Soil N2O and CH4 emissions from fodder maize production with and without riparian buffer strips of differing vegetation

Purpose Nitrous oxide (N2O) and methane (CH4) are some of the most important greenhouse gases in the atmosphere of the 21st century. Vegetated riparian bufers are primarily implemented for their water quality functions in agroecosystems. Their location in agricultural landscapes allows them to intercept and process pollutants from adjacent agricultural land. They recycle organic matter, which increases soil carbon (C), intercept nitrogen (N)-rich runof from adjacent croplands, and are seasonally anoxic. Thus processes producing environmentally harmful gases including N2O and CH4 are promoted. Against this context, the study quantifed atmospheric losses between a cropland and vegetated riparian bufers that serve it. Methods Environmental variables and simultaneous N2O and CH4 emissions were measured for a 6-month period in a replicated plot-scale facility comprising maize (Zea mays L.). A static chamber was used to measure gas emissions. The cropping was served by three vegetated riparian bufers, namely: (i) grass riparian bufer; (ii) willow riparian bufer and; (iii) woodland riparian bufer, which were compared with a no-bufer control. Results The no-bufer control generated the largest cumulative N2O emissions of 18.9 kg ha−1 (95% confdence interval: 0.5–63.6) whilst the maize crop upslope generated the largest cumulative CH4 emissions (5.1±0.88 kg ha−1 ). Soil N2O and CH4-based global warming potential (GWP) were lower in the willow (1223.5±362.0 and 134.7±74.0 kg CO2-eq. ha−1 year−1 , respectively) and woodland (1771.3±800.5 and 3.4±35.9 kg CO2-eq. ha−1 year−1 , respectively) riparian bufers. Conclusions Our results suggest that in maize production and where no riparian bufer vegetation is introduced for water quality purposes (no bufer control), atmospheric CH4 and N2O concerns may result.The Department of Higher Education and Training (New Generation Gap of Academics Program) and National Research Foundation-Thuthuka.https://www.springer.com/journal/11104dm2022Plant Production and Soil Scienc

Maize growth and yield as affected by different soil fertility regimes in a long term trial

Maize is the world’s third most important cereal after wheat and rice. It serves as a staple food to more than 1.2 billion of the world population. However, its production is threatened by declining soil fertility; mainly due to low inputs of fertilizers containing major elements to replenish lost soil nutrients and unsustainable soil tillage practices linked to mono-cropping. To examine the influence of N, P and K and residual compost on maize growth and yield, an experiment was carried out at the Hatfield Experimental Farm of the University of Pretoria. Utilizing the long-term maize trial, controls (0 and W), seven inorganic fertilizer treatments (N, P, K, NP, NK, PK & NPK) and seven organic + inorganic fertilizer treatments (WN, WP, WK, WNP, WNK, WPK & WNPK) were used. The influence of these fertilizer and residual compost treatments on maize seed viability (germination), plant growth, reproductive development, pollen performance, grain yield parameters, yield and grain yield water-use efficiency was investigated. Higher seed viability was associated with balanced soil nutrient status (WNPK & NPK), whilst deficient soil nutrient status (0, N, P & K) resulted in lower seed viability. Plant growth (plant height, total dry mass and LAI) and reproductive development (tassel length, ear length, and days to tasseling and silking) were positively influenced by a balanced soil nutrient status and residual compost. Deficiencies in soil nutrients restricted maize plant growth and delayed reproductive development. This highlighted the importance of a balanced soil nutrient status in attaining a vigorous crop and good reproductive development. Soil nutrient deficiencies (0, P & K treatments) enhanced the production of pollen (mass per plant), but resulted in low pollen quality (viability and germination). Balanced soil nutrient status (WNPK & NPK) resulted in the production of high quality pollen (viability and germinability), which however had a low mass. In both 2012/2013 and 2013/2014 seasons, maize grain components; cob length, number of kernel rows per cob, number of kernels per row, mass per kernel and mass of 100 kernels were positively influenced by balanced soil nutrient status. Grain yield and water use efficiency were also positively influenced by a balanced soil nutrient status (WNPK & NPK), whilst deficient soil nutrient status had a negative effect.Dissertation (MScAgric)--University of Pretoria, 2015.tm2015Plant Production and Soil ScienceMScAgricUnrestricte

Evaluating the potential of different carbon sources to promote denitrification

Please read abstract in the article.https://www.cambridge.org/core/journals/journal-of-agricultural-sciencehj2021Plant Production and Soil Scienc

Soil methane (CH4) fluxes in cropland with permanent pasture and riparian buffer strips with different vegetation

Please read abstract in the article.South African Department of Higher Education and Training; National Research Foundation-Thuthuka and Rothamsted Research through its Institute Strategic Programme.https://wileyonlinelibrary.com/journal/jpln2022-12-15hj2022Plant Production and Soil Scienc