Influence of Nutrient Management Practices on Growth and Yield of Pearl Millet in Melia dubia Based Agri-Silvi System

Pearl millet (Pennisetum glaucum L.), the world’s hardiest warm season cereal crop (Reddy et al., 2012). Globally it ranks sixth after rice, wheat, maize, barley and sorghum in terms of area (Khairwal et al., 2007) and share 42% of total world production (Ramesh et al., 2006). In India, it is the fifth most important cereal grain crop next to rice, wheat, maize and sorghum. Pearl millet is an indispensable arid and semi-arid crop of India (Ramesh et al., 2006) cultivated as dual purpose (food and feed) crop in over 7.12 m ha ranking fourth among total cereals (Agricultural Statistics at a Glance, 2016). The recent spurt in prices of wheat, rice and maize and growing demand for non-food uses (cattle and poultry feed, alcohol and starch industries), pearl millet became cheaper alternative sources (Reddy et al., 2013). Further, the nutritional value of this crop offers much scope to development of value added products in new health conscious consumer segments (Yadav et al., 2011) as it contains more fibre and is good for diabetic International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 7 Number 06 (2018) Journal homepage: http://www.ijcmas.com


Introduction
Pearl millet (Pennisetum glaucum L.), the world's hardiest warm season cereal crop (Reddy et al., 2012). Globally it ranks sixth after rice, wheat, maize, barley and sorghum in terms of area (Khairwal et al., 2007) and share 42% of total world production (Ramesh et al., 2006). In India, it is the fifth most important cereal grain crop next to rice, wheat, maize and sorghum. Pearl millet is an indispensable arid and semi-arid crop of India (Ramesh et al., 2006) cultivated as dual purpose (food and feed) crop in over 7.12 m ha ranking fourth among total cereals (Agricultural Statistics at a Glance, 2016). The recent spurt in prices of wheat, rice and maize and growing demand for non-food uses (cattle and poultry feed, alcohol and starch industries), pearl millet became cheaper alternative sources (Reddy et al., 2013). Further, the nutritional value of this crop offers much scope to development of value added products in new health conscious consumer segments (Yadav et al., 2011) as it contains more fibre and is good for diabetic

