Effects On Its Growth And Root (Storage Root) Architecture Within Cassava Intercropping Maize

In order to optimize the technique of cassava intercropping maize,5 treatments including equidistant row cassava monocropping(T1),wide-narrow row cassava monocropping(T2),equidistant row cassava intercropping 1 row maize(T3),wide-narrow row cassava intercropping 1 row maize(T4),wide-narrow row cassava intercropping 2 rows maize(T5)were conducted.The growth,the maize yield,root architecture,the root system and soil nutrients in the symbiosis period,as well as the growth,yield,benefit,storage root configuration,quality and soil physical and chemical properties in the mature period of cassava were measured to illustrate the interaction mechanism between the cassava and maize.The conclusions are as follows:1.Effects on the growth of the above-ground,yield,quality and benefitGrowth of the above-ground: During the symbiosis,the above-ground growth of maize and cassava within wide-narrow row patterns were both better than that with equidistant row.Cassava intercropping significantly increased plant height by26.4%～34.4%,and increased the half width of crown by 5.7%～9.0% compared with cassava monoculture.Compared with T3 and T4,T5 significantly increased the plant height of maize by 9.5%～11.5% and the stem diameter of maize by 14.4%～18.1%.At maturity,for the growth of the above-ground,intercropping was better than monoculture,and equidistant row was better than the wide-narrow row.Yield: The maize yield of T5 was significantly better than that of T3 and T4.It’s shown that the total number of ears was significantly increased by 45.1%～59.7%,the yield of fresh ears was significantly increased by 70.9%～76.4%,and the fresh weight of stem and leaf was extremely significantly increased by 38.6%～44.6%.The cassava yield of T5 was better than the other 4 treatments,and compared with monoculture,intercropping increased the diameter of storage root by 7.2%～10.3%,the yield of fresh storage root by 31.4%～56.2%,the yield of dry storage root by 34.7%～58.4%,the yield of starch by 37.5%～60.1%,and the harvest index by 35.1%～40.5%.Quality: During the symbiosis,the content of phosphorus and potassium in roots basically showed that surface layer(0～10 cm)> middle layer(10～20 cm)> deep layer(20～30 cm),and intercropping > monocropping,and T5 had the highest nutrient indexes.At maturity,the content of nitrogen and ash in storage root within cassava intercropping maize were higher than those in monocropping,and compared with monocropping,the nitrogen content,ash content of wide-narrow row intercropping were increased by13.8%～20.7%,5.0%～9.9%,respectively,and T5 had the highest content of nitrogen,potassium,soluble sugar and ash.Benefit: Intercropping increased the total output value by 40.9%～77.8% and the net income by 40.6%～88.9% compared with the corresponding monocropping;except for T4,wide-narrow row increased the total output value,net income and ROI compared with equidistant row.Among them,T5 increased the total output value by 24.2%～78.6%,the net income by 31.6%～90.1%,and the ROI by 24.2%～26.2% compared with the other four treatments.2.Effects on the roots of the under-groundRoot structure in the symbiosis period: The root systems were distributed horizontally and symmetrically from dense to sparse where from the center towards the surround around the individual plant of maize or cassava.The root system of single maize was distributed with "dense top and sparse bottom,narrow top and wide bottom",and 68.7%～77.3% root weight(RW),46.2%～49.4% root length(RL),and 52.7%～59.3%root surface area(RSA)of it gathered in the soil belt,where is "10 cm deep and 10 cm wide on the two sides along maize planting line".The root system of single cassava was distributed with "top dense and sparse bottom,wide top and narrow bottom",and50.8%～61.4% RL and 47.7%～57.2% RSA of fine roots(≤1.5 mm)of it gathered in the soil belt,where is "10 cm deep and 20 cm wide on the two sides along the base terminal line of cassava stem ".Meanwhile,35.7%～42.0% RL and 39.3%～48.8% RSA of rough roots(>1.5 mm)and 35.9%～46.3% RW of total root weight gathered in the soil block within the range of "10 cm deep,20 cm wide on the two sides along the base terminal line of cassava stem,30 cm wide on the two sides along the central line of cassava stem".There was weave growth among the root systems between cassava and maize,and the dense growth belts or blocks of them did not overlap each other,therefore,the roots interaction between cassava and maize was weak competition,particularly,T5 was weakest competition in the two intercropping models.Storage root configuration in the mature period: The half width of storage root across the ridge direction was 20.6～26.4 cm,the half width of storage root along the ridge direction was 30.2～36.2 cm,and the depth of storage root was 22.5～24.7 cm.85.7%～100.0% of the number of storage root and 97.2%～100.0% of the weight of storage root were distributed in the range of 0～30 cm along the half width of storage root across the ridge direction;95.1%～98.5% of the number of storage root and 98.1%～99.8%of the weight of storage root were distributed in the range of 0～40 cm along half width of storage root along the ridge direction;93.7%～99.2% of the number of storage root and97.6%～99.9% of the weight of storage root were distributed at the depth of 0～25 cm.The storage roots of T5 were the most deeply and widely dispersed in the half width of longitudinal and beside the cassava cutting or depth of storage root.3.Effects on the physical and chemical properties of soilSymbiosis period: The content of soil alkali-hydrolyzed nitrogen and available phosphorus and available potassium were basically showed that surface layer(0～10cm)> middle layer(10～20 cm)> deep layer(20～30 cm);and soil nitrogen,phosphorus and potassium content were basically showed that intercropping > monocropping,among which,T5 had most of the highest nutrient indexes.Mature period: intercropping increased organic matter by 8.1%～10.0%,alkali-hydrolyzed nitrogen by 2.3%～9.3%,available potassium by 5.5%～27.8%,and available potassium by 5.6%～38.2% when compared with monocropping.The wide-narrow row increased the content of organic matter by 13.3%～15.3% and the content of available phosphorus by 10.4%～33.7% when compared with equidistant row.All indexes of T5 were the highest.