Forage Maize Research Articles

Influence of Ensiling Timing and Inoculation on Whole Plant Maize Silage Fermentation and Aerobic Stability (Preliminary Research)

Despite efforts to prevent atypical ensiling conditions, such as delayed ensiling or sealing, these issues frequently occur in practice. This study aimed to investigate the effects of delayed ensiling (forage held for 24 h) and sealing, along with inoculation using a blend of Lentilactobacillus buchneri and Lactococcus lactis, on the characteristics of the resulting silages. Whole-plant maize (Zea mays L.) was treated with or without a commercial inoculant and ensiled (36% dry matter) for 60 days in 3.0 L glass containers. The forage was either ensiled immediately or subjected to a 24 h delay before ensiling. During the delay, the forage was either covered or left uncovered. Each treatment was replicated five times. All data were analyzed using the MIXED procedure of SAS statistical software (version 9.4; SAS Institute Inc., Cary, NC, USA). Delaying the ensiling process by 24 h worsens fermentation parameters, significantly increases dry matter (DM) losses (p < 0.01), and significantly reduces aerobic stability and the hygienic quality of the silage (p < 0.01), as evidenced by higher concentrations of undesirable fermentation products and elevated yeast and mold counts. The inoculation has a significant impact on both forage before ensiling and the characteristics of the resulting silage. Maize forage treated with inoculant showed a lower temperature increase by 8.2–8.1 °C (p < 0.01) when delayed for 24 h before ensiling. In silages, it also resulted in a reduced pH (p < 0.01); increased concentrations of lactic acid; acetic acid; and 1,2-propanediol (p < 0.01); and decreased levels of negative fermentation indicators such as ammonia-N, alcohols, and butyric acid (p < 0.01) During both the fermentation and aerobic exposure periods, inoculated silages exhibited up to 36% and 2.6 times lower (p < 0.01) dry matter loss, while suppressing the growth of yeasts and molds by up to 2.6 and 3.1 times (p < 0.01), respectively, compared to non-inoculated silages. The results of this study support the recommendation to minimize the duration of aerobic exposure of fresh forage during silo filling and to use LAB-based inoculants.

Advancements in breeding for high oil content in maize (Zea mays. L)

Maize is one of the world’s most important food crops, supplying>5% deity energy. Due to its wider adaptability, high yield potential, maize is widely utilized as food and animals world worldwide. It enriched with caloric starch and the high energy in its oil. The kernel oil content in commercial high-oil maize hybrids averages ∼8%, far lower than that in developed high-oil maize lines (as high as 20%). The maize seed/kernel consisted of endosperm (82%) and the germ (embryo and scutellum) (12%). The germ region makes up 80–84% of kernel oil, with the aleurone and endosperm making up 12% and 5%, respectively. High-oil maize may serve as a valuable forage maize germplasm for breeding. Maize oil is also considered as high-quality oil for human health due to the high proportion of polyun-saturated fatty acids. Selection for high oil increases the proportion of germ and further content of germ oil. The problems that over-shadow the successful production of high-oil corn are low grain yield potential, physiological cost of oil synthesis, low seed vigor, low kernel weight, shorter seed longevity, and poor germination of high-oil corn lines. It is necessary to make efforts to generate nested populations or use marker-assisted recurrent selection (MARS) to accumulate the advantageous quantitative trait loci (QTLs) in the pa-rental lines. The oil content of maize inbreeds and hybrids could be further improved with the use of transgenes, genomics, and metabolic engineering technologies in new insight for the development of high oil maize breeding and strategies.

Evaluating the Impact of UVC Exposure on Forage Maize Seeds under Hydroponic Condition

