Symposium no. 22 Paper no. 1262 Presentation: oral Alleviation of root zone constraints through foliar application of zinc and boron for grapes PRABU C.P. and SINGARAM P. Department of Soil Science and Agricultural Chemistry, Tamil Nadu Agricultural University, Coimbatore - 641 003, Tamil Nadu, India Abstract Since more than 75 percent of soils under grapes (Vitis vinifera L) in South India are low in zinc (Zn) and boron (B), a field experiment was conducted at a farmer's field in South India during the year 1999-2000 in a Zn and B deficient soil. The primary aim of the study was to alleviate Zn and B deficiency through foliar and soil applications. The study was conducted in a calcareous sandy loam soil to study the influence of Zn and B applied either individually or in combination through soil or foliage on yield and quality of grapes. The results revealed that foliar application of ZnSO 4 0.5 per cent + borax 0.2 per cent combination applied twice during vegetative (20 days after pruning) and full bloom stages excelled others by having more yield with highest Juice percentage, Total soluble solids (TSS), Total sugars and Sugar/acid ratio. The acidity was lowest in the same treatment. The micronutrients have not influenced the ph and specific gravity of juice. Keywords: zinc (Zn), boron (B), yield, TSS, and acidity Introduction Grapes contribute 50 percent of the total production of fruits in the world. In India, it is grown in an area of nearly 0.25 lakh hectares with an annual production of 4.08 lakh tonnes. The climatic conditions are favorable in parts of South India. So that five crops are taken in two years by staggered pruning techniques. As the cultivation of grapes is fast expanding, it is being taken up on a wide range of soils and agroclimatic situations. The growers face many problems that limit the full expression of growth and productivity. The notable and the most frequent of these problems are found to be related to nutrition owing to its unique physiological plasticity. Because of faster growth, continuous fruiting habit and heavy yield, grapes requires nutrients throughout its growth period. After a series of trials it had been possible to arrive at an optimum, N, P and K fertilizer schedule for grapes. In recent times, however the yields are found to be erratic. The depletion of secondary and micronutrients due to intensive cultivation could be one of the reasons limiting the yield of grapes. A sharp decline in available micronutrients with continuous cropping at recommended dose of NPK application has been widely reported in vineyards. This resulted in micronutrient deficiencies in the vineyards and more than 75 percent of soils under grapes in South India are low in Zn and B content. Despite the fact that the micronutrients have also got definite effect on the quality and yield of grapes, much attention has not so far been given to this aspect of viticulture. Muscat is the most ideal cultivar in South India. Many workers have reported positive effects of Zinc and Boron on yield and quality of grapes (Kumar and 1262-1
Bhushan, 1978; Sanjaykumar and Pathak, 1992). Information regarding the effect of Zn and B nutrition on yield and quality is lacking under local conditions as far as Muscat grapes is concerned. Hence the present study was undertaken at a farmr's field near Tamil Nadu Agricultural University, Coimbatore to study the effect of Zn and B nutrition on yield and quality of grapes and to suggest a suitable method for Zn and B application. Zn and B deficiency in grapes Zinc deficiency probably ranks second to nitrogen deficiency and results in little leaf or rosette. According to Winkler (1962), Zn deficiency symptoms are frequently found in vineyards on sandy soils. The symptoms usually appear when the secondary shoot growth starts. The primary and secondary shoot tips are affected first. The principal symptoms of Zn deficiency are the chlorotic pattern, small size of the affected leaves and particularly the widened petiolar sinus. With some varieties particularly Muscat of Alexandria, the first effect of Zn deficiency is a very straggly cluster. Berries on the straggly clusters may range in size from very small with undeveloped short berries. Boron is essential for germination of pollen and its deficiency leads to the flower abortion and consequently abscission. Boron is essential for the synthesis of auxin but deficient plants also have an excess of auxin level possibly because of decreased activity of IAA-oxidase. Both a deficiency and an excess of auxin have an appreciable effect on abscission. Instead of dropping, the