Management of rice production systems to increase productivity

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Sta Cruz and Wada (1994) found substantial variation in nitrogen uptake between rice ecotypes (upland and lowland type cultivars), plant types, hybrids, and plants with different growth duration. Plant types based on leaf erectness, panicle number and growth duration were the most important. Nitrogen uptake during spikelet initiation, flowering, and maturity reportedly increased with growth duration. The variation in nitrogen uptake among genotypes with different growth duration is due to differences in the duration of the vegetative lag period (Sta Cruz and Wada, 1994). Weed competitiveness and yield potential under low input conditions of upland rice also need improvement. It is important to examine the relationships between grain yield and nitrogen utilization and the economics of production. Traditional African rice varieties are generally well adapted to the major stresses found in upland areas such as drought, blast and panicle diseases, but generally their yields average a low 1 t/ha. Selections from traditional varieties, when grown under rainfed and low fertilizer input, tend to produce moderately higher yields in farmers’ fields than do introduced varieties, particularly those introduced from Asia. The West African Rice Development Association (WARDA) embarks on developing varieties primarily from selections among African varieties or from hybridization between African and exotic varieties. 29
2.1.6. Nutrient Dynamics in Tropical Soils Most of the fertilizer nitrogen currently used by small farmers of the world for food production purposes is on high yielding varieties (HYVs), which are more responsive to nitrogenous fertilizer than traditional cultivars. In spite of the responsiveness of rice HYVs to nitrogen fertilization, the efficiency of its use is low, often below 40% and in some cases even less than 30%. This leads to massive and undesirably energy losses in both production and transportation. Therefore, improving nitrogen use efficiency should be given a top research priority. Raun et al. (2002) have calculated that the 67% loss of applied N to cereal crops globally is equivalent to $15.9 billion. Yet the fastest growing sector of the fertilizer market is for N fertilizers. Depending on the source of fertilizer, N costs approximately $0.49 kg ‐1 . It is more affordable in the developed countries than in the developing countries, where access to fertilizer is limiting and usage very low, especially among subsistence farmers in The Gambia and those in other Sub‐Saharan nations. Replenishing depleted and poor soils with inorganic amendments is not given high priority. The immediate goal is economic survival, not preservation of the environment (Campbell et al., 1995). Upland rice is repeatedly grown on the same plot of land for several years, and when the fertility level goes down the farmer clears a new forest using slash‐and‐burn techniques, and shifts his or her cultivation to this new more fertile plot. This shifting cultivation practice causes deforestation and loss of biodiversity. Upland rice often needs a higher level of fertilization than does lowland rice per unit of production. In The Gambian farming system more fertilizer is applied to lowland rice than upland rice because of the higher returns from 30
Page 1 and 2: MANAGEMENT OF RICE PRODUCTION SYSTE
Page 3 and 4: MANAGEMENT OF RICE PRODUCTION SYSTE
Page 5 and 6: BIOGRAPHICAL SKETCH The author was
Page 7 and 8: ACKNOWLEDGMENTS The author is indeb
Page 9 and 10: TABLE OF CONTENTS CHAPTER ONE: RICE
Page 11 and 12: 3.3.2. Effect of Seedling Age at Tr
Page 13 and 14: Table 10. Grain Yield from Low‐In
Page 15 and 16: Table 28. Soil Sample Analysis at T
Page 17 and 18: Table 46. Yield Parameter SRI Ferti
Page 19 and 20: Figure 10. Grain Yield at Different
Page 21 and 22: context of food security. As there
Page 23 and 24: management of soil nutrients and so
Page 25 and 26: enough fertilizer was available to
Page 27 and 28: the importation of agricultural inp