Background: UV radiation, with shorter wavelengths than visible light, plays a pivotal role in stimulating growth processes and boosting the synthesis of beneficial compounds in plants. Moreover, it triggers morphological changes and genetic responses, shaping plants’ physical traits and adaptability. Nevertheless, a nuanced understanding is necessary as excessive UV exposure can also cause harm, underscoring the complexity of the relationship between UV radiation and plants. The study aimed to evaluate the effect of ultraviolet C (UVC) light exposure on the germination and growth of forage maize seeds under controlled conditions in an indoor crop. One sample of seeds was exposed to UVC light, while the other was not. Methods: The experiment was carried out for 14 days, with the plants subjected to mixed blue-red light, fertigation and kept at a maximum external temperature of 30°C and maximum internal temperature of 25.1°C. UVC light is applied for 10 minutes to the seeds before germination. Result: The results showed that the plants exposed to UVC light had an average growth increase of 3cm compared to those that did not receive the treatment. However, the protein content of both sets of seedlings was similar. The study suggests that further research is necessary to determine the optimal duration and distance for UVC exposure to minimize any potential negative effects on the plants. It also highlights the need to investigate the effect of UVC radiation on the nutritional content of hydroponic crops to ensure that the increased growth does not come at the expense of nutritional quality. The experiment was carried out in Medellin, Colombia, with a maximum solar radiation of 1000 W/m2 and an altitude of 1500 meters. Overall, the study provides evidence that UVC radiation can enhance the growth of hydroponic maize seedlings, but more research is needed to fully understand its effects. At the end, there is an improvement in the growth of forage corn in seeds that have been subjected to UVC light compared to those that have not. It is worth highlighting the need for more research on changes in nutritional components in general.

Detection of kernels in maize forage using hyperspectral imaging

In this study, the use of hyperspectral imaging was examined to enhance the kernel processing assessment of maize forage, which is crucial for optimizing the production of dairy cow feed and biogas production. As the visual contrast between the kernels and other crop particles is quite limited, spectral imaging could provide better kernel classification. A pushbroom hyperspectral imaging system was used, scanning samples collected during maize harvesting in the 400–1000 nm range. A PLSDA model for pixel classification was developed to distinguish kernel spectra from the other particles in the forage, achieving a pixel-level classification accuracy of 95.2 %. Next, the most important wavelengths were identified by means of a stepwise procedure using the Wilks Lambda criterion. A Pixel classification using the top five discriminating wavelengths achieved nearly the same accuracy as the full spectrum wavelength model (95.2 % compared to 93.5 %) and did considerably better than the RGB classifier’s 86.3 % accuracy. Finally, these top 5 discriminating wavebands were applied in an object detection deep learning model, more specifically a Faster R-CNN model. While object detection based on these 5 wavebands stilled outperformed object detection based on RGB wavebands, detection performance, as measured by AP50, was rather low. This weak performance resulted from the low resolution of the hyperspectral imaging camera.

Effect of nitrogen fertilizer and zinc sulfate on growth, physiological, biochemical and nutrient use efficiency in fodder maize under irrigation regimes

To investigate the effect of nitrogen fertilizer and zinc (Zn) sulfate on growth, physiological, biochemical, and nutrient use efficiency in fodder maize under drought stress, an experiment was conducted during two cropping years 2019 and 2020. The experiment was performed as a split-factorial in the form of a randomized complete block design with four replications. The main factor was irrigation regimes in three levels: full irrigation (without stress or 100% of field capacity), irrigation based on 75% of field capacity, and irrigation based on 50% of field capacity. The first sub-factor included urea fertilizer at three levels of 0, 69, and 138 kg ha−1. The second sub-factor included foliar application of zinc sulfate at three levels of 0, 2, and 4 mg kg−1. The results showed that the highest fresh weight of maize fodder was obtained under conditions of full irrigation and the use of 138 kg ha−1 of N. The use of zinc at all irrigation levels increased the fresh weight of maize fodder. These results confirmed that if higher amounts of N are used, more zinc should be used to achieve a higher yield of maize forage. With the increase in the severity of drought stress, the concentration of nitrogen and phosphorus in the crop tissue, as well as the efficiency of using nitrogen and phosphorus, decreased. The highest value of nitrogen use efficiency was obtained in full irrigation conditions, using 69 kg ha−1 of N and 4 mg kg−1 of zinc. In addition, at all irrigation levels, the efficiency of using this element decreased with increasing zinc consumption.

