Effect of Irrigation Scheduling on F Different Directi Rice Varieties

Abstract

An experiment was conducted during Kharif 2015 at water management research farm, Sher-e-kashmir University of agricultural sciences and technology of Jammu (J&K), India to study the effect of irrigation scheduling on yield and nutrient uptake of different direct seeded basmati rice varieties. Results revealed that, irrigation schedules control recorded significantly higher grain yield (3370 kg ha-1) and straw yield (6030 kg ha-1) and which was on par with irrigation at 2 days interval through sprinkler at 150% PE over the other treatments. Var. Pusa-1509 recorded significantly higher grain yield (3240 kg ha-1) which was on par with Pusa-1121 (2960 kg ha-1) and non-significant effect of varieties was observed on the straw yield. However, irrigation schedules control recorded significantly higher uptake of nitrogen (61.09 kg ha-1), phosphorus (19.70 kg ha-1) and potassium (116.18 kg ha-1) and Pusa-1509 also recorded significantly higher uptake of nitrogen (51.87 kg ha-1), phosphorus (16.51 kg ha-1) and potassium (103.68 kg ha-1).

Introduction

Rice (Oryza sativa L.), the staple food of more than half of the population of the world, is an important target to provide food security and livelihoods for millions. World’s rice demand is projected to increase by 25% from 2001 to 2025 to keep pace with population growth (Maclean et al., 2002), and therefore, meeting ever increasing rice demand in a sustainable way with shrinking natural resources is a great challenge. The most common methods of rice crop establishment are direct sowing (dry direct seeding and wet direct seeding) and transplanting. Direct seeded rice (DSR) technique is becoming popular now a day because of its low-input demanding nature.

Presently, in direct seeded rice (DSR) is gaining momentum due to labor shortage during peak season of transplanting and availability of water for short periods. Direct seeding of rice refers to the process of establishing the crop from seeds sown in the field rather than by transplanting seedlings from the nursery. Direct seeding avoids three basic operations, namely, puddling (a process where soil is compacted to reduce water seepage), transplanting and maintaining standing water. DSR under aerobic conditions is one of the alternatives to replace traditional transplanting method. According to Lafitte et al. (2002), concept of DSR comprises of use of rice varieties, which are nutrient-responsive and well adapted to aerobic soils with yield potential of 70-80% of high-input flooded rice. The development of short duration, early-maturing cultivars and efficient nutrient management techniques along with increased adoption of integrated weed management methods have encouraged many farmers to switch from transplanted to DSR culture. Rice varieties exhibit wide variation in the production of high density grains which showed maximum potential for grain filling and test weight. Keeping these facts in view, the present investigation was undertaken as effect of irrigation scheduling on yield and nutrient uptake of different direct seeded basmati rice varieties.

Materials and Methods

An experiment was conducted during Kharif 2015, at water management research farm, Sher-e-kashmir University of agricultural sciences and technology of Jammu (J&K), India (situated at 32o40’ N latitude and 74o58’ E longitude with an altitude of 332 m above mean sea level). The soil was sandy loam in texture having a pH of 8.23, EC 0.18 (dS/m) organic Carbon (0.36%), total N (231.17 kg ha-1), available phosphorus (13.21kg ha-1) and available potassium (142.17 kg ha-1). The experiment was conducted in strip plot design with replicate thrice consisted of five irrigation schedules viz. Control (Normal transplanting with recommended water management practice), Irrigation/saturation at 0.3 bar suction at 15 cm depth* (* Suction measured by Tensiometer installed at 15 cm depth), Irrigation/saturation at 0.4 bar suction at 15 cm depth* (* Suction measured by Tensiometer installed at 15 cm depth), Irrigation at 2 days interval through sprinkler at 125% PE (cumulative value of pan evaporation for 2 days) and Irrigation at 2 days interval through sprinkler at 150% PE (cumulative value of pan evaporation for 2 days) in vertical plots and three varieties viz. Basmati-370, Pusa-1121 and Pusa-1509 in horizontal plots.

The crop was sown in the 3rd week of June. The recommended dose of fertilizer was applied as per the variety. Rice from each net plot in each replication was harvested and dried. The grains after threshing were weighed and recorded as grain yield per net plot. Further, this net plot grain yield was converted to grain yield per hectare.

Chemical analysis of plant sample

The plant samples were taken from each plot at the time of harvesting for estimation of N, P and K concentration. The samples were oven dried, then finely grounded with electric grinder and analyzed for nitrogen, phosphorus and potassium concentration. N, P and K uptake in grain and straw samples were calculated by multiplying per cent nutrient content with their respective dry matter accumulation as per the formula given below:

Nutrient content (%) x dry matter accumulation (kg ha-1)

Nutrient uptake (kg ha-1) = 100

Nitrogen content of grain and straw were estimated by modified micro-kjeldhal’s method as outlined by Jackson (1967) and expressed in per cent. The phosphorus content of grain and straw were determined by Vanadomolybdo phosphoric acid method and absorbance of the solution was recorded at 430 nm using spectrophotometer and potassium content in plant sample (grain and straw separately) was determined by flame photometer method.