ISSN: 2319-7706 Volume 7 Number 06 (2018)
Journal homepage: http://www.ijcmas.com A field experiment was conducted during Kharif, 2017 consisting of integrated nutrient management practices in Pearl millet inter cropped in Melia dubia based Agri-silvi system on sandy loam soils of Agroforestry Research Block, AICRP on Agroforestry, Rajendranagar, Hyderabad. The experiment was laid out in Randomized block design with three replication and eight treatments viz.,T 1 -Control (no fertilizer and manure), T 2 -100% RDF (80-40-30 NPK kg ha -1 ) through normal urea, T 3 -100% RDF through neem coated urea, T 4 -75% RD N + 25% N Poultry manure, T 5 -75% RD N + 25% N FYM, T 6 -75% RD N + Pongamia green leaf manure @ 10 t ha -1 , T 7 -75% RD N + Azotobacter @ 500 g ha -1 , T 8 -Sole crop without trees (100% RDF). Results of the experiment revealed that, sole crop without trees (T 8 ) recorded significantly higher plant height and dry matter accumulation followed by 100% RDF through neem coated urea (T 3 ) and 75% RD N + Pongamia green leaf manure 10 t ha -1 (T 6 ). Leaf area per plant is highest with T 8 but was on par with T 6 and significantly superior to rest of the treatments. SPAD meter readings were found highest with T 3 which was on par with T 8 and significantly superior to all other treatments. Grain yield and stover yield were found significantly highest with T 8 followed by T 3 and T 6 . and heart patients. Increase in productivity of pearl millet is likely to have high socioeconomic impact as it is cultivated by small and marginal farmers. Importance of the pearl millet in low cost agriculture of small and marginal farmers was highlighted during annual pearl millet workshop held at Junagadh Agricultural University on 23 March 2013 (ICAR 2013). In the workshop, pearl millet was described as a future crop under climate change scenario. Tolerance to drought and heat and better adaptability of pearl millet to climate change has been reported from African Sahel (CO 2 Science, 2011).
Agricultural practices have major impact on global carbon cycle and leading to increase in the global temperature during 20 th century by 0.6 ± 0.2°C at an average rate of increase of 0.17°C per decade since 1950 (Dubey and Lal, 2009). Hence, crop production practices which leads to lesser emissions are more desirable for sustainability and environmental safety from any production system. Urea formulations designed to synchronize N release with plant needs, optimum N supply to crops, proper animal and crop residue management, use of controlled release fertilizers, nitrification inhibitors and proper water management are being assessed to reduce emissions (Asgedom et al., 2014). Use of chemical fertilizers like neem coated urea inhibits the nitrification rate which is intended to improve the efficiency or uptake of N by plants and reduces NO 3 and N 2 O release into the environment (Hala et al., 2014).
Increased use of fertilizers without organic recycling has not only aggravated multinutrient deficiencies in soil-plant-system but also detrimental to soil health and has created environmental pollution. Judicious combination of organic manures and chemical fertilizers depending upon the availability, nature and properties of the soil and crops to be grown would not only maximize the crop production and improve the quality of agricultural produces but would also help in maintaining the soil fertility (Madhavi Lata et al., 2014). Nutrient management, recycling, soil quality improvement and land productivity as a holistic approach is good efficient indication which will be achieved through cropping system studies rather than single season crop. There is a great risk of growing food grains in degraded and cultivable wastelands.
Organic amendments such as FYM are the major source of organic manure. Poultry manure contains higher content of N which is readily available to crops and also possess various micro-nutrients (Pratap et al., 2008). Pongamia green leaf contains higher content of easily mineralizable N, important for improvement of soil physical properties and is a good source of nutrients for low fertility soils under dryland agriculture. Azotobacter is a free-living nitrogen fixing bacteria which fixes about 20-40 kg N ha -1 year -1 besides producing growth promoting substances (Ranveer Singh et al., 2013).
Due to global warming there was change in climate and impact is moderate to very serious in many countries in general and particular in African and Asian continents. To address climate change thoroughly, there is a need to bring the trees to the forefront and support farmers to intensify and diversify their agroforests (Aariff Khan and Krishna, 2016).Sequestering carbon in tree biomass by way of integrating trees into landscapes as agroforestry, forestry and plantations is a costeffective climate change mitigation strategy (Josep et al., 2008 andPrasad et al., 2012). Suitably selected trees in an agroforestry system enhance the system productivity and act as sink for atmospheric carbon. The system as a whole contributes to mitigate climate change with secondary benefits of food security, increased farm income, restored biodiversity, maintained watershed hydrology and improved soil health and people livelihood (Roy andTewari, 2012 andSingh et al., 2007). Due to harsh and fragile ecology of arid and semi-arid region, required to identify or develop economic and viable land use system. In such situation, agri-silvi system, particularly during initial 5-6 years have ample scope to exploit the interspaces of the trees for growing arable crops.
Among different tree species, Melia dubia has been screened as one of the best alternate of pulpwood species (Parthiban et al., 2009). It belongs to the family Meliaceae, commercially known as Malabar Neem and is locally called as Malabar Vepa. It is a large deciduous and fast growing tree with wide spreading branches, straight and tall bole. M. dubia with its multi-various uses like pulpwood, timber, fuel wood and plywood can fit as a suitable species for agro and farm forestry plantation programme (Saravanan et al., 2013).
With the present scenario of environment pollution which is detrimental to the sustainability there is an urgent need for adoption of farming practice which ensures soil health, human health, animal health and environmental health. Keeping this background in mind, an experiment was conducted to assess the influence of nutrient management practices on growth and yield of pearl millet in Melia dubia based agri-silvi System

