Recognizing Challenges to Iowa’s Annual Cropping Systems

Iowa’s soybean and corn cropping systems are among the most productive in the world yet, producing consistently high yields remains uncertain. This publication discusses possible solutions to problems that limit soybean yield in Iowa.https://lib.dr.iastate.edu/extension_ag_pubs/1194/thumbnail.jp

Alternatives for Drought-damaged Soybeans—Bean Crop or Forage

As people reflect on the reasons for the irregular development and poor soybean production in Iowa this year, the next important questions relate to evaluation of crops in individual fields and planning when and how to harvest them to the greatest economic advantage. This evaluation involves reviewing normal crop growth and development, assessing the condition of the crops in individual fields relative to normal and to think through several harvest scenarios. Will this field have a harvestable soybean crop? Are there concerns about the crops? What use or management alternatives do I have

Cropping systems and soil quality and fertility in south-central Uganda

Little is known about how cropping systems influence soil quality and fertility in Uganda. Some cropping systems are more valued and as a result are given more nutrients and planted in certain soils, all of which leads to varying soil quality and fertility. This study compared soil quality (soil pH, cation exchange capacity (CEC), electric conductivity (EC), total N, and depth to restrictive layer (DRL)) and fertility (extractable P, K, Ca, Mg, and Na, and base saturation (BS) from five cropping systems (banana (Musa × paradisiaca L.)-dominant (B), coffee [Coffea robusta (L.) Linden]-dominant (C), banana-coffee (BC), annual with no crop rotation (ANR), and annual with crop rotation (AR); fertilized and unfertilized soils; and three soil types (black (Phaeozem), red (Ferralsol), and black-stony) in south-central Uganda. The analysis included farm assessments to establish management history of studied fields and soil sampling from 52 fields in Masaka District, Uganda. Main-effects ANOVA was employed to determine differences in means in soil under different cropping systems, soil types, and fertilizer use. Soil quality (pH at depths of 0 to 10 and 20 to 30 cm, CEC, and EC) and fertility (extractable Ca and Mg) varied by cropping system. The AR and B systems had higher soil quality and fertility compared to other cropping systems. Soil quality (pH at depths of 0 to 10 and 0 to 15 cm and DRL) and soil fertility (extractable P and K) varied by soil type. Black and black-stony soils had higher soil quality and fertility than red soils. Soil quality and fertility did not vary by fertilizer use. The results of this study indicate that both cropping system and soil type are associated with soil quality and fertility in south-central Uganda

Nutritional Composition of Grain Legume Leaves and the Impact of Leaf Removal on Yield

Grain legumes can thrive in adverse environments, making them a climate-smart technology for hunger mitigation. Although several countries rely immensely on grain legumes to meet daily protein intake requirements per capita, the potentiality of leaf utilization for protein and other nutrients has not been widely considered; additionally, insufficient information is available on leaf removal effects on yield and leaf nutritional composition of grain legumes. A 2-yr experiment was conducted in central Iowa, USA, to determine the effects of leaf removal rates on nutritive value of removed leaf tissue and subsequent grain yield of cowpea [Vigna unguiculata (L.) Walp.], lablab [Lablab purpureus (L.) Sweet], and soybean [Glycine max (L.) Merr.]. Across entries, dry leaf mean nutrient concentration was 229 g kg–1 for CP, and 17,832, 4461, 21,991, 3702, 113, 205, and 86 mg kg–1 for Ca, Mg, K, P, Mn, Fe, and Zn, respectively. Yield and major yield attributes were affected by leaf removal rate in 2014, but not in 2013. In 2014, grain legumes with 0% leaf removal had 20, 32, and 35% greater yield and seeds weighed 6, 11, and 12% more than those with 33, 66, and 99% leaf removal, respectively. Aboveground biomass, yield, and yield components also differed among entries both years. Grain legume leaf utilization as vegetable or forage may improve human and ruminant nutrition by using leaves, especially in developing countries

