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Open Access
Combined application of granular preparations of pre-emergent herbicides and fertilizers in rice
(Department of Agronomy, College of Horticulture, Vellanikkara, 1995) Bindu, N K; KAU; John, P S
A field experiment was conducted at the Agricultural Research Station, Mannuthy under the Kerala Agricultural University during the first crop season of 1994 to find out the effect of pre-emergent herbicides and fertilizers in rice. The experiment was laid out in a randomized block design and consisted of fourteen treatments with three replications. Broadleaved weeds and sedges dominated the field. Among broadleaved weeds, Mono choria vaginalis and sphenocleazeylanica were predomint. Shoenoplectus lateriflorus and Cyperus difformis were the prominent sedges present in the field and Echinochloa colonum,saccolepis interrrupta and Isachne miliacea were the important grasses present. Butachlor, anilofos and oxyflourfen under different methods of application reduced the weed Population. Though oxyflourfen recorded high weed control efficiency, it was highly phytotoxic to the rice crop and resulted in poor crop stand. Butachlor and anilofos applied as homemade granular (GP) preparation or as spray alone, or in combination with fertilizer was safe to the crop. The available nutrient in the soil was not affected by the different methods of application of butachlor and anilofos, alone or when combined with fertilizer. Butachlor and anilofos as spray or as GP applied alone, or in combination with fertilizer recorded similar crop growth characteristics, yield and yield attributes. Nutrient up taken by weeds was lower in butachlor and anilofos treatment. Lower weed index values were recorded in butachlor and anilofos treatment. The highest return per rupee was obtained from anilofos treatments. The highest return per rupees was obtained from anilofos treatments. In general, combined application of anilofos or butachlor GP with fertilizer gave efficient control of weed, produced higher grain yields and high return per rupee invested. It also reduced cost, energy and time of weed control operation.
Open Access
Root Distribution patterns of Banana and Colocasia in Coconut Gardens
(Department of Agronomy, College of Horticulture, Vellanikkara, 1994) Suja Eapen, KAU; Abdul Salam, M
An investigation was undertaken at the College of Horticulture, Vellanikkara during 1993-94 to study the root disribution patterns of banana and colocassia in coconut gardens. The experiments were aimed to study the root distribution patterns of banana var. Palayankodan growth in the open and in the coconut garden under rainfed and irrigated conditions. It was also aimed to study the variation in the root distribution patterns of colocasia var. Cheuchempu grown in the coconut garden and in the open. A 32p plant injection technique and a direct profile excavation technique were employed to study the root distribution patterns. The salient results of the investigation are abstracted below. BANANA Root production of banana grown in the open was considerably more compared to that grown in coconut garden. Rainfed banana produced more roots compared to irrigated banana. The root distribution patterns of banana vary with growing condition. In the coconut garden, the root system of rainfed banana was spreading and that of irrigated banana was compact. When grown in the open condition, the root system of rainfed banana was compact and that of irrigated banana was spreading. The active root zones of rainfed banana grown in the open, irrigated banana grown in the open, rainfed banana grown in the coconut garden and irrigated banana grown in the coconut garden were the root zones comprising L0-60 D0-60, L0-60 D0-80, L0-80 D0-60 and L0-60 D0-60 respectively. COLOCASIA Root production of colocasia was more with the plants grown in the open compared to that grown in the coconut garden. Root distribution patterns of colocasia differ between the plants grown in the coconut garden and in the open. The root system of colocasia grown in the coconut garden is deep compact and that of the plants grown in the open is deep spreading. The active root zone of colocasia in the open and in the coconut garden are the root zones comprising L0-20 D0-40 and L0-10 D0-40 respectively. 32P plant injection technique is an efficient method for root system studies in both banana and colocasia.
