STUDIES ON INTEGRATED NUTRIENT MANAGEMENT IN WHEAT

Transcription

1 STUDIES ON INTEGRATED NUTRIENT MANAGEMENT IN WHEAT THESIS ABSTRACT SUBMITTED TO CHAUDHARY CHARAN SINGH UNIVERSITY, MEERUT, U.P. FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN AGRONOMY BY BHUPENDRA KUMAR Enrol. No. M UNDER THE SUPERVISION OF Dr. O.V.S. Thenua Assoc. Professor & Ex. Head DEPARTMENT OF AGRONOMY AMAR SINGH (P.G.) COLLEGE, LAKHAOTI BULANDSHAHR, (U.P.), INDIA 2012

2 Studies on integrated nutrient management in wheat Introduction Bhupendra Kumar and O.V.S. Thenua Department of Agronomy Amar Singh (P.G.) College, Lakhaoti Bulandshahr, (U.P.), India Wheat (Triticum aestivum L.) is grown in an area of 29.3 million hectares with a total production of 85.9 million tonnes at an average yield of 2938 kg/ha in India. In the Indo-Gangetic plains it is grown with the use of high analysis chemical fertilizers alone in the last several years causing wide spread deficiency of nutrients. The declining nutrient supplying capacity and deficiency of several nutrients in the wheat growing areas has been observed to be one of the major reasons for the lowering of average yield of the crop in many areas in the northern India. The first and most immediate attention should be given to nutrient management to sustain and increase the productivity of wheat and also to reduce the cost of production by reducing the use of costly chemical fertilizers. The technique of soil fertility management is one of the critical components of any cropping system designed to enhance and sustain productivity. Therefore, the technology adaptation for correct dose of fertilizer that can assure economic optimum crop yield as well as sustain soil nutrient reserve, yet not environmentally degrading in the long run is the need of time. Further, the rise in the prices of chemical fertilizers has made them unaffordable to many small and marginal farmers. Even the resource rich farmers are feeling that their use is resulting in reduced factor productivity. Nutrient needs of crop plants can be met through a number of sources viz., chemical fertilizers, organic manures, recycled wastes and by-products, biological nitrogen fixation (BNF), natural minerals and to a lesser extent nutrients recycled through irrigation waters and precipitation. These supplement the soil nutrient reserves for nourishing the crops. The organic and biological sources of nutrients have low nutrient contents and are usually not abundantly available. An enormous amount of organic fertilizer would be required to maintain soil fertility levels. Therefore, a combination of both inorganic and organic fertilizers is the answer for sustainability. The integrated plant nutrition system (IPNS) involves judicious combination of fertilizer, biofertilizers and organic manures. The conjunctive use of various sources of nutrients including chemical, biological and organic sources of nutrient is one of the options available for mitigating the nutrient deficiencies in many areas.

3 Therefore it is necessary to compare various organic manures with chemical fertilizers to find the most effective combination. Keeping all these things in view a research project entitled Studies on integrated nutrient management in wheat was carried out to study and evaluate the sources of nitrogen in conjunction with biofertilizers on the performance of wheat. Materials and Methods A 2 year field experiments were conducted at the Agronomy Research Farm, Kisan (P.G.) College, Simbhaoli Ghaziabad (U.P.) during rabi seasons of and The experimental site had a subtropical climate with a hot and dry summer, very cold winter and mild to heavy rains. The soil was sandy loam in texture, well drained and of medium fertility with slightly alkaline in reaction. It was poor in organic carbon with low to medium in fertility status. The treatments consisted of different combinations of sources and levels of nitrogen viz., control (T 1 ), Azotobactor (T 2 ), Azospirillum (T 3 ), farm yard manure 5 t /ha (T 4 ), 50 kg N /ha (T 5 ), 100 kg N /ha (T 6 ), 150 kg N /ha (T 7 ), 50 kg N /ha + Azotobactor (T 8 ), 50 kg N/ha + Azospirillum (T 9 ), 50 kg N/ha + Azotobactor + 5 t FYM /ha (T 10 ) and 50 kg N/ha + Azospirillum + 5 t FYM /ha (T 11 ). These 11 treatments were tried in randomized block design replicated thrice. The treatment plots were 8 m x 3.6 m in size. Wheat var. Shresth (HD 2687) was used as test crop. The crop was raised as per the recommended package of practices except the treatments. The experiment was carried out as per the normal procedures for standard agronomic trial. The crop was quite normal and the influence of the treatments was not affected by any other extraneous factors like adverse climate or incidence of pests and diseases etc. All the growth and yield parameters were recorded at regular interval as per the standard procedures and they were analyzed as per the analysis of variance (ANOVA) technique and the critical differences between the treatments were worked at 0.05 probability. The economics were worked out using the prevailing market prices for both inputs and outputs. The chemical analysis of plant and soil was carried out to work out the nutrient uptake and soil nutrient availability status after the harvest of crops in both the years.

