annenberg media ♪ by: narrador: bienvenidos al episodio 30 de destinos. primero, algunas escenas de este episodio. iay! iraquel! dormí mucho. sí, y te hizo bien. así estarás más descansada.

¿y roberto? todavía no se sabe nada. siguen trabajando. pero... ¿están seguros de que tiene suficiente aire? hombre: iroberto! iroberto! iroberto! también en este episodio vamos a aprender vocabulario relacionado con la ciudad. en los barrios se pueden encontrar varios negocios como: mercados... supermercados... farmacias... tiendas pequeñas... y grandes almacenes. y vamos a comparar las grandes ciudades con los pueblos.

los pueblos son diferentes de las grandes ciudades. aunque cada pueblo tiene un centro no hay edificios muy altos. generalmente, el centro consiste en una plaza y muchas veces en la plaza está el ayuntamiento. iroberto! hombre: iroberto! iroberto! ¿hay algún mensaje para mí? ah, sí. le llamó la señorita rodríguez. captioning of this program is made possible

by the annenberg/cpb project and the geraldine r. dodge foundation. en el episodio previo cuando raquel y angela llegaron al sitio de la excavación ya sacaban a dos personas. pero ninguna de las dos era el hermano de angela. hombre: ies villa! ies villa! ies andrés villa y está bien! justo en ese momento, hubo otro derrumbe en la excavación. roberto castillo quedó atrapado de nuevo y no se sabía nada de él. angela estaba desesperada. al día siguiente, en la ciudad de méxico

la familia castillo desayunaba y hablaba de varios asuntos. sí, carlitos tiene un poco de fiebre. carlos se lleva muy bien con los niños. ayer estuvo jugando con ellos todo el día cuando tú no estabas. sí, llegué un poco tarde. mientras la familia desayunaba, carlos hablaba con su hijo quien estaba enfermo la noche anterior. todavía tienes un poco de fiebre. muy preocupado porque no tenía noticias de raquel arturo bajó a la recepción del hotel y preguntó por ella. no, la reservación no ha sido cancelada pero ella aún no se ha registrado en el hotel. gracias.

solo, y sin amigos en esta gran ciudad arturo salió a la calle. este es un plano de la ciudad de méxico o como la llaman los mexicanos, méxico, o el d.f. como todas las ciudades grandes la ciudad de méxico consiste en tres partes principales: el centro numerosos barrios y zonas y las afueras. en el centro, hay grandes edificios altos. en ellos se encuentran oficinas... hoteles grandes...

y otros negocios. en los barrios se pueden encontrar varios negocios como: mercados... supermercados... farmacias... tiendas pequeñas... y grandes almacenes. los pueblos son diferentes de las grandes ciudades. aunque cada pueblo tiene un centro no hay edificios muy altos. generalmente, el centro consiste en una plaza y muchas veces, en la plaza está el ayuntamiento que es la sede del gobierno municipal.

también hay una iglesia. como en la gran ciudad en los pueblos también hay negocios típicos: farmacias, tiendas y mercados. pero a diferencia de las grandes ciudades en los pueblos pequeños generalmente no hay supermercados y grandes almacenes. y cerca de uno de estos pueblos pequeños en la meseta mexicana raquel y angela esperan saber algo de roberto quien todavía está atrapado en una excavación arqueológica. iay! iraquel!

dormí mucho. sí, y te hizo bien. así estarás más descansada. ¿y roberto? todavía no se sabe nada. siguen trabajando. pero... ¿están seguros de que tiene suficiente aire? ven, vamos a ver. así estarás más tranquila. sí. vamos. ihola! miren. están poniendo unos tubos. así el aire fresco podrá llegar hasta roberto. por favor, café para las señoritas y para mí. gracias. gracias. deberíamos ir al pueblo a telefonear. tienes razón. ojalá pueda comunicarme con la familia y también con arturo.

por favor, señor. mande ud., señor. es la primera vez que vengo a esta ciudad y no conozco nada. quiero ir a varios lugares. mire. quiero ir a una farmacia a una tienda para hombres a un almacén, a un mercado a un supermercado. muy bien, señor. podrá encontrar todo eso aquí en esta colonia. estamos aquí. en esta calle hay una tienda de ropa para hombres muy buena. mm-hm. y en esta calle hay un almacén donde se vende de todo. hay un mercado pequeño aquí también hay un supermercado a ver... sí, aquí. si sale y va a la izquierda en la esquina hay una farmacia. muchas gracias. a sus ordenes.