Open Access
Response of cucumber (Cucumis melo L.) to drip irrigation under varying levels of nitrogen and potash
(Department of Agronomy, College of Agriculture, Vellayani, 1997) Lakshmi, S; KAU; Sasidhar, V K
Two field experiments and one observational trial were conducted in the Instructional Farm, College of Agriculture, Vellayani during 1992 and 1993 to study the effect of drip irrigation and application of N and K fertilizers on the growth and yield of cucumber. In the preliminary observation trial (Experiment I a) three levels of drip irrigation, (2, 3 and 4 I plant-1 day-1) four timings of irrigation (1, 2, 3 and 4 hours) and two number of drippers per plant (1 and 2 dripper plant-1) were evaluated and based on the results of this experiment, the number of drippers per plant and duration of drip irrigation was standardised. Experiment 1 b was conducted to standardise the method of application of fertilizers in Experiment 2 and 3 for which cucumber plants raised under different levels of drip irrigation (2, 3 and 4 I plant-1 day-1). This was conducted during April 1992. The results of these experiments indicated the duration for drip irrigation as 3 hours per day and one number of dripper per plant to be the best. The spread and depth of root system of cucumber plants raised under drip irrigation pointed out that the fertilizers as a ring around the base of the plant at a distance of 20 cm will be within the root zone of the plant. The experiments 2 and 3 were laid out in the field with three levels of drip irrigation (2, 3, and 4 I plant-1 day-1), three levels of nitrogen (35, 70 and 105 kg ha-1) with three levels of potassium (25, 50 and 75 kg ha-1) with three drip irrigation controls (2, 3 and 4 I plant-1 day-1) and farmer's practice. The yield of cucumber was highest at the drip irrigation level of 31 planr-1 day-1. Irrigation at this level favourably influenced the vegetative characters, yield attributes and yield. But root dry matter was not influenced by the different drip irrigation level while the root spread and root depth were highest at the drip irrigation level of 41 plant-1 day-1. When different levels of nitrogen applied were observed, the vegetative characters yield attributes and yield were found to be favourably influenced at 70 kg N ha-1. The root spread of cucumber was highest at the highest level of N applied (l05 kg ha-1). Potassium at 50 kg ha-1 produced the highest yield due to its favourable influence on the vegetative and yield characters. There was no influence of potassium on my of the root characters studied. The soil moisture status was highest up to 30 cm depth in all drip irrigated treatments while in pot watered plots, the soil moisture was higher in the lower layers below 30 cm. The field water use efficiency was highest at the drip irrigation level of 3 I plant-1 day-1, 70 kg nitrogen ha-1 and 50 kg potassium ha-1. The nitrogen, phosphorus and potassium uptake by the plants and fruits were highest at the drip irrigation level of 31 plant day I, 70 kg N ha-I and 50 kg K ha-I. The physical optium levels of drip irrigation was 31 plant -1 day -1, 93 kg N ha-1 and 65 kg K ha-1 in the first season. When another crop is repeatedly grown in the same field, the Nand K levels can be reduced to 75 kg ha-1 and 60. kg ha-1 but drip irrigation is required at the rate of 31 plant-1 day-1. This resulted in higher benefit cost ratio of 2.83 and internal rate of returns of 23%. The payback period of this project worked out to 1.13 years.
Open Access
Soil test crop response studies in cassava in laterite soils of Kerala
(Department of Agronomy, College of Agriculture, Vellayani, 1997) Kumari Swadija, O; KAU; Sreedharan, C
An investigation was undertaken at the College of Agriculture, Vellayani to establish soil test crop response correlation for soil test based balanced fertilizer prescription for cassava var. M-4 in laterite soils of Kerala. The field investigation consisted of fertility gradient experiment, STCR experiment and technology verification trial. The fertility gradient experiment was conducted during April- May 1994 in the Instructional farm, Vellayani. The desired gradient in soil fertility was created in one and the same field by applying graded doses of N, P and K fertilizers and raising fodder maize var. African Tall. The STCR experiment was conducted in the same field during June '94-March '95 using the test crop, cassava var. M-4. The treatments consisted of factorial combinations of four levels of N (0, 50, 100 and 150 kg ha-1), three levels of P (0, 50 and 100 kg P2O5 ha-1) and five levels of K (0, 50, 100, 150 and 200 kg K20 ha-1) along with three levels of farmyard manure (0, 6.25 and 12.50 t ha-1) fitted in a response surface design. Using multiple regression model, the fertilizer adjustment equation for N at varying soil test values for available N for maximum tuber yield (t ha-1) of cassava in laterite soil was derived as FN = 136.6 - 0.2 SN where FN is fertilizer N (kg ha-1) and SN is soil available N (kg ha-1). The equation becomes FN = 136.6 - 0.2 SN - R for economic tuber production where R is the ratio of cost of one kg of fertilizer N to price of one kg of tuber. At varying soil test values for organic carbon% (OC) the above equations become FN = 226.13 - 378.13 OC for maximum tuber yield and FN = 226.13 - 378.13 OC - 1.25 R for economic tuber yield. The behaviour of fertilizer P and K was found to produce responses other than 'normal' and hence optimisation could not be done for fertilizer P and K for maximum and economic tuber yield at varying soil test values. The nutrient requirements of cassava var. M-4 were estimated to be 6.58, 2.37 and 6.28 kg N, P2O5 and K2O respectively to produce one ton of tuber. In the laterite soil, the efficiencies of contribution of nutrients from the soil for cassava were calculated as 40.17, 41. 