Nitrogen uptake in cotton+greengram intercropping system as
influenced by integrated nutrient management
S. M. NAWLAKHE 1 AND D. D. MANKAR2
Department of Agronomy
Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola-444 104 (M. S.), India
(Received : February, 2010)
ABSTRACT
The field experiments on cotton+greengram intercropping were conducted during thekharif seasons of 2000-01 and 2001-02 under rainfed condition in randomized block design with three replications to study the effect of integrated nutrient management on nitrogen content of seed, straw and nitrogen uptake of seed, straw and total uptake of cotton and greengram individually as well as in cotton+greengram intercropping system. The results revealed that nitrogen content in seed was improved by application of inorganic, organic and INM. There was, however, no significant difference between inorganic and integrated nutrient management. Nitrogen content in straw was improved by integrated nutrient management treatments. Effect of FYM was greater than Leucaena. Total uptake of nitrogen was increased by integrated nutrient management using FYM over inorganic fertilizer alone. Integrated nutrient management recorded 3.2 and 3.8 kg/ ha increased nitrogen uptake during 2000-01 and 2001-02, respectively.
Key words : Cotton, greengram, integrated nutrient management, intercropping systems, nitrogen uptake
INTRODUCTION
Cotton is an important cash crop of central and western part of country with huge potential in employment generation and has important role in economic activity. Average productivity of lint in India is hardly 300 kg/ ha as compared to the world average of 550 kg/ha (Singhal, 2003). In India, Maharashtra is important cotton growing state occupying cotton acreage of about 31.05 lakh hectares with average lint yield of 147 kg/ha during the year 2001-02 (Anonymous, 2003). The productivity is still low (126 kg/ha) in Vidarbha. The major causes of low productivity of cotton in Vidarbha are erratic behaviour of rainfall, growing of cotton on marginal and sub-marginal land and less adoption of improved technology.
Under rainfed farming situation, intercropping in cotton is advised instead of sole cropping which gives stability in production to augment the monetary returns and also may compensate losses under adverse condition. Greengram as intercrop in cotton appears most
suitable in Vidarbha under dryland condition. This is because of biomass incorporation, smothering effect on weeds, least competition and addition of nitrogen by biological fixation of nitrogen.
Cotton being a important cash crop, the use of chemical fertilizer is very popular. Fertilizer is costly input, its availability is becoming a problem and also has harmful effect on environment. To overcome these problems and to maintain sustainability, better fertilizer economy, yield maximization and efficient natural resource management, several workers suggested integrated nutrient management supply system (Pagaria et al., 1995; Nambiar and Abrol, 1989; Padole et al.,
1998).
The information on nitrogen uptake in relation to yield is essential to work out the quantity of fertilizers/nutrients to be supplied for cotton+greengram intercropping system.
Integrated nutrient management is studied in sole crops but the information on integrated nutrient management under intercropping system is limited. Considering
the importance of integrated nutrient management and alternative to present fertilizer recommendations with economizing production and sustainability, the present investigation was planned.
MATERIALS AND METHODS
A field experiment was conducted during thekharif seasons of 2000-01 and 2001-02 under rainfed condition on farm of AICRP for Dryland Agriculture, CRS, Dr. PDKV, Akola (M. S.) in randomised block design replicated thrice. Net plot size was 8.4 × 9.0 m and variety used was PKV-Rajat (AKH-84635) of cotton and Kopergaon of greengram. The eight treatments comprising organic and inorganic sources of fertilizer were :
T1–Control i. e. no fertilizer
T2–50 kg N+25 kg P2O5/ha through inorganic fertilizer i. e. 100% RDF
T3–25 kg N+12.5 kg P2O5/ha through inorganic fertilizer i. e. 50% RDF
T4–25 kg N/ha through Leucaena lopping
T5–25 kg N/ha through farm yard manure T6–25 kg N+25 kg P2O5/ha through inorganic
fertilizer+25 kg N/ha through Leucaena
lopping
T7–25 kg N+25 kg P2O5/ha through inorganic fertilizer+25 kg N/ha through farm yard manure
T8–50 kg N/ha through Leucaena lopping+25 kg P2O5/ha through inorganic fertilizer
The spacing for cotton was kept at 60 x 30 cm and for greengram 30 x 10 cm. One row of greengram was intercropped between two rows of cotton. The experiment is the part of
long term experiment that was taken on same land since 1987-88 without changing randomization. The season of 2000-01 and 2001-02 represents fourteenth and fifteenth year of the experimentation.
