Effect of irrigation and fertigation scheduling on growth and yield of guava ( Psidium guajava L . ) under meadow orcharding

A study was conducted during 2009 to 2010 and 2010 to 2011 to find out the effect of irrigation and fertigation scheduling on growth and yield of guava (Psidium guajava L.). The experiments were laid out in factorial randomized block design with sixteen treatment combinations which included four irrigation levels (basin, 50, 75 and 100% irrigation of irrigation water/cumulative pan evaporation) along with four fertigation levels, including, basal dose, 50, 75 and 100% water soluble fertilizers and replicated thrice. The nitrogen, phosphorus and potassium (NPK) fertilizers were applied through fertigation as well as soil application to test various attributes of 3-years-old guava cv. Shweta under meadow (ultra high density) orcharding. The investigation indicated that 100% irrigation of irrigation water/cumulative pan evaporation (I3) through drip resulted in maximum plant height (1.97 m), canopy volume (0.98 m 3 ), girth of primary branches (2.41 cm), leaf area (62.94 cm 2 ) and fruit weight (163.71 g). However, I2 (75% irrigation of irrigation water/cumulative pan evaporation) resulted in maximum plant spread east westnorth south (1.91 to 1.79 m), fruit yield/plant (5.87 kg) with benefit:cost ratio of 2.62. Use of 60, 30 and 30 g NPK/plant/year produced maximum leaf area (63.39 cm 2 ), fruit weight (162.43 g) and fruit yield/plant (6.01 kg). Interaction effect of irrigation and fertigation levels showed that 100% irrigation of irrigation water/cumulative pan evaporation + 100% water soluble fertilizers gave maximum plant height (2.07 m), canopy volume (1.24 m 3 ), girth of primary branches (2.48 cm), leaf area (66.08 cm 2 ), fruit diameter 6.69 cm (polar) and 5.97 cm (equatorial), fruit weight (182.17 g), yield/plant (6.59 kg). However, maximum benefit:cost ratio of (2.91) was obtained as 75% irrigation of irrigation water/cumulative pan evaporation + 75% water soluble fertilizers.


INTRODUCTION
Drip irrigation proved efficiently in providing irrigation water and nutrients to the roots of plants, while maintaining high yield production.Modern drip irrigation has arguably become the world's most valued innovation in agriculture since the invention of the impact sprinkler, which replaced flood irrigation.This is because high water application efficiencies are often possible with drip *Corresponding author.E-mail: sunil_ciah@yahoo.co.in.irrigation, since there is reduced surface evaporation, less surface runoff, as well as minimal deep percolation.Moreover, a drip irrigation system can easily be used for fertigation, through which crop nutrient requirements can be met accurately.Due to the way the water is applied in a drip system, traditional surface applications of timedrelease fertilizer are sometimes ineffective, so drip systems often mix liquid fertilizer with the irrigation water.Water is the most limiting natural resource hindering the economic development of any developing country, also decrease crop yield.In the present-day context, improvement in irrigation practices, including schedules and methods, is needed to increase crop production and to sustain productivity levels.Basin irrigation is the conventional method widely used to irrigate most of the fruit crops grown in Rajasthan, India.However, this method uses more water compared to other high-tech water-saving irrigation methods such as sprinkler, drip etc.Many researchers have reported the higher application efficiency of drip irrigation systems over the conventional basin irrigation systems (Salvin et al., 2000;Bharambe et al., 2001;Agrawal and Agrawal, 2007) compared to drip and basin irrigation systems in fruits and found that there was savings of 40 to 60% more irrigation water than basin irrigation methods.Singh et al. (2006) reported that irrigation requirement met through drip irrigation along with polythene mulch gave the highest yield of guava (37.70 t/ha) with 164% greater yield as compared to ring basin irrigation.
Fertilizers should be applied in a form that becomes available in synchrony with crop demand for maximum utilization of nutrients from fertilizers.Fertigation enables adequate supplies of water and nutrients with precise timing and uniform distribution to meet the crop nutrient demand.Further, fertigation ensures substantial saving in fertilizer usage and reduces leaching losses (Kumar et al., 2007).Similar to frequent application of water, optimum split applications of fertilizer improves quality and quantity of crop yield than the conventional practice.Sharma et al. (2011) observed higher guava yield through fertigation than basin irrigation.
Guava is an important fruit crop grown in almost all parts of India and is one of the most preferred fruit crops in Southern Rajasthan.Due to lack of information on irrigation management techniques, the average yield of the crop in Southern Rajasthan is very low because of either excess or deficit soil moisture.The crop is generally grown with basin irrigation, which has low water use efficiency.Many farmers in the state are now becoming interested in growing the crop with drip irrigation.The government is also offering financial assistance to farmers who use this technique, especially for fruit and vegetable crops.However, some farmers in the state are reluctant to adopt drip technology due to lack of information on irrigation and fertigation scheduling techniques.Also, not much information on seasonal water requirements of guava by drip irrigation is available.Hence, this present study was undertaken to examine the growth and yield using different irrigation and fertigation schedules by drip irrigation and to suggest the most efficient irrigation and fertigation schedule that would attain the highest growth and yield of the crop.