4 Results and Discussion Growth attributes The plant height was significantly influenced by the nutrient management practices (Table 1). The application of 150 kg N /ha recorded higher plant height. As nitrogen is very critical for initial growth, its sufficient availability will play a pivotal role and acts as precursor for many other growth activities. Thus the nutrient management practices involving higher nitrogen content increased the yield. Conversely the plant height was the lowest in the no nitrogen applied control. Similarly the control with no nutrient application recorded the lowest drymatter accumulation among all the treatments. As nutrients play a crucial role in both these parameters, the absence of nutrients in the initial stage itself affected both plant height and drymatter accumulation. This was further confirmed when both plant height and drymatter accumulation were observed to be significantly higher with the application of nutrients in the treatments viz. 150 kg N/ha, 100 kg N/ha (T 6 ),, 50 kg N/ha + Azotobactor + 5 t FYM/ha and 50 kg N /ha + Azospirillum + 5 t FYM /ha. The seed treatment with biofertilizers viz. Azotobactor and Azospirillum although increased the plant height and drymatter accumulation as compared to control it was not comparable with other treatments. Since the biological nitrogen fixation starts after initial growth and ceases early, it may not be sufficient alone. However its conjunctive use could be more effective as observed in 50 kg N /ha + Azotobactor and 50 kg N /ha + Azospirillum showing higher plant height and drymatter accumulation. Likewise the farm yard manure (FYM) as source of nutrients is another factor that also influences the other soil biological as well as chemical conditions leading to higher growth. The number of tillers in a plant is another indicator as to how the plant growth system is conditioned by the nutrient management practices. As the tillering habit follows a particular phasic manner, within that the nutrient application shows the response. The nitrogen being a major nutrient it recorded higher tiller number at the highest level of nitrogen, indicating the higher requirement of nitrogen for cereals. The biofertilizers, farm yard manure (FYM) and conjunctive use of nitrogen and biofertilizers however could not match the nutrient demand of the crop for effecting higher tillers per half meter row. The days to 50% flowering and physiological maturity in wheat were affected significantly by the nutrient management practices. The days to flowering and physiological maturity also got influenced by the overall pattern of growth and growing

5 conditions prevailing. The control recorded significantly fewer days to 50% flowering as compared to all other treatments. The rest of the treatments recorded statistically similar number of days to 50% flowering. And among them the highest number of days for 50% flowering was noticed in treatments 150 kg N /ha and 50 kg N /ha + Azospirillum + 5 t FYM /ha. Yield attributes All the yield attributes under observation viz. number of ears per half meter row, weight of ears per half meter row, ear length, number of spikelets per ear and test weight in wheat were significantly influenced by the application of nutrients as compared to control (Table 2). Wheat is basically a very exhaustive crop needing sufficient nutrient supply for full expression of its potential. Thus the application of 150 kg N/ha showed the highest values in all these parameters. The conjunctive use of nitrogen, biofertilizers and farm yard manure (FYM) further recorded higher values of these parameters. The biofertilizers alone or farm yard manure (FYM) alone could not really match the nitrogen requirement of the crop thus were able match the performance of yield attributes observed in the 150 kg N /ha or the 50 kg N /ha + Azotobactor + 5 t FYM/ha or 50 kg N /ha + Azospirillum + 5 t FYM /ha. The control with no added nitrogen showed the lowest values of these parameters. However the magnitude of difference was not as expected it may be due to the fact that the control also received same quantum of other nutrients at par with other treatments except the nitrogen. Yield and harvest index of wheat The biological yield, grain yield, straw yield and harvest index were all significantly influenced by the nutrient management practices (Table 3). The hihgest biological yield was recorded by the application of 150 kg N /ha. The lowest biological yield was recorded by control. The grain yield was higher with the application of 150 kg N /ha followed by application of 100 kg N /ha, 50 kg N /ha + Azotobactor + 5t FYM/ha and 50 kg N /ha + Azospirillum + 5t FYM/ha. The control recorded the lowest grain yield in both the years of experimentation. The highest straw yield was observed with the application of 150 kg N /ha in both the years and it was par with 100 kg N /ha, 50 kg N /ha + Azotobactor, 50 kg N /ha + Azospirillum, 50 kg N /ha + Azotobactor + 5t FYM/ha and 50 kg N /ha + Azospirillum + 5t FYM/ha. The harvest index too was significantly higher with the application of 150 kg N /ha. Under ideal conditions of nutrient management practices, the crops extract the

