Managing Hybrid Rice in High Elevation

[Pages:3]Managing Hybrid Rice in High Elevation

Tagumpay sa Palay Article for January 2012 Column By: Nelson Paraguison, District Agronomist, Pioneer Hi-Bred Philippines, Inc. Published In: Manila Bulletin Agriculture Magazine January 2012 issue

"The earlier, the better". This popular saying may not only to apply to the usual preference of growers for early-maturing hybrids, but also to the proper care of the rice plants early in the season. As many farmers can attest, young plants that were managed very well in the first stages (vegetative phase) are usually better prepared against various environmental stresses than those in poorly managed fields. Hence, plants that are healthier during the vegetative phase have better chances of giving good yields. Green and disease-free plants can also inspire their owners to continue managing and protecting their fields as these help them ensure that their investment will bear good fruits.

Seedling Management

Growing hybrid rice such as PHB71 is no different from growing ordinary varieties of rice except during seedling management. This is because you only need a small amount of seeds that may range from 15 kg to 20 kg per hectare to be sown in a 300 sq. meter seedbed. Given this amount of seeds (not to mention the value of hybrid seeds), the grower must ensure that proper management of seedbed is undertaken. (Inbred rice growers may not be that mindful as their seeding is normally much higher at around 40 to 120 kg of seeds per hectare which means they can afford a certain level of seedling mortality).

When we say proper management, we mean the application of organic fertilizer to loosen the soil when pulling seedlings from the seedbed, correct timing, and proper amount of fertilizer for the seedlings, vigilant maintenance of water levels at 2-3cm in order to prevent the soil from becoming too hard, and proper control of pests. What's interesting is that hybrid rice can be planted at just 1-2 seedlings per hill and still give growers better yields and income. With the value and yield potential of hybrids, it is important that every seedling is properly cared for and survives to bear fruit. Users of inbred varieties, on the other hand, will use 3-5 seedlings per hill and sometimes even more, depending on their practices.

Optimum Planting Space

One basic cultural management to control or mitigate pests and disease occurrence is to follow proper plant spacing. Increasing plant populations tend to increase the risk of disease infection and may actually create a favorable environment for insect pests. On the other hand, a very low plant population is also not a good thing since it may not result in the optimum yield levels that will

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make rice farming profitable. The optimum planting space when using hybrids such as PHB71 is 20 cm by 20 cm or 250,000 hills per hectare during the wet season and 20 cm x 15 cm during the dry season or 333,333 hills per hectare during dry season. It is generally recommended to plant 1-2 seedlings per hill.

Water Management

With water being a precious resource nowadays, farmers are encouraged to use water saving techniques wherein one supplies just enough water at a given stage of the rice plant's growth. This practical approach in managing irrigation water can prove to be costefficient, and it has added benefits in minimizing percolation rates due to hydrostatic pressure and prevention of surface runoffs. These processes tend to deplete the soil of nutrients. The presence of too much water can also be conducive to some diseases such as bacterial leaf blight, bacterial leaf streak and sheath blight.

Water can also be a good tool in managing weeds and the golden apple snail (GAS).

Our experience with hybrids is very positive when water is managed very well by the farmer; on many occasions, excellent yields and profitability are attained. Below are suggestions for the timing and procedure of applying irrigation water:

1. Within one week after transplanting, maintain the soil at saturated levels to establish better root-soil contact and control snail infestation.

2. During the tillering to early reproductive stage, occasionally drain the field for good soil aeration to stimulate better and deeper root growth, induce more productive tillers, establish better root anchorage (to lessen lodging incidence), and the removal of some toxic substances from the soil.

Balanced Fertilization

It is natural to expect that hybrids will require more nutrients than inbred because of their difference in yield potential. While inbred varieties will yield, on the average, around 180-200 grains per panicle, hybrids have been found to double that potential number of grains per panicle (300-400 grains). That gap in potential can only be realized if growers follow a different approach in nutrient management, and that it should start early in the season.

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It is advisable for farmers to have their soil analyzed to assess its nutrient supplying capacity. In the absence of this, they may follow a general fertilizer recommendation from private companies or public institutions which are normally products of their scientific studies. Pioneer has generated their own fertilizer recommendations for PHB71, as seen below:

Note that as a general principle, the split application of fertilizers is always good as it can help manage nutrient losses and allow growers to supply only the needed amount and type of nutrients at any given time. The dry season will normally give better returns on fertilizer investment than in the wet season due to some obvious reasons such as better solar radiation in the dry season and the disease and lodging issues in the wet season. Nevertheless, Pioneer hybrids are expected to perform better even in a regular farmer's field using his own fertilization program.

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