Forage sorghum production under rainfed farming in sites with and without climate restriction for maize cultivation

Forage sorghum is a crop that can be planted in semiarid regions, due to its greater adaptability to dry climate environments, and can replace maize in these regions, which are often unsuitable for its production. Thus, the objective of the study was to evaluate the structural, morphological and nutritional characteristics of 23 sorghum hybrids forage cultivated in rainfed conditions, planted in different climate conditions, comparing the hybrids, in order to determine what produces the best in the climatic conditions of the explored region, and also to indicate whether this crop can be planted as a replacement for maize in environments not suitable for planting it. The research was conducted in climate BSh in the Municipality of Alvorada do Gurgueia, and climate Aw in the Municipality of Bom Jesus, both in the state of Piauí from 2014 to 2015. Each trial consisted of 20 experimental forage sorghum hybrids [Sorghum bicolor (L.) Moench], and three commercial hybrids. A randomized block design was used, with three replications in a factorial scheme (2 × 23). The growth characteristics determined were hybrid × climate interaction for the variables plant height, lodging and leaf/stem ratio. For the variable number of tillers, there was a significant difference only between hybrids. There was no difference between hybrids only for the lodging variable of climate Aw. The other variables showed a difference in all hybrids evaluated. There was an interaction for production of dead matter and total dry forage mass between the different environments and hybrids evaluated. For leaf production, there was an effect only for the different environments. For the chemical characteristics, there was an interaction for all variables analyzed between the different environments and hybrids evaluated. The semi-arid region of the State of Piauí, climate BSh which presents a high climatic risk for maize cultivation, proved to be favorable for forage sorghum production. The forage sorghum also presented agronomic characteristics similar to those found in semi humid climate Aw, a favorable region for maize cultivation. In addition, the tested hybrids showed good chemical characteristics, so the BSh climate has great exploratory potential for the cultivation of forage sorghum.

Effect of replacement of forage sorghum silage with biomass sorghum silage in diets for dairy heifers

This trial aimed to analyze the replacement of forage sorghum silage (FS silage) with biomass sorghum silage (BRS 716 silage) in diets for heifers ¾ Holstein x ¼ Zebu on their nutrient intake and digestibility, nitrogen balance, microbial production, feeding behavior, and animal performance. Eight heifers with average age 18±4 months (mo) and average body weight (BW) 271 ± 57 kg were used. The experimental design was double-Latin square, 4×4, being four diets, four experimental periods and four animals. Four experimental diets with 0, 33, 67 and 100% substitution of forage sorghum silage with biomass sorghum silage were used. The roughage:concentrate ratio in the total dry matter (DM) of the diets was 75:25. The fraction “b” of DM was higher in the BRS 716 silage. There was no difference (p> 0.05) for dry matter intake (DMI; p = 0.45) and total digestible nutrients intake (p = 0.76). The dry matter digestibility (DMD), crude protein, ether extract and neutral detergent fiber increased linearly with the inclusion of BRS 716 silage. The feeding times, ruminating and idle have not been changed (p > 0.05). The replacement of FS silage with BRS 716 silage did not modify the average daily weight gain (ADG; p > 0.05; mean 1.30 ± 0.025 kg). Biomass sorghum silage can replace up to 100% forage sorghum silage in the diets of ¾ Holstein x ¼ Zebu heifers.

Swath Grazing Forage Sorghum and Pearl Millet Observations Regarding Quality and Utilization as Winter Feed

Swath grazing provides a viable winter feedoption for beef cows in Iowa.

TRINEXAPAC-ETHYL REDUCES PLANT HEIGHT AND SEED YIELD IN FORAGE SORGHUM

Forage sorghum presents tall plants, what makes mechanicalseed harvesting a difficult task. Plant hormones can reduce plant height andfacilitate the harvesting. Thus, the objective of this study was to evaluatethe effect of the growth regulator trinexapac-ethyl on plant height and seedyield in forage sorghum. This research was carried out at Embrapa Maizeand Sorghum, in two seasons (2017 and 2018), in a randomized completeblock design, four replications and three varieties (BRS Ponta Negra, 1141574and 0947216) under application of Trinexapac-ethyl in two stages of the plantgrowth (V8, V12, V8 + V12). The characteristics evaluated were: plant height,seed yield and mass of 1000 seeds. The effect of the hormone was significantin both stages of growth, with a significant reduction in plant height. Thehormone applied twice at growth stages V8 + V12 had a greater effect inreducing plant height. However, the hormone reduced seed yield in the threevarieties, what implies the need for further studies comparing the advantageof plant height reduction and the loss in seed yield.

Influence of previous crops and fungicide seed treatment in the incidence and control of damping-off caused by Rhizoctonia solani in cotton seedlings under greenhouse conditions

ABSTRACT The aim of this study was to verify the influence of previous crops and fungicide seed treatment in the incidence and control of damping-off caused by Rhizoctonia solani in cotton seedlings under greenhouse conditions. This experiment was carried out during two years at Embrapa Western Agriculture, in Dourados, Mato Grosso do Sul State, Brazil. In addition to cotton (treated and untreated seeds) and fallow, the following cover crops were tested as previous crops: black oats, millet, corn, forage sorghum, soybean, common beans, crotalaria (Crotalaria juncea), brachiaria (Urochloa ruziziensis) and brachiaria (Urochloa ruziziensis) + crotalaria (Crotalaria juncea). The fungicide mixture used as treatment to cotton seeds was triadimenol + pencycuron + tolylfluanid (50 + 50 + 30 g a.i./100 kg seeds). Seeds from cotton and previous crops were sown in soil contained in plastic trays and pots; the seeds were placed in individual and equidistant 3cm-deep wells. Inoculation of R. solani was obtained by homogeneously distributing the fungal inoculum onto the substrate surface (2.5g/tray and 0.34g/pot). The fungus was grown for 35 days on autoclaved black oat seeds subsequently ground to powder using a mill (1mm). Damping-off was daily evaluated from the seventh day after sowing. There was a significant effect of the interaction previous crops x fungicide treatment (P<0.05). The fungicide seed treatment was efficient in controlling seedling damping-off caused by R. solani and its effect was potentiated when grasses were the previous crops. Use of grasses such as brachiaria (Urochloa ruziziensis), black oats, millet, corn and forage sorghum as previous crops, besides fallow, significantly contributed to a smaller R. solani population in the soil, which resulted in lower rates of cotton seedling damping-off. On the other hand, using cotton continuously, as well as the legumes soybeans, beans, crotalaria (Crotalaria juncea), and brachiaria (Urochloa ruziziensis) + crotalaria (Crotalaria juncea) as previous crops to cotton, was consistently associated with higher rates of seedling damping-off, contributing to the increase or at least the maintenance of R. solani inoculum in the soil. The highest damping-off percentages were observed in plots under continuous cotton cultivation without fungicide seed treatment. The present results reinforce the need of improving damping-off control in cotton seedlings by adopting integrated management programs in areas infested with R. solani.

Effects of row spacing and planting density of forage sorghum on dry matter yield, morphologic parameters, nutritive value, and predicted milk yield of dairy cows

This study was undertaken to evaluate the effects of different row spacings and planting populations on dry matter yield, nutritive value, and predicted milk yield of BRS 658 forage sorghum hybrid growing in Brazilian conditions. A late relative maturity forage sorghum [Sorghum bicolor (L.) Moench; 110 d-115d to soft dough stage; BRS 658 – Embrapa] was planted at 3 row spacing (0.5, 1.0 and 1.5 m) and at 3 planting population (50 x 103, 100 x 103, and 150 x 103 plants.ha-1). Treatments were arranged in a randomized complete block design in a 3 x 3 factorial arrangement, using 4 replicate plots per row spacing x plant population combination. At harvest, weights of whole-plant sorghum forage were obtained to calculate DM yields. Chemical composition was assessed by performing wet chemistry analysis. Plant height, stem diameter, and harvest were performed 110 days after sowing (DAS). Estimated milk yield per unit of forage and per hectare were calculated using Milk2006. Summative equations were used to predict TDN and NEL. Yield of wet and DM forage sorghum exhibited a negative quadratic response as row spacing increased, reaching the maximum yield response at row spacing of 1.23m and 1.22m, respectively. In addition, negative linear effect was detected for both wet and DM sorghum forage yield as planting density increased. Regarding agronomic measurements, sorghum height exhibited a negative linear pattern as plant density increased. Otherwise, stem diameter increased as planting density increased. Whole-plant sorghum forage DM content decreased linearly with increasing planting density. Conversely, ashes increased linearly as planting density increased. Neutral detergent insoluble protein exhibited a positive quadratic effect with increasing planting density, reaching the minimum value when planting density was 104.2 x 103 plants.ha-1. Finally, a negative quadratic effect for predicted milk yield per hectare was also observed with increasing row spacing, whereas the maximum milk yield per hectare value was detected when row spacing was 1.20m. In conclusion, taking into account a subtropical climate, the ideal row spacing and planting density recommendation for a high yield and nutritional quality sorghum forage are 1.2 m and 104 x 103 plants.ha-1, respectively.