3 3 and 48.60% N, P2O5 and K2O respectively. The fertilizer efficiencies were worked out as 54.38, 47 and 52.650% N, P2O5 and K2O respectively. The efficiencies of contribution of nutrients from farmyard manure were calculated as 78.24, 57.33 and 69.66%) N, P2O5 and K2O respectively. From the above basic data, fertilizer prescription equations for specific yield targets of cassava var. M-4 in the laterite soil were derived as given below. Without FYM FN = 12.10 T - 0.74 SN FP2O5 - 5.04 T - 2.02 SP FK2O = 11.93 T - 1.10 SK With FYM FN = 12.10 T - 0.74 SN - 1.44 ON F P2O5 - 5.04 T - 2.02 SP - 2.79 OP FK2O = 11.93 T - 1.10 SK - 1.58 OK where FN, F P2O5 and FK2O are fertilizer N, P2O5 and K2O respectively in kg ha-1, T is the target of tuber yield in t ha-1, SN, SP and SK are soil available N, P and K in kg ha-1 respectively and ON, OP and OK are quantities of N, P and K supplied through organic manure in kg ha-1 The technology verification trial was undertaken during June '96-March. '97 in the laterite soil in three farmers' fields in Thiruvananthapuram district and also in the Instructional Farm, Vellayani. The treatments consisted of Package of Practices recommendation for fertilizer, fertilizer recommendation by the Soil Testing Laboratory and fertilizer doses for the yield targets of 15, 20 and 25 t ha-1 along with a uniform dose of 6.25 t ha-1 of farmyard manure for all treatments. The fertilizer doses based on targeted yield equations recorded higher tuber yield and net income, benefit cost ratio and net returns per rupee invested over the fertilizer recommendation by the Soil Testing Laboratory and Package of Practices recommendation emphasising the need for site specific recommendation based on soil tests. The yield targets of 15 and 20 t ha-1 recorded more than cent per cent achievement and the yield target of 25 t ha-1 recorded about 90% achievement. Higher tuber yield, benefit cost ratio and net returns per rupee invested could be achieved for the yield target of 20 t ha-1. The fertilizer dose for the yield target of 15 t ha-1 recorded the highest returns per rupee invested on fertilizers. The study has revealed the superiority of fertilizer application based on targeted yield approach over the semi-quantitative approach employed in the soil testing laboratories and generalised state level Package of Practices recommendation for the crop. In this approach, the fertilizer dose can be adjusted in accordance with the specific objective and available resources of the farmer.
Open Access
Development of subsurface pad irrigation system for tomato
(Department of Agronomy, College of Agriculture, Vellayani, 1995) Abdul Nassar, K; KAU; Jaikumaran, U
An experiment was conducted in the summer rice fallows of the Agricultural Research Station, Mannuthy during 1995 to develop and test subsurface pad irrigation system for tomato and to compare it with surface irrigation. The soil was sandy clay loam, medium in organic carbon and available potassium and high in available phosphorus. The eight treatments comprised of combination of four frequencies of irrigation (IW/CPE ratios of 1.2, 0.9, 0.6 and 0.3) and two irrigation systems (subsurface pad irrigation and surface irrigation). The experiment was laid out in randomized block design with three replications. Poly bags filled with saw dust placed 45 cm beneath the surface at the frequency of one pad for every four plants formed SSPI. Water was supplied to pads by laterals supplying 40 mm of water per irrigation. The study revealed that tomato responded very well to irrigation. Biometric characters like plant height, number of leaves and leaf area index and yield attributing characters like number of flowers, number of fruits and total weight of fruits per plant were favourably influenced by frequent irrigation under both the systems of irrigation. The fruit yield increased with frequency of irrigation and maximum at the IW/CPE ratio of 1.2. The plants irrigated by surface method grew taller, had more leaf area index, produced more number of green leaves, flowers, fruits and total fruit weight per plant compared to the plants irrigated under SSPI system at the irrigation frequencies of IW/CPE ratios 1.2, 0.9, and 0.6. But at the IW/CPE ratio of 0.3, the subsurface irrigated plants performed better than the surface irrigated plants both in terms of growth and yield attributing characters. The crop receiving irrigations through SSPI systems consumed lesser amount of water at all the frequencies of irrigation compared to surface method. This decline at the IW/CPE ratios of 1.2, 0.9, 0.6 and 0.3 were to the tune of 22,30,40 and 18 per cent respectively. The soil moisture extraction from 0-15, 15-30 and 30-60 cm layers in SSPI was 62-70, 24-29 and 6-12 per cent respectively whereas in surface irrigation the respective values were 62-64, 22-23 and 13-15 per cent. The soil moisture redistribution was rapid in the case of surface irrigation whereas it was gradual in the case of SSPI. Moisture content in the case of SSPI was maximum at the radial distance of 15 cm from the pad on either sides whereas in surface irrigation there was no remarkable difference in the moisture content with respect to radial distance from the plant.