Chemical analysis of soil

Representative soil samples from the experimental plot were drawn from the top 15 cm depth before sowing of the crop. Similarly, the surface soil samples from 0 to 15 cm depth were also collected from each experimental plot at harvest. Soil samples thus collected were air dried under shade, powdered with wooden mallet and passed through 2 mm sieve and analyzed for nitrogen, phosphorus and potassium content. Available nitrogen was determined by alkaline permanganate method as outlined by Subbiah and Asija (1956). Available phosphorus was determined by Olsen et al., 1954 and available potassium was determined by ammonium acetate extractable K method using flame photometer as outlined by Jackson (1973).

Statistical analysis and interpretation of data

Data recorded on various parameters of the experiment was subjected to analysis by using Fisher’s method of analysis of variance (ANOVA) and interpreted as outlined by Gomez and Gomez (1984). The levels of significance used in ‘F’ and ‘t’ test was P= 0.05. Critical difference values were calculated where F test was found significant.

Results and Discussion

Grain and straw yield

The outcomes of the study showed that scheduling of irrigation at various thresholds and basmati rice varieties significantly influenced the grain and straw yield is presented in Table 1. The highest grain (3370 kg ha-1) and straw yield (6030 kg ha-1) was observed with irrigation scheduling with Control (Normal transplanting with recommended water management practice) which was found at par with Irrigation at 2 days interval through sprinkler at 150 % PE. The decrease in grain and straw yield in other treatments was due to the decreased soil water content as a result of differential irrigation schedules and hence showed greater sensitivity for biomass production, leaf area and tillers production. There was a consistent trend of decline in grain and straw yield as the irrigation threshold increased from 0.3 to 0.4 bar. Lower yield of direct seeded rice under greater water deficit was largely due to reduced panicle density, higher tiller mortality and reduction in fertility which could be due to abnormal pollen development as a result of insufficient availability of assimilates under higher stress conditions as reported by Sudhir-Yadav et al. (2011), Zubaer et al. (2007) and Venuprasad et al. (2007). Application of irrigation at 2 days interval through sprinkler at 150% PE resulted in comparable yield to transplanted rice. This was due to the availability of moisture near to field capacity at 0-20 cm depth after irrigation scheduling which resulted in more availability of nutrients in soil solution.

In respect to var. Pusa-1509 was recorded significantly higher grain yield (3240 kg ha-1) which was on par with Pusa-1121 (2960 kg ha-1). This might be due to greater vegetative growth and better light interception which resulted in higher leaf area index and later on higher dry matter partitioning towards economic part. Yield variability among rice cultivars could also be attributed to genetic characters. Ramanjaneyulu et al. (2014) revealed that phenotypic expressions largely depended upon genotypic ability.

Nutrient Concentration

Among the treatment, the nitrogen, phosphorus and potassium content in grain and straw as influenced by irrigation schedules and varieties were differed significantly (Table 2). Highest N, P and K concentration was recorded with irrigation scheduling control which was on par with Irrigation at 2 days interval through sprinkler at 150% PE. In terms of varieties significantly highest N, P and K concentration was observed with var. Pusa-1509 which was found at par with Pusa-1121.

Nutrient uptake

Irrigation scheduling control recorded significantly higher nitrogen, phosphorus and potassium uptake by direct seeded rice (61.0, 19.7 and 116.1 kg ha-1, respectively) and which was on par with the Irrigation at 2 days interval through sprinkler at 150% PE (55.5, 17.4 and 110.1 kg ha-1, respectively). This might be due to the fact that under adequate soil moisture there is more solubilization of nutrients and thereby increasing more availability to plants and hence increased uptake.

However, Irrigation/Saturation at 0.4 bar suction at 15cm depth recorded significantly least nitrogen, phosphorus and potassium uptake by direct seeded rice (27.4, 7.8 and 75.4 kg ha-1, respectively). In terms of var. Basmati-370 recorded significantly least nitrogen, phosphorus and potassium uptake (36.2, 10.4 and 93.7 kg ha-1, respectively). This might be because of reason that Pusa-1509 being high yielding variety recorded higher N, P, K content and more dry matter accumulation that led to higher nutrient uptake values. Similar observations were recorded by Mallareddy and Padmaja (2013) and Mahajan et al. (2012).

Available nutrients in soil after harvest of crop

In soil, after harvest of crop, the available nutrients viz., nitrogen, phosphorus and potassium were significantly influenced by the irrigation schedules and varieties. Results revealed that, Irrigation/Saturation at 0.4 bar suction at 15cm depth recorded significantly higher available nitrogen, phosphorus and potassium in soil after harvest of crop (227.3, 12.6 and 138.9 kg ha-1, respectively). This might be due to differential uptake of N, P and K with irrigation schedules.

In the different basmati rice varieties Basmati-370 recorded significantly higher available nitrogen, phosphorus and potassium in soil after harvest of crop (221.0, 11.5 and 136.1 kg ha-1, respectively) as compared to Pusa-1121 and Pusa-1509 but both were statistically at par. This might be due to differential uptake of N, P and K by rice cultivars. Fageria et al. (2010) also reported difference in soil nutrient status after harvest of rice crop and observed that highest available N, P and K in soil was recorded with var. having significantly lower N, P and K uptake values for both grain and straw.