Effects of Deep Vertical Rotary Tillage on Soil Water Use and Yield Formation of Forage Maize on Semiarid Land

Forage maize is one of the most important feed crops for livestock production, and is mainly grown in northwest China. However, their growth is often stressed by limited soil water availability due to the arid climate. To provide more soil moisture, a high-efficiency tillage technique was required to make crops effectively use soil moisture in deep soil layers. Deep vertical rotary tillage is a promising choice for this purpose. In this study, a long-term (2020–2022) field experiment consisting of three treatments, i.e., traditional tillage (TT), deep rotary tillage (DT), and deep vertical rotary tillage (VRT), was carried out in semiarid areas of Loess Plateau, northwest China, to investigate the effects of VRT on soil water storage (SWS), phase crop evapotranspiration (ETc) during the pre- and post-flowering periods, dry matter accumulation, grain yields and the water use efficiency (WUE) of forage maize. The results showed that VRT significantly improved the absorption of soil moisture from deep layers, especially in dry years. During the pre-flowering period of a dry year (2020), VRT decreased SWS by 7.6%–10.0% in the 60–180 cm layer, and by 17.6%–18.5% in the 180–300 cm layer, respectively, compared to DT and TT. As a result, VRT increased ETc during the pre-flowering period by 6.1% and 9.2%, respectively. In wet years (2021 and 2022), VRT increased total ETc by 2.0%–7.9% in 2021, and by 10.1%–14.9% in 2022, respectively. On average, VRT increased the dry matter weight per plant by 1.0%–7.8%, grain yields by 2.4%–38.6%, biomass yields by 3.4%–16.2%, and WUE by 10.1%–30.0%, respectively. Particularly, the benefit of VRT for increasing yields and WUE was more noticeable in dry years. It can be concluded that VRT is a drought-tolerant and yield-boosting tillage technique that is suitable for rain-fed forage maize in semiarid areas of Loess Plateau, northwest China.

Maximizing food equivalent unit yield for forage maize production without notably compromising dry matter yield and feed quality in a semi-arid region

Food equivalent unit (FEU) is a vector used to measure the value of food based on its calorie and protein content and their digestibility. However, the optimal planting density and N application rate for maximizing the FEU yield (FEUY) of forage maize (Zea mays L.) is still poorly understood in the fast-growing animal husbandry regions of the Chinese Loess Plateau. Here, a 2-year consecutive field experiment was conducted to explore the impacts of planting density, N application rate, and their interactions on growth, dry matter yield (DMY), forage quality, and FEUY of a dominant forage maize cultivar. Planting density significantly affected the stem diameter, LAI, DMY, and dry matter allocation (DMA) of the leaf. Initially, increasing the N rate increased the stem diameter, LAI, FEUY, and DMY of forage maize and then decreased. The stem diameter, LAI, FEUY and above-ground DMY peaked under 180 kg∙ha−1 N in both years. Moreover, N application significantly increased the crude protein content of the whole plant and decreased the acid detergent fiber content. The surface fittings of the 2-year study indicated that 110,000 plants∙ha−1 (plant density) and 171.2 kg∙ha−1 (N rate) obtained the greatest DMY (19.0 t∙ha−1). The grade index (a comprehensive evaluation index for forage quality) peaked at 15.4 MJ∙d−1 under 94,000 plants ha−1 and 270 kg∙ha−1. The 110,000 plants∙ha−1 plant density and 181.5 kg∙ha−1 N rate jointly maximized the FEUY (11,125.4 FEU∙ha−1), maintaining 99.9 % of the maximum DMY and 97.5 % of the maximum grade index. Thus, 110,000 plants∙ha−1 plant density and 181.5 kg∙ha−1 N rate are recommended for high-productivity forage maize production, without notably compromising dry matter yield and feed quality. This research is conducive to advancing the coordinated development of forage crop cultivation and herbivorous livestock farming in semi-arid rainfed areas.

