Jawad Ullah

This study examines how intensive agricultural management influences ammonia-oxidizing microbial communities (AOB and AOA) in banana monoculture systems, with implications for nitrogen cycling and soil acidification dynamics. While previous research has documented the impact of synthetic fertilizers and pathogens on microbial populations in agroecosystems, the responses of active AOB/AOA taxa under combined nitrogen and disease stressors remain largely uncharacterized. We employed soil microcosms established from a native forest (Y0), a two-year-old (Y2), and a twelve-year-old (Y12) banana plantation. Treatments included urea amendment, Fusarium oxysporum f. sp. cubense (Foc) inoculation, and their combination. AOB/AOA activity was quantified via ¹³CO₂ DNA stable isotope probing, while community composition was analyzed through high-throughput 16 S rRNA gene sequencing. Our results revealed distinct microbial community patterns across land-use types and treatments. AOB dominated in banana plantation soils, with their abundance significantly increasing (p < 0.05) in the Y12 system compared to Y0. Conversely, AOA were predominant in the forest soil. Urea amendment and Foc co-application synergistically enhanced AOB activity in banana soils, withariant community shifts observed across all microcosms. Specifically, urea addition in Y0 soil promoted Nitrosotaleales 1.1-AOA (20.16%) and Nitrosospira cluster 2AOB (88.23%), whereas co-treatment induced a dominance shift to Nitrosospira cluster 3a (72.12%). In Y2 soils, urea alone supported Nitrosospira cluster 2-AOB (84.53%) and Nitrososphaerales Group 1.1b-AOA (72.4%), while combined amendments further increased Nitrosospira cluster 3a-AOB abundance compared to urea-only treatment. These findings establish that AOB play a critical functional role in nitrogen transformation under intensive cropping systems, with their activity patterns strongly influenced by both fertilization and pathogen stressors.

Understanding the agronomic interventions that ensure higher crop yields and minimize their chances of failure is critical for meeting global nutritional demands. Rice is a staple food crop that is prone to lodging risk, particularly when higher yields are desired. The potential role of a combined application of Zinc (Zn) and Silicon (Si) in determining the grain yield and lodging resistance has been rarely investigated under field conditions. Thus, field trials were carried out to evaluate the grain yield and lodging resistance of rice at two different locations i.e., Qionghai and Wuzhishan, under three levels of Zn (0, 40, and 80 kg ha⁻¹) and Si (0, 120, and 240 kg ha⁻¹). The results showed that Zn application at the rates of 40 and 80 kg ha⁻¹ increased rice yield by 9% and 5% at Qionghai, and by 5% and 6% at Wuzhishan, respectively. The improved grain yield due to Zn application could be attributed to the increased panicles m⁻², splikelets m⁻², and aboveground biomass. Meanwhile, Zn failed to show any remarkable impact on stem and root lodging susceptibility. Conversely, no significant influence of applying Si on grain yield was observed, while its application at the rates of 120 and 240 kg Si ha⁻¹ enhanced the stem and root lodging resistance (denoted by their respective safety factors, for stem (SF_s) and for root (SF_r) by 32% and 22% at Qionghai, and by 11% and 34% at Wuzhishan, respectively, compared to zero Si application. The improved lodging resistance in terms of SF_s and SF_r could be ascribed to the increased stem bending strength and anchorage strength, while self-weight moment of whole plant decreased. In summary, a beneficial role of Si in lodging resistance and Zn in yield enhancement were evidenced in the present study across the two sites. It can be concluded that by combining 40 kg Zn ha⁻¹ with 120 kg Si ha⁻¹, both grain yield and lodging resistance could be simultaneously improved in rice crops.

Straw returning is an environmentally friendly method to improve soil health and agricultural productivity by reusing organic waste products. However, fields are often also treated with inorganic fertilizers, and the effect of the interaction between phosphate fertilizer application and straw return on crop yield remains unclear. Therefore, a full-factorial, two-year field experiment was conducted on sweet corn (NARC-16 in late 2021 and Kashmeri-19 in early 2022) to explore how crop yield may be optimized by combining straw return with efficient phosphate fertilization. The experiment involved the application of DAP, SSP, and NP (three different types of phosphates) and the application of crop waste byproducts, namely the residual stover left after sorghum and maize harvesting. We compared control fields with no crop waste or phosphate addition (CR0 and PS0) to experimental plots treated with various phosphates and straw return. Growth parameters such as days to emergence, tasseling, silking and maturity, emergence rate (emergence m⁻²), height of plant, number of leaves, leaf area per plant, and yield were evaluated, and the influence of the treatment on the economic value of crops was estimated. Phosphorus and straw return were applied at rates of 90 kg per hectare and 5 tons per hectare, respectively. The best P-crop straw combination treatment involved DAP (90 kg ha⁻¹) with the incorporation of 5 tons’ ha⁻¹ of maize straw, which resulted in delayed tasseling (50 days), early silking (68 days), taller plants (178 cm), improved thousand-grain weight (233 g), maximum biological yield (11,349 kg ha⁻¹) and grain yield (3760 kg ha⁻¹). The application of DAP with maize straw return resulted in the highest plant height, biological yield, and grain yield of sweet corn during the second year of the experiment, despite the first year’s yield being influenced by a natural disaster. This combined management strategy (using either DAP or crop residuals) was found to have a more a favorable cost–benefit ratio (BCR) efficiency. In conclusion, increasing the use of crop residuals can help reduce the expensive application of synthetic mineral fertilizers like SSP and NP, while significantly increasing sweet corn production and improving profit margins. Considering the importance of environmental friendliness and sustainable agriculture, the combined use of DAP and straw return is considered a viable method.

Reusing organic wastes in land applications would enhance the recovery of resources, following the concepts of the circular economy. The sugarcane-based sugar industry produces various by-products (e.g., sugarcane filter mud, molasses, and bagasse) that have the potential to contribute to crop production and soil fertility, owing to their high contents of organic matter and nutrients. Although the agricultural benefits of compost utilization in agriculture have been well-documented, to the best of our knowledge, few scientific data are currently available on the effects of sugarcane filter mud combined with the application of compost for increasing crop production. Thus, a field experiment was carried out to study how sugarcane filter mud, in combination with two compost sources, affected the growth and yield of sweet maize (Zea mays var. saccharata). We compared (i) two types of compost made from brassica residue and household waste applied at a rate of 9 t ha⁻¹, and (ii) two application rates of sugarcane filter mud: 0 and 2 t ha⁻¹ to two controls without any compost application: one with (+SFM) and one without (−SFM) sugar filter mud. The results highlighted that all crop growth and yield parameters benefited more from the domestic waste compost than from the brassica straw compost. Moreover, the addition of sugar filter mud to the compost further boosted the crop performance. Based on the above results, we concluded that the addition of sugarcane filter mud to locally available composts is a feasible approach for more sustainable production of sweet maize, combining efficient waste disposal and the provision of organic matter to the soil.