Evaluation of different [lowland rice] production and component technologies

The efficiency of applied organic N fertilizer in lowland rice seldom exceeds 50%. This is very low considering the high price of this farm input. However, by using the site-specific nutrient management (SSNM) technique, better efficiency was attained by increasing grain yield. SSNM was refined through farmers' field demonstrations. It is more effective than conventional methods because it is crop based and it advocates real time nutrient management. The average yield with SSNM was 11% higher than farmers' fertilizer practice while profitability increased by 4,200/ha. Questions on sustainability of using inorganic fertilizers as main source of plant nutrients are being addressed by the inorganic fertilizer trial that was started in 1969. The continuous NPK fertilizer application yielded highest (8.18 t/ha), while the non-application of P, K, PK or NPK resulted in significant yield loss based on the 69th cropping of lowland rice. The study further showed that balanced fertilizer application and time of application sustain high yields regardless of source. The long-term effect of organic fertilizers on lowland rice is an important consideration in soil fertility management. Among the indigenous organic fertilizer materials, chicken manure (CM) consistently showed advantage on yields from the two experiments and from 4th season long-term organic fertilizer trial. Soil microbial biomass and activity increased at 14th day after treatment application (DATA). Peaks occurred at 27 DATA but the highest was in plots with CM, followed by rice straw compost + CM + inorganic N fertilizer. Phototrophic biomass was high in plots with CM at 55 DATA. The Systems of Rice Intensification (SRI) is an alternative management technique for a more environment-friendly rice farming. It is more manageable in smaller farms (less than half hectare), and it has better water control with good irrigation and drainage. Conventional methods of growing lowland rice use too much irrigation water. Water resources, however, are becoming scarce and costly. Hence, alternative rice production technologies that can save more water, especially in water-scarce environments, are being developed. Controlled Irrigation (CI) can reduce the amount of water applied in the field by an average of 25% without reducing yield. It is effective in shallow well or deep well irrigated areas and those at the tailends of bigger irrigation systems. Aside from CI, aerobic rice technology (ART) is being localized. Based on preliminary studies, ART can save more water than the previous water-saving techniques and can even cater to rainfed areas. However, issues like weeds, pests, tillage, and fertilizer managements are still being addressed. Characteristics and classification of the major lowland rice soils were sourced from secondary data sets. Majority of rice soils in Region 1 have dry soil moisture control section in some or all parts for greater than 90 cumulative days in most years, but moist in some parts for greater than 180 cumulative days or continuously moist in some parts for at least 90 consecutive days (ustic moisture regime). Soils in Regions 2, 4, 8, 10, and 11 have reducing conditions that are free of dissolved oxygen because the soil is saturated by groundwater that is always at or very close to the surface or by water of the capillary fringe due to its position in landlocked depressions fed by perrennial streams (aquic moisture regime). The soil moisture control Section in Region 3 and Region 6 is not dry in any part for 90 cumulative days (udic moisture regime); while soils in Region 5 has an equal number of aquic and udic moisture regimes. Presented and discussed are the different soil orders wheremost of the lowland rice soils of the Philippines belong.