Crop Manipulation for Sustainable Upland Agriculture--Spatial and Temporal System
“ Whatsoever a man soweth; that shall he also reap”
(Paul of Tarsus , Galatians VI.7, Wikiquote)
KEYWORDS: Climate change, Temporal system, Spatial system, Uplands, Hilly land, Crop production, Ideotype breeding, Intercropping, Alley cropping
Climate change has been with us for the last 100 years or so. Aberrant weather has become intense and increased in frequency in recent years that threatens life and property.Nevertheless; whether the cause is natural or man-made, the effect is still the same, crops are destroyed.The most affected area is the crop lands in the uplands or hilly land. These lands suffer most from combined effects of desertification, acidification, salination, deforestation and many other physical and biological degradation that make these lands unfavorable for crop production.
Climate change and food production
The impact of climate change in some regions will be more severe than others ,for instance Africa and part of USA and Australia productivity will be affected as severe drought visit the land while countries in Oceania and Europe will have more favorable weather conditions for crop production.
Diversity of food crops grown will be influenced by the climatic change in ambient temperature. Comparing two temperature regimes, regardless of variation in temperatures, crop diversity will be reduced that tend to undermined farmers choice. What is more threatening is . if the three great cereals namely; rice, corn and wheat failed to deliver the expected output, millions will be hungry by 2025.
Geography of upland soils
According to Garrity (1991), uplands or sloping lands are the most extensive ecosystem in South East Asia covering 60 to 90% of the land area, while worldwide, the uplands or dry lands accounts 41% of the earth surface and supplies 40% food for over 2 billion population. If one can turn these lands more productive, food security and economic stability of the regions will be assured.
Characteristics of upland soils
Uplands are characterized by dry, water-less environment. Soils undergo various levels of degradation, mostly acidic, lack essential nutrients, low in biological activity, therefore; unfavorable for crop production. The uplands has been variously defined, according to Webster (2005) areas of the land above flood level or elevated above the lowlands along rivers and between hills: or land elevated above other land, or the higher ground of a region or district (Collin English Dictionary,1998).
Methods of crop manipulation
Farmer possessed knowledge on how to farm the uplands or hilly lands. For centuries they have been tilling the land providing them food security and economic stability, moreover, change in climatic pattern undermined this age-old practices. Presently some practices becomes destructive as farmers opened protected areas for farming (eg. “Kaingin” or “ slash and burn”) as a result of climatic change that made their previous land unproductive This article present some of their techniques how to manipulate crops to fit their farming environment.
“Whatever is removed from the soil by the previous crop should be replenished for the succeeding crop”
Crop manipulation involves variation in the choice of species and cultivars, timing of events, plant density, fertility status, provision for irrigation, and other factors including the farmer itself.Furthermore, in a true sense, crop manipulation is the diversity of management practices taken in specific combinations and arrangement wherein the farmer has a great deal to say. According to Tourte(1983)..".that farmers should participate in developing and evaluating technology for their own use, is so evident that it has generally been ignored.In the past and still today,few efforts to help farmers has been designed with their participation"
A. Spatial Arrangement - Intercropping
Intercropping is the best way of illustrating crop manipulation by "temporal" and or "spatial ” arrangement of planting of crops.It is the growing of two or more crops species in mixed cultures on the same land by putting the crops in alternate stripes or rows. Normally a short and a tall-growing crop or a quick and late maturing crops used as intercrops.The two cropping system are called spatial and temporal system, respectively.
There are a number of benefits derived from these systems. Growing crops in the uplands, two important climatic elements must be considered, water and light. For instance in “Spatial” arrangement the rows are space planted closer to each other to maximize space and at the same time prevent water loss from evaporating over exposed soil surface as temperature rises, in this way availability of water is extended until harvest.
Conserving water is very important since it is one of the raw materials in the food manufacturing process known as photosynthesis. In temporal arrangement, the intercrops are planted on the same lot but maturity differs, the main crop maybe early maturing and harvested ahead while the second crop later or vice versa. The advantage here is that the plant debris left by the harvested crop can serve as much of the second crop thus conserving precious water and as the source of organic matter.The mulch cover served as coolant that tend to promote biological activity thus rendering the soil beneficial to the crop.
Nutrient rich soil will generate more CO2 ( from microbial activity), in addition to atmospheric CO2 thus, an internal source of carbon dioxide is made available throughout the growing season. Moreover, in these systems of manipulating crops to maximize use of water and light, plant competition must be avoided. Farmers employed by varying the stature of the intercrops.
The primary crop may be tall while the secondary crop shorter. Examples of Spatial arrangement are two rows of corn for every 4-rows of upland rice or mung bean. or rice-legume, rice-sweet potato, etc. the number of rows may vary for each intercrop.
For temporal arrangement, examples are sugarcane at the juvenile stage with mung bean, coconut with papaya, pineapple or coffee.Note that the stature of the intercrops vary especially with perennial crops. Coconut and pineapple is a positive combination. Pineapple being a CAM (crassulasean acid metabolism) plant obtain CO2 during night time only, therefore, does not compete with coconut for CO2 during daytime.
Temporal separation of CO2 acquisition between the two crops is very effective and beneficial to both, thus maximizing crop productivity on the same land. Coconut x Banana is a negative combination, the wiry roots of coconut will be pierced the succulent root of Banana. When this happen growth of Banana is drastically affected, both crops have fibrous root system, thus competition cannot be avoided between the two crops to the disadvantage of Banana.
