suggest that making planting mistakes in a year when the season stays wet does not carry heavy penalties in terms of total stand count.

 

 

 

Figure 1. Long-term monthly rainfall average (30-year average) and rainfall amounts for 2000 and 2001 at Purdue agronomy research farm in West Lafayette, Indiana.

 

Table 1. Final plant stand count (x1000) for eight planting practices for no-till corn on soybean residue in the study period 2000 and 2001 at West Lafayette, IN. Values represents averages for germinated corn seedlings three weeks after planting.

 

 

   In 2001 when the planting season was drier, treatments still exhibited similar characteristics except for TS that had significantly lower final stand count (p<0.0115) with 10,000 plants/acre less than NT treatment (compared to 1,000 plants/acre less in 2000 when it was wet). This suggests that planting too shallow may be the worst mistake when planting no-till corn when the weather happens to remain dry during the growing season. Visual observations indicated some desiccation of seedlings during the third week of growth. If we are able to predict that it will be a drier year, it would be beneficial to plant in wet soils as these seedlings emerge and establish themselves earlier as indicated by the TW treatment (Table 1). The DS treatment had the second lowest stand count followed by CS, showing that in a dry environment, any factors that limit access to moisture or root development may have a negative effect on seedling establishment.  Starter fertilizer has been shown to have no effect on final stand count (Niehues et al., 2004). In our study, using no starter or double starter had no significant effect on final stand count.

 

 

   Corn height measurements were conducted to determine if these malpractices limited the plant’s vigor and capacity to grow. Average heights of plants just before silking are shown on Table 2. Increased growth rates have been shown to translate to increased grain yield (Osborne, 2005). In both years, the TW treatment had significantly shorter plants than the other treatments. Coincidentally in 2001, TW had the highest final stand count of 29,000 plants/acre (Table 1). Although this did not translate into taller corn, it resulted into higher yields (Table 3). Visual observations showed thicker stems for this treatment on both years. This suggests that planting in cold-wet soils may have a direct effect on final height of plants.

 

Table 2. Final plant heights for eight planting practices for no-till corn on soybean residue in the study period 2000 and 2001 at West Lafayette, IN. Values represent averages for heights of plants just before silking 10-weeks after planting.

 

   In 2001, CT, NS, NT, and LPW treatments had significantly taller plants than the other treatments that had a root or moisture limitation such as TS and CS. Other researchers have found that corn growth rates are similar among tillage systems (Beyaert et al., 2002), and that yield and higher vegetative growth are only improved with starter fertilizer on soils testing low in phosphorus (Osborne, 2005). Although our soils were not low in phosphorus, similar responses were observed in 2000 when moisture was abundant.

 

   The NS treatment responded most to N when it was added as a side-dress (UAN) to all treatments in both years. In 2001, the response to side-dressing was markedly lower than in 2000 when moisture was not limiting. These results support the practice of side-dressing to boost growth and yield whether it is a wet or drier year (Niehues et al., 2004).

 

 

   Yield is the ultimate measure of returns from investments on time and resources in no-till corn production. Yield values representing yield-weighted averages for each harvest within the year and adjusted to 15% moisture are given in Table 3. Yield differences were evident among the malpractices between the wet year 2000 and the drier year 2001. In 2000, TW was the highest yielding treatment, significantly higher than CS, NS, TS, and LPW, despite having significantly shorter plants (Table 2) than the rest of the treatments. The lowest yielding treatment in 2000 was NS, and in 2001 it was TS. When moisture was a limiting factor in 2001, all planting practices yielded the same except for the TS treatment that yielded 50% less than other treatments (Table 3).

 

   In general, planting too shallow translated to lower yields whether the growing season was wet or dry. Likewise, plant height had no effect on yield as seen from the TW treatment in 2001. Although DS had higher yields in both years, there were no significant differences with NT and CT, and therefore we conclude that mistakenly doubling the fertilizer rate does not translate to substantially higher yields. In this study, doubling starter fertilizer reduced yields by 7 bu/acre in a wet year but increased yield by 3 bu/acre in a drier year (Table 3). Other studies have shown that grain yield usually increases as tillage intensity decreases in years with drier conditions (Beyaert et al., 2002). This was not the case in our study as both NT and CT had similar yields in 2001 when conditions were drier during the growing season (Table 3).

 

Table 3. Corn yield for eight planting practices for no-till corn on soybean residue in the study period 2000 and 2001 at West Lafayette, IN. Values represent yield-weighted for each harvest within a year.

‡Within columns, means followed by the same letter are not significantly different at P = 0.05 by Fisher’s protected LSD.

 

 

 

   Farmers using no-till practices should plant corn with the “normal treatment” which means they need to use starter fertilizer, plant to proper depth, adjust press wheels to correct spring pressure, avoid compacted zones, and not plant too early. Results from this study would encourage the farmer to continue to do just that with a few exceptions. Conventional tillage will yield equally the same although costs per unit area might be higher. With improved genetics and fungicide treatment of seeds, planting too wet and early in soybean residue actually results in higher yields whether the growing season turns out be wet or dry. If planting mistakes do occur in this process, then yield penalties are minimal and may not be as large as commonly thought. This is because yield differences seem to be a factor of climate, especially moisture, rather than malpractices. However, the worst mistake that can be made in planting corn is planting too shallow as it may result in significant yield losses especially if the growing season turns out to be dry. Therefore this should be the first and last adjustment a farmer should check before dropping down the drill.

 

   Moisture plays a significant role in corn production. Ensuring that seeds are planted at the right depth is important in attaining good yields. Likewise, planting dates may have a greater effect on final plant count and yield because planting early produced consistently similar or higher ratios of plants and yield compared to normal no-till and conventional tillage. It still holds true that “the early bird gets the worm”.

 

 

Beyaert, R. P., Schott, J. W., & White, P. H. (2002). Tillage effects on corn production in a coarse-textured soil in Southern Ontario. Agron. J. 94:767-774.

 

Buah, S. S. J., Polito, T. A., & Killorn, R. (1999). No-tillage corn hybrids response to starter fertilizer. J. Prod. Ag. 12:676-680.

Carter P. R., Nafziger,

---