Experimental site and climate
The experiment was conducted at Horticulture Farm of the Mechanical analysis of soil showed that the soil contains 31.85%sand, 28.40% silt and 39.75% clay portion.Organic carbon, available nitrogen, phosphorus and potassium of soil were 0.75%, 253.5, 27.5 and 271.4 kg ha -1 , respectively.

Treatment application
The experiment was laid out in factorial randomized block design (FRBD) with three replications during 2009 to 2010 and 2010 to 2011, on uniform 3-years-old 'Shweta' guava plants planted at the spacing of 2 × 1 m.There were 4 levels of irrigation, namely basin irrigation (I0), 50% irrigation of irrigation water/cumulative pan evaporation (IW/CPE) (I1), 75% irrigation of IW/CPE (I2) and 100% irrigation of IW/CPE (I3) and 4 levels of fertigation basal dose (60, 20, 40 g NPK/plant/year (F0), 30, 10, 10 g NPK/ plant/year water soluble fertilizers (WSF) (F1), 45, 20, 20 g NPK/plant/year WSF (F2) and 60, 30, 30 g NPK/plant/year WSF (F3) along with 16 treatment combinations.The experiment was laid out in factorial randomized block design with 3 replications and 2 plants were kept in each treatment.The irrigation was applied to guava plants as per treatments.The basin irrigation system was scheduled on the basis of climatological approach with an IW/CPE ratio of 0.8.The drip irrigation was scheduled as suggested by Mane et al. (2006).The drip irrigation was supplied at one day interval while, basin irrigation at 7 days interval.The daily USDA class A open Pan evaporation readings were obtained from meteorological observatory, Agronomy farm of Rajasthan College of Agriculture, Udaipur.As per the treatments, water soluble fertilizer grade  were applied in 5 splits from fruit set to maturity stage and remaining nitrogen were supplemented through urea.The basal dose (F0) of phosphorus and potassium were fully applied by ring method in the month of July, while nitrogen was applied in 2 split doses, one with basal dose in July and another after fruit setting in October through ring basin at 30 cm away from main trunk.Nitrogen was applied as urea, phosphorus as single super phosphate and potassium as muriate of potash.The plants were prunned twice a year in the months of February and September.

Observations recorded
The data on tree height (m), plant spread from north-south and east-west (m) and girth of primary branches (cm) were recorded using meter scale and vernier caliper.Leaf area (cm 2 ) was measured with the help of leaf area meter (Systronics).Five leaves per plant run on the leaf area meter and averaged.It directly gives the value in m -2 .Canopy volume was calculated as the method described by the Samaddar and Chakrabarti (1988) and expressed in (m 3 ).
Fruit diameter, polar and equatorial was taken with the help of Vernier caliper.Average fruit weight was recorded with the help of an electronic balance.Mature fruits were harvested periodically from each treatment separately and the weight was recorded with the help of single pan balance and expressed in kilogram.Further, fruits/ha were calculated by multiplying the fruit yield/plant to the number of plants/ha.The relative economics of drip and different fertigation levels along with man power required for the irrigation, fertigation and weeding on the basis of cost of treatment on plot basis and converted into fruit yield/plant as well as per hectare.The net income was obtained by subtracting the treatment cost from gross income.It was expressed on net excess income over the control.