“A seed need time, a little rain and a little sun to become a great tree "
From: A Bug's Life
B. Temporal Arrangement - Alley Cropping (Contour farming ,Hedge-row planting, Strip planting)
Uplands have been described in many ways as hilly, sloping and or dry lands. Despite the harsh and rugged terrain farmers have adopted technologies to make this land productive.
Among these technologies is Alley cropping or contour farming. With slopes ranging from 10 to18% farming in this land is unproductive for it will only hasten soil erosion and various forms of degradation.Alley cropping and contour hedgerows are the dominant farming system in the hilly lands or uplands of South East Asia.
This system manipulates crop production to support food and livelihood of the farmers.The system follows an alternate succession of a strip of hedgerows of leguminous tree species established along the contour of the slope and an open space or alley of 5 to 6 meters wide which is devoted to food crop production.
The hedgerows of closely spaced plants provide the barrier to soil erosion and at the same time the supply of green manure to cereal crops grown in the alleys and fodder to ruminant animals.Pruning of the hedgerows is done 3 to 10 times each year and prunings are incorporated to the soil in the alley (Lantican,2001).
Among the tree species used as hedgerows, Ipil-ipil (Leucaena ieucocephala L.) is the most effective in reducing run-off and soil erosion. Furthermore, farmers in the uplands see to it that harvesting or maturity of intercrops does not coincide with one another hence extending food supply for the whole cropping season. This is a good management practice by the upland farmers to ensure food security and stability to the system.
A basic plan must be drawn first as to the kind of hedgerow species to be planted and the food crops to be integrated including ruminants.
C. Indirect System
The indirect system of crop manipulation in this case, involved manipulations through genetic, physiological, morpho-anatomical and plant breeding. The main goal of this endeavor, however, is to developed crops first that are tolerant to various stresses that affect agriculture in the uplands rather than yield per see.
Many workers along this fields believed it can be done though the complexity may vary from system to system. For instance Zobel (1983) categorized the complexity of seven characters, thus agronomic is the most complex character for genetic improvement.
According to Zobel(1983),the process of exploring any desirable attributes such as efficiency of water use often at the highest level , in the case of agronomic characters such as planting density and timing of canopy closure are determined directly or indirectly by morphological characteristics. and these in turn by anatomical characteristics, and so on to the genetic level (gene). Each character has its own unique heritable components, therefore, to some extent amenable to breeding procedures.
Hierarchical pattern of seven levels charaterization
levels of complexity
Application of plant morphology and anatomy can be best appreciated by changing crop architecture, breeding to reduce leaf shading is advantageous to maximize trapping of radiant energy wherein the lower leaves even received the adequate amount of sunlight. By changing leaf angle and orientation will make the crop more efficient in harvesting radiant energy from the sun.
In rice, instead of tall, high tillering varieties with planophile leaf (horizontal orientation) may be replaced by short, low- tillering plant types.With less tillers (10-15), erectophile leaf (vertical orientation) to reduce light competition among leaves and between plants, photosynthate is invested in developing strong and shorter culm to support long and heavy grained panicles.
In corn ,Hybrids are the new plant ideotype, high yielding ,responsive to N- fertilization, adapted to mechanization and an excellent monoculture crop, unfortunately this crop is not suited to the uplands where farmers generally used open-pollinated varieties adapted to variable upland environment and minimal resources of the farmer.
2. Physiological and genetic
Understanding physiology in the context of upland agriculture can be best explained from plant responses to their environment yield could be the best measure how adapted a crop maybe to their environment but direct quantification could not explain such response.
Easten and Sullivan(1983) indirectly assessed the performance of two groups of plants (C3 and C4 plants) on their response to temperature.It appears that C4 plants were superior over C3 plants where, temperature maxima for C4 plant was higher during photosynthesis and growth. The effect of temperature is to directly influenced photosynthesis by damaging photosynthetic apparatus.
The superiority of C4 plants over C3 plants is ascribed to their high thermal tolerance and tissue integrity. Growth under high temperature also slow down until irreversible damage is attained, growing point stopped to divide and elongate. Some plant organs like roots, acquisition of water tend to slow down when root hairs no longer capable of transporting water to the shoots thus affecting photosynthesis and other water requiring processes and consequently, yield.
Tempreture variations for photosynthesis and growtrh
Process and type of plants
C3 planrs (herbaceous)
C3 plants (herbaceous)
Recommendations and Conclusions
Climate change will be with us today and tomorrow, how it will end, we don't know, nevertheless, mankind's future will be at stake.Upland agriculture will be the most affected by climate change, therefore, upland farmers should be cognizant of its effects.To make farming in the upland sustainable, adapting Spatial and or Temporal arrangements of planting crops is the valuable system.
Benefits derived from using these systems are plenty, aside from food security and economic stability, it renders the land ecologically sound and stable.There are variations to these systems, moreover crop manipulation is a farmer's decision as to what system to use, best fit for specific situation of the farm. In this way, farmers will have freedom to choose with.
In conclusion, crop manipulations are needed in upland agriculture to boost food production and renders the land ecologically sound and stable.The interplay of different disciplines (eg. plant breeding) may facilitate the development of new plant ideotype appropriate for upland agriculture. Likewise, physiologist, geneticist and even farmers may come together to craft the most responsive cultivar to changing upland environment.On the last note, Dr. Jose P. Laurel once said that "The seeds of moral discipline must be nurtured from within ...not from without ".
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