Pakistan J. Agric. Res. Vol. 27 No.1, 2014 PERFORMANCE OF SUMMER FORAGE AND THEIR RESIDUAL EFFECT ON SUBSEQUENT OAT CROP IN SUBTROPICAL SUBHUMID POTHWAR, PAKISTAN

Imtiaz Ahmad Qamar*, Maqsood Ahmad*, Gulshan Riaz* and Sartaj Khan*

ABSTRACT:- The present study was conducted to assess the performance of five tropical forage legumes namely sesbania (Sesbania aculeata), cowpeas (Vigna unguiculata), rice (), lablab (Lablab purpureus) and cluster bean (Cymopsis tetragonoloba) with reference to a cereal fodder reference crop of millet (Pennisetum typhoides) and their residual effects on the succeeding oat crop at the National Agricultural Research Centre, Islamabad, Pakistan, under rainfed conditions without application of fertilizers in Randomized Complete Block Design. The highest dry matter yield was obtained from millet (8.9 tha-1), followed by cowpeas (4.5 tha-1), sesbania (4.4 tha-1), rice beans (2.9 tha-1), lablab bean (2.2 tha-1) while cluster bean produced lowest dry matter (1.7 tha-1). Cluster bean had the highest crude content (23.2 %) followed by cowpea (22.6 %), lablab bean (21.6 %), rice bean (20.1 %) and sesbania (19.1 %). Millet had the lowest crude protein content of 6.2%. Dry matter yield of oats owing to the previous crops was least after millet (7.5 tha-1) and ranged from 8.5 to 8.9 tha-1 after sesbania, cluster bean and cowpeas. Differences in crude protein content of oats as affected by the previous crops were non-significant and ranged from 9.4% to 9.7%. Differences in crude protein yield of oats as affected by the preceding crops were statistically significant and ranged from 705 to 854 kg ha-1. These differences were due to variation in their dry matter. It was concluded that cereal sequenced cropping system gave overall higher yield of the cropping system. Inclusion of tropical forage legumes into the current cereal based farming system of Pothwar would not only increase forage availability to the underfed of the area resulting in the increased livestock production but will also improve the N fertility of the soil. Potentially higher production of the subsequent non-leguminous crops will result as residual effect of this improved N status.

Key Words: Forage Legumes; Cropping System; Residual Effects; Dry Matter Yield; Crude Protein Yield; Pakistan.

INTRODUCTION Pothwar. Farmers are growing more and more cereals like sorghum, millet The increase in population and and wheat and are omitting traditio- reduction in productive agricultural nal fallow practices. The soils are in land due to urbanization have forced general low in fertility and in particu- farmers to adopt more intensive cro- lar deficient in organic matter. Grow- pping system in the rainfed areas of ing continuous cereal crops has fur- * Rangeland Research Institute, National Agricultural Research Centre, Park Road, Islamabad, Pakistan. Corresponding author: [email protected]