gracias. buenas. ¿podría usar su teléfono? sí, señorita. puede ud. usarlo. gracias. entonces, raquel trata de llamar a pedro. ( señal de comunicando ) pero la línea está ocupada. ihola! hola, guillermo. sí, soy yo. no, desde méxico. ¿cómo va todo? ¿qué clase de problemas? operadora: gran hotel de la ciudad de méxico, buenos días.

buenos días. mire, le llamo de larga distancia. me llamo raquel rodríguez... ¿rodríguez? ud. había hecho una reserva para ayer? sí, señorita. yo hizo una reservación pero... le paso con la recepción. ¿cómo? ino, espere...! recepción, buenos días. buenos días, me llamo raquel rodríguez... iah! señorita rodríguez, la esperábamos ayer. sí, es que ha habido un accidente. ¿un accidente? ¿se encuentra ud. bien? sí, yo estoy bien, pero... ¿desea cancelar la reservación? no, no, no, no. no deseo cancelar mi reservación. sólo quiero saber si ha llegado el señor arturo iglesias. sí, señorita. ¿la comunico con su habitación? sí, por favor, muchas gracias. ( teléfono suena )

( sigue sonando ) no contesta. no está en su habitación. sie sonand ) ( suspira ) no hay caso. tendré que llamar otra vez. ( teléfono suena ) ¿sí? iah, sí! muchas gracias. tu llamada a puerto rico. ihola! sí, señorita. con el señor jaime soto, por favor. gracias. mientras raquel y angela se comunican con puerto rico arturo va de compras. va a una farmacia... a una tienda...

a un almacén... y también a un supermercado. mientras está de compras, se para frente a un cine. dan una película que le interesa. arturo: tal vez invitaré a raquel y a mis sobrinos a ver una película. hola, pati. ¿pasa algo malo? no, no. no es nada. estás preocupada. sólo problemas con el trabajo. ¿en la universidad? no, en el teatro. dejé a mi asistente a cargo de todo. el es muy competente pero hay problemas con el productor. ¿qué puedes hacer? no sé... tal vez tenga que regresar a nueva york.

( se aclara la voz ) ( teléfono suena ) industrias castillo saavedra. hola. ¿ofelia? sí, aquí carlos. ay, ¿qué tal, señor castillo? ¿cómo está? lo echamos mucho de menos por aquí. como ya sabemos ofelia es la secretaria de carlos castillo. pero no es mexicana como carlos. ofelia es cubana. en miami, se siente mucho

la presencia de la cultura cubana. se ve en las calles en las tiendas y claro, en las personas. mi nombre es edi gonzález. bienvenidos a miami. ¿quiere un poco de café cubano? la mayoría de los cubanoamericanos se han establecido en los estados unidos por razones políticas. en mil novecientos cincuenta y nueve fidel castro asumió el poder en cuba. muchas personas se oponían al nuevo gobierno de castro y se fueron de la isla. aunque los cubanos han trabajado para integrarse a la vida norteamericana también han conservado su propia cultura. y esta parte de miami, se llama "la pequeña habana". en mil novecientos ochenta

llegó una nueva ola de cubanos de la isla-- otros refugiados políticos. ofelia era una de estos refugiados. a algunos de los cubanoamericanos les gustaría regresar a su país natal. sí, ¿cómo no? yo tengo muchas ganas de ir a cuba. otros, sobre todo los más jóvenes, no conocen la isla. son norteamericanos, de ascendencia cubana y forman parte del rico mosaico cultural de este país. ¿y cómo están los demás? todos bien por aquí, todos bien. ah, mire por cierto, hoy fuimos a comer a un restaurantito que está por aquí cerca y nuevo. ¿ah, sí? cubano?

cuando venga tiene que ir para allá. fuimos con una amiga a almorzar. oye, ¿cómo van las cosas en la oficina? ¿cómo? ( suspira ) ihola! ¿lograron comunicarse? yo hablé con mi familia en puerto rico. raquel está intentando llamar a méxico otra vez. ¿hay algo nuevo? no... mira, yo creo que tendremos que esperar hasta la tarde. ay... ¿tanto tiempo? van lento, angela, pero seguro. pobre roberto. estará desesperado. tendrá que tener paciencia. ya no falta tanto. por fin pude dejarle un mensaje a tu tío arturo, pero en casa de pedro la línea está siempre ocupada. ¿podemos ir a la excavación? mira, no vale la pena. ¿por qué no se quedan aquí en el pueblo? necesitan descanr. tiene razón. ¿hay un hotel?