The experimental soil was clayey in texture, slightly alkaline in reaction (pH 7.8), available N (264.8 kg/ha) and P2O5 (30.2 kg/ ha) were medium, while available K2O was moderately high (315.9 kg/ha). The climate of area is semi-arid with annual average precipitation of 815 mm in 35 days received from June to September. The temperature range of area is 10.70C to 42.40C. During
2000-01 total rainfall received was 534.3 mm (76% of normal ) in 33 days and during 2001-02 was 619.1 mm (83.5% of normal) in 32 days.
The observations on nitrogen content (%) of seed and stalk of cotton, grain and straw of greengram and nitrogen uptake (kg/ha) by seed and stalk of cotton, by grain and straw of greengram and total uptake by cotton, total uptake by greengram and total uptake (kg/ha) by intercropping system in cotton+greengram intercropping were recorded. The plant samples were collected after harvest and analysed for nitrogen content by standard methods (Piper, 1966).
RESULTS AND DISCUSSION I. Nitrogen Uptake Study of Cotton
The data regarding nitrogen content and its uptake by cotton stalk and seed are presented in Table 1.
Table 1. Nitrogen content and its uptake by cotton as influenced by different treatments
Treatment N content (%) Nitrogen uptake (kg/ha)
Stalk Seed Stalk Seed Total
2000-01 2001-02 2000-01 2001-02 2000-01 2001-02 2000-01 2001-02 2000-01 2001-02 T1 0.388 0.397 3.628 3.316 3.65 6.29 21.88 9.88 25.53 16.17 T2 0.457 0.463 4.188 4.338 5.89 8.60 37.90 17.00 43.79 25.60 T3 0.416 0.425 3.717 3.415 4.55 7.57 26.99 10.25 31.54 17.82 T4 0.490 0.481 4.090 3.782 5.96 9.31 35.99 14.26 41.95 23.57 T5 0.518 0.510 4.102 3.795 7.03 9.64 37.37 12.33 44.40 21.97 T6 0.522 0.527 4.116 3.810 6.66 11.01 36.26 15.35 42.92 26.36 T7 0.528 0.535 4.129 3.822 7.41 12.71 39.64 16.70 47.05 29.41 T8 0.509 0.503 4.109 3.800 5.90 9.62 34.52 12.88 40.42 22.50 S. Em± - - - 1.07 0.66 C. D. (P=0.05) - - - 3.24 2.01
Nitrogen content in cotton stalk : During both the years higher nitrogen content in cotton stalk was observed due to application of half dose of N through chemical fertilizer+ half dose of N through FYM/Leucaena lopping with full phosphorus (T7 and T6). This was closely followed by the treatments having sole organic N through FYM (T5) and inorganic P + full N through Leucaena loppings (T8). Among the exclusive chemical treatments, full recommended dose of fertilizer (T2) recorded more nitrogen content than half RDF (T3) and
control (T1). But the inorganic alone resulted in less percentage of nitrogen in cotton stalk when compared with pure organic (T4 and T5) and combined organic + inorganic treatments (T6, T7 and T8). Similar trend of nitrogen content was observed during both the years. The higher nitrogen content due to integrated nutrient management, organic and inorganic treatments over control might be due to more availability of nitrogen compared to control.