14 IMTIAZ AHMAD QAMAR ET AL. ther depleted the soil of nitrogen improve soil physical characteristics, (Qamar et al., 1999). Application of increase soil microbial activity, re- nitrogenous fertilizers in developing store organic matter and have effec- countries like Pakistan is limited due tive control on weeds (Ghosh et al,. to high cost, problems in getting cre- 2007). dit and poor economic conditions of The nitrogen-fixing legumes have the farmers. Cereal-cereal crop rota- been used in crop rotations for cen- tion has depleted the soils of impor- turies to reduce soil erosion, improve tant nutrients and organic matter soil organic matter and physical pro- (Hayat et al., 2008). perties, help reduce pest damage and There are large feed deficits contribute N to the succeeding crops. especially of green forage in Pakistan Sometimes legumes can be used to indicating that poor livestock keepers supplement perennial pasture, or cannot take advantage of the growing silage and hay crops (McCartney and market for livestock products to Fraser, 2010). Tropical forage legu- improve their livelihoods. Improve- mes may have a potential to improve ment and integration of forage nitrogen status of the soil and may be legumes into crop-livestock systems preserved as highly nutritious hay or can improve crops and livestock and added to maize silage to improve make the system more sustainable. crude protein content. Forage legu- Forage legumes provide high-protein mes when harvested, leave a sub- fodder for livestock, and improve soil stantial quantity of nitrogen into the fertility through nitrogen fixation soil in the form of crop residues and (Anonymous, 2012). After cereals, thus have a positive residual effect on legumes are the second most the yield of subsequent cereal crops. important source of human food and Rowland et al. (1994) have estimated animal forage. It is through nitrogen that significantly higher yields of fixation that legumes provide grain and straw yields of cereals can tissue that is high in protein. be expected when grown after legu- Rhizobia bacteria penetrate the mes in the temperate regions of legumes' roots, creating pink nodules . Nitrogen is the main limit- that bind nitrogen gas found ing factor to the grain and straw yield naturally in the atmosphere. This of the cereal crops after water (Shah fixation provides a usable source of et al., 2003). It has been estimated nitrogen to the legumes in return for that net benefits of the legumes are needed by the bacteria often in the range of 50-100kg ha-1 of (O'Hara, 2001). This mutual interac- the applied fertilizer (Phoomthaisong tion between the two species is known et al., 2003). The farmers are facing a as a symbiotic relationship. In agri- shortfall of 30-80 kg N ha-1. With cultural practices, legumes are used continued cereal cropping, fertilizer N as an organic way to amend the soil must be supplemented with rotations and reduce crop nutrient deficiency. utilizing legumes break crops to in- Mankind has known for millenniums crease supply and availability of of the importance of legumes environ- nitrogen (Mohd-Radzman et al., mentally. Legumes help in solublizing 2013). insoluble phosphorus in the soil into As there is a persistent energy soluble form available to the plant, crisis in the third world countries and

15 PERFORMANCE OF SUMMER FORAGE LEGUMES fertilizers are going out of the reach of (Lablab purpureus) and cluster bean the farmers due to their higher cost, (Cymopsis tetragonoloba) with biological nitrogen fixation by legu- reference to a cereal fodder reference mes has become one of the most att- crop of millet (Pennisetum typhoides) ractive strategies for the development and residual effect of these legumes of sustainable farming systems. The in comparison to millet on the yield role of biological nitrogen fixation in and crude protein of succeeding oats legumes is well understood and docu- crop in the subtropical subhumid mented, it has been reported that Pothwar plateau of Pakistan under some species/varieties of legumes are rainfed conditions. better than others (Okmen et al., 2007). A part of the biologically fixed MATERIALS AND METHOD nitrogen is available to the succee- ding non-leguminous crop through The study was conducted in the decomposition and mineralization of fields of Fodder Programme, Crop legume residues due to low C:N ratio Sciences Institute, National Agricul- as compared to cereal residues. Nitro- tural Research Centre, Islamabad, gen benefits in legume cereal cro- Pakistan, situated in the subtropical pping sequence have also been sub humid Pothwar plateau. Soil type attributed to transfer of biologically was non-calcareous silty clay with pH fixed nitrogen. On the contrary nitro- 7.4. The experiment was laid out in gen benefits are not attributed to the randomized complete block design transfer of the fixed nitrogen but to (RCBD) with three replications. The the greater immobilization of nitrate plot size was 10.8m2. Sowing of the during decomposition of cereal as co- experiment was done with a hand mpared to legume residues (Qamar, pulled drill at a recommended seed 1997). Nitrate sparing is a consistent rate. The crop was harvested at 50% trait of legumes in rotation systems flowering for legumes and heading and may be due to nodulation in- stage for millet from each plot for duces retardation of the legume root estimation of green fodder yield. One- growth (Marcellos et al., 1998). kg green fodder sample at harvesting Forage legumes have a great time was collected at random for potential as high quality feed and estimating dry matter yield from each capacity to fix atmospheric nitrogen plot. The collected sample were and can be included into the present weighed, dried in an oven at 100 oC for cereal – cereal cropping sequence of 48h and up to a constant weight and the Pothwar area for improving soil again weighed to calculate the dry fertility. Hence it was imperative to matter yield for each species. Five investigate their yield potential and were selected at random in their residual effects (Qamar et al., each plot for estimation of plant 1999). The present study was con- height. Crude protein was estimated ducted to assess the performance of by micro Kjeldahl method (AOAC, legumes in terms of yield and crude 1975). After this trial, boundaries of protein content of the five tropical for- each plot were clearly demarcated age like sesbania (Sesbania aculeata), and oats were sown in exactly same cowpeas (Vigna unguiculata), rice plots to find the residual effect on the beans (Vigna umbellata), lablab bean legumes, if any. The field was