no. pero se pueden quedar con la hermana maría teresa. ella es muy buena y les puede dar dónde bañarse y descansar. mujer: vámonos. josé maría, no te quedes atrás. haces la tarea, víctor. adiós. niños: iadiós! mujer: vámonos, pepe, no te quedes atrás. hasta mañana. hasta mañana. adiós. buenas tardes. muy buenas tardes. ¿es ud. la hermana maría teresa? sí, la misma. ¿uds. no son de aquí, verdad? no. me llamo raquel rodríguez y ésta es mi amiga, angela castillo. pues, mucho gusto. el padre rodrigo nos dijo que ud. nos permitiría descansar aquí. el hermano de angela es uno de los atrapados en la excavación. ah, sí. el padre me habló de eso ayer. iqué horrible todo eso! pero dios nos protege a todas, mi hijita. no te preocupes. pronto sacarán a tu hermano. gracias, hermana. así espero.

y por supuesto pueden quedarse aquí. ipasen, pasen! angela, ¿por qué no sacamos las maletas del carro? así nos podemos cambiar de ropa. bueno, yo las espero adentro. no necesitan tocar. pueden pasar con sus cosas. voy a buscar un lugar para uds. mientras tanto. gracias, hermana. maría teresa: no hay de qué. no hay de qué. buenas tardes. buenas tardes, señor. ¿desea la llave de su habitación? sí, por favor, la trescientos siete. ¿hay algún mensaje para mí? ah, sí. le llamó la señorita rodríguez. ¿cómo te sientes? ¿mejor? sí, mucho mejor. hermana, quiero agradecerle... nada de gracias. esta es una casa de dios y todos son bienvenidos.

mira. te voy a traer una taza de café, ¿te parece? tu amiga vendrá pronto, ¿no? creo que sí. bueno. traigo otra para ella también. siéntate, si quieres. gracias. iqué curioso! ( suspira ) bueno. en unos minutos vamos a volver al lugar de la excavación. ¿recuerdan cómo comenzó el día? esta mañana, angela y yo estábamos en la excavación.

¿y qué hacía angela? ¿esperaba noticias o dormía? angela dormía. dormía porque anoche el doctor le dio un calmante. pronto angela se despertó. me preguntó si yo sabía algo nuevo sobre roberto. pero no había noticias. entonces angela pensó en algo muy importante. ¿recuerdan?

angela pensó en que si roberto tenía suficiente aire. más tarde, intenté comunicarme con pedro. ¿y qué? lo conseguí o no? no lo conseguí porque como siempre la línea estaba ocupada. buenas. ¿podría usar su teléfono? sí, señorita. puede ud. usarlo. gracias. en el momento en que raquel llamó a pedro la línea sí estaba ocupada. pati hablaba con alguien en nueva york. y era una conversación importante. sí, entiendo perfectamente.

pero por lo menos angela pudo comunicarse con su tío en puerto rico. y yo hablé con alguien del hotel. ¿para qué hablé al hotel? ¿para cancelar mi reservación? recepción, buenos días. buenos días. me llamo raquel rodríguez... iah! señorita rodríguez, la esperábamos ayer. sí, es que ha habido un accidente. ¿un accidente? ¿se encuentra ud. bien? sí, yo estoy bien, pero... ¿desea cancelar la reservación? no. no quería cancelar mi reservación. quería hablar con arturo, pero no pude. el no estaba en su habitación.

por fin le dejé un mensaje. ojalá lo reciba. raquel no lo sabe, pero arturo sí recibió su mensaje. y ahora está muy preocupado. después de mis líos con el teléfono angela y yo vinimos aquí. y gracias a la hermana maría teresa pudimos descansar y bañarnos. y así ha pasado otro día en méxico. aquí está el café. gracias. hola, angela. te ves muy bien. parece que ese bañito te refrescó mucho, ¿eh? ¿gustas un poquito de café? ay, no, muchas gracias. estoy muy preocupada por mi hermano y quiero regresar al lugar de la excavación cuanto antes. ¿estás lista? sí, un momentito. ahora vamos. espero que ya hayan sacado a roberto. yo también.