6 nutrient to reach maximum yielding potential as was observed with 150 kg N /ha. The yield is the culmination of all the growth and yield attributes. Since this treatment did consistently well in growth and yield parameters it got translated in to high yielding as well. Further, the higher harvest index indicates as how much a crop can translocate to economic parts, in this case the grains of wheat. The higher harvest index due to conjunctive use of nitrogen, biofertilizers and farm yard manure (FYM) clearly indicated the usefulness of the combined application of organic and inorganic sources of nutrients as compared to only sole nutrient source even under higher levels as in 100 kg N /ha. N, P and K uptake The total uptake of N, P and K was significantly influenced by the nutrient management practices (Table 4). Application of 150 kg N /ha recorded higher values as compared all other treatments. The application of 100 kg N /ha, 50 kg N /ha + Azotobactor + 5 t FYM /ha and 50 kg N /ha + Azospirillum + 5t FYM/ha were next in order. The biofertilizers recorded higher values as compared to control. The application of farm yard manure 5 t/ha and 50 kg N /ha being at par recorded higher values over biofertilizers. The conjunctive use of 50 kg N /ha + Azotobactor and 50 kg N /ha + Azospirillum being at par recorded significantly higher N, P and K uptake as compared to application of 100 kg N /ha alone. This clearly shows that combination of sources would be more useful as compared to individual sources. The lowest N, P and K values were observed in control. This is mainly due to the fact that this treatment did not provide the sufficient quantity of nutrients and also did not achieve higher yields. As the uptake is the function of higher nutrient content and yield, lower values observed in both the factors resulted in lower uptake of nutrient in this treatment. Protein content and yield; agronomic efficiency and apparent nitrogen recovery The protein content in grains of wheat was significantly higher in treatment receiving 150 kg N /ha (Table 5). It was closely followed by 100 kg N /ha and 50 kg N /ha + Azotobactor + 5 t FYM /ha. The protein yield was highest with the application of 150 kg N /ha it was followed by 100 kg N /ha and 50 kg N /ha + Azotobactor + 5 t FYM /ha. The lowest protein yield was observed in control. As nitrogen is the base material for the protein synthesis, application of higher quantity of nitrogen in 150 kg N /ha recorded higher N content and also incidentally the same treatment recorded higher yield, both protein content and higher protein yield were observed in this treatment. Although other treatments recorded higher protein content and yield they could not match this treatment. The agronomic efficiency was higher with 50 kg N /ha + Azotobactor + 5 t

7 FYM /ha. It was followed 50 kg N /ha + Azospirillum + 5t FYM/ha and 50 kg N /ha + Azotobactor. The lowest agronomic efficiency was recorded with the application of 150 kg N /ha. As the nitrogen dose increases the yield per nutrient decreases, thus although the 150 kg N /ha recorded higher yield the agronomic efficiency was lower. On the contrary, the 50 kg N /ha + Azotobactor + 5 t FYM /ha and the 50 kg N /ha + Azospirillum + 5 t FYM /ha with lower amount of nitrogen recorded higher agronomic efficiency. The apparent nitrogen recovery too exhibited similar trend as observed in the agronomic efficiency. This is again due to the fact that higher uptake of nitrogen was possible in lower doses and while higher doses did not match the uptake proportionately. OC, available N, P and K balance in soil The highest organic carbon and available nitrogen balance in soil were observed with the application of nutrients as combination of organic and inorganic sources as in the of treatments 50 kg N/ha + Azotobactor + 5 t FYM/ha, 50 kg N /ha + Azospirillum + 5 t FYM/ha (Table 6). The lowest values were observed in control where no nutrients were applied. It clearly indicated the fact that in the presence of supplemented nutrients, the depletion of nutrients from the soil will be less. The highest negative balance observed in control could be attributed to the fact that the crop removed a large quantity of nutrient albeit less as compared to other treatments but entirely from the soil s own sources depleting it considerably. The nutrient management treatments did not affect the balance of P and K after the harvest of wheat as the crop received all the nutrients viz., P and K at par in all the treatments. There could not be much of a difference. Economics The gross expenditure remained same for both the years this is attributed to the fact that there was no cost variation in the treatments in both the years (Table 7). The gross returns, net returns and B:C ratio were higher in treatment receiving 150 kg N /ha. It was followed by application of 100 kg N/ha, 50 kg N/ha + Azotobactor + 5 t FYM /ha and 50 kg N /ha + Azospirillum + 5 t FYM/ha. The lowest values of gross returns, net returns and B:C ratio were recorded in control. The highest returns and B:C ratio in 150 kg N/ha could be attributed to the fact that it recorded higher grain yield that too with the lowest cost of cultivation. Further the conjunctive use of biofertilizers, nitrogen and farm yard manure (FYM) could yield fairly well, but the fact that the cost of farm yard manure (FYM) was relatively higher and that resulted in higher cost of cultivation and reduced the B:C ratio.

