Haile Tewolde

Broiler Litter Application Effects On Selected Trace Elements Under Conventional And No-till Systems

This study was conducted on two separate commercial farms representing no-till at Coffeeville and conventional tillage system at Cruger in Mississippi to evaluate the dynamics of selected some trace elements in response to long-term broiler litter application to cotton. The soil at Cruger is a Dubbs silt loam (fine-silty, mixed, active, thermic Typic Hapludalfs) and at Coffeeville is an Ariel silt loam (coarse-silty, mixed, thermic Fluventic Dystrochreps). In each site, the experimental design was a randomized complete block with eight treatments replicated four times. Treatments included broiler litter rates of 0, 2.2, 4.5, and 6.7 Mg ha−1 in some combination with 0, 34, and 67 kg nitrogen ha−1. Commercial nitrogen, phosphorus, and potassium fertilizer at recommended rate was also included. At Coffeeville location at the end of third year, soil surface (0-15 cm) total C and total copper (Cu), zinc (Zn), and arsenic (As) significantly increased with increasing broiler litter applications. In Coffeeville under the no-till system, application of broiler litter at the highest rate (6.7 Mg ha−1) significantly increased soil surface (0-15 cm) total C, total Cu, Zn, and As by 28%, 67%, 51%, and 69%, respectively, as compared with unfertilized control. At Cruger location, changes in soil C and trace elements were less responsive to treatment applications. Downward movement of Cu and Zn was limited to 15 cm of soil depth, but As was detected at about 30 cm of soil depth at high broiler litter application rate. Despite elevated concentrations of trace metals at the soil surface, their concentrations in the soils were in the range considered normal with no potential threat to the ecosystems.

Fiber Quality Response of Pima Cotton to Nitrogen and Phosphorus Deficiency

Abstract Imposing a moderate level of nutrient deficiency may be an effective management strategy to limit vegetative growth and enhance maturity of Pima cotton (Gossypium barbadense L.). Whether such deficiency affects fiber quality of American Pima cotton, however, is not well known. A field study was conducted in 1991 and 1992 to determine the fiber quality responses of Pima cotton to nitrogen and phosphorus fertilization ranging between deficient and excess. Pima cotton cv. “S‐7” was treated with nitrogen rates ranging between 0 and 269 kg ha−1 in a factorial combination with phosphorus rates ranging between 0 and 44 kg ha−1. Fiber property measurements included fiber length, strength, fineness, elongation, and color properties. Increasing rate of applied nitrogen significantly (P ≤ 0.05) increased fiber length, elongation, micronaire, and color characteristics and reduced fiber uniformity ratio in 1991. Increasing nitrogen rate significantly (P ≤ 0.10) increased fiber length, uniformity index, and yellowness in 1992, when the degree of nitrogen deficiency imposed by the lowest nitrogen rate was not as severe as the deficiency imposed by the same treatment in 1991. Phosphorus did not significantly (P ≤ 0.10) affect any of the important fiber properties—length, strength, or micronaire—in either cropping season. These results indicate moderate level of nitrogen or phosphorus deficiency does not affect Pima cotton fiber quality. Nitrogen or phosphorus deficiency severe enough to reduce fiber quality and affect marketing of Pima cotton is unlikely to be encountered under normal Pima cotton production practices.

Comparison of Broiler Litter and Commercial Fertilizer at Equivalent N Rates on Soil Properties

A 3-year study was conducted to determine the effects of broiler litter relative to inorganic fertilizer on soil nutrient content and quality in an upland Loring silt loam soil. Treatments included annual broiler litter rates of 0, 2.2, 4.5, 5.6, 6.7, 10.1, and 13.4 Mg ha−1 y−1 and commercial fertilizer rates of 34, 68, 90, 112, 134, and 168 kg nitrogen (N) ha−1 y−1. Broiler litter application linearly increased soil total carbon (C), microbial biomass C, extractable soil phosphorus (P), potassium (K), soil cation exchange capacity (CEC), and the stability of soil aggregate. At the highest broiler litter rate, the stability of soil aggregate was 34% greater than inorganic fertilizer. Application of broiler litter or fertilizer N at rate greater than 6.7 Mg ha−1 or 90 kg N ha−1, respectively, exceeded plant N utilization potential as evidenced by higher end-of-season soil residual nitrate (NO3)-N. Broiler litter is more effective in improving soil physical, chemical, and biological components than conventional fertilizer.