Nitrogen content of cotton seed : Nitrogen content of cotton seed was increased due to various treatments over the control. Highest nitrogen content (4.188%) was recorded due to application of full recommended dose through fertilizers (T2) during both the years. This was followed by the treatments having integrated use of organics +inorganics (T7, T6 and T8) and sole organic treatments (T5 and T4). Half RDF (T3) through fertilizer recorded low nitrogen in cotton seed as compared to full RDF. Nitrogen uptake by cotton crop : During both the years the uptake of nitrogen
by cotton seed was more than five times that of stalks. Treatment differences were statistically significant during both the years of experimentation.
During 2000-01, total uptake of nitrogen by cotton was highest (47.05 kg/ha) where the crop was supplied 50% N dose through inorganic + 50% N through FYM with full phosphorus dose (T7). It was significantly higher than the total uptake by treatment T2. It was followed by half N through FYM (T5) and full recommended dose of fertilizer (T2). Sole
organic application of FYM/ Leucaena loppings (T5 and T4) recorded increased total uptake of nitrogen but the treatment (T4) had lower uptake than the integrated nutrient treatments (T6 and T7) and 100% RDF (T2).
During 2001-02, the total nitrogen uptake of 29.41 and 26.36 kg/ha was observed due to supply of integrated nutrient using FYM (T7) or Leucaena loppings (T6) and was followed by full RDF (T2). Alone Leucaena application (T4) recorded more nitrogen uptake than sole FYM (T5). Simillar results were also reported by
Pagaria et al. (1995), Durgude et al. (1996), Padole et al. (1998) and Santhy et al. (1998). II. Nutrient Uptake Study of Greengram
The data regarding nitrogen content and its uptake by greengram plant and grain are presented in Table 2.
Nitrogen content in straw of greengram : The nitrogen content was increased due to various treatments over control (Table 2). The nitrogen content in straw Table 2. Nitrogen content and its uptake by greengram as influenced by different treatments
Treatment N content (%) Nitrogen uptake (kg/ha)
Straw Grain Straw Grain Total
2000-01 2001-02 2000-01 2001-02 2000-01 2001-02 2000-01 2001-02 2000-01 2001-02 T1 0.621 0.610 3.122 3.119 2.94 5.39 7.09 11.01 10.03 16.40 T2 0.680 0.687 3.180 3.184 5.12 8.45 9.25 16.05 14.37 24.50 T3 0.672 0.675 3.164 3.173 3.91 7.39 8.16 12.85 12.07 20.24 T4 0.677 0.682 3.170 3.180 3.64 6.48 7.93 12.27 11.57 18.75 T5 0.686 0.698 3.185 3.352 3.48 6.64 7.61 12.57 11.09 19.21 T6 0.700 0.704 3.220 3.296 4.07 8.19 8.89 14.77 12.96 22.96 T7 0.715 0.727 3.382 3.450 6.09 9.71 10.72 19.11 16.81 28.82 T8 0.682 0.690 3.196 3.255 4.49 8.12 8.66 14.68 13.15 22.80 S. Em± - - - 0.60 1.03 C. D. (P=0.05) - - - 1.82 3.14
was higher due to application of inorganic fertilizer+organic manure (treatments T7 and T6) when compared to those with pure organic or inorganic treatments during 2000-01. These treatments were followed by 50% N through sole FYM (T5) and complete RDF (T2). Application of full RDF (T2) observed more nitrogen content in straw than that of sole
Leucaena loppings application (T4), use of half RDF (T3) and control.
During 2001-02, the nitrogen content in straw was higher due to application of N through fertilizer+N through FYM/Leucaena
loppings in 50 : 50 proportion with full phosphorus (T7 and T6). These were followed by full organic FYM (T5), organic+inorganic
treatment (T8) and pure RDF (T2) but latter not varying among themselves in nitrogen content. Regarding chemical fertilizer, similar trend was observed.