Open Access
Foliar absorption of nitrogen and phosphorus by cashew
(Department of Agronomy, College of Horticulture, Vellanikkara, 1994) Mini Abraham, KAU; Abdul Sala, S M
An investigation was undertaken at the College of Horticulture, Kerala Agricultural University, Vellanikkara during 1993-'94 to study the foliar absorption of nitrogen and phosphorus by cashew. The main objectives of the study were to develop a method to study the foilar absorption of 14c-urea and 32p and to identify the factors affecting foliar absorption of nitrogen and phosphorus by cashew. It was also aimed to compare the root absorption with foliar absorption and to study the leaf anatomy of cashew in relation to foliar absorption. The experiment was done using three month old cashew seedlings and six year old cashew trees (var.Anakkayam-l). The salient findings are abstracted below. A leaf washing technique was developed to quantify the foliar absorption of 14c-urea and 32p• Accordingly a sequential washing programme involving four washings each with 50 ml of 2 per cent teepol was found to be reasonable to quantify the foliar absorption of 14C-urea and 32P in cashew. Factors affecting foliar absorption of urea and phosphorus by cashew have been identified. Leaf age, leaf surface, duration allowed for absorption, time of application in a day, month of application in an year and presence of a surfactant in the spray solution are certain important factors that are found to decide the extent of absorption of foliar applied 14C-urea and 32P in cashew. Greater absorption of foliar applied urea was obtained when nutrient solution was sprayed in 0.05 per cent teepol between 11 00 hours and 14 00 hours, directing the spray to the lower surface of terminal leaves of latest flush during March and by giving a minimum absorption period of seven days. The efficiency of foliar applied phosphorus was increased by spraying around 11 00 hours to the lower surface of basal leaves of latest flush during December and by giving a minimum absorption period of six days. Root absorption from solution culture was more compared to foliar absorption in the case of 14C-urea and 32P .The absorption efficiency of 32P both through root and leaf was low compared to 14C-urea. The cashew leaves contain thicker cuticle. on the upper surface with no stomata and thinner cuticle on the lower surface with large number of stomata. The latest flushes of a six year old cashew tree (var. Anakkayam-1) during flushing account for 80 per cent of total leaf area in the crown.
Open Access
Enhancing the Nitrogen Use Efficiency in Bhindi With Nitrification Inhibitors
(Department of Agronomy, College of Agriculture, Vellayani, 1994) Bindu Kurup, S; KAU; Pushpakumary, R
An experiment was conducted at the Instructional Farm, College of Agriculture, Vellayani inorder to find out the effect of nitrification inhibitors in enhancing the nitrogen use efficiency in bhindi. The treatments consisted of four levels of nitrogen viz., 50 kg ha-1, 100 kg ha-1, 200 kg ha-1 and 300 kg ha-1 and three nitrification inhibitors viz., urea, neem cake and mahua cake. Phosphorus and potassium were applied as per package of practices recommendation. The results revealed that nitrogen levels significantly influenced most of the growth and yield contributing characters, yield of bhindi, uptake of nutrients and available nutrient status of soil. Biometric observations like number of leaves, branches, root spread, DMP, LAI, RGR, NAR and CGR increased with increasing levels of nitrogen and the maximum was produced by the highest levels of nitrogen (300 kg ha-1). F1 produced the maximum height and F2 the longest tap root. Time of 50 per cent flowering and number of flowers per plant was maximum with the highest levels of nitrogen (F4). Whereas other yield contributing characters like number of fruits per plant, percentage of fruit set, length and girth of fruit, fruit yield per plant and total yield of bhindi was maximum with F2 (100 kg N ha-1 ). Quality aspects like crude protein and ascorbic acid content of fruits, uptake of nutrients by plant and fruit as also maximum with the highest levels of nitrogen (F4). However, the height of the first bearing node and chlorophyll content of leaves remain unchanged with increasing levels of nitrogen. The optimum level of nitrogen to get maximum fruit yield and net profit was worked out as 142 kg N ha-1 . Nitrification inhibitors caused significant variation in some of the characters like root spread, LAI RGR, NAR, CGR, number of flowers and fruits per plant, percentage of fruit set, length and girth of fruit, crude protein content and ascorbic acid content of fruit, uptake of nutrients by plant and fruit and available nutrient status of soil. In all these cases neem cake blended urea recorded the highest value followed by mahua cake blended urea. From the economic point of view, the maximum net profit of Rs. 11787.74 was obtained for neem cake blended urea and among nitrogen levels, 100 kg N ha-1 recorded the highest net profit of Rs. 16017.50. Thus neem cake blended urea at 100 kg N ha-1 can be suggested as the best economic dose of nitrogen for getting maximum yield and net profit.
