Effect of Cattle Slurry on Growth, Biomass Yield and Chemical Composition of Maize Fodder

The effect of biogas slurry application on biomass production and the silage quality of corn

OBJECTIVE

The objective of this study was to evaluate the effect of biogas slurry application on biomass production and the silage quality of corn.

METHODS

A field experiment was conducted in which corn was grown using different biogas slurry application rates. The effect of 25% to 500% biogas slurry nitrogen replacement (T1 to T14) on the yield and quality indices of corn were studied by field plot experiments.

RESULTS

The results revealed that biogas slurry application improved the stem diameter and relative feed value of corn silage in treatments T13 and T11. Moreover, the fermentation quality of corn silage was improved due to an increase in lactic acid content; in comparison with the chemical synthetic fertilizer (CF) group. The crude protein contents of corn silage had no obvious change with increasing biogas slurry application. However, the forage quality index of acid detergent fiber was decreased (p<0.05) in the T11 group compared with the CF group. In addition, higher (p<0.05) 30 h in vitro dry matter digestibility and 30 h in vitro neutral detergent fiber digestibility were observed in the T11 and T13 groups than in the CF group.

CONCLUSION

Based on these results, it was concluded that the optimum biogas slurry application rate for corn was approximately 350% to 450% biogas slurry nitrogen replacement under the present experimental conditions.

Biogas slurry application could potentially reduce N2O emissions and increase crop yield

The huge excrement quantity from the increasing large-scale livestock stressed the ecological, environmental deterioration. As a major benefit for handling livestock manure, the slurry of biogas (BS) is developed during the production of biogas that might increase plant productivity. However, nitrous oxide (N₂O) emissions from BS are considered a significant danger to the environment due to global warming potential. Furthermore, applying different proportions of BS combined with chemical fertilizer (CF) on N₂O productions in the North China Plain (NCP) remains unclear. Herein, two sequential field trials were performed by maize-wheat rotations to substitute the CF by BS and reduce N₂O emissions while keeping the crop yield stable. Four treatments were conducted, including T1, T3, T6, and CK. A total of 226.5 kg N ha^-1 used in the maize-wheat rotation system. Additionally, different ratios of BS (100%, 80%, and 50%) combined with CF were used in wheat season in the tillering stage. Results showed integrated applications of BS with CF have potential for reducing N₂O emission. Our findings showed that the maximum grain yield of CF was 6250 kg ha^-1, which might be achieved by applying 38% BS and 62% of CF. This ratio yielded 1.03 kg ha^-1 N₂O emissions, which was 15% lesser than the N₂O emission of CK, 1.21 kg ha^-1. Considering whole growing period of wheat biogas treatments significantly reduced the cumulative N₂O emissions from 17% to 26% compared to CF. To achieve maximum yield and minimum N₂O emissions, an optimum 38% BS ratio has been suggested. The integrated use of BS and CF provided the greatest grain yield because of necessary nutrients provided by both slurry and CF. Consequently, N₂O emissions reduced based on frequency and type of fertilizer. In conclusion, 38% ratio of BS combined with 62% CF would be a suitable approach to mitigate N₂O emission and simultaneously increase crop yield in NCP.

Nitrogen fertiliser value of biogas slurry and cattle manure for maize (Zea mays L.) production

Recovery of nutrients from biogas slurry (BGS) as a soil amendment, on low input smallholder farms in sub-Saharan Africa, could improve agricultural production and minimize contribution of the agroecosystems to CO₂ emissions. Comparative effects of BGS and cattle manure (CM) on maize dry matter, grain yield, uptake of nitrogen (N), phosphorus (P) and potassium (K), and soil total N, extractable P and exchangeable K after harvest were studied, relative to chemical fertiliser (CF). The field experiment was conducted in the 2016/2017 and 2017/2018 growing seasons and was arranged in a randomized complete block design replicated four times with (i) BGS, (ii) CM and (iii) CF as the treatments. Each treatment was applied at 40, 80 and 120 kg Nha⁻¹. Additional P was added to BGS and CM to have the same added P as in the CF treatments. The CM treatment had higher dry matter than both BGS and CF in both seasons at each N rate. Maize grain yield from CF treatment was higher than the two organic fertilisers at each N rate, while the BGS treatment had higher grain yield than CM except at 40 kg Nha⁻¹. When applied at the same N rate, BGS resulted in lower P and K than CF, and had higher extractable P with lower exchangeable K when compared with CM. The findings imply that while BGS provided nutrients, it resulted in lower maize dry matter than CM and lower grain yield than CF, but raised total N and available P, over time.

The Effect of Biogas Slurry Application on Biomass Production and Forage Quality of Lolium Multiflorum

The development of ecological circular agriculture has been highly encouraged to recycle agricultural wastes, reduce mineral fertilizer input, and protect the environment. Biogas slurry (BS), a by-product of biogas production generated from anaerobic digestion of animal waste and crop residues, is often considered a substitute to reduce mineral fertilizer input. Being a cheap source of organic matter and plant nutrients, its application may improve soil fertility and yield quality and quantity. The field experiments were conducted in 2016 and 2017 to study the plant growth responses and forage quality by applying biogas slurry to replace chemical synthetic fertilizer (CSF). Results revealed that biogas slurry combination with chemical synthetic fertilizer significantly (p < 0.05) improved the growth of Italian ryegrass on treatment with T2, and the Italian ryegrass dry matter was increased by more than 9.00%, while the stem-to-leaf ratio was decreased by more than 12% (second cutting), in comparison with only chemical synthetic fertilizer group. In the case of forage quality, the crude protein (CP) and crude fiber (CF) content had a significant difference was observed between the T0 and T2 treatment group. Compare with the chemical synthetic fertilizer group, the CP content improved by 10.35%, and the CF content decreased about 10.00%. Based on these results, it was concluded that the application of 37.5 kg/ha CSF + 100.5 t/ha BS could improve the production of biomass and forage quality in Italian ryegrass.