Materials and Methods
Field experiment was conducted during kharif, 2017 at Agroforestry research block, AICRP on Agroforestry, Rajendranagar, Hyderabad which is geographically situated at 17 o 19' N latitude, 78 o 28' E longitude and at an altitude of 555 m above mean sea level which is situated in the Southern Telangana Agro-climatic zone of Telangana state. The experimental soil was sandy loam texture with pH (6.23), EC (0.135 dS m -1 ) and OC (0.77 %). The soil was medium in available nitrogen (287.6 kg ha -1 ), low in available phosphorus (41.31 kg ha -1 ) and medium in available potassium (214.0 kg ha -1 ). The experiment was laid out in a randomized block design and replicated thrice, treatments comprised of T 1 Control (no fertilizer and manure), T 2 100% RDF through normal urea, T 3 100% RDF through neem coated urea, T 4 75% RD N + 25% N Poultry manure, T 5 75% RD N + 25% N FYM, T 6 75% RD N + Pongamia green leaf manure @ 10 t ha -1 , T 7 75% RD N + Azotobacter @ 500 g ha -1 , T 8 Sole crop without trees (100% RDF).
Pearl millet was intercropped in Melia dubia of six years old wherein, the trees are at a spacing of 5 m x 4 m. Pearl millet was sown on 4 th July, 2017 and harvested on 6 th October. During the growing season, the mean weekly maximum, minimum temperature, relative humidity, sunshine hrs day -1 and rainfall were 30.3ºC, 21.9ºC, 90%, 66.9%, 4.7 hrs dy -1 and 6.6 mm in 0.4 rainy days. Pearl millet variety PHB-3 was planted at a spacing of 45 cm x 15 cm using seed rate of 5 kg ha -1 . The quantity of organic manures was applied as per the treatments. The N, P and K were applied through normal urea, neem coated urea, SSP and MOP as per the treatments. Entire dose of phosphate and potash and half dose of N were incorporated into the soil basally at the time of final land preparation. The remaining half N was applied as split application at 30 DAS. Azotobacter @ 500 g ha -1 was applied as seed treatment to the treatment specified.
Plant samples of pearl millet from gross plot were collected to record dry matter production at 30, 45, 60 DAS and at harvest. To determine grain yield, ear heads from the net plot were harvested and sun dried. Threshing was done by beating the ear heads with sticks.
The separated grains were cleaned, dried in sun to bring down the moisture content to 12%. To determine stover yield, stalks were cut at ground level and weighed after sun drying. The data were subjected to analysis of variance procedures as outlined for randomized block design factorial concept (Gomez and Gomez, 1984). Statistically significance was tested by F-value at 5 % level of probability and critical difference was worked out where ever the effect were significant.

Plant height
The influence of different nutrient management practices on plant height of pearl millet was significant in different treatments ( Table 1). As the crop advanced from 30 DAS to harvest, the plant height increased progressively and showed a marginal increase at harvest. In all stages of crop growth, significantly higher plant height was recorded in T 8 (sole crop without trees) (209.8 cm) at harvest over all treatments followed by T 3 (100% RDF through neem coated urea) (194.8 cm) which is on par with T 6 (75% RD N + PGLM 10 t ha -1 ) (183.2 cm).
During initial stages of crop, nutrients are readily available through inorganic fertilizers, whereas during later stages of crop the nutrients are supplied by both inorganic as well as organic forms due to decomposition, thus making higher availability of nutrients which resulted in better root development and high photosynthetic rate. Moreover, the nutrient concentration of pongamia green leaf manure is higher when compared to poultry manure and FYM and hence higher plant height was recorded. The increased availability of nutrients in the soil through mineralization of organic sources could have triggered cell elongation and multiplication resulting in high growth rate of shoots in turn plant height of pearl millet over control. These results were in agreement with the findings of Amit Kumar et al., (2017), Giribabu et al., (2010) and Dahiya et al., (2008).

Dry matter production
The dry matter production increased significantly at 30, 45, 60 DAS and harvest in all the treatments. Higher and continuous nutrient availability from sources of nitrogen and phosphorus upto the crop maturity improved the photosynthetic activities of the plant and caused increase in dry matter accumulation and also might be due to better translocation of carbohydrates and their utilization for the production of more leaves with increase in age and nutrient application and the cumulative effect of progressive increase in growth parameters. Similar findings were reported by Parihar et al., (2012) and Parashar et al., (2011) (Table 2).
T 8 treatment recorded significantly higher dry matter production at harvest (6178 kg ha -1 ) followed by T 3 treatment (5629 kg ha -1 ) and T 6 treatment (5133 kg ha -1 ) whereas T 2 (4642 kg ha -1 ) and T 3 (5629 kg ha -1 ) treatments are on par with each other. This might be due to nitrogen contribution from pongamia leaves and inorganic nitrogen supplied through fertilizers resulting in more number of tillers, maximum leaf area and high photosynthesis leading to accumulation of higher dry matter which reflected in stem length and thickness that lead to increased biomass either fresh or dry (Bheemaiah and Subrahmanyam, 2004). Balanced nutrition due to release of macro and micro nutrients with application of inorganics and organics under favourable environment might have helped in higher uptake of nutrients. This accelerated the growth of new tissues and development of new shoots that have ultimately increased the dry mater accumulation (Ramdev Togas et al., 2017). 75% RD N + 25% N FYM and 75% RD N + Azotobacter were on par with each other and significantly superior over control at all growth stages. The better response of crop to bio fertilizer over control might be attributed to increased nitrogen availability by fixing appreciable amount of molecular nitrogen and made available for plant growth and synthesizes growth promoting enzymes like indole acetic acid (IAA), gibberellins, vitamins and also altered the microbial balance in the rhizosphere and produced metabolites that stimulated the plant development (Patel et al., 2014).