Nitrogen Fertilization Strategies for Forage Maize Genotypes: Agronomic Performance, Nitrogen use Efficiency and Economic Assessment and Deter- mination of Economical N Fertilizer Rate

A field investigation was conducted using factorial experiment in randomized block design with seven genotypes and three nitrogen (N) levels (80, 120 and 160 kg N/ha) with three replications at Dr Rajendra Prasad Central Agricultural University, Pusa, Bihar, India during kharif season, 2022. The objective of the study was to assess the nitrogen use efficiency, productivity and profitability of forage maize genotypes under different N levels. Among, the genotypes, J-1006 and among N levels, application of 120 kg ha-1 registered the maximum green and dry fodder yield and crude protein yield (CPY). The highest partial factor productivity of N fertilizer (PFPN) was recorded with J-1006 (103.3 kg DM/kg N applied) and application of lowest dose i.e. 80 kg/ha (99.1 kg DM/kg N applied) among genotypes and N levels, respectively. J-1006 (Rs 78109 ha-1 and 3.62) and application of 120 kg N ha-1 (Rs 65716 ha-1 and 3.21) was profitable in terms of net returns and B:C ratio among genotypes and N levels, respectively. The economic optimum dose of N for tested fodder maize genotypes was found to be 139 kg/ha.

Spectral Index-Based Estimation of Total Nitrogen in Forage Maize: A Comparative Analysis of Machine Learning Algorithms

Nitrogen plays a fundamental role as a nutrient for the growth of leaves and the process of photosynthesis, as it directly influences the quality and yield of corn. The importance of knowing the foliar nitrogen content through Machine Learning algorithms will help determine the efficient use of nitrogen fertilization in a context of sustainable agronomic management by avoiding Nitrogen loss and preventing it from becoming a pollutant for the soil and the atmosphere. The combination of machine learning algorithms with vegetation spectral indices is a new practice that helps estimate parameters of agricultural importance such as nitrogen. The objective of the present study was to compare random forest and neural network algorithms for estimating total plant nitrogen with spectral indices. Five spectral indices were obtained from remotely piloted aircraft systems and analyzed by mean, maximum and minimum from each sample plot to finally obtain 15 indices, and total nitrogen was estimated from the georeferenced points. The most important variables were selected with backward, forward and stepwise methods and total nitrogen estimates by laboratory were compared with random forest models and artificial neural networks. The most important indices were NDREmax and TCARImax. Using 15 spectral indices, total nitrogen with a variance of 79% and 81% with random forest and artificial neural network, respectively, was estimated. And only using NDREmax and TCARmax indices, 73% and 79% were explained by random forest and artificial neural network, respectively. It is concluded that it is possible to estimate nitrogen in forage maize with two indices and it is recommended to analyze by phenological stage and with a greater number of field data.

Effects of harvest date and additives on maize silage quality under boreal conditions

There is increasing interest in Finland to cultivate maize for silage, although the climatic conditions are in the borderline for maize due to the short and cool growing season. This may result in an immature crop that differs from typical maize for ensiling by having low dry matter (DM) and starch concentrations. We evaluated the preservation characteristics of forage maize during 2019 and 2020 harvested in Helsinki, Finland, at two stages of maturity. The DM concentration of the crops ranged from 230 to 360 g kg-1, and starch concentration from 179 to 283 g kg-1 DM. The crops were ensiled in laboratory scale using four different chemical organic acid based additives or a heterofermentative lactic acid bacteria inoculant. A control silage without additive treatment was also included. All silages were well fermented with low pH (average 3.75) and proportion of ammonia N in total N (average 47 g kg-1). Formic acid based additives restricted silage fermentation and most chemical additives improved the aerobic stability of maize silages compared to the control and inoculant treated silages that, under the conditions of the current study, did not differ from each other.

Effect of Planting Density and Nitrogen Levels on the Yield Attributing Characters of Fodder Maize (Shalimar Fodder Maize-1)

Maize (Zea mays L.) is widely known as a ready-made fodder crop. Maize is the third major cereal crop in the world, and in India, it ranks third. Maize has been an important cereal crop owing to its highest production potential and wider adaptability to varied agroclimatic conditions, hence being called the ‘Queen of Cereals’. The production potential of forage maize can be altered with changes in agronomic practices. The present study was undertaken with the objective of improving the yield attributes and quality traits of forage maize (Shalimar Fodder Maize-1). The experiment consisted of two factors, viz., three planting densities (viz., D1= 30cm x 10cm, D2= 40cm x 10cm, and D3= 50cm x 10cm) as main plots and five nitrogen levels (viz., N1= Control, N2= 75% RDN (recommended dose of nitrogen), N3= 100% RDN, N4= 125% RDN, and N5= 150% RDN) as subplot treatments with three replications, laid out in split plot design (SPD). The parameters such as yield attributes, and quality parameters were significantly higher when plants were grown at a density of 30 cm x 10 cm with a nitrogen level of 150 % RDN.