8 Table 1. Growth attributes of wheat at harvest as influenced by nutrient management practices Treatment Plant height (cm) Tillers/half m row DM/ half m row (g) Days to 50% flowering Control Azotobactor (Azot.) Azospirillum (Azos.) Farm yard manure 5 t/ha kg N /ha kg N /ha kg N /ha kg N /ha + Azot kg N /ha + Azos kg N /ha + Azot. + 5 t FYM /ha kg N /ha + Azos. + 5 t FYM /ha SEm LSD (p=0.05)

9 Table 2. Yield attributes of wheat at harvest as influenced by nutrient management practices Treatment Ears/ half m row Ear wt/ half m row Ear length (cm) Spikelets /ear Test weight (g) Ears/ half m row Ear wt/ half m row Ear length (cm) Spikelets /ear Control Azotobactor (Azot.) Azospirillum (Azos.) Farm yard manure 5 t/ha kg N /ha kg N /ha kg N /ha kg N /ha + Azot kg N /ha + Azos kg N /ha + Azot. + 5 t FYM /ha kg N /ha + Azos. + 5 t FYM /ha SEm LSD (p=0.05) Test weight (g)

10 Table 3. Biological yield, grain yield, straw yield (t/ha) and harvest index (%) of wheat as influenced by nutrient management practices Treatment Biological yield Grain yield Straw yield Harvest index Biological yield Grain yield Straw yield Harvest index Control Azotobactor (Azot.) Azospirillum (Azos.) Farm yard manure 5 t/ha kg N /ha kg N /ha kg N /ha kg N /ha + Azot kg N /ha + Azos kg N /ha + Azot. + 5 t FYM /ha kg N /ha + Azos. + 5 t FYM /ha SEm LSD (p=0.05)

11 Table 4. Total N, P and K uptake (kg/ha) of wheat as influenced by nutrient management practices Treatment N P K N P K Control Azotobactor (Azot.) Azospirillum (Azos.) Farm yard manure 5 t/ha kg N /ha kg N /ha kg N /ha kg N /ha + Azot kg N /ha + Azos kg N /ha + Azot. + 5 t FYM /ha kg N /ha + Azos. + 5 t FYM /ha SEm LSD (p=0.05)

12 Table 5. Protein content (%), protein yield (kg/ha) in grains of wheat and agronomic efficiency of nitrogen (AE N )(kg grain/kg N) and apparent nitrogen recovery (ANR) (%) as influenced by nutrient management practices Treatment Protein Protein Protein Protein * AE N ANR * * AE N ANR * content yield content content Control Azotobactor (Azot.) Azospirillum (Azos.) Farm yard manure 5 t/ha kg N /ha kg N /ha kg N /ha kg N /ha + Azot kg N /ha + Azos kg N /ha + Azot. + 5 t FYM /ha kg N /ha + Azos. + 5 t FYM /ha SEm LSD (p=0.05) * Mean of 3 replications

13 Table 6. Organic carbon (OC), N, P and K balance in soil after the harvest of wheat as influenced by nutrient management practices Treatment OC N P K OC N P K Control Azotobactor (Azot.) Azospirillum (Azos.) Farm yard manure 5 t/ha kg N /ha kg N /ha kg N /ha kg N /ha + Azot kg N /ha + Azos kg N /ha + Azot. + 5 t FYM /ha kg N /ha + Azos. + 5 t FYM /ha SEm LSD (p=0.05) NS NS NS NS

14 Table 7. Cost of cultivation, gross return, net return and benefit-cost ratio in wheat as influenced by nutrient management practices Treatment Cost of cultivation Gross return Net return B:C ratio Cost of cultivation Gross return Net return B:C ratio Control Azotobactor (Azot.) Azospirillum (Azos.) Farm yard manure 5 t/ha kg N /ha kg N /ha kg N /ha kg N /ha + Azot kg N /ha + Azos kg N /ha + Azot. + 5 t FYM /ha kg N /ha + Azos. + 5 t FYM /ha SEm LSD (p=0.05)