Leaf area plant -1
The increase in leaf area was more between 45-60 DAS, however, it was maximum at 60 DAS. The production of maximum leaf area at 60 DAS can be due to more light interception and presence of more number of active leaves at this stage.
The decrease in leaf area plant -1 beyond 60 DAS may be attributed to the periodical shedding of mature and lower leaves.
Leaf area recorded in control was significantly lower as compared to all other integrated nutrient management treatments.
The increase in leaf area in pongamia green leaf manure along with inorganic fertilizer treated plot over the rest of the treatments could be due to higher available nitrogen and organic carbon with the use of organics that caused increase in leaf size which ultimately resulted in higher leaf area plant -1 . The results were in agreement with the findings of Giribabu (2006) and Prasad et al., (2010).

SPAD values
SPAD meter values indirectly indicate chlorophyll content in leaves in the crop canopy. SPAD values were found to increase gradually from 30 to 60 DAS and declined at harvest in all treatments (Table 4). This might be due to gradual loss of plant growth promoter activity over a period of time as they are photolabile and relatively unstable in vivo as well as in vitro system and also because of decrease in applied soil nitrogen due to leaching or by volatalization loss according to Shekhar Kumar (2004).

Table.1 Plant height (cm) of pearl millet as influenced by nutrient management in Melia dubia
based agri-silvi system Table.2 Dry matter production (kg ha -1 ) of pearl millet as influenced by nutrient management in Melia dubia based agri-silvi system  Table.3 Leaf area plant -1 (cm 2 ) of pearl millet as influenced by nutrient management in Melia dubia based agri-silvi system  Table.5 Grain and Stover yield of pearl millet as influenced by nutrient management in Melia dubia based agri-silvi system SPAD values at all growth stages were recorded higher in 100% RDF through neem coated urea on par with sole crop without trees and significantly superior over 75% RD N + PGLM 10 t ha -1 , 100% RDF through normal urea, 75% RD N + 25% N FYM, 75% RD N + 25% N poultry manure, 75% RD N + Azotobacter and control respectively.

Grain yield
It was revealed from the results ( Table 5) that the highest grain yield was produced with sole crop without trees (3182 kg ha -1 ) followed by 100% RDF through neem coated urea(2920 kg ha -1 ) which was on par with 75% RD N + PGLM 10 t ha -1 (2667 kg ha -1 )and significantly higher over rest of the treatments. The percentage increase in grain yield with sole crop, 100% RDF through neem coated urea and 75% RD N + PGLM 10 t ha -1 over control was 273.47%, 243.89% and 213.03% respectively. Reduced yield in pearl millet intercropped in Melia dubia treatments compared to sole crop may be ascribed to competition for light, moisture and nutrients with suppressing effect on crops and reduced solar radiation on crop canopy. Similar results were reported by Deswal and Nandal (2008), Prasad et al., (2011) and Kumar et al., (2013).
Increase of grain yield might also be due to the increased photosynthetic activity which resulted in higher accumulation of photosynthates and translocation to sink due to better source and sink channel which resulted in higher grain yield. These observations corroborate with those made by Patil and Shete (2008). The efficacy of inorganic fertilizer in improving grain yields was much pronounced when it was combined with organic manures (Pratap et al., 2008). The variation in yield is attributed to improved growth and ear head characters that increased availability and absorption of nitrogen from soil which enhanced metabolic activities, translocation and synthesis of nutrients resulted in higher grain yield. The beneficial effect of nitrogen application through various sources on grain yield of pearl millet has also been reported by Meena et al., (2003) and Hadda et al., (2005).
Significant increase in yield with organics and inorganics together was attributed to build up of humus, organic carbon which improves the soil properties and increased availability of nutrients with addition of manure.
An increase in uptake of plant nutrients empowered the plant to manufacture more quantity of photosynthates resulting in more stover yield. Similar results were reported by Thumar et al., (2016).