Inoculant Use on Soybean Seed

Inoculating soybeans with products containing the bacterium Bradyrhizobium japonicum is considered an inexpensive management practice to increase yield. However, yield gain from inoculants on soybean is inconsistent. This publication discusses the benefits and limitations of inoculant use on soybean.https://lib.dr.iastate.edu/extension_ag_pubs/1188/thumbnail.jp

Application of a Formulated Humic Product Can Increase Soybean Yield

Application of humic products to crops remains controversial. We conducted a field study in Iowa over four environments from 2012 to 2014 examining productivity of soybean [Glycine max (L.) Merr.] receiving foliar application of a humic product at one of four application times based on plant development. Humic product application never influenced soybean height at harvest. Soybean yield increased following application of the humic product in two of four environments, but application timing was not completely consistent between these two environments. In one 2012 environment, humic product application at V2, V6, and R2 resulted in greater yield than the untreated control. In the other 2012 environment, application of the humic product at V2 resulted in improved yield over the untreated control. Application of the humic product never influenced seed oil concentration; however, seed protein concentration was decreased following application of humic product at V2 and R2 in a single 2012 environment. Use of the formulated product influenced returns from –$81 acre−1 to +$171 acre−1, depending on the environment. The environments where humic product application positively influenced yield and seed quality had greater rainfall deficits and air temperatures above the long-term average

Narrow rows may lift bean yield

Soybean row spacing: What is optimum for today’s production systems? Row spacing used by soybean farmers in Iowa has varied from 6 to 40 inches. What row spacing should you consider if you are contemplating buying a new planter for soybeans? Can narrower row spacing improve yield and profitability

Integrating sheep grazing into wheat–fallow systems: Crop yield and soil properties

The two predominant systems for weed management in summer fallow are tillage with a field cultivator or multiple applications of broad spectrum herbicides with zero tillage. Both systems are based on substantial use of off farm resources. Our objective was to determine if strategic grazing of sheep may allow grain growers to more sustainably manage crop residues, volunteer crop, and other weeds during fallow periods. We conducted a study near Bozeman, Montana, USA, comparing three fallow weed management systems in two crop rotations from 2005 to 2008. Fallow weed management systems were conventional tillage, chemical-fallow (herbicide application), and sheep grazing. The crop rotations were summer fallow–spring wheat and summer fallow–winter wheat. In late fall, chemical-fallow treatment had greater residue cover and soil water content than did tilled- or grazed-fallow. At 0–15-cm depth, soil had lower bulk density in chemical- and tilled-fallow than in grazed fallow. Similarly, soil NO3-N, Ca, SO4-S concentrations and EC were lower following grazed-fallow than tilled-fallow, but Na concentration was higher following grazed-fallow than tilled- or chemical-fallow. Following spring and winter wheat, soil properties were not influenced by treatments. Grain yield was greater in winter wheat than in spring wheat but the trend reversed in protein concentration. Although soil properties varied among treatments, fallow management system had little influence on yield or quality of spring and winter wheat. Sheep grazing during fallow periods had limited impact on subsequent wheat yield and quality, and is a suitable practice for weed and residue management in wheat–fallow systems

Understanding Soybean Plant Population Recommendations for Iowa

Concerns over rapidly escalating seed prices have caused farmers, agronomists, and seed suppliers to revisit soybean planting rates. This publication discusses optimum soybean planting rates in Iowa and surrounding states. This is a must read for those who want to reduce their seed input costshttps://lib.dr.iastate.edu/extension_ag_pubs/1179/thumbnail.jp

Selecting Soybean Varieties

Selecting the right combination of high yielding genetics and agronomic traits is the first management decision toward a successful soybean crop. This publication provides the reader with several tools that can be used to select high yielding soybean varieties best-suited to Iowa growing conditions.https://lib.dr.iastate.edu/extension_ag_pubs/1192/thumbnail.jp