Effects of intercropping and regulated deficit irrigation on the yield, water and land resource utilization, and economic benefits of forage maize in arid region of Northwest China

Intercropping has been widely recognized to have great advantages in terms of increasing yield, controlling pests and diseases, and saving land, particularly in developing countries. Regulated deficit irrigation reduces water consumption and improves water productivity (WP). However, it is unclear whether the combination of intercropping and deficit irrigation could improve crop yield and WP simultaneously. In this experiment, three planting modes, including forage maize (Zea mays L.) monoculture (M), lablab bean (Lablab purpureus L.) monoculture (L), and maize-lablab bean intercropping (ML) were used. Six irrigation modes were set for each planting mode, including severe water deficit (W1), late water deficit (W2), alternate water deficit (W3), late moderate water deficit (W4), early moderate water deficit (W5), and full irrigation (W6). Results showed that compared with M, the ML treatment significantly increased the fresh forage yield (9.8%–17.0%), hay yield (9.5%–13.1%), crude protein yield (22.9%–25.9%), and WP (7.8%–8.7%). The W5 treatment achieved similar fresh forage yield, hay yield, and crude protein yield as that of the W6 treatment but reduced irrigation water by 25% and increased the WP (21.9%–24.8%). Intercropping achieved a high-water equivalence ratio (WER;1.52–1.81) and land equivalence ratio (LER;1.56–1.84), indicating its advantages over monocultures. The W6 treatment had the lowest WER and LER, suggesting that excessive irrigation can reduce the efficiency of utilizing land and water resource in maze-based forage production. Among all treatments, ML–W5 achieved the highest net income and output to input ratio. Overall, intercropping of forage maize and lablab bean with moderate deficit irrigation at an early stage could be used as a high-yield and efficient forage production system in the arid areas of northwest China.

Drip-tape irrigation depth: water use efficiency, yield and forage quality in maize

Objective: to evaluate the effect of the drip-tape irrigation depth on the efficiency of water use, yield, nutritional quality and profitability of forage maize, a study was established by installing drip-tape at a depths 0.05, 0.15 and 0.30 meters. Design/ Methodology/ Approach: a randomized block experimental design was used. Treatments evaluated consisted of the installation of drip-tape at three depths 0.05, 0.15 and 0.30 m; each treatment in three replicates. The experimental unit was a 15 m2 surface (comprising four 5m-long furrows, with a 0.76 m separation between furrows). Results: results showed that with the drip-tape installed at a depth of 0.15 m, the highest biomass production and water use efficiency were obtained, without modifying the bromatological quality of the forage. However, the best benefit-cost ratio corresponded to the drip-tape installed at 0.3 m, recovering $1.27 for each MXN peso invested in crop production. Limitations/ Implications of the study: water scarcity in arid and semi-arid regions is a global problem, so it is necessary to use irrigation methods that make water use more efficient without reducing crop yield. Findings/conclusions: the installation of the drip-tape at a depth of 0.15 m is recommended, due to the improvement in yield and water use efficiency without affecting nutritional quality of the forage or profitability of maize crop.

Effect of phosphorus and zinc levels on maize (Zea mays L.) forage production grown in calcareous soil in Peshawar valley

Effect of phosphorus and zinc levels on maize (Zea mays L.) forage production grown in calcareous soil in Peshawar valley

Fermentation characteristics of maize–forage legume mixtures ensiled in small-scale silos

