What Dr. Luke has to Say About Relieving Drought Stress Brought by Crop Management - Part II


Managing Drought Stress by Supplemental Irrigation - Part II


The agricultural expert yesterday had talked about five factors needed for the development of a sustainable dryland farming system.  These five factors were Conservation Tillage, Weed Control, Soil Fertility Management, Diversified Farming and Species Selection and Variety.  Yesterday he had talked about the first two and today he said he would talk about soil fertility management, diversified farming and species selection and variety. 

Wang Ying Nian was at the lecture yesterday and really enjoyed the talk.  He knew he was facing a big problem as his crop yield was decreasing and this was primarily due to a decreased amount of rain.  He knew he very much needed an irrigation system to help his crop yield to be better.  However, he also knew he did not know how to do this.  Thus the need to hear from the agricultural expert and learn from him the best and most affordable way to develop an irrigation system which would help his crops and farm.

The agricultural expert said he would today first talk about soil fertility management.  He started by saying that during times of drought it is important to have a crop, which is healthy and free from any other stress.  One way of doing this is to have appropriate levels of fertilizer applied to the soil.  Sometimes it is hard to justify applying fertilizer when drought conditions look likely, but a crop that does have adequate fertility during a drought is much more likely to survive.  It is a common practice to reduce seeding rates during drought conditions.  For example reduce the seeding rate by 25% and then you can reduce the fertilizer needed by 25%.  This will cut the cost of planting the crop; a crop planted at lower populations will also require less water to produce a crop.

Next the agricultural said he would talk about diversification of farming. Diversification of farming is an ancient but an effective approach to reduce the risk associated with farming in unpredictable environments. Reduced diversification to the extent of mono cropping is possible only if a high level of control is possible over the crop environmental conditions. Such control method (irrigation, chemical pest control, etc’) are among the main reasons for the more recent environmental quality problems found to be associated with mono cropping.

Diversification of cropping to reduce risk is especially important under dryland conditions.

   1.      Spatial diversification of fields. The farmer’s land is divided into several fields or plots, which may differ in their topography, soil and hydraulic properties. Some fields may be prone to flooding while others do not hold water.  Certain fields may be on a warmer slope while others on a cooler one. The different field conditions allow to achieve a better fit between the crop and the environment and to reduce the general probability of stress affecting the farmer.

   2.      Crop diversification is an important feature of traditional farming. It takes an advantage of the generally low correlation between crops in performance when grown in a single stress environment. Crops differ in their response to a given environment and this difference is used to reduce the risk associated with growing one crop.  “Mixed cropping” or “intercropping” is an example of a traditional and a successful approach to crop diversification on a single parcel of land, where two or more crops are grown. If for some reason only one crop is grown, a certain (though lower) level of risk reduction can be achieved by variety diversification. Planting of several crop varieties offer a better probability for reducing loss due to environmental stress, as compared with growing one variety only.

   3.      Temporal or time diversification may achieve the same result as variety diversification.  The purpose of setting a distinct planting date is to optimize crop development with respect to seasonal climate, mainly rainfall in rain-fed agriculture. Ideally the crop is planted at the beginning of the rainy season, rainfall peaks when crop evapotranspiration peaks and it terminates just before harvest time. When such conditions are reasonable predictable, planting date can be set to optimize production. Where the timing of rainfall is very unpredictable, adopting more than one planting date for the given crop can reduce the risk involved with untimely rainfall and a given planting date.

Finally the agricultural expert he would talk about species selection and variety.  He started this section by saying that short growth duration (generally defined by early flowering) constitutes an important attribute of ‘drought escape’, especially for conditions of a late-season drought stress. On the other hand, longer growth duration is often associated with high yield potential. Consequently, using drought escape as a solution may involve a cost in terms of reduced yield potential. This is serious, especially when the moisture environment is unpredictable and may vary to a large extent between years. The unpredictability of the environment may reach a state where short growth duration is a drawback, especially in continuous flowering plants that offer a potential for regrowth and productivity upon recovery. The final decision on the optimum growth duration has, of course, to consider additional factors, such as late-season disease and insect pressure or periods of frost.

Plant size as expressed mainly in terms of single plant leaf area has a major control over water-use. Small plants and reduced leaf area are generally conducive to low productivity while they limit water use. Botanists have long recognized small plants bearing small leaves withstand drought very well.  However, their growth rate and biomass are generally lower.

The agricultural expert concluded his talk by saying, it is not uncommon to come across opinions that drought resistance is “very complex” or “confusing” or “difficult”. However, conserving water is the key to surviving a drought.

Wang Yin Nian was very glad to have heard this talk.  It was very helpful to help him begin to understand all that is involved in helping his crops in drought situations.  However, he still was concerned about how he could do all of this work and afford it.  He knew he must make changes or continue to loose more and more crops each year.  If the trend continued he would be bankrupt in several years.  Certainly he and his wife did not want the lack of water to end in bankruptcy. 

As Wang Yin Nian was walking away from the lecture he began talking with one of his friends.  Wang Yin Nian asked this friend if he had the same concerns about drought and loosing his crops in the future if something did not change.  His friend said he knew that things could get worse.  However, he said he also knew who was in ultimate control of the outcome of his crops.  Wang Yin Nian asked who that person was?  His friend told him that Jesus Christ was in control of what happened to his crops.  Wang Yin Nian thought this was an odd answer.  He had vaguely heard of Jesus Christ and thought he was related to some religion but could not understand how Jesus Christ could help his crops.  Wang Yin Nian asked his friend to explain what he meant.