Nitrogen content in greengram grain : All the treatments positively influenced the nitrogen content in greengram grain as compared to control treatments. During 2000-01, use of organic manure through Leucaena
loppings/FYM combined with chemical fertilizer (T7,T6 and T8) enhanced the nitrogen
content than sole organic or inorganic treatment. Among sole organic treatments application of FYM (T5) showed more nitrogen content in greengram grain than application of sole Leucaena loppings (T4). However, nitrogen content was near about similar to that recorded under complete RDF treatment (T2). Half RDF (T3) was low in nitrogen content than full RDF but more than control.
During 2001-02, the organic+inorganic treatment (T7) ranked higher in nitrogen content in greengram grain and was followed by pure FYM application (T5). Rest of the trend was found similar to that of previous year.
Nitrogen uptake by greengram crop : During both the years, the treatment differences were significant and all the treatments recorded more nitrogen uptake than control i. e. no fertilizer.
During both the years, the greengram cv. Kopergaon removed significantly higher nitrogen when N was applied through fertilizer and FYM in 50 : 50 proportion with full
phosphorus dose (T7) than full recommended dose through fertilizers (T2). Among other integrated treatments, T6 and T8 not much variation in uptake of nitrogen was observed. The sole N application through either Leucaena
loppings or FYM (T4 and T5) ranked low in nitrogen uptake than integrated and sole chemical treatments. Regarding chemical fertilizers, application of ½ RDF (T3) although recorded minimum nitrogen uptake than full RDF (T2) but was more than control and pure organic treatments (T4 and T5).
III. Total Uptake of Nitrogen by Cotton+ Greengram Intercropping System The data presented in Table 3 show that during 2000-01 the integrated combination of half dose of nitrogen through inorganic plus remaining half dose through FYM (T7) removed higher N, followed by full recommended dose through fertilizer (T2). Among other integrated treatments (T6 and T8) no much variation in uptake of nutrients was observed. Exclusive nitrogen application through Leucaena
loppings/FYM (T4 and T5) ranked low in N uptake than complete inorganic treatment (T2). Regarding chemical fertilizer, application
of half RDF (T3) although recorded minimum nutrient uptake than full RDF (T2) and pure organic treatments (T4 and T5) but was more than control (T1).
Table 3. Total uptake of nitrogen by cotton+greengram intercropping system as influenced by different treatments and pooled mean yield Treatment Total uptake of nitrogen (kg/ha)
2000-01 2001-02 Average T1 35.56 32.57 34.07 T2 58.16 50.10 54.13 T3 43.61 38.06 40.84 T4 53.52 42.32 47.92 T5 55.49 41.18 48.34 T6 55.88 49.32 52.60 T7 63.86 58.23 61.05 T8 53.57 45.30 49.44 S. Em± 1.49 1.25 -C. D. (P=0.05) 4.53 3.82
-During 2001-02 integrated nutrient combination using FYM (T7) recorded higher nitrogen uptake and was followed by full RDF treatment (T2). Among organics only, no variation in nitrogen uptake was noticed in
T4 and T5, although the uptake was less than integrated treatments (T6, T7 and T8) and full RDF (T2). Complete RDF (T2) removed more nitrogen than half RDF (T3) and control.
On the basis of averages of total uptake of nitrogen, it was found that integrated nutrient management treatments using FYM (T7) removed higher nitrogen and was followed by full RDF (T2).
Thus, it can be concluded that nitrogen content in seed was improved by application of inorganic, organic and integrated nutrient management. There was, however, no significant difference between inorganic and integrated nutrient management treatments. Nitrogen content in straw was improved by integrated nutrient management treatments. Effect of FYM was greater than Leucaena. Total uptake of nitrogen was increased by integrated nutrient management treatments using FYM over inorganic fertilizer alone. Integrated nutrient management treatments recorded 3.2 and 3.8 kg/ha increased nitrogen uptake during 2000-01 and 2001-02, respectively.
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