In
Pakistan there are many factors which cause low mung bean yield like use of
less seed rate, inappropriate sowing methods, low nutrients application and use
of traditional low yielding varieties. Another factor is poor stand
establishment which also decrease the yield.
Deficiency of different nutrients causing yield reduction. Imbalance use
of fertilizer (N, P and K) results in wastage of large amount of nutrients in
term of losses and fixing and
immobilization feature. Therefore, balance use of fertilizers should be adopted
in order to get higher yield.Water stress is also an imporatant
problem for plants because water deficiency effect on every stage of
crop and it is a main reason for low yield and biomass. Water scarcity is one
of the biggest yields limiting factors for all crops. Water is source for
nutrient movement and photosynthesis.
Drought is one of the severe abiotic
stresses that decrease the agricultural productivity (Farooq et al., 2009). If water is deficit it
reduced yield up to 50%. Water scarcity condition also cause reduction in rate
of photosynthesis resulting in low yield. Water deficit condition also reduced
the stomatal opening and it effect photosynthesis and resulting in low yield
(Yordanov et al., 2003). Drought
effects on every stage of crop such as pollination, grain development etc.
results in low crop productivity and yield. Agriculture is one of the biggest
fresh water users in the world. However,
now a day’s use of municipal waste water has been increased in agriculture due
to scarcity of fresh water. Municipal
waste water contains large amount of heavy metals like lead and other toxic
substances which accumulate in plant biomass and decrease the quality of crop.
Water logging in mungbean
field is also a problem which decline the yield of mungbean. This crop is
mainly grown in rainfed areas and cannot bear the water logging in early stage
of germination. One of the several physiological affects is to reduce
photosynthesis. Stomatal closure also
attributed with decrease rate of photosynthesis under water logged soil. The rate of
photosynthesis also decreased with reduced ribulose bisphosphate carboxylase
(RuBisCO) activity and increase in rate of photorespiration under water logged
soil. In addition, soil nitrogen also reduced due to volatilization and
denitrification.
Poor stand establishment is also one of
the biggest factors for low yield. If number of plants reduced then poor crop
stand resulting in less productivity and reduced yield. Low population
decreased the biological as well as economic yield of crops. Different experiments were conducted across
the world to find the optimum seed rate for mung bean. In wider space crop,
number of branches compensate the low number of plants resulting in higher
yield. However, that number of branches per plant reduced with increasing plant
population
Sowing date is also an important factor
which determine the yield of mungbean. Early sowing cause germination problem
and other environmental hazards cause low yield. Early sowing and late sowing
both cause problems because plant don’t resist unfavorable condition. Sometime
in late sowing temperature fluctuate and resulting in unfavorable condition for
normal growth of plants. Late sowing delayed in time of emergence and maturity
and cause yield reduction.
Fertilizer are needed in
optimum amount because it plays very important role in growth and development
of plants. A balance amount of micro and macronutrients is required to obtain
high yield and good quality products. Micronutrients also play role in
improving grain yield and quality of products. Imbalance application of
fertilizer causes low yield of mungbean. As reported that
nutrient deficiency had important role in yield reduction. Nitrogen
plays a vital role in increasing grain yield. Optimum nitrogen application
increased photosynthesis, net assimilation rate and leaf area production.
Weed infestation is also one
the major problem that decrease yield. Weeds compete with crop plants for
light, water, space and nutrients causing low yield. Weeds also provide place
for insect’s pest resulting in more yield loss. Weeds also have allelopathic
effect which affects the growth of plants. Allelopathic effect means production
of allelochemicals which affect the growth of other plant. Under poor fertile
soil weeds grow faster than crops and offer competition with crop for resources
and resulting in decrease in leaf area index, biomass and photosynthetic
activity. Weeds infestation also decrease yield of crop about 29.2% under no
control for weeds and under control weed affect yield about 12.8%. Annually a
loss of about 28 million rupees is recorded due to weed infestation.
Soil salinity is one of the
biggest problems around the world. Salinity level also affect the yield of mung
bean. soil salinity affects Mungbean crop growth and productivity. About 400 million hectares around the globe
is salt affected which is about 25% of total area in the world. Salinity also
cause the ionic imbalance and salt like Na had negative effect on growth and
productivity. If salts are present in high amount then water uptake for plant is
very difficult. Oxidative effect also caused by salts which damage the plant
cells. Salinity also affect the crops at early stage that reduce germination,
reduce crop growth and resulting in major loss to yield. Salt affected soil
because of osmotic stress results in drought condition which leads to water
shortage for plant and severly affect the plant growth. Another major reason
for low yield is lack of micronutrients in soil throughout the world. Micro
nutrient is deficient worldwide due to some conditions like pH, salt stress,
nature of soil and organic matter in soils which affect plants, and humans.
Micronutrient deficiency is one of the
major constraints for productivity of crop that caused by primarly, due to low
content of fertilizer and secondly due to unavailability to plants.
Micronutrients deficiency induced morphological (small size of xylem vessels,
decrease yield), physiological and induce heavy pest infestat. A balance combination of macro and micro nutrients played a
very important role in the higher yield. Macro and micronutrients application
have imperative role in getting higher crops yield with better nutrition status.
Most of the soils lack micro and macro nutrients that can be achieved through
nutrient management. Deficiency of different nutrients causing yield reduction.
For better plant growth mineral nutrients like iron and zinc are required with
various other fertilizer like nitrogen and phosphorous in different cropping
zone. Micronutrient deficiencies also affect the physiological and metabolic
function of plant and micronutrients are required by plant in small amount for
better growth and yield. Nutrient deficiency is a serious threat towards low
yield of pulses. Micronutrient deficiency in the soils not only reduced
productivity but also the nutritive quality of the crops. It also contributes
to malnutrition.
Iron is an important micronutrient which
play significant role in different process of plant when applied with other
nutrients. Micronutrients like Fe, Zn and boron (B) help in nucleic acid,
chlorophyll, protein synthesis and enzymatic activity required in
photosynthesis in plants. Ziaeian and Malakouti revealed that Fe and Zn
application significantly increased protein contents in seeds and also improved
concentration of these micronutrients in seeds. Iron is trace element but its
availability to plants positively affects the plat physiology which
significantly reflected in better yield. Deficiency of Fe causes chlorosis of
leaves in different crops. However, foliar spray of Fe in the form of FeSO4
cured chlorosis. Iron has key role in
different steps of photosynthesis pigment metabolism and in structure of
chloroplast. Its deficiency produced many problems like chloroplast structure
is modified and amount of protein decrease from electron transfer complexes.
Therefore, application of mineral
fertilizer improved the micronutrient contents of leaf and grain in wheat crop .
So that Fe and other micronutrient collectively affect the development, growth
and yield of wheat crop. In humans, Fe and Zn deficiency is also serious
problem for health. Iron and Zn deficiency is very high in young children and
pregnant women. Furthermore, Fe deficiency cause anemia in humans.
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