Statistical analysis
The data obtained on various characters were subjected to Factorial RBD analysis and interpretation of the data was carried out in accordance to Panse and Sukhatme (1985).

Growth characteristics
The maximum plant height 1.97 m was recorded in I 3 (100% irrigation of IW/CPE) as compared to basin irrigation (I 0 ) 1.82 m.Under fertigation levels, maximum plant height 1.96 m was recorded in F 3 (60, 30, 30 g NPK water soluble fertilizers) as compared to minimum 1.81 m in F 1 (30, 10, 10 g NPK water soluble fertilizers).The interaction effect of irrigation and fertigation levels was non-significant.
Plant spread (EW&NS) was maximum in I 2 (75% irrigation of IW/CPE) 1.91 m and 1.79 m as compared to minimum 1.74 m and 1.65 m in basin (I 0 ).However, under fertigation levels maximum plant spread was recorded in F 3 (60, 30, 30 g NPK water soluble fertilizers) 1.89 m and 1.80 m as compared to minimum 1.70 and 1.65 m in F 1 (30, 10, 10 g NPK water soluble fertilizers).Interaction effect of irrigation and fertigation levels showed significant effect on plant spread E-W direction only.On two years pooled data basis I 2 F 3 (75% irrigation of IW/CPE + 60, 30, 30 g NPK water soluble fertilizers) resulted maximum plant spread 1.97 m as compared to minimum 1.54 m in I 0 F 1 (basin irrigation + 30, 10, 10 g NPK water soluble fertilizers).The interaction effect on plant spread N-S was non-significant.
Girth of primary branches was maximum in I 3 (100% irrigation of IW/CPE) 2.41 cm.However, it was minimum in I 1 (50% irrigation of IW/CPE) 2.28 cm.Under fertigation levels maximum girth of primary branches 2.41 cm was in F 3 (60, 30, 30 g NPK water soluble fertilizers) as compared to F 1 (30, 10, 10 g NPK water soluble fertilizers) 2.27 cm.Interaction effect of irrigation and fertigation levels was non-significant.Leaf area was influenced by irrigation level I 3 (100% irrigation of IW/CPE) resulted in maximum leaf area of 62.94 cm 2 as compared to basin (I 0 ) 56.12 cm 2 .Further, the application of F 3 (60, 30, 30 g NPK WSF) produced maximum leaf area 63.39 cm 2 as compared to minimum 57.20 cm 2 in F 1 (30, 10, 10 g NPK plant -1 year -1 ).Interaction effect of irrigation and fertigation levels was non-significant.
Application of drip irrigation during experimentation effectively increased vegetative growth parameters over basin irrigation and the favourable influence on vegetative growth of the plant might be due to the constant supply of water to the plant.This maintains the soil moisture at optimum level eliminating water stress to the plant resulting in greater vigour (Subramanian et al., 1997).Bhardwaj et al. (1995) and Maas and Van (1996) reported that vegetative growth of the plants was found to be influenced favorably by uniform distribution of water in the soil through drip irrigation to young fruit trees.Plant height and canopy spread were significantly better under alternate day drip irrigation over conventional method in aonla (Chandra and Jindal, 2001).The results are in accordance with the findings of Shukla et al. (2001) in aonla, Shirgure et al. (2004) in acid lime, Sulochanamma et al. (2005) and Agrawal and Agrawal (2007) in pomegranate.
Among various fertigation levels, higher doses showed better vegetative growth of the plant.It might be due to application of higher dose of fertilizers attributed to better nutritional environment in the root zone as well as in plant system.Nitrogen, phosphorus and potassium are most indispensable of all mineral nutrients for growth and development of the plant as these are the basis of fundamental constituents of all living matter (Throughton et al., 1974).According to Baruah and Mohan (1991), potassium application increases leaf area index in banana.Both nitrogen and potassium may be important nutrient for leaf growth and development.Total nitrogen and potassium uptake was appreciable higher with increasing nitrogen and potassium rate with more frequent than with less frequent fertigation.Klein et al. (1989) found that vegetative growth was correlated positively with the amount of nitrogen applied.Results are in accordance with the findings of Shirgure et al. 2001) in Nagpur mandarin.
The results are in the confirmation with Prasad et al. (2003) found that fruit quality in terms of weight, size and juice content was better in drip-irrigated pomegranate plants than that in the basin irrigated plants.Similarly, in fertigation level F 3 (60:30:30 g NPK plant -1 year -1 ) registered the maximum physical characteristics of fruits closely followed by in level F 2 .The possible explanation for increase in fruit diameter, average fruit weight, pulp weight, and pulp/ seed ratio by F 3 treatments might be due to increase in vegetative growth.Kumar et al. (2009) recorded highest bunch weight (weight, length and diameter) with 100% recommended dose of fertilizer in banana.Similar findings were also observed by Boora et al. (2002) in sapota.The interaction effect between irrigation and fertigation levels were found significant for average fruit weight, pulp weight and pulp/seed ratio.The results are in conformity with the findings of Thakur and Singh (2004).They reported that application of 100% of recommended dose through fertigation recorded maximum fruit weight, pulp weight, length and breadth of mango cv.Amrapali fruit.Similarly, Singh et al. (2005) also reported that trickle irrigation with 947 L water per plant per year + 100% recommended N fertilizer gave the maximum fruit length, fruit circumference and fruit weight in papaya.