ojalá hayan podido avanzar en el túnel. gracias por el café, hermana. de nada. las veo luego, ¿no? sí. hasta luego. hasta luego, hermana, y muchas gracias. ivayan con dios! pobre muchacha, con su hermano atrapado. dios, te pido que lo saquen pronto. hombre: iroberto!

iroberto! iroberto! captioned by the caption center wgbh educational foundation

annenberg media ♪ for more information on the college television course for information about this and other annenberg media programs call 1-800-learner and visit us at www.learner.org.

funding for this program is provided by annenberg media. narrator: agriculture provides us with the food we need to survive. to keep pace with an ever-growing population, scientists created new seed varieties that provided outstanding yields but also required increased inputs -- more fertilizer and more pesticides -- but at what cost to the environment?

peter kenmore of the united nations food and agriculture organization has been working with farmers for 30 years to decrease the use of pesticides in rice production. dr. kenmore: we have been able basically to substitute brains for chemicals. and in that sense, the growth rate stays up but less chemicals are used. narrator: in the yaqui valley of mexico, researchers are finding that excess fertilizer runoff from wheat crops is affecting marine life in the gulf of california. so they are turning to technology to decrease fertilizer inputs without decreasing yields. dr. ortiz-monasterio: technology like this can result in a win-win situation, where the farmer benefits and at the same time the environment benefits. narrator: by showing farmers how to reduce pesticide and fertilizer use, both research teams hope to minimize environmental impacts while still producing enough food for our growing population.

a staple throughout the globe, rice is an eential crop, providing 60% of the calories for half of the world's population. dr. peter kenmore of the food and agriculture organization of the united nations in rome, italy, has been conducting research about rice production in countries in southeast asia for 30 years. dr. kenmore: rice, now and probably for the last 4,000 or 5,000 years, feeds more individuals of the species homo sapiens than any other food. evolutionarily, why is it a good bet? because it grows in places that are flooded. you can grow it in places where other crops won't grow. flooding tends to kill most of the weeds that would grow up and compete with the rice,

so you have got an added advantage. so you can put it into what would otherwise be a marginal envirment. rice has been a good bet, and you've got loads of places where folks have been able to count on a harvest. narrator: rice successfully fed humans for thousands of years. but in the middle of the 20th century, population growth exploded, outpacing food production. to head off potential food shortages, governments encouraged and even mandated farmers to change their practice, requiring fertilizers to stimulate growth along with pesticides to control the insects that eat rice plants. but the results were surprising. dr. kenmore: pesticides sometimes created a contradictory result, which was you sprayed insecticides in the rice field and you got 500 to 1,000 times more insects

that were eating rice than you had without the insecticide. so that's a mystery. and from that time on, all through south and southeast asia, every year different countries would report problems like this. the first response was spray more. and that created often more of a problem. narrator: why would using pesticides create more pests? dr. kenmore: the beginning of the solution of the mystery is to see there are not just two ecological trophic levels. it isn't just the rice and the things that eat rice. there's the rice, the things that eat rice, and the things that eat the things that eat rice. so you have three levels. and when you spray, you kill both top levels except for t eggs ofhe pests that are inse the . when they hatch, there's nothing to eat them, and they go on happily reproducing, and you get a population explosion. it means that the pest population is freed from its natural controls, and that's what happened in rice.

narrator: these findings led kenmore to promote natural alternatives to pesticides for various crops, an approach known as integrated pest management, or ipm. ipm relies on detailed knowledge of pests and how they interact within the ecosystem to help determine the best way to control these insects with the least damage to the environment. dr. kenmore: integrated pest management accepts there will always be some pests in every field. if there's a low number of pests, they provide food for the natural enemies. if there's too many pests, one should intervene. sometimes one can intervene with a biological introduction, which can be, for example, a pathogen, like a virus or bacteria that eats insects. sometimes, in rare cases, one can intervene by introducing an insect from a different place

who will then naturally go in, eat pests, reproduce, and stay in the field eating the pests from then on. and in the last step -- pesticides, only when the naturally occurring pest control isn't keeping the pests to the desired levels. integrated pest managent us all of these approaches. it tries to avoid disrupting the natural ecosystem of that crop field. narrator: the next challenge for kenmore and his team was to persuade rice farmers, who had been using pesticides for years, to adopt this approach. settle: now, you might say, as people do, if pesticides are so bad for the system, why are the farmers continue using it? it's not obvious to the farmer what's going on in this system. they don't have a means of comparing what would or would not take place