Poultry Manure Application Time Impact on Corn Grain Production in a Crider Silt Loam

Abstract Adopting proper management practices for poultry litter (PL) is critical to increase N efficiency, maximize yield, and reduce negative environmental impacts. This study investigated the effects of application time (fall and spring) of two PL rates (9.0 and 18.0 Mg ha−1) and commercial N-P-K fertilizer blend (224 kg N ha−1, 84 kg P ha−1, 145.6 kg K ha−1) on selected soil properties and corn (Zea mays L.) grain yield in Central Kentucky. Application time response was measured by grain yield, whole plant nutrient concentrations and uptake, and soil nutrients availabilities. Application time of the PL and commercial fertilizer did not influence grain yield or plant nutrient concentrations and uptake. Grain yield was increased by the two PL rates, and no difference was found among the PL and commercial fertilizer. Whole plant uptake and concentrations of N, P, and K increased when PL plant available N-P-K increased. Soil inorganic N was 17% (18 kg ha−1) greater from spring than fall applications of the high PL rate when sampled midseason. Application time did not influence inorganic N at the low PL rate. Greater soil available K resulted from fall than spring applications of the PL, but Mehlich 3 available P was not influenced by PL application time. Results indicate that fall applications of PL have equal potential as spring applications without compromising plant available nutrients and yield. In addition, the low PL rate was adequate in N, P, and K to meet the soil’s requirement for optimum yield, without significant nutrient accumulation and loss.

Continuous and Residual Effects of Broiler Litter Application to Cotton on Soil Properties

Abstract The residual effect of broiler litter on soil properties is not well documented. Field studies were conducted in Coffeeville on an Ariel silt loam soil and Cruger on a Dubbs silt loam soil to evaluate the residual effect of repeated broiler litter application to cotton (Gossypium hirsutum L.) on soil properties. Broiler litter was applied at 0, 2.2, 4.5, and 6.7 Mg ha−1 and 4.5 Mg ha−1 plus 67 kg N ha−1 from 2002 to 2007. Phosphorus and K were applied as recommended by the Mississippi Soil Testing Laboratory. After 3 years of consecutive applications, in 2005 each plot was divided into two equal sub-plots where one half continued to receive the same treatments, whereas the other one half was not fertilized from 2005 to 2007. Soil samples were taken from all plots at the end of the experiment in 2007. Continuous broiler litter application over 6 years increased soil total C, N, microbial biomass C, and soil test P levels at both locations. However, soil bulk density was reduced at the highest broiler litter application rates only at Coffeeville. Three years after broiler litter application was terminated, at rates greater than 2.2 Mg ha−1 soil pH, total soil C and N, microbial biomass C, and soil test P levels were still greater than the control at Coffeeville location. In this study, we have shown that after 3 years broiler litter application to cotton resulted in positive residual effects on the soil nutrient pool and maintained soil fertility levels, particularly under no-till system.

Runoff quality from no-till cotton fertilized with broiler litter in subsurface bands.

Surface broadcast of broiler litter to no-till row crops exposes the litter and its nutrients to risks of loss in runoff water and volatilization and may limit the potential benefit of litter to the crops. Subsurface banding of litter could alleviate these risks. A field study was conducted in 2008 and 2009 on an upland Falkner silt loam soil to determine the effect of broiler litter placement on runoff nutrient losses from no-till cotton ( L.). Treatments included surface broadcast broiler litter applied manually, subsurface-banded litter applied by tractor-drawn equipment, and no broiler litter, all in combination with or without winter wheat ( L.) cover crop residue. Broiler litter rate was 5.6 Mg ha. The experimental design was a randomized complete block with a split-plot arrangement of treatments replicated three times. In 2008, simulated rainfall was used to generate runoff 27 d after litter application. Subsurface-banded litter reduced runoff total C, N, P, NH, NO, Cu, Zn and water-soluble P (WP) concentrations by 72, 64, 51, 49, 70, 36, 65, and 77%, respectively, compared with surface broadcast. The reductions were greater in 2009 where runoff occurred 1 d after litter application. Bacterial runoff was decreased by one log with subsurface-banded litter compared to surface broadcast. Except for C, NH, N, and WP, the presence of winter cover crop residue did not affect the load or runoff nutrient concentrations in either year. The results indicate that subsurface banding litter to no-till cotton substantially reduces nutrient and bacterial losses in runoff compared with surface broadcasting.

Effects of Subsurface Banding and Broadcast of Poultry Litter and Cover Crop on Soil Microbial Populations

Agronomic management is aimed at managing the crop environment to maximize crop yield, but soil biology is often ignored. This study aimed to compare the application of poultry litter via broadcast and subsurface banding versus standard inorganic fertilizer to cotton ( L.) and their effects on soil bacterial populations and fecal indicator bacteria. The study comprised a randomized complete block design, with fertilizer and time of application as treatment effects and cover crop as a main effect. Soil cores were collected and analyzed from 2008 to 2014. Fecal indicator bacteria were at detection limits for all treatments, where the integron 1 gene was significantly elevated in litter plots. There were few differences between litter application approaches, but both significantly increased key biogeochemical genes over control plots, whereas a cover crop only increased soil moisture and urease C. Data suggested a positive residual effect of litter application with 16S, phosphatase A, and urease C genes elevated over controls, but similar to standard fertilizer plots. High-throughput 16S ribosomal RNA analysis suggested increased diversity and enrichment indices in litter and standard fertilizer over untreated control plots. Litter and standard fertilizer effects persisted 4 and 2 yr after application, respectively, as evidenced by residual library community structures. This study demonstrated the positive effects of litter application on the soil bacterial community when compared with untreated control plots. Some differences between standard fertilization and litter practices were noted and suggest that there is a positive residual effect on soil microbial populations associated with both practices.