inflorescence may show complete drying up and a set with high percentage of short berries. The short berries resulting from B deficiency fail to elongate properly and thus tend to be round or oblate in shape. Beside these the death of the primary shoots, short internodes, a characteristic chlorosis, necrotic areas in the tendrils might occur. Materials and Methods The present investigation was carried out in a farmer s field at Mathampatti during the year 1999-2000 on fully grown six-year-old Muscat grape vines. The soil tested calcareous (CaCO 3 37.5 g kg -1 ) sandy loam with ph 8.1, organic carbon 5.25 g kg -1, DTPA Zn 1.05 mg kg -1 and hotwater soluble B 0.23 mg kg -1. The experiment was laid out in a randomized block design having 12 treatments each replicated three times. The treatment details are as follows. Treatments T 1 : Control T 2 : ZnSO 4 soil application 10 g vine -1 T 3 : ZnSO 4 soil application 20 g vine -1 T 4 : Borax soil application 4 g vine -1 T 5 : Borax soil application 8 g vine -1 T 6 : ZnSO 4 10 g + Borax 4 g vine -1 soil application T 7 : ZnSO 4 10 g + Borax 8 g vine -1 soil application T 8 : ZnSO 4 20 g + Borax 4 g vine -1 soil application T 9 : ZnSO 4 20 g + Borax 8 g vine -1 soil application T 10 Foliar spray ZnSO 4 0.5% -Two times T 11 Foliar spray Borax 0.2% -Two times ZnSO 4 0.5% + Borax 0.2% foliar spray-two times T 12 1262-2
In treatment T 1, T 2, T 3, T 4, T 5, T 6, T 7, T 8 and T 9, the nutrients were applied in soil as basal dose and in treatments T 10, T 11 and T 12, the nutrients were applied as foliar sprays twice during vegetative (20 days after pruning) and again at full bloom stage. Foliar spray was given in the morning hours between 6.00 to 9.00 A.M., using a rocket sprayer. The doses were supplemented with recommended doses of NPK 250,160 and 600 g vine -1 respectively. Yield of vines was recorded on actual weight basis. The ripened clusters were harvested, weighed and expressed in g. Ten clusters were selected randomly for recording various physical and chemical (TSS, reducing sugars and acidity) characteristics following the standard procedure of AOAC (1980). The collected data were analysed statistically. Results and Discussion Total yield The data (Table 1) revealed that under all the treatments the yield was better than the control. The treatment T 12 produced the highest yield (6.30 kg vine -1 ). The lowest yield was recorded in the treatment T 1 (2.84 kg vine -1 ) which was followed by the treatment T 5 (3.20 kg vine -1 ). Similar yield improvement due to Zn and B spray in vine was reported by Kumar and Bhushan (1978), Tesu et al. (1988) and Ezzili (1994). The increase in yield in case of Zn and B treated vines may be due to the fact that in these vines fruit set was more and berry drop was less. Table 1 Effect of Zinc and Boron on yield and quality characters of grapes. Treatments Yield kg vine -1 Juice content TSS ( o Brix) Reducing sugar Non reducing sugar Total Sugar Acidity T 1 -Control 2.86 53.0 13.0 7.84 2.11 9.95 1.20 8.29 Sugar/ Acid Ratio T 2 -ZnSO 4 10 g vine -1 3.28 56.5 14.2 7.88 2.35 10.23 1.15 8.81 T 3 - ZnSO 4 20 g vine -1 3.89 57.0 14.8 8.47 2.48 10.95 1.15 9.52 T 4 -Borax 4 g vine -1 3.71 57.5 14.2 7.90 2.23 10.13 1.14 8.89 T 5 - Borax 8 g vine -1 3.21 56.5 14.5 7.93 2.39 10.32 1.15 8.97 T 6 -T 2 +T 4 4.41 58.0 14.9 8.47 2.51 10.98 1.13 9.72 T 7 -T 2 +T 5 3.29 57.0 14.5 8.01 2.31 10.32 1.15 8.98 T 8 -T 3 +T 4 5.80 64.0 15.7 8.63 2.95 11.58 1.11 10.33 T 9 -T 3 +T 5 3.30 56.5 14.2 7.92 2.33 10.25 1.14 8.99 T 10 -Foliar spray ZnSO 4 0.5% 5.35 59.0 15.5 8.11 2.44 10.55 1.12 9.50 T 11 - Foliar spray borax 0.2% 4.94 58.0 14.8 8.21 2.48 10.69 1.12 9.54 T 12 -T 10 +T 11 6.30 68.0 15.8 8.95 2.97 11.92 1.10 10.84 SED 0.157 1.532 0.09 0.039 0.021 0.075 0.025 0.215 CD(0.05) 0.32 3.17 019 0.08 0.04 0.15 0.05 0.44 Fruit quality Juice content It is clear from the Table 1 that juice percentage increased under all treatments than control. Among the treatments, T 12 gave the highest juice percentage (68 %) and it was significantly better than all other treatments. According to Manchanda et al. (1972) higher juice content could be obtained by micronutrient application and deficiency cause decrease in juice content. 1262-3