This study was conducted to evaluate the ensiling characteristics of maize–forage legume mixtures in small-scale silos. Sole and intercrops forage materials were harvested 80 days after planting and ensiled in small-scale silos, that is: plastic bags, plastic drums, and small pits, for 60 days. After ensiling, samples were collected to examine the chemical composition, microbial community and fermentation quality. Mixed silages stored in the drum silos had significantly (p ≤ 0.05) higher DM content (35.69%) than that from pit and bag silos. The drum silos had significantly (p ≤ 0.05) higher crude protein concentration (20.57% DM) in sole legume silages than other silo types. Neutral detergent fibre concentration (39.76% DM) of sole forage silages was greatest in bag silos than in other silos. High in vitro dry matter digestibility and water-soluble carbohydrate values (58.15 and 12.19% DM respectively) for mixed silages were recorded in drum silos. Bag silos showed lower numbers of lactic acid bacteria and higher populations of enterobacteria (4.86 and 4.26 log10 CFU g−1 respectively) in sole forage silages than other silos. Mixed silages ensiled in drum silos produced significantly lower (p ≤ 0.05) pH (3.03) and ammonia nitrogen content (3.73% TN) compared to pit and bag silos. The study concluded that ensiling maize–forage legume mixtures in drum silos can have a positive effect on the nutritive value of ruminants’ feeds. Therefore, the recommended forage type for ensiling is mixed silages.

Impacts of one-time large amounts of leafy vegetable waste incorporated into dryland fields on soil fertility and forage maize production

A large amount of vegetable waste is often dumped into the environment, causing serious pollution in major market distribution areas. This paper explores the feasibility and optimization of incorporating vegetable waste into dryland fields to improve soil fertility and crop productivity. The experimental design included three quantities of fresh leafy vegetable waste (QVW) buried into the soil: 800, 1600, and 2400 t·ha−1 and three covering soil thicknesses (CST): 10, 20, and 30 cm. Zero QVW was the control NW. By planting forage maize for two consecutive years, the variations of soil parameters and aboveground dry biomass (ABM) of maize plants were observed. Compared with the NW, the incorporation led to a distinct decline in soil bulk density (BD) by 2.00–17.41%, an increase in soil moisture (SM), organic carbon (SOC), total nitrogen (TN), and microbial carbon (MBC) by 5.84% −29.72%, 5.93% −50.17%, 16.98% −245.71% and 19.66% −304.08%, respectively. Topsoil conductivity (EC) and soil inorganic nitrogen (IN) were 3.81–9.43 fold and 19.02–88.29 fold that of NW. BD was significantly negatively correlated with the QVW and CST. SM, SOC, TN, and IN increased significantly with the increase of QVW and CST. The topsoil EC was significantly positively correlated with QVW, and negatively correlated with CST. The sequestration rates of SOC and nitrogen were significantly positively correlated with CST. The ABM in the incorporating vegetable waste treatment was 1.59–2.74 fold that of NW. The ABM showed a parabolic relationship with QVW (R2 = 0.97 **), and a linear relationship with CST (R2 = 0.91 **). Conclusively, the optimal QVW was 1346 t·ha−1, and the corresponding CST was 30 cm. Excessive QVW can cause topsoil salinization and constrain crop growth. Increasing CST contributes to sequestrating more water and nutrients and mitigating secondary salinization of the soil.

Cultivation of forage maize in boreal conditions – Assessment of trade-offs between increased productivity and environmental impact

The cultivation of whole crop forage maize (Zea mays L.) for cattle feed has a potential for increased forage yield while reducing nitrogen (N) fertilisation compared to perennial grass-based systems. However, the possible environmental trade-offs of forage maize cultivation remain unknown in the boreal region due to the short growing season which limits cultivation practices. The aim of this study was to compare the environmental impact of forage maize with more widely cultivated forage crops in Finland that include perennial silage grass mixtures and whole crop spring cereal harvested as silage. The use of plastic mulch film in forage maize cultivation was included in the assessment as well. A life cycle assessment (LCA) was conducted including impact categories for global warming potential; marine and freshwater eutrophication; terrestrial acidification; freshwater, marine and terrestrial ecotoxicity; land use; and fossil resource depletion. Additionally, soil organic carbon (SOC) stock changes under long-term cultivation of the studied forage crops were simulated with the C-TOOL and Yasso20 models with methodological comparisons. The only clear differences between the studied crops were that the land use was lower (−26–48%) for forage maize, and the freshwater eutrophication (+59–67%) and terrestrial acidification (+10–57%) were higher for perennial grasses compared with other forages. A risk for decreased SOC stock under continuous forage maize cultivation was observed. Forage maize could be used to supplement perennial grass cultivation without major associated environmental risks. Future research shall be conducted on the effect of forage choices on the environmental impact of boreal dairy milk production and on decreasing the current high uncertainty associated with nitrous oxide (N2O) emission factors and SOC stock modelling choices.