with or without pesticides. narrator: to help introduce these alternate approaches to the farmers, the researchers started farmer field schools. bill settle supervises these schools in southeast asia and west africa. settle: i worked in 20 countries with this program. and most farmers think that anything that is crawling in a rice field is potentially damaging the rice. they think that any little damage to the rice plants is going to result in yield loss. so there's a lot of inherent fear with regards to the nature in front of them. so to tell them not to be using pesticides, after "we" have been telling them to use pesticides for the last 40 years, since the 1960s and '70s, is difficult. what we do in our training programs is help the farmers demonstrate for themselves what's going on by doing simple experiments. narrator: experiments are designed for farmers to be able to observe and understand

how pests are controlled in a system without pesticides. settle: we start with two plots. one is the conventional plot, where they do what they normally do, they apply the insecticides like they normally would. the other plot is something that is the experimental plot. call it the ipm plot. and even there we don't tell them what to do, but we sort of suggest, "well, let's try not using pesticides and see what happens." and since no one person is invested in the outcome -- it's a group plot of land that we are supporting -- there's no risk associated with it. dr. kenmore: and they start by looking at the crop, looking at the size and quality of the plants, and then by looking at the different kinds of insects and fungi that are observed, bringing samples back, and then each working group giving a mini seminar to the whole field school on what they observed in the field.

narrator: although similar to kenmore's findings, the farmers' results often surprise them. in untreated fields, herbivores that ate rice plants were kept under control by natural predators. but in fields where pesticides were used, plant-eating herbivores grew at tremendous rates, since the populations of their natural predators were greatly reduced by the pesticides. dr. kenmore: why farmers doing experiments is so important is they get to test what they have been told so that it puts them in the position of being the critical peer reviewer of the assertions coming from the trainer. narrator: farmers are encouraged to move beyond their initial scientific observations by creating even more robust experiments. ecosystem studies called insect zoos are designed to determine how various bugs will affect the rice fields. dr. kenmore: then you say, "well, i've got a bug here

"which nobody knows the name of, so we got to test it. is it going to eat rice, or is it going to eat bugs?" so you put it into a cage with rice and bugs, and you see what it eats. [ speaking native language ] settle: she's saying that this is a dragonfly and that it's useful for eating brown plant hoppers as well as other pests. narrator: another set of experiments helps farmers understand how much insect damage the plants can sustain and still produce economically viable yields. dr. kenmore: if you take 50% of the leaves off a rice plant when it's a month old, will the yield of that clump be any different from the yield at the end of the season of a clump where you didn't cut the leaves off? and if there isn't any difference, which usually there isn't, you can begin to own the concept that rice can absorb damage and you don't need to spray every time you see leaf damage.

narrator: farmer field schools have led to major changes in agricultural practice. during the 1990s, millions of indonesian farmers decreased pesticide use by tens of millions of dollars. at the same time, total rice production did not decrease but continued to increase. dr. kenmore: with farmer field schools, they were empowered enough to grow the rice while using less pesticides. the school has been able basically to substitute brains for chemicals. and in that sense, the yields stay up, the growth rate stays up, but less chemicals are used. narrator: integrated pest management has been adopted throughout the world, including the united states. in arkansas, a group of farmers is looking for alternatives to pesticides for an emerging pest that threatens rice production,

the sugarcane borer. dr. bernhardt: what we do not know is how much the sugarcane borer is similar to the rice stalk borer in its habits, how its populations are affected by the cropping patterns. it has quite a number of wild hosts, a lot more than our rice stalk borer. and all of that is going to play a big role in whether this becomes a major pest for arkansas or whether it's going to be a minor pest, like our rice stalk borer. narrator: last season, rice farmer clay poole was the first ever to experience the negative effects of the sugarcane borer. poole: we had some problem areas in a particular field and didn't really know what we were looking at. we discovered that we had a pest that is called the sugarcane borer. it did significant yield damage. we had spots in the fields where we lost right at probably 100 bushels to the acre. that $3 a bushel, that adds up.

when it all boils down, that's my profit. narrator: in between growing seasons, the farmers hope to control the pests by getting rid of the stubble, or remaining stalk from the previous year's harvest. poole: standing stubble was where they liked to overwinter. now, that's enough stem and stalk left there for a borer to actually bo in. research has shown that the destruction of the stubble after harvest is one of the best ways to control the threshold and the buildup of the sugarcane borer. possibly we'll knock them down enough where we won't have a buildup to where they become devastating to the rice industry. we are trying to get it to where insecticide would be the last resort that we have to use to control this pest. narrator: the farmers will need to wait until the next harvest to determine if their solution was successful. poole: we're looking out for the land. the land makes us money.