16 IMTIAZ AHMAD QAMAR ET AL. ploughed up and was briefly left of all the species with a plant height of fallow prior to sowing the following 174 cm. Among legume species, ses- oats crop. The field was again pre- bania was tallest with a plant height pared with a cultivator plough (twice) of 156 cm followed by cowpeas (112 and plank and a high yielding oat cm), rice beans (91 cm), lablab bean variety “Scott” was sown exactly in (84 cm) and cluster bean (54 cm). the same plots with the help of a hand There were significant differences pulled drill with rows placed 30 cm among fresh and dry matter yield of apart. The crop was grown solely forage legumes and millet. The hig- under rainfed conditions without hest fresh matter yield was obtained fertilizer application. Data on plant from millet (22.3 tha-1). Among legu- height, fresh and dry weight, plant me species, sesbania produced the height and crude protein content of highest fresh matter of 19.2 tha-1 oats were collected at heading stage. followed by cowpeas (17.3 tha-1), rice Data were analyzed statistically using beans (14.5 tha-1), lablab bean (10.9 procedure described by Steel and tha-1) and least by cluster bean (6.5 Torrie (1980). tha-1). Dry matter yield almost follow- ed the same pattern. The highest dry RESULTS AND DISCUSSION matter yield was obtained from millet (8.9 tha-1), followed by cowpeas (4.5 Data on plant height, fresh forage tha-1), sesbania (4.4 tha-1), rice beans yield, dry matter yield, crude protein (2.9 tha-1), lablab bean (2.2 tha-1) while content and yield of sesbania (Sesba- cluster bean produced lowest dry nia aculeata), cowpeas (Vigna ungui- matter of 1.7 tha-1 (Table 1). culata), rice beans (Vigna umbellata), There were marked differences lablab bean (Lablab purpureus) and regarding crude protein content am- cluster bean (Cymopsis tetragono- ong all the forage legumes and millet. loba) along with a cereal fodder refe- Cluster bean had the highest crude rence crop of millet (Pennisetum ty- protein content of 23.2 % followed by phoides) revealed highly significant cowpea (22.6 %), lablab bean (21.6 differences (Table 1). Millet was tallest %), rice bean (20.1 %) and sesbania

Table 1. Plant height, forage yield and crude protein content of summer forage legumes and millet

Species Plant height Fresh matter Dry matter Crude protein Crude protein (cm) yield (tha-1) yield (tha-1) content (%) yield (kg ha-1)

Sesbania 156 19.2 4.4 19.1 843 Cowpeas 112 17.3 4.5 22.6 1007 Rice bean 91 14.5 2.9 20.1 572 Lablab bean 84 10.9 2.2 21.6 474 Cluster bean 54 6.5 1.7 23.2 388 Millet 174 22.3 8.9 6.2 551 LSD 6.8 1.1 0.2 0.6 40.1

17 PERFORMANCE OF SUMMER FORAGE LEGUMES (19.1 %). Millet had the lowest crude duced highest fresh and dry matter protein content of 6.2 % which was yield owing to the previous legume less than one third of any legume crop. Oats produced more than 30 species used in this study (Table 1). tha-1 fresh matter when grown after Differences of crude protein yield ha-1 cluster bean and sesbania (Table 2). were significant among all the species Dry matter yield of oats owing to the except for rice bean and millet where previous crops followed the same difference was non-significant. Cow- pattern. It was least after millet and pea produced more than 1000 kg ha-1 lablab bean (7.5 tha-1) and ranged protein followed by sesbania (843 kg from 8.5 to 8.9 tha-1 after sesbania, ha-1), rice bean (572 kg ha-1), millet cluster bean and cowpeas. Differe- (551 kg ha-1), lablab bean (474 kg ha-1) nces in crude protein content of oats whereas cluster bean produced only as affected by the previous crops were 388 kg ha-1 of crude protein yield non-significant and ranged from (Table 1). 9.4% to 9.7%. Differences in crude Data on plant height, fresh forage protein yield of oats as affected by the yield, dry matter yield, crude protein preceding crops were statistically sig- content and yield of oats was nificant and ranged from 705 to 854 significantly higher owing to the kg ha-1. These differences were due to previous sesbania and cluster bean differences in their dry matter yield (120 cm) and least after millet (111 (Qamar et al., 1999). cm). However, differences in plant Farmers of the Pothwar region height owing to cowpea, rice bean and are facing difficult situation to earn lablab bean were statistically non- their livelihood through rainfed agri- significant (P>0.05). Fresh forage culture. They have in general small yield and dry matter yield of oats as land holdings and limited resources affected by the previous crops showed to maximize their crop production marked differences and oats pro- through expensive chemical inputs. duced significantly (P<0.05) less yield Mono crop cereal production has after millet (24.8 t fresh and 7.5 t deteriorated soil fertility and organic DMha-1). On the other hand, oats pro- matter. Potentially productive soils

Table 2. Plant height, forage yield and crude protein content of oats owing to preceding summer forage legumes and millet

Previous Plant height Fresh matter Dry matter Crude protein Crude protein Crops (cm) yield (tha-1) yield (tha-1) content (%) yield (kg ha1)

Sesbania 120 33.8 8.9 9.6 854 Cowpeas 114 31.6 8.7 9.5 827 Rice bean 112 29.5 7.8 9.5 741 Lablab bean 110 27.9 7.5 9.6 720 Cluster bean 120 34.0 8.5 9.7 825 Millet 111 24.8 7.5 9.4 705 LSD 8.8 2.6 0.6 0.3 45.8

18 IMTIAZ AHMAD QAMAR ET AL. are going out of cultivation due to production but will also improve the rapid soil erosion (ABAD, 1987). Al- N fertility of the soil. Potentially though sufficient forage resources are higher production of the subsequent available in certain parts of the year, non-leguminous crops will result as they face acute feed deficit during residual effect of this improved N May-June and October-November status. However, it is suggested that (Mohammad, 1989). The results of long-term comprehensive trials on the present study suggest that if the cereal legume rotations on farmer's present farming system of the region field may be carried out to get is changed to include tropical forage comprehensive data before final legumes over some area during recommendations are made to the kharif, it will have beneficial effects on farmers. overall production, productivity and economics. Introduction of tropical LITERATURE CITED forage legumes will not only increase quality and overall availability of ABAD. 1987. Master Plan for Barani forage but will also improve the Areas Development. Interim Re- sustainability of the system. These port. Agency for Barani Areas legumes may be converted into high Development, Rawalpindi, quality hay for the feed deficit period Pakistan. of October and November. Anonymous. 2012. Annual Report for Results indicate that beneficial ICARDA Research Programme on residual effects owing to the tropical Livestock and Fish. ICARDA, forage legumes on the subsequent Aleppo, Syria. p.216-224. oats crop will produce more fodder AOAC 1975. Association of the oat during winter that can be Official Analytical Chemists. Offi- converted into hay or silage for May cial Methods of Analysis. 12th and June (Table 2). Forage legumes edn. Washington, DC. when harvested leave substantial Ghosh, P. K., K. K. Bandyopadhyay, amount of nitrogen into the soil as R. H. Wanjari, M. C. Manna, A. K. crop residues (Jabbar et al., 2010). Misra, M. Mahanty, and R. A. However, there are several factors Subba. 2007. Legume effect for which affect biological nitrogen enhancing productivity and nu- fixation and transfer this biologically trient use efficiency in major cro- fixed nitrogen to the subsequent non- pping systems – an Indian pers- leguminous crop. These vary from pective. J. Sustainable Agric. crop, site, season and cropping 30(1):59-86. sequence (Peoples et al., 2009). Hayat, R., S. Ali, M. T. Siddique, and It is concluded that cereal legume T. H. Chatha. 2008. Biological sequenced cropping system gave nitrogen fixation of summer legu- overall higher yield of the cropping mes and their residual effects on system. Inclusion of tropical forage subsequent rainfed wheat yield. legumes into the current cereal based Pakistan J. Bot. 40(2): 711-712. farming system of Pothwar will not Jabbar, A., R. Ahmad, I.H. Bhatti, A. only increase forage availability to the Rehman, Z.A. Virk, and S.N. underfed livestock of the area Vains. 2010. Effect of different resulting in the increased livestock rice-based intercropping systems

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