Besides carbon (C) sequestration, biochar (BC) is recently believed to deliver multiple eco-friendly benefits to the soil for enhancing crop productivity. Use of mineral fertilizers coupled with BC been suggested a promising sustainable strategy for increasing crops yield. However, imperative study is needed to investigate (1) BC integration with multiple legumes crop adjusted in summer gape for pooling more organic carbon and nitrogen, and (2) subsequently looking into its synergism with mineral N in the following crop. Therefore, two years’ field experiments were conducted on maize under cereal based cropping pattern with the adjustment of legumes (i.e., mungbean, cowpea, and Sesbania) with a fallow in summer. In legumes, treatments consist of (0 and 50 t ha⁻¹) BC application. However, N rates of 0, 90, 120, 150 kg ha⁻¹ were added to the subsequent maize crop. Preceding legumes plots with the use of 50 t ha⁻¹ biochar enhanced maize grain yield, above ground biomass, stover N, grain N, soil C, and N content after maize harvest and N use efficiency as compared to non-legumes with BC and legumes without BC plots. N application increased grain yield, above-ground biomass, stover N, grain N, and soil N but reduced N use efficiency with higher rates. Conclusively, the integration of biochar and legumes is a promising option for increasing the entire farm production of cereal-based cropping systems. This increment in yield was associated with supplying a viable input of N and C to soil and increased yields from this supplementary ‘summer gap’ crop.

Biochar fertilization improves soil fertility and carbon sequestration, implying agricultural and environmental advantages. The effect of different sized previously applied biochar and biofertilizer agents on succeeding crops remains poorly known for legume–cereal cropping cycles. This study compared different particle-sized biochar and biofertilizer strains applied to lentils for their residual impact on subsequent maize growth, nutrition, and soil fertility without further polluting the environment. Three particle sizes (<2, 2–5, 5–10 mm) of Babul tree (Acacia arabica) wood biochar was obtained through grinding and sieving and applied prior to the lentil (first) crop at a rate of 500 g m⁻². The commercial Rhizobium leguminosarum products Biozote-N and Rhizogold were inoculated to lentil seeds before sowing. The effect of biochar and biofertilizer agents on the succeeding maize (second) crops was evaluated for soil and crop performance. Findings revealed that particle sizes of <2 mm biochar and Biozote-N inoculation enhanced plant height, leaf area and leaf area index, biological yield, and thousand grain weight of the subsequent maize crop. Maize grain yield was enhanced by 2.5%, tissue N uptake by 15%, nitrogen uptake efficiency by 17%, grain protein content by 15%, extractable P by 17%, and soil bulk density by 3% with a residual biochar particle size of <2 mm and Biozote-N inoculation. It was concluded that the finely grounded (<2 mm) biochar particle combined with inoculation of Biozote-N was superior to larger particle sizes for enhancing crop growth and improving soil fertility status at the residual level, benefiting the subsequent crop in a legume–cereal rotation system.

Canola crop has the potential for both seeds and grazing. Optimal planting density, time of nitrogen (N) fertilizer application and rates are the major aspects for successful qualitative traits and canola yield formation. In this content, optimization of planting density, N levels and its time of application in dual purpose canola are needed. This study was carried out in RCB design with split pot arrangement having three repeats during winter 2012–2013 and 2013–2014. The study evaluated N levels (120 and 80 kg N ha⁻¹), cutting treatment, N application timings and planting density (20 and 40 plants m⁻²) effects on qualitative traits and yield of canola. No-cut treatment had 7.02%, 2.46%, and 4.26% higher, glucosinolates, oil, and protein content with 31.3% and 30.5% higher biological and grain yield respectively, compared with grazed canola. Compared with no-cut canola, grazed canola resulted in 7.74% of higher erucic acid. Further, application of N at 120 kg N ha⁻¹ had 8.81%, 5.52%, and 6.06% higher glucosinolates, percent protein, and seed yield, respectively than 80 kg N ha⁻¹. In-addition, the application of N into two splits was most beneficial than the rest application timings. Cutting had 15% reduction in grain yield of canola and fetched additional income of 143.6 USD compared with no-cut. Grazing resulted in a 23% reduction in grain yield while had additional income of 117.7 USD from fodder yield. Conclusively, the application of N in two splits at 120 kg N ha⁻¹ combined with 20 plants m⁻² is a promising strategy to achieve good qualitative attributes and canola yield under dual purpose system.

Identifying the contributions of climate factors and fertilization to maize yield is significant for the assessment of climate change impacts on maize production under semiarid conditions. This experiment was conducted with an overall objective to find how N fertilization and cultivar interactions along with climatic conditions determine the mineral composition and maize yield responses of four divergent maize cultivars grown under eight different fertilization levels. The results showed that element contents were significantly affected by year (Y), cultivar (C), N fertilization, and N × C interaction. The element contents of grains were mainly influenced by N rate or N × C interactions. The results showed that maize yield was significantly affected by year (Y), genotype (G), N fertilization (N), and Y × G × N interaction. These results implied that the maize yield was significantly affected by changes in genotypes and environments. Overall, our findings are a result of the interactions of genetic, environmental, and agronomic management factors. Future studies could evaluate more extreme plant densities, N fertilizer levels, and environments to further enhance our understanding of management effects on the mineral composition and maize yield in calcareous soil.