Wang Yin Nian's friend asked if they could sit down.  The he turned to a place in the Bible and read the following.  'I will lift up my eyes to the hills-where does my help come from?  My help comes from the Lord, the Maker of heaven and earth.  He will not let your foot slip-he who watches over you will not slumber; indeed, he who watches over Israel will neither slumber nor sleep.  The Lord watches over you- the Lord is your shade at your right hand; the sun will not harm you by day or the moon by night.  The Lord will keep you from all harm- he will watch over your life; the Lord will watch over your coming and going both now and forevermore (Psalms 121.1-8).' Wang Yin Nian's friend told him he had a steadfast hope that even in drought times God would provide for him.  Wang Yin Nian's friend said he had a steadfast trust in God's protection over he and his family's life.

Wang Yin Nian thought this was great but he asked his friend how could he acquire that protection?  Wang Yin Nian's friend showed him another section in the Bible, which said the following.  Jesus said, 'the kingdom of heaven is like a man who sowed good seed in his field.  But while everyone was sleeping, his enemy came and sowed weeds among the wheat, and went away.  When the wheat sprouted and formed heads, then the weeds also appeared.  The owner's servants came to him and said, Sir, didn't you sow good seed in your field?  Where then did the weeds come from?  An enemy did this, he replied.  The servants asked him, Do you want us to go and pull them up?  No, he answered, because while you are pulling the weeds, you may root up the wheat with them.  Let both grow together until the harvest.  At that time I will tell the harvesters.  First collect the weeds and tie them in bundles to be burned; then gather the wheat and bring it into my barn (Matthew 13.24-30).' 

Wang Yin Nian's friend then said that Jesus later explained this parable.  Again from the Bible Wang Yin Nian's friend read the following.  Jesus explained the parable by saying, 'the one who sowed the good seed is the Son of God.  The field is the world, and the good seed stands for the sons of the Kingdom.  The weeds are the sons of the evil one, and the enemy who sows them is the devil.  The harvest is the end of the age and the harvesters are angels.  As the weeds are pulled up and burned in the fire, so it will be at the end of the age. The Son of Man will send out his angels, and they will weed out of his kingdom everything that causes sin and all who do evil.  They will throw them into the fiery furnace, where there will be weeping and gnashing of teeth.  Then the righteous will shine like the sun in the kingdom of their father.  He who has ears to hear, let him hear (Matthew 13.37-43).'

Wang Yin Nian's friend explained that our decision is whether to be a part of God's purposes and work or not.  The option is clear.  When we sin and do wrong we separate ourselves from God and become like the weeds in this story.  Wang Yin Nian was unclear as to exactly what sin was.  His friend explained that it is anything, which goes against what God has for us or wants us to do.  We can find what this is in the Bible. 

Wang Yin Nian's friend went onto explain that the real problem is that all of us have gone away from God.  The Bible says that 'for all have sinned and fallen short of the glory of God (Romans 3.23).'  It doesn't matter; all of us have deliberately gone our own way and away from God's way.  How can we get to God Wang Yin Nian wanted to know?  His friend said that God already had given the answer.  He again showed him a place in the Bible.  This place said, 'you see, at just the right time, when we were still powerless, Christ died for the ungodly.  Very rarely will anyone die for a righteous man, though for a good man someone might possibly dare to die.  But God demonstrated his love for us in that while we were sinners, Christ died for us (Romans 5.6-8).'

Even while we were doing wrong God provided the solution to our sins.  That solution was that Jesus Christ had already died for our sins.  His friend told him that the result of this death for our sins was eternal life for us and a better life now.  That is why Wang Yin Nian had such trust in God.  He showed him another place which said, 'for the wages of sin is death but the gift of God is eternal life through Jesus Christ our Lord (Romans 6.23).'  The parable of the weeds just discussed showed our wrongdoings or sins towards God causes us eternal death.  However, through Jesus Christ's death on the Cross-we can have eternal life.

Wang Yin Nian wanted to know how he could have this eternal life and life and confidence in God now which his friend had.  Wang Yin Nian's friend showed him another place in the Bible which said, 'if you confess with your mouth the Lord Jesus and believe in your heart that God raised him from the dead you will be saved (Romans 10.9).'  Wang Yin Nian's friend said you must believe and confess that Jesus is Lord of the world and your life because he died on the Cross-for your sins.  Then you must believe that after he died on the Cross-he was later raised from the dead to show God's power over sin and death.  If you believe these two things you will be saved from your sins to have life now and eternally with Jesus Christ.

Wang Yin Nian wanted that life so he would not have to be like the weeds in the story and could have the confidence that even in the midst of lack of water he could be confident that God was working for him.  Wang Yin Nian prayed this prayer after his friend.  'Dear Lord Jesus, I know that I have sinned against you. I believe that you died on the Cross-for my sins so I would not have to bear the punishment for my sins.  I believe that after you died three days later you rose from the dead and are alive now.  I ask that you come into my life and save me from my sins.'  Wang Yin Nian prayed this prayer and gained eternal life.  You too can pray this prayer if you believe it and have life now and eternally with Jesus Christ.