Open Access
Effectiveness and crop seletivity of pre-emergence herbicides under different methods of application in puddled rice
(Department of Agronomy, College of Horticulture, Vellanikkara, 1995) Mohan Kumar, P D; KAU; Savithri, K E
A field experiment was conducted at the Agricultural Research Station, Mannuthy under the Kerala Agricultural University during the second crop season of 1992-93 to find out the effectiveness and crop selectivity of pre-emergence herbicides under different methods of application in puddled rice. Twelve treatments were com- pared with two controls (hand weeded and unweeded). The experiment was laid out in Randomised Block Design with three replications. Sedges and broadleaved weeds dominated the weed flora. Among the sedges, Schoenoplectus lateriflorus, Cyperus iria, C. difformis and Fimbristylis miliacea were the prominent species, and the broadleaved weeds included Mono- choria vaginalis, Marsilia quadrifoliata, Sphenochlea zeylanica and Nymphaea nouchali. The broad leaved weeds were effectively controlled by pretilachlor + safener, oxyflourfen and pendimethalin, besides butachlor and thiobencarb. All the herbicides except pendimethalin and anilofos gave good control of sedges. Oxyflour- fen spray showed the highest weed control efficiency among the herbicides tested. Sand mixed broadcasting of herbicides was found to be lesser toxic than spray in all the herbicides except pretilachlor + safener, where the safener present protected the crop completely from phytotoxicity. Crop growth characteristics were highly influenced by the herbicide and method of application. Pretilachlor + safener, oxyflourfen and thiobencarb were found superior. Yield attributes were relatively unaffected by the different treatments. Pretilachlor + safener spray recorded the highest yield, among herbicides. Sand mixed broadcasting of all other herbicides produced a slightly higher grain yield compared to spray. Nutrient uptake by crop was directly related to the dry matter accumula- tion. The lowest weed index value was registered by pretilachlor + safener spray. Pretilachlor + safener spray recorded the highest total returns and its sand mixed broadcast realised the highest return per rupee invested on weed control.
Open Access
Dynamics of the absorption of forms of N by crops plants
(Department of Agronomy, College of Horticulture, Vellanikkara, 1995) Retheesh, P K; KAU; Balachandran, P V
An investigation was conducted at the Radiotracer Laboratory, College of Horticulture, Vellanikkara in the year, 1993 which consisted of two parts. In the first part absorption of different forms of nitrogen relative to its concentrations at different growth stages of rice was studied using labelled and non-labelled fertilizers. To know the molecular absorption of urea 14C-labelled urea fertilizer was used and the presence of 14C in the plant was taken as an evidence for the absorption of molecular form of urea. In the case of ammoniacal and nitrate forms of N, 15N-labelled and non-labelled materials were used alternately to find out the preferential absorption. In the second part of the investigation an attempt was made to know the possibility of molecular absorption of urea by a few selected plantation crops. The uptake of N and dry matter production were higher when rice plants were supplied with a combination of ammonium and nitrate in equal proportions. Among the three forms of nitrogen supplied at different combinations, nitrate N recorded the highest uptake when present along with urea N or ammoniacal N or both. Though the presence of urea had a repressing effect on the uptake of nitrate, ammonium enhanced the nitrate uptake. The uptake of nitrate N was more in the presence of ammonium than in its absence. With respect to ammonium uptake it was found that urea and nitrate had more or less similar influence on it. It was seen that rice plants absorbed molecular form of urea even in the presence of other readily available forms of nitrogen. The molecular absorption of urea by rice plants was found to vary from 12-18 percentage of the total N uptake. When urea was supplied along with ammonium and or nitrate the uptake of urea was found reduced. The quantity of urea absorbed by the plantation crops was found negligible and ranged from 0.5-3.3 µg per g of the plant dry weight.

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