Fruit yield
The 2-year pooled data presented in Table 3 reveals that irrigation, fertigation level and their interaction resulted to significant increase in the fruit yield/plant and per hectare.Among various level of irrigation, maximum fruit yield was recorded in I 2 (75% irrigation of IW/CPE) (5.87 kg/plant  et al. (1999) who obtained higher yields from dripirrigated plots at an IW: CPE ratio of 0.8 compared with those irrigated using a conventional system in papaya.Patil and Patil (1999) observed that guava fruit yield was highest when irrigated at an IW: CPE ratio of 0.8 and Singh et al. (2007) revealed that 164% greater yield in case of drip (VD) as compared to that of ring basin irrigation (VRB) in guava.The treatment drip (VD) showed the highest yield and lowest yield was observed in ring basin (VRB) irrigation method.Patel and Patel (1998) reported that the increase in yield was mainly because of better growth of the plant under optimum amount of nutrients in pomegranate crop.Firake and Kumbhar (2002) yield obtained upon treatment with 100% NPK RRSSF + DI was significantly higher than 100% NPK RRCF + DI (11.88 vs. 9.54 t/ ha) and was at par with 70 % N, 80% P and K + DI and 70% NPK + DI in pomegranate.Similarly, Singh and Singh (2005) in papaya and Sharma et al. (2011) in guava also reported similar findings.
The results are in conformity with the findings of Agrawal and Agrawal (2007) who found maximum B:C ratio in 60% of water applied through drip (1:2.85) and lowest under control (1:1.95) in pomegranate.Similarly, Singh et al. (2007) also found maximum benefit-cost ratio (6.73) in guava under drip and least in the treatment ring basin (2.16).However, under fertigation level water soluble fertilizers that are given through drip are more expensive but the results are encouraging.Nevertheless, basal dose of N, P and K could be given through drip in the form of urea, single super phosphate and muriate of potash which is less expensive compared to the water soluble fertilizers used under the study.In turn, this may further increase the magnitude of net profit.Therefore, research on this line is called for.

Table 1 .
Effect of irrigation and fertigation levels and their interaction on plant height, plant spread, canopy volume, girth of prim ary branches and leaf area of guava.

Table 2 .
Effect of irrigation and fertigation levels and their interaction on fruit diameter, fruit weight, pulp weight and pulp: seed ratio of guava.

Table 3 .
Effect of irrigation and fertigation levels and their interaction on yield and B:C ratio of guava.