Breeding for improved digestibility and processing of lignocellulosic biomass in Zea mays.

Forage maize is a versatile crop extensively utilized for animal nutrition in agriculture and holds promise as a valuable resource for the production of fermentable sugars in the biorefinery sector. Within this context, the carbohydrate fraction of the lignocellulosic biomass undergoes deconstruction during ruminal digestion and the saccharification process. However, the cell wall's natural resistance towards enzymatic degradation poses a significant challenge during both processes. This so-called biomass recalcitrance is primarily attributed to the presence of lignin and ferulates in the cell walls. Consequently, maize varieties with a reduced lignin or ferulate content or an altered lignin composition can have important beneficial effects on cell wall digestibility. Considerable efforts in genetic improvement have been dedicated towards enhancing cell wall digestibility, benefiting agriculture, the biorefinery sector and the environment. In part I of this paper, we review conventional and advanced breeding methods used in the genetic improvement of maize germplasm. In part II, we zoom in on maize mutants with altered lignin for improved digestibility and biomass processing.

Nitrogen Fertilization Boosts Maize Grain Yield, Forage Quality, and Estimated Meat Production in Maize–Forage Intercropping

Crop–livestock integrated systems such as intercropping and crop rotation have been critical for sustainable agriculture, promoting land use intensification throughout the year. The success of these systems under no-till depends on numerous factors, and the choice of forage grass is paramount. In this study, maize grain yield, forage dry matter yield, bromatological quality, and estimated meat production were assessed in a field experiment where maize (Zea mays L.) was intercropped with Guinea grass (Megathyrsus maximus cv. Tanzania) and palisade grass (Urochloa brizantha cv Marandu) under N rates from 0 to 270 kg ha−1. Nitrogen fertilization resulted in the highest forage dry matter yield, on average, 2.9-fold higher than the N-unfertilized treatments. The highest maize grain yield was obtained with 270 kg ha−1 of N, 48% higher than all other treatments. Guinea grass intercropped with maize and fertilized with 270 kg ha−1 of N resulted in an estimated meat production 27% higher than palisade grass at the same N rate. However, at the final cut, Guinea grass fertilized with 270 kg ha−1 of N led to the highest neutral detergent fiber, acid detergent fiber, and cellulose. While palisade grass seems to impose lower competition with maize, Guinea grass increases estimated meat production.

Effects of Vachellia mearnsii Tannin Extract as an Additive on Fermentation Quality, Aerobic Stability, and Microbial Modulation of Maize Silage.

Maize silage is produced to alleviate the effects of forage shortages on ruminant animals, particularly during the dry season. Microorganisms play a significant role in silage fermentation and thus, to a large extent, determine the silage quality. The modulation of silage microorganisms may help to inhibit undesirable bacteria and improve the silage quality. Therefore, condensed tannin extract from Vachellia mearnsii bark was used as an additive in maize silage during ensiling. Hence, this study evaluated the effects of a tannin extract (condensed tannin) additive on the fermentative quality, aerobic stability, and bacterial composition of maize silage. A mini-silo experiment on maize with five treatments was conducted for 75 days. The silage treatments were as follows: (T1) maize forage with no inoculation (negative control); (T2) maize forage inoculated with LAB and 1% tannin extract; (T3) maize forage inoculated with LAB only (positive control); (T4) and maize forage inoculated with LAB and 2% tannin extract; (T5) maize forage inoculated with LAB and 3% tannin extract. The results showed that the additives modulated the silage microorganism composition. However, this was without affecting the silage's fermentative quality and aerobic stability. All the silages recorded a pH below 4.2, which indicated well-fermented silage. The tannin extract suppressed the growth of undesirable bacteria, such as Dysgonomonas, Gluconacetobacter and Clostridium genera, while promoting desirable bacteria, such as Lactobacillus and Weissella genera, which were attributed to the silage quality. It is thus concluded that tannins can be strategically used as silage additives to modulate the microbial composition of silage and improve the silage quality by promoting the dominance of the desirable bacteria in the silage.