and if you damage the land or if you abuse the land, your land is not going to make you money. narrator: in the yaqui valley of mexico, wheat farmers are also caught in the struggle between making a living and protecting the environment. the yaqui valley is an irrigated plain on the northwest coast of mainland mexico that grows enough wheat each year to feed as many as 20 million people. thanks to advanced seed varieties, supported by irrigation and generous fertilizer application, the yaqui valley has earned the title "the breadbasket of mexico." yet even with this bountiful harvest, farmers' incomes are barely keeping pace with their expenses. and the excess nitrogen from their fertilizer washes out of their fields and threatens marine ecosystems,

the underground water supply, and even the atmosphere. can farmers maintain their standard of living and still protect the environment? this question is being explored by a fruitful collaboration between researchers at stanford university and agronomists in mexico. pamela matson, a professor and biogeochemist from stanford university, is one of the directors of this study. matson: i study the chemical interactions between plants and microorganisms and soil and water and atmosphere systems, and i focus in particular on nitrogen. a lot of my research is focused on what happens with nitrogen fertilizers in agricultural systems and how they affect the environment. narrator: an essential element for all living things, nitrogen is the main nutrient in many fertilizers. matson: all organisms need a lot of nitrogen.

plants and people and all different kinds of animals and microorganisms use nitrogen in our cells, and we need a lot of it. and of course, we are literally bathed in it. the atmosphere is 78% dinitrogen, so there should be plenty, right? but the problem is that most organisms don't have access to that dinitrogen in the atmosphere. they can't use it. they can't get at it. narrator: while certain bacteria can convert this nitrogen into forms that other organisms can use, for many crops, more nitrogen is still required. and nitrogen fertilizer allows plants to receive the much-needed nutrient that they lack. the use of fertilizer dramatically increased during the green revolution, where, from the 1940s through the 1960s, new seed varieties were introduced in many developing nations, helping avoid widespread famine. dr. naylor: the green revolution is just adapting crop varieties

to have much higher yields on a limited land base. and the key factor was new seeds for plant types, and these plant types were dependent on fertilizer inputs to get those higher yields. narrator: the green revolution began in the yaqui valley of cimmyt, which is the spanish acronym for the international maize and wheat improvement center. dr. ivan ortiz-monasterio is a senior scientist in the wheat program. in cimmyt's experimental plots, he examines the effects of a wide range of growing conditions, such as nitrogen levels. dr. ortiz-monasterio: what you can see here we have grown without applying any nitrogen fertilizer. it's a wheat crop with very severe nitrogen deficiency. the older leaves, which are at the bottom, start turning yellow first,

and then you also have a pale-green color rather than an intense green. also, the wheat plant produced tillers, or side stems, and here we don't see any tillering. we only have one stem. and, of course, you also see the stunting of the plant. these plants should be at least twice the height. narrator: in the next plot, 75 kilograms of nitrogen per hectare were applied. but the wheat is still showing signs of nitrogen deficiency. dr. ortiz-monasterio: i think the yield here -- it will probably be about 2 tons. and the break-even point for the cost of production -- it's about 4 1/2 to 5 tons. so it would be complete economic failure. narrator: in the final plot, 250 kilograms of nitrogen per hectare were applied,

the average amount used by a farmer in the yaqui valley. this is usually enough to guarantee a yield of 7 tons per hectare. to ensure against crop failure, wheat farmers in the yaqui valley apply these very large amounts of nitrogen fertilizer, more than necessary in a typical year. some of this is in the form of ammonia gas, which is bubbled into the irrigation water and reaches the fields during irrigation events. but a large amount -- about 75% -- is applied in dry form one month before they actually plant the seeds. matson: they were worried that if they didn't get it on early, they might not be able to get it on later when it starts raining or if it starts raining. so they were trying to avoid risk. of course, what they didn't realize is that they were probably losing a lot of nitrogen before they ever even got the seeds into the ground.

narrator: and this excess nitrogen can be damaging to the environment. matson: one of the problems with all that extra nitrogen going onto land and fertilizer is that it doesn't all get used by plants. it doesn't all get taken up. in fact, maybe on average 50% of it doesn't stay in agriculture systems but rather gets transported out of the fields where they were applied, and the trogen goes off to the atmosphere in a number of different forms, including nitrous oxide, which is a greenhouse gas, nitric oxide, which is an air pollutant. and some of the nitrogen in agriculture fields just leeches out through the soils into groundwater systems, or it runs off the surface into surface-water systems, like streams and rivers and lakes. and there it causes a number of different problems. the big issue for us is how to manage nitrogen, that nitrogen fertilizer, better

so that we can still increase plant growth, we can still get high yields, but we prevent the loss of that nitrogen into the atmosphere or into the water system. rrat: in the yaqui vley, the researcheam conducted several experiments to determine where the excess nitrogen was going. to find out if it was leeching into the water, the researchers followed the irrigation system to where it drains into the gulf of california. if this water contains excess nitrogen, it may cause large blooms of single-celled plants called phytoplankton. these blooms can cause harm to the ecosystem, because once the phytoplankton die, the decomposing process leads to very low levels of oxygen in the water. matson: and that kills fish, kills shellfish,

drives fish away, and causes lots of harm to the coastal marine environments and also causes a lot of economic losses to the fisherpeople who use those resources. narrator: researchers used satellite images in combination with water samples to determine if the irrigation runoff from the yaqui valley was affecting the coastal waters in the gulf of california. dr. beman: we found these intense blooms that seemed to coincide with fertilization and the irrigation in the yaqui valley. as we generated more data and were able to compare them with what we knew was going on in the agriculture system, we really did find this tight correspondence. narrator: motivated by these results, the researchers worked to find ways to maintain maximum yields but reduce the environmental impact of the fertilizer runoff. matson: in our best practice, farmers would have applied less nitrogen,

but they would have applied more of it at planting, none of it a month before planting. it seemed like a great idea. it worked in most farmers' fields. it worked in the experiment station. and we talked with farmers about it. but they didn't adopt it. [ speaking spanish ] [ speaking spanish ] narrator: when the research team talked with farm owners like sergio, they found that a one-size-fits-all solution was not appropriate in the yaqui valley due to the wide variability of climate and soils. but there was another obstacle to gaining the farmers' support. matson: the other thing that we discovered in our research is that one of the reasons they weren't trying the new practice is that the credit unions, their credit unions,

were telling them not to. the credit unions can recommend what kind of production practices should occur so that the chances in success at being paid back are the highest. and so although we have been recommending reductions in fertilizer use, the credit unions are often recommending increased fertilizer use. narrator: the research team began searching for an approach that could be adapted for each farmer. ortiz-monasterio collaborated with dr. bill raun at oklahoma state university, who had been developing a handheld radiometer called a greenseeker. this device can assess nutrient needs in real time and help farmers optimize future nitrogen applications. the instrument calculates total average biomass and the amount of chlorophyll in the leaves, data linked to the overall health of the plants.

armed with these real-time measurements, ortiz-monasterio helped develop a management strategy for nitrogen enrichment. on each plot, the first step is to establish a nitrogen-rich strip, a few hectares that have enough extra nitrogen applied to guarantee maximum crop yields. the nitrogen-rich strip has to represent a level of nitrogen that doesn't have any nitrogen deficiency. that's going to be our reference. once we have the nitrogen strip well established, around 45 days after planting, we come along with the sensor, and we take the readings in the n-rich strip, and then we take the readings in the rest of the plot. narrator: the readings are called in to a researcher, who calculates how much additional nitrogen fertilizer the farmer must apply

so this particular field can obtain the same yield as the n-rich control strip. much to the surprise of some of the farmers, the calculations often show that the plot requires little or no additional nitrogen in this second application to achieve maximum yields. these techniques will not only reduce the environmental impact of excess fertilizer but will also save the farmers money, a fact that was very appealing to the credit unions. matson: ultimately, when they saw that the handheld-radiometer approach works and that could save their farmers a lot of fertilizer and thus save them a lot of money, they decided to invest in them for their members. so the credit unions themselves bought the handheld radiometers for all of their members to use. and they bought it because it was a money-saving device. narrator: while not all wheat farmers in the yaqui valley have adopted this practice,

the researchers are making progress in this pivotal year. dr. ortiz-monasterio: last year we had only seven fields. this year we jumped to 174. so in my opinion, this year is crucial. if we are successful, i think this is going to explode and be widely adopted. and i think this is a wonderful example how a technology like this can result in a win-win situation, where the farmer benefits and at the same time the environment benefits.

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