Page 29 and 30: 12000 10000 8000 6000 4000 2000 0 4
Page 31 and 32: The reason for the decline in The G
Page 33 and 34: 2.1. Introduction CHAPTER TWO: LOW
Page 35 and 36: tend to produce moderately higher y
Page 37 and 38: available nitrogen and phosphorus r
Page 39 and 40: Table 3. Soil Test Data from Upland
Page 41 and 42: flood/drought cycle, which is provi
Page 43 and 44: educed transpiration due to soil wa
Page 45 and 46: management practices (dry land/irri
Page 47: Sta Cruz et al. (1994) identified d
Page 51 and 52: efficiency (Cassman and Harwood, 19
Page 53 and 54: (1) Higher mineralization rate in t
Page 55 and 56: Translocation of N from the vegetat
Page 57 and 58: NUEp = TDM / NPLANT (3) From equati
Page 59 and 60: 4) The NuMaSS can be used to predic
Page 61 and 62: 1. Zero application (Control) 2. Lo
Page 63 and 64: are averages of duplicated assays a
Page 65 and 66: show any significant differences be
Page 67 and 68: Table 8. Low‐Input Upland Rice Tr
Page 69 and 70: stress conditions that prevailed du
Page 71 and 72: Fertilizer Level Variety Grain Yiel
Page 73 and 74: Harvest Index Harvest Index 0.6 0.5
Page 75 and 76: Tissue N (%) Tissue N (%) Tissue N
Page 77 and 78: According to Fukai et al. (1999) hi
Page 79 and 80: NUE(grain) g per g (N) NUE(grain) g
Page 81 and 82: Necessary inputs for the nitrogen m
Page 83 and 84: Determining Crop N: The first step
Page 85 and 86: Hierarchy for NSoil: 1. You will en
Page 87 and 88: e able to access a value from the d
Page 89 and 90: Figure 10. Grain Yield at Different
Page 91 and 92: season, but in the event that major
Page 93 and 94: In many cases, results did not meet
Page 95 and 96: 1995 worked with Malagasy farmers a
Page 97 and 98: 3.1.3. Water Management Water contr
Page 99 and 100:
diffusion from the soil‐water int
Page 101 and 102:
and rewetting of soils as practiced
Page 103 and 104:
2. SRI will increase rice yields be
Page 105 and 106:
Three sets of rice nurseries were p
Page 107 and 108:
Two rice varieties, IET 3137 and IT
Page 109 and 110:
tillering variety, with plant heigh
Page 111 and 112:
Gambia prefer bigger seedlings beca
Page 113 and 114:
Figure 12. Number of New Roots Re
Page 115 and 116:
Seedling Age 5‐Days 5‐Days 10
Page 117 and 118:
Table 14. SRI vs. Conventional Prac
Page 119 and 120:
The difference in 1000‐grain weig
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Variety Inter Space (cm) ITA 306 IE
Page 123 and 124:
104 SRI management practice using 3
Page 125 and 126:
fertilizer, but no better panicle f
Page 127 and 128:
increase in fertilizer application.
Page 129 and 130:
transplanting urea fertilizer was a
Page 131 and 132:
112 Applying just compost alone gav
Page 133 and 134:
submerging the 7‐day old seedling
Page 135 and 136:
116 An increase in SRI yields in su
Page 137 and 138:
4.1. General conclusions CHAPTER FO
Page 139 and 140:
practices are 2 to 3 times higher t
Page 141 and 142:
application. This study has proven
Page 143 and 144:
APPENDIX 1: FIELD LAYOUT V. High‐
Page 145 and 146:
Table 26. Soil Sample Analysis at H
Page 147 and 148:
Low‐Input 40‐40‐40 APPENDIX 3
Page 149 and 150:
Table 32. Low‐Input Upland Rice T
Page 151 and 152:
Low‐Input 40‐40‐40 Table 34.
Page 153 and 154:
Table 36. Nitrogen‐Use Efficiency
Page 155 and 156:
Table 38. SRI vs Conventional Pract
Page 157 and 158:
Table 40. Grain Yield from SRI Prac
Page 159 and 160:
Fertilizer Level Table 42. SRI Fert
Page 161 and 162:
Table 44. SRI Fertilizer Management
Page 163 and 164:
Table 46. Yield Parameters SRI Fert
Page 165 and 166:
Cabrera, M.L. 1993. Modeling the fl
Page 167 and 168:
148 Dunsmore, J.R., A.B. Rains, G.D
Page 169 and 170:
150 Hassink, J., Lebbink, G. and Va
Page 171 and 172:
152 management in agricultural syst
Page 173 and 174:
154 Root traits to increase drought
Page 175 and 176:
156 emission from rice fields: The
Page 177 and 178:
158 on ammonia volatilization losse
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Management of rice production systems to increase productivity

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