Total soluble solids (TSS) The TSS one of the important quality attributes exhibited a significantly positive effect due to application of Zn and B nutrition through foliage. The treatment (T 12 ) had the highest TSS (15.80º Brix) accounting 21.53 percent increase over control. The control recorded the lowest TSS (13.00º Brix) which was significantly lower than all the treatments. This was supported by Daulta et al. (1983) who obtained berries with high TSS content due to foliar spray of Zn (0.2 to 0.6%), Fe (0.1 to 0.4%) and / or boron (0.05 to 0.1%) at full bloom stage. Reducing and non reducing sugars The data on reducing sugar content in the fruits clearly indicated that Zn and B supplements altered the reducing sugars in fruits. The reducing sugar was significantly higher in T 12 (8.95 %) thus increasing the quality of the fruit further. The lowest reducing sugar was recorded in the treatment T 1. The high reducing sugar predominantly glucose recorded due to Zn and B application might have been influenced by the micronutrients Zn, B, Fe and Mn which probably activated the enzyme responsible for photosynthesis thus resulting in synthesis and accumulation of monosaccharides particularly of glucose. Non reducing sugars predominantly the sucrose content increased significantly in the experiment by Zn and B application. Total sugars The data on total sugar content revealed a pattern similar to reducing sugar content. The treatment T 12 registered higher values (11.92 %) than the control (9.95%). This finding is in accordance with the results obtained by Yamdagni et al. (1979 ) and by Sanjay Kumar and Pathak (1992). Acidity Application of Zn and B to grapevines significantly reduce the acidity and increase the quality. The acidity of the fruit was significantly reduced in treatment T 12 (1.10 %) with a reduction of 8.3 percent over control. The highest acidity percentage was recorded in T 1 (1.20 %) Similarly significant reduction in acidity recorded in this study was well supported by the work of Yamdagni et al. (1979) and Bacha et al. (1997). Sugar / acid ratio Significant differences in sugar / acid ratio were observed due to Zn and B application through soil and foliage, either alone or in combinations. Among the treatments, T 12 recorded as the most effective in producing good quality fruits with increase in sugar / acid ratio (10.84). This produced 30.75 percent increase in sugar / acid ratio over the control. Conclusion Considering the findings it is concluded that foliar application of ZnSO 4 0.5 percent and borax 0.2 percent foliar spray at vegetative and full bloom stages could be recommended to the farming community to alleviate rootzone constraints due to CaCO 3 to Zn and boron availability to grapes, and thereby increase yield and quality of grapes. Acknowledgement The authors thank the Department of Soil Science and Agricultural Chemistry for providing facilities and assistance to conduct the research. The authors would also like to convey their gratitude to Mr.sivasubramaniam, Landlord, Mathampatti for favour and facilities provided at his farm for conducting field experiments in a successful way. 1262-4
References AOAC. 1980. Official methods of Analysis of Analytical Chemists, 13 th ed. Association of the Official Analytical Chemists, Washington, DC. Bacha, M.A., S.M. Sabbah and M.A. Hamady. 1997. Effect of foliar application of Fe, Zn and Mn on yield, quality and leaf mineral composition of Thompson seedless and Roumy red grape cultivars. J. King Saud Univ. Agric.Sci. 9:127-140. 127-140. Daulta, N.S., R. Kumar and V.P. Ahlawat. 1983. A note on effect of micronutrients sprays on quality of Beauty seedless grapes. (V.vinifera L.) Haryana J. Hort. Sci.12 (3):198-199. Ezzili, B. 1994. Effect of pinching back and trace elements on fertility and mineral element contents of leaves in Alicante grenache noir variety. Bulletin de l OIV, 67: 757-758. Kumar, S. and S. Bhushan. 1978. Effect of applying zicn, manganese and boron to the vines of cultivar Thompson seedless on their vigour, yield and nutrient status. J.Res.India. 15(1):43-48. Manchanda, H.R., V.C. Shukla and N.S. Randhawa. 1972. Effect of soil and foliar application of Zn and foliar application of Cu, Mn, Fe and in combination with Zn on the incidence of chlorosis, fruit fall, granulation and fruit quality in sweet orange variety Blood red. Indian J. Hort. 29: 19-29. Kumar, S. and R.A. Pathak. 1992. Effect of foliar application of nutrients on the yield and quality of grapes (Vitis vinifera L.) cv. Perlette. Prog.Hort. 24(1-2):13-16. Tesu, V., L. Jianu, V. Muraru, T. Iuroaie and G. Arghir. 1988. Response of some grape vine to foliar nutrition with trace elements and a bioactive substances. Hotr. Abstr. 58(10):6562. Winkler, A.J. 1962. General Viticulture. University of California press. Barkley and Los angeles. 633 p. Yamdagni, R., D. Singh and P.C. Jindal. 1979. Note on the effect of Zn sprays on yield and quality of Thompson seedless grapes. Indian. J. Agric. Res. 13(2):117-11. 1262-5