Zinc Fertilization and Rice Production

Abstract

Introduction

Materials and Methods

Tissue samples were collected at maximum tillering and panicle initiation. These samples were analyzed for Ca, S, Mg, Al, P, K, B, Zn, Mn, Cu, and Na. Field measurements include tiller counts, panicles per row, spikelets per panicle, seed weight, dry matter accumulation, and yield.

Results

Table 1a. Average rice yields and seeds per panicle for 'Cypress' in 1998 and1999.	Table 1b. Average rice yields and seeds per panicle for 'Kaybonnet' in 1998 and 1999.	Table 1c. Average rice yields and seeds per panicle for 'Drew' in 1998 and 1999.
Treatment Seed/panicle Yield Cypress 1998 1999 1998 1999 No lime No Zn 104 92 104 151 Lime No Zn 145 81 112 139 No lime Soil Zn 109 89 107 133 Lime Soil Zn 95 101 121 146 No lime Foliar Zn 123 95 105 142 Lime Foliar Zn 147 93 110 145	Treatment Seed/panicle Yield Kaybonnet 1998 1999 1998 1999 No lime No Zn 127 128 150 146 Lime No Zn 130 117 134 152 No lime Soil Zn 116 128 134 146 Lime Soil Zn 125 136 137 130 No lime Foliar Zn 132 140 149 153 Lime Foliar Zn 115 125 130 138	Treatment Seed/panicle Yield Drew 1998 1999 1998 1999 No lime No Zn 141 109 135 153 Lime No Zn 143 104 140 142 No lime Soil Zn 152 87 146 139 Lime Soil Zn 112 105 131 138 No lime Foliar Zn 136 85 138 151 Lime Foliar Zn 153 116 141 146

The lime treatments consistently increased the soil pH, mostly from pH 6.3 to pH 7.2. Soil zinc levels were dramatically increased by soil zinc applications. Liming generally reduced the plant availability of zinc and manganese; however, this reduced availability was still sufficient to support rice growth (Table 2).

Table 2. Average soil test values for samples collected post harvest 1999.

Treatment	pH	Zn ppm	Mn ppm
No lime No Zn	6.3	1.21	42
Lime No Zn	7.0	1.35	30
No lime Soil Zn	6.8	8.91	32
Lime Soil Zn	7.2	3.25	30
No lime Foliar Zn	6.4	3.01	37
Lime Foliar Zn	7.2	2.05	30

The rice varieties 'Cypress', 'Kaybonnet', and 'Drew' each showed zinc plant tissue levels above the deficiency level (approximately 20 ppm Zn), indicating that the soil was supplying sufficient zinc to support rice. The plant tissue levels of Ca, Mg, S, P, K, Na, Fe, Al, Cu, and B were normal. The plant tissue levels for manganese were excessive (Tables 3 a,b,c).

Table 3a. Average plant tissue levels for Zn and Mn for the rice variety 'Cypress' 1998 and 1999.	Table 3b. Average plant tissue levels for Zn and Mn for the rice variety 'Kaybonnet' 1998 and 1999.	Table 3c. Average plant tissue levels for Zn and Mn for the rice variety 'Drew' 1998 and 1999.
Treatment Zn ppm Mn ppm Cypress 1998 1999 1998 1999 No lime No Zn 44 54 1266 1104 Lime No Zn 21 55 1247 1269 No lime Soil Zn 34 49 1240 1107 Lime Soil Zn 36 58 1105 1242 No lime Foliar Zn 24 58 1341 1261 Lime Foliar Zn 27 46 1289 1182	Treatment Zn ppm Mn ppm Kaybonnet 1998 1999 1998 1999 No lime No Zn 36 48 1772 1167 Lime No Zn 31 46 1827 977 No lime Soil Zn 28 65 1698 1231 Lime Soil Zn 36 61 1569 1250 No lime Foliar Zn 30 41 1629 1132 Lime Foliar Zn 32 53 1178 1181	Treatment Zn ppm Mn ppm Drew 1998 1999 1998 1999 No lime No Zn 37 44 1392 1126 Lime No Zn 30 52 1571 1468 No lime Soil Zn 48 63 1758 1384 Lime Soil Zn 25 66 1199 1269 No lime Foliar Zn 33 53 1343 1374 Lime Foliar Zn 41 54 1371 1131

Conclusion

Acknowledgement