Influence of seed proportion and cutting interval on fodder production potential of oat (Avena sativa L.) sown in mixture with legume and non legume

Abstract

A study was conducted to investigate the fodder production potential of oat sown in mixture with legume and non legume under different seeding proportions. For this purpose two field experiments were carried out at the Agronomic Research Area, Department of Agronomy, University of Agriculture, Faisalabad, during the years 2010-11 and 2011-12. In the first experiment, oat was intercropped with berseem at 100, 75, 50 and 25% of oat recommended seed rate (SP 1 , SP 2 , SP 3 , SP 4 , respectively) and mixtures were harvested after 60, 75 and 90 DAP. In the second experiment oat was intercropped with barley and canola with seeding proportion 75:25, 50:50 and 25:75% of oat:barley/canola. Seed ratios of each crop were based on recommended seed rates. Results of first experiment showed that on an average, increase in oat seed proportion from 25 to 50, 50 to 75 and 75 to 100% in mixture increased the germination count by 42.74, 25 and 21.82 seedling m -2 which reflect an increase of 88.05, 27.39 and 18.76%, respectively. During first cut, numbers of leaves plant -1 of oat were not significantly affected by its seeding proportion. Significantly higher numbers of leaves plant -1 were observed when harvesting was done 75 days after planting. Plant height, green and dry matter yields of oat were increased with advanced cutting stage and increased oat seeding ratio while number of tillers of oat per plant, berseem green and dry matter yields decreased with increased oat seeding proportion in the mixture. All mixtures produced mixed green forage/DM yields higher than berseem alone but lower than oat alone. Mixed (oat + berseem) green/dry forage yields at first cut increased with delayed cutting and increased oat proportion in mixture as on average, total dry matter yields were 2.84, 6.8 and 11.58 t ha -1 , at HI 1 , HI 2 and HI 3 , respectively. Similarly during first cut total dry matter yields at SP 1 , SP 2 , SP 3 and SP 4 were 7.50, 7.45, 7.30 and 6.57 t ha -1 , respectively. Crude protein and ash concentrations of both intercrops decreased while ADF and NDF concentrations increased with increased oat proportion in mixture and delaying the harvest. During both the years, treatment HI 3 -SP 2 produced highest crude protein yield (1.36 and 1.18 t ha -1 ). During first cut, on an average, CP concentrations of mixtures at SP 1 , SP 2 , SP 3 and SP 4 were 5.7, 7.8, 12.9 and 19.8 g kg -1 , respectively higher than oat alone. Maximum ADF and NDF concentrations were recorded by oat alone while the minimum was observed in berseem alone. On average berseem re-growth dry matter yield at SP 1 , SP 2 , SP 3 and SP 4 were 4.91, 5.62, 6.05 and 6.97 t ha -1 , respectively, however, maximum re-growth dry matter yield was recorded from berseem alone (8.66 t ha -1 ). Among the mixtures maximum re-growth crude protein yield (2.13 t ha -1 ) was recorded by treatment HI 3 -SP 4 . Maximum grand total (first cut + re-growth) green (9839 t ha -1 ), dry matter (19.72 t ha -1 ) and crude protein yields (3.33 t ha - 1 ) were observed from treatment HI 3 -SP 4 . All mixtures recorded higher LER values than unity (ranging from 1.01 to 1.28). Oat proved to be the dominant species in mixture based on competition ratio and aggressivity values. Therefore, to harvest higher dry matter yields of better nutritional quality distributed over season, oat ratio in mixture should not exceed 25% in mixture with berseem, and mixture should be harvested at early heading stage of oat. In the second experiment, oat plant height increased while number of tillers decreased with increased oat seeding proportion in mixture while number of leaves plant -1 remained unaffected. In mixture oat growth was more suppressed by canola than by barley as oat green and dry matter yields were lower in mixture with canola than barley. Green and dry matter yields of canola, as a fraction of its yield in sole crop, were higher in mixture than barley at each seeding proportion. During the second year, maximum dry matter yield was recorded xixfrom oat alone (16.93 t ha -1 ) while in first year 50:50% oat:canola mixture gave the highest dry matter yield (17.55 t ha -1 ) which was statistically similar to oat alone. No mixture showed clear yield advantage over component sole crops. Out of 12 mixtures (combined of both years) only 2 mixtures produced statistically higher dry matter yield than at least one of corresponding intercrop. CP yields (2.93 and 2.51 t ha -1 , during first and second year, respectivley) and concentrations were recorded maximum by canola alone. Oat:canola mixtures yielded more CP yields than oat:barley mixtures at all seeding ratios. At seeding ratios 25:75, 50:50 and 75:25% oat:canola mixtures have 13.36, 14.21 and 15.64% CP concentrations compared to 10.48, 10.77 and 10.88% by oat:barley mixtures, respectively. Significantly lower NDF and ADF concentrations were recorded from canola alone. NDF and ADF concentrations in mixtures decreased with increased barley and canola proportion in oat:barley and oat:canola mixtures, respectively. LER values exceeded unity only for mixtures 75:25% oat:barley (1.05 and 1.06 during first and second year, respectively) and 50:50% oat:canola mixture (1.03 and 1.03 during both the years, respectively). Barley and canola were dominant species in mixture with oat at 50:50% and 75:25% oat:barley/canola mixtures however oat was dominant species in 25:75% oat:barley/canola mixture. Therefore, to have higher forage yield of good quality oat:canola mixture should be sown with 50:50% ratio however if oat is to be mixed with barley, oat:barley ratio should be 75:25%.