Skip to main content
ARS Home » Research » Publications at this Location » Publication #197431
Title: Soil-applied nitrogen and composted manure effects on soybean hay quality and grain yield

Author
item HEITHOLT, JAMES - TAES, DALLAS, TX
item KEE, DAVID - EL DORADO CEM. CO., TX
item SLOAN, JOHN - TAES, DALLAS, TX
item Mackown, Charles
item METZ, SUE - TAES, DALLAS, TX
item KEE, AVA - TEXAS A&M UNIV.-COMMERCE
item SUTTON, RUSSELL - TAES, DALLAS, TX

Submitted to: Journal of Plant Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/21/2007
Publication Date: 2/1/2007
Citation: Heitholt, J.J., Kee, D., Sloan, J.J., Mackown, C.T., Metz, S., Kee, A.L., Sutton, R.L. 2007. Soil-applied nitrogen and composted manure effects on soybean hay quality and grain yield. Journal of Plant Nutrition. 30:1717-1726.

Interpretive Summary: In the southern Great Plains soybean is sometimes harvested as a hay crop, particularly when environmental conditions preclude a favorable harvest as a grain crop. This is particularly true when soybeans are grown on the Blackland soils of northeast Texas. Forage from soybeans produced on these soils have high digestibility but tend to have low crude protein concentrations which may be linked to poor nitrogen (N) nutrition due to low N fixation and available soil N. We compared grain and forage responses of soybean that received no applied fertilizer N to those that received organic and manufactured sources of N applied to Blackand soils of northeast Texas. None of the soil treatments increased soybean grain yield or forage yield although manufactured N fertilizer slightly increased forage crude protein concentration in one of the three comparison tests conducted. It appears that the N nutrition of soybean may be limited occasionally, but the combination of soil and climatic conditions hindering N nutrition of soybean grown in the northeast Texas environment are unknown at this time. The results of this research provide state extension personnel, crop consultants, and producers with information necessary to prevent unnecessary additions of organic and manufactured N sources to soybeans grown in this region of the southern Great Plains.

Technical Abstract: Grain yield in many soybean experiments fail to respond to fertilizer nitrogen (N). A few positive responses have been reported when soybean were grown in the southern US, when N was applied near flowering, and when biosolids were added. In a previous study, we reported low N concentrations of soybean forage in north Texas on a high pH calcareous soil and thus, suspected an N nutrition problem. Consequently, we initiated this study to determine whether selected preplant N sources broadcast and incorporated into a Houston Black clay (fine, smectitic, thermic Udic Haplusterts) might increase forage N concentration, forage yield, or soybean grain yield. In 2003, N was applied as ammonium nitrate (AN) up to 112 kg N/ha and dairy manure compost (DMC) was applied at rates of 4.9, 9.9, 15.0, and 19.9 Mg/ha. The DMC contained 5.9, 2.6, and 6.7 g/kg of total N, P, and K, respectively; thus DMC added 29 to 116 kg N/ha. In 2004, AN was applied at rates of 112 and 224 kg N/ha and DMC was applied at 28 and 57 Mg/ha; thus, DMC added 168 to 335 kg N/ha. In another 2004 test, biosolids, a biosolids/municipal yard waste compost mixture (BYWC), and AN were compared. The biosolids contained 31, 18, and 2.9 g/kg total N, P, and K, respectively. The BYWC mixture contained 8.8, 6.1, and 3.4 g/kg of total N, P, and K, respectively. Biosolids were applied at 10 Mg/ha (310 kg N/ha), BYWC was applied at 58 Mg/ha (510 kg N/ha), and AN up to 224 kg N/ha. None of the soil treatments increased soybean grain yield or forage yield although AN